STUDIES ON
THE FAUNA OF
CURAÇAO AND OTHER
CARIBBEAN
ISLANDS:
No.
90.
Snakes of the genus Alsophis
in Puerto Rico
and the Virgin Islands
by
Albert
Schwartz
(Miami)
Introduction
.
177
GENERAL TREATMENT
178
Variation
184
SYSTEMATIC TREATMENT
192
Alsophis portoricensis portoricensis
192
Alsophis portoricensis prymnus
194
Alsophis portoricensis variegatus
198
Alsophis portoricensis aphantus
200
Alsophis portoricensis richardi
203
Alsophis portoricensis nicholsi
208
Alsophis portoricensis anegadae
210
Alsophis sancticrucis
214
Taxonomic arrangements
217
References
219
The
purpose of the present paper is to define these forms and delimit
Alsophis.
The eastern end of the Greater Antilles between the Mona and
the Anegada
passages is composed of isolated Mona in the former
passage, Puerto Rico (including its satelliteislets), Vieques, Culebra,
and the Virgin
Islands. The major islands of the Virgins
are
St.
Croix, St. Thomas, St. John, Tortola, Jost van Dyke, Virgin Gorda,
and Anegada;
there
are
as
well
a multitude
of smaller islands,
islets,
and rocks.
Of the Virgin
Islands,
St.
Croix to the south is
separated from the Virgin Bank, whereas the balance of the Virgins
(except
Anegada)
are
separated
from one another by
narrow
and
relatively
shallow
channels.
From
this
entire region
have
been
described six
forms
of
the Antillean snake
genus
178
GENERAL
TREATMENT
The first (as
now accepted)
name applied to Alsophis
from the
Puerto Rico-Virgin Islands area is sancticrucis Cope,
1862, described
from St. Croix. In the following year REINHARDT & LUTKEN named
A. portoricensis
from Puerto Rico;
this
was followed over half
a
century later by Alsophis anegadae Barbour,
1917, from the north-
easternmost Virgin,
Anegada.
Alsophis
variegatus
Schmidt
from
Mona was named in
1926,
followed in
1937 by
Alsophis
nicholsi
Grant from Buck Island south of St. Thomas; later (1946) this same
author described richardi (as
a
race
of nicholsi)
from
St.
Thomas
itself.
Thus there
are presently
available six
names for the popu-
lations of Alsophis between Mona and Anegada.
As
a slight complication,
the
name Alsophis
antillensis Schlegel
had been regularly
applied
to the
non-Puerto Rican populations,
or even at times (SCHMIDT 1928, p.
139) to snakes from Puerto Rico.
BRONGERSMA
(1937),
having
restudied
the
SCHLEGEL
cotypes,
found them to
be
a composite
of Dryadophis
boddaerti, Alsophis
sancticrucis,
and
another species
of Alsophis
which
was identical
their ranges more closely than heretofore, and to comment upon the
interrelationships
between them.
Since Alsophis
is
either extremely rare
or extinct on many
of the larger Virgin
Islands, and is likewise
not exceptionally common onPuerto Rico itself, the present
study
could
not
have
been undertaken
without
the complete cooperation of
the
following curators, who have loaned specimens for study: CHARLES M. BOGERT and
GRACE M. TILGER, American Museum of Natural History (AMNH); JAMES BÖHLKE
and EDMOND
V. MALNATE, Academy of Natural
Sciences of Philadelphia (ANSP);
ALICE
G.
C. GRANDISON,
British
Museum
(Natural History)
(BMNH);
NEIL D.
RICHMOND, Carnegie Museum
(CM); WILLIAM E. DUELLMAN,
Museum of Natural
History, University of Kansas (KU); ERNEST E. WILLIAMS, Museum of Comparative
Zoology, Harvard
University (MCZ);
CHARLES
F.
WALKER
and
GEORGE R. ZUG,
Museum
of Zoology, University of Michigan (UMMZ);
DORIS
M.
COCHRAN
and
JAMES A. PETERS, United States National Museum (USNM). Specimens in my own
collection are designated Albert Schwartz Field
Series (ASFS); I have
also utilized
specimens in the collections
of RICHARD
THOMAS (RT)
and
DENNIS R.
PAULSON
(DRP). For the assembling of Alsophis from the area under study I wish to acknow-
ledge the
capable assistance
of
GERALD
D.
GAGNON,
RONALD
F.
KLINIKOWSKI,
DAVID
C. LEBER,
and
RICHARD
THOMAS.
The illustrations
for the present paper
have
been executed by
Mr.
KLINIKOWSKI and
he
has
my gratitude for this
task.
179
to that found on Guadeloupe
in the Lesser Antilles;
BRONGERSMA
chose the Guadeloupe-like specimen as the lectotype of A. antillensis,
thereby replacing
the name (leucomelas)
then in use for the Guade-
loupe species.
None of the cotypes of A. antillensis except the speci-
men at that time identified as A.
sancticrusis
originated
in the
Puerto Rico-Virgin
Islands region,
and
none of SCHLEGEL'S speci-
mens appeared
to have
come from
St. Thomas (as
the describer
stated).
Thus
the
name
A.
antillensis
Schlegel
as
restricted
by
BRONGERSMA is not applicable to any Alsophis of the region
under
study.
The
fact
that
since the
introduction of the
mongoose in
the
Virgin
Islands
and
Puerto Rico Alsophis
has
either disappeared
completely
or has become extremely
rare
makes resolution of the
systematic and biological problems rather difficult. Another is that
no one has ever spent sufficiently
long time on any of the smaller
Virgins, or has visited any of the smaller Virgins repeatedly enough,
to secure
an adequate
series from these islets. Presently,
Alsophis
appears to be extinct
on Vieques,
St. Croix, and St. Thomas. It is
very rare on Tortola, where the natives know of it;
a specimen was
collected there
as late
as
1963 at Bellevue,
and I have examined
it
casually
in Roadtown. Fortunately,
these
snakes
can
still
be
secured on many of the satellite islands (for example,
Water Island,
Hans Lollick,
Great and Little St.
James, Dog
Island,
all off of
St. Thomas)
about the larger Virgins
where they no longer
occur.
The
major
exception
to
this
statement is
St.
Croix,
where
A.
sancticrucis
has not to my knowledge
ever been recorded or taken
from any of the three islets (Protestant
Cay,
Buck Island,
Green
Cay) off of St. Croix;
of these three islets,
Buck
is infested with
mongoose and Protestant is occupied by
a hotel,
so that chances of
the survival
of
the large
and conspicuous
sancticrucis
on
these
islets is
most unlikely.
Messrs.
LEBER
and THOMAS visited Green
Cay, and although they spent two hours on the islet and were able
to secure other St. Croix endemics, no snakes were seen. It is possible
that sancticrucis never occurred on Green Cay, or that it still persists
there in small numbers; certainly there is
no
sure evidence that it
does not occur there now.
180
On
the
large Virgins
which
lack
mongoose, Alsophis
may
be
quite common (Virgin Gorda for example), and although we secured
only two on Anegada in a day's collecting,
natives reassured us that
snakes were often seen. On some of the smaller islets (Peter, Guana)
Alsophis
is moderately
abundant,
and even
a half day's
visit
will
yield
a few specimens.
In
Puerto Rico,
Alsophis
is
presently
widespread
and locally
abundant.
The
genus still
occurs
very
abundantly
on
Caja
de
Muertos of the south coast of Puerto Rico;
HEATWOLE,
SADE
&
HILDRETH
(1963)
reported
an
Alsophis
from
Cayo
Santiago
off
the eastern coast of Puerto Rico. The status of the population
on
Desecheo and
that of
Mona is presumably
unchanged,
although
in three days,
no Alsophis
were taken by WEAVER et al. (1961) in
1960. Judging at least
from the
numerous specimens
secured by
Major CHAPMAN
GRANT and
others
on
Mona,
the
snake must
be
common there. Interestingly,
ROLLE, HEATWOLE, LEVINS & TORRES
(1964)
did not
secure
Alsophis
on Monito Island,
which
lies only
three miles northwest of
Mona. Although
Alsophis
is
apparently
still common
on Culebra to the east of Puerto Rico,
Mr.
THOMAS
did not
encounter any
snakes
in half
a
day's
collecting
in
the
vicinity of Dewey.
Alsophis sancticrucis,
fortunately,
is an eminently
distinct form,
and presents
no nomenclatorial nor biological problems;
the only
question involving this species is its relationships
to other members
of
the
genus in
the
West
Indies.
The nomenclatorial
problems
involved, however, with the names portoricensis,
anegadae, variega-
tus, nicholsi
and richardi are complex,
and have at their base the
biological
relationships
of
these
named
(and
other
unnamed)
populations
of Alsophis.
A brief historical summary of the
use of
these names is complex but necessary to understand the problems
involved.
The reader should be aware, in perusing the following
information, that
the
name antillensis,
as
explained
above,
is
no
longer
applicable
to
snakes
from
this
region;
its
use
below
is
confusing but mandatory historically.
BOULENGER (1894, 2, p. 122-123) recognized two species of Alsophis (= Dromicus
sensu Boulenger) from the Puerto
Rico
- Virgin
Islands
area: sanctaecrucis
(sic)
and antillensis.
The
former
was known
from St. Croix,
Puerto
Rico,
and Santo
181
Domingo, and
was characterized
as having scales in
17 rows,
170 to
198 ventrals,
and
120 to
147 subcaudals.
As
is evident from the
distribution noted above, Bou-
LENGER included
three
species
in
his
“sanctaecrucis”:
sancticrucis,
melanichnus
from Hispaniola, and portoricensis. All are considered
as synonyms of “sanctaecrucis”
by
him.
However,
BOULENGER listed
as specimens in the
British Museum
only
four
snakes
from St. Croix, so it is
evident that his
inclusion
of melanichnus
and
portoricensis is due to his lack of knowledge of these two species. Alsophis antillensis
on the other hand was characterized by having scales in
19 rows,
172 to
189 ventrals,
and
116 to
142 subcaudals.
This species was attributed
to Vieques, St. Thomas,
and St. John in the area under discussion, Martinique, Dominica,
and Guadeloupe
in the Lesser Antilles, and Hispaniola. BOULENGER had actually examined specimens
only from St. Thomas, Vieques, and Dominica, however.
As
BOULENGER used the
name antillensis, it
was likewise a composite, since both Dominica
and Guadeloupe
have (or have recently had) the species A. antillensis
(sensu stricto BRONGERSMA),
Martinique lacks Alsophis (its only colubrid
snake, Dromicus
cursor,
has
17 scale
rows),
and the Hispaniolanrecord
may have applied to Dromicus parvifrons which
has
19 scale
rows
at midbody. (Parenthetically, other than A. melanichnus
noted
above for Hispaniola, A. anomalus
is
also known from that island; it has, however,
21
scale rows (fide COCHRAN
1941, p. 349)). In summary, then,
BOULENGER recog-
nized two species in the
area under study,
one with
17 and the other with
19 scale
rows; it
is this basic
difference
which has clouded
the problem for the last
three-
quarters of a century.
STEJNEGER (1904, p.
700
et seq.)
studied Alsophis from Puerto Rico
and adjacent
islands, and distinguished two species, portoricensis and antillensis, the former with
17 scale rows and without any
distinctive pattern on the fifth scale
row,
the latter
with
19 scale rows and with
every second or third scale in the fifth row particolored
dark below
and light above. He
attributed portoricensis to Puerto Rico,
Mona and
Desecheo islands, although he
examined only three specimens (two from Humacao
and
one from Desecheo).
STEJNEGER recorded
antillensis
from
Culebra, Vieques
(fide BOULENGER),
and St. Thomas; he examined
material only from Culebra
and
St.
Thomas.
STEJNEGER also
(loc. cit.) briefly discussed
BOULENGER'S subsequent
use of
the combination
“Dromicus
(= Alsophis) sanctaecrucis portoricensis”,
and
felt that the
two forms portoricensis
and sancticrusis
merited
specific rank, a situ-
ation which has persisted until today.
SCHMIDT (1928, p.
139 et seq.) again studied the Puerto Rican
and Virgin Islands
Alsophis.
Once
more two
species
are distinguished
on the
basis
of STEJNEGER'S
(and BOULENGER'S) midbody scale row counts; additionally SCHMIDT had previously
(1926) described A. variegatus from Mona, so that there were three species recognized
from the area. Also, BARBOUR
had
named A. anegadae in the intervening period,
and although the Virgins were not studied
in
a detailed
manner by SCHMIDT, he
mentioned
anegadae.
The counts
and distributions
of the three species may be briefly summarized
as
follows:
1)
antillensis
-
scales usually in 19, occasionally in 17, rows,
ventrals
170 to
189,
subcaudals
116 to 144; known from St. Thomas, St.
John, Virgin Gorda, Anegada
(thus A. anegadae is regarded as
a synonym of antillensis), Vieques, Culebra, and
Puerto
Rico. The Puerto Rico
record
is based upon two specimens taken at Coamo
Springs,
a male with
17 scale rows and a female with
19, both with "nearly typical
antillensis ” coloration
and a high number (184 and
185) ventral scales.
182
2) portoricensis
-
scales in
17 rows,
ventrals
169 to 179 in males,
175 to 183 in females,
subcaudals
125 to
134 in males,
115 to
128 in females; known
from Puerto Rico,
Desecheo, and
Caja
de
Muertos.
SCHMIDT
commented
on the
reduction
of scale
rows in this species to
13,
14 or
15 scales posteriorly (with
14 the modal condition
on Puerto Rico), and on the pale coloration
of a single Caja
de Muertos specimen.
Desecheo snakes (two) were regarded as
close to Mona
material in coloration, but
in
scale counts they
were "evenly divided"
between Mona and Puerto
Rico speci-
mens.
3) variegatus
-
scales in
17 rows,
ventrals
170 to
181, subcaudals
112 to
126. The
preanal reduction
of dorsal rows to
15 scales afforded "the most constant distinction
from Alsophis portoricensis.” Finally,
while
speaking
of A.
antillensis,
SCHMIDT
(1928, p. 141) noted
that his two Coamo
Springs specimens "agree closely in colo-
ration with the color variety described by
BARBOUR from Anegada and,
as Ido not
wish to admit of adiscontinuous
distribution of A. anegadae, it seems best to include
both Puerto Rican and Anegadian specimens with A.
antillensis.”
The
work
of Major CHAPMAN GRANT in the Puerto Rican region added
greatly
to the knowledge of the fauna of that area. In
a long series of papers between
1931
and
1946, Major GRANT published extensively
on the herpetology of this region;
as far
as Alsophis is concerned, the following data
were presented.
GRANT
(1931)
collected
28 specimens of A.
antillensis
on Culebra, but
(1932a) did
not collect
any
member of the genus
on Vieques, where he regarded it
as "probably nearly extinct
except
on outlying keys
or possibly
the eastern tip of the Island." Later, GRANT
(1932b) reported four
specimens of A. portoricensis
from Caja
de Muertos, and
noted that "The Alsophis do not resemble the series of eight A. portoricensis in the
Grant collection,butresemble the series ofthirty A. antillensis in the same collection,
in
color and pattern but not in squamation." In
a brief but interesting summary
of the Puerto Rican members of the genus,
GRANT
(1932c) stated that there were
two distinct species in the Puerto Rico region. Although these
are characterized
as
having
17 and
19 scale rows at midbody. GRANT did not clearly associate names with
these counts, although by
inference
the
17 scale row
snake
is portoricensis (Puerto
Rico, Caja
de Muertos, Desecheo, Mona
- thereby including variegatus with portori-
censis
but making no concomitant nomenclatorial
change)
and
the
19 scale
row
snake is antillensis (Virgin Islands, Culebra
and Pinero Island; the latter is presently
shown on Puerto
Rican maps
as Isla Pineros).
In criticising SCHMIDT for recording
antillensis
from Puerto
Rico
on the
basis
of the
two
Coamo
Springs specimens.
GRANT effectively removed this species from the Puerto Rican list. GRANT felt that
the
three
forms
involved
(portoricensis,
variegatus,
antillensis)
were
primarily
distinguished on the basis
of pattern, although specimens with
the pattern of one
form within the
range of another
were known by
him.
The four Caja de Muertos
specimens were regarded as portoricensis, although they were "about equally divided
between the three patterns." The Isla Pineros series of sevenwas assignedto antillensis,
although they "seemed at first to be slightly aberrant A. portoricensis.”
In a series of papers dealing with faunal lists of the various Virgin Islands, GRANT
(1932d) regarded A. antillensis
as probably extinct onSt. J ohn, collected two speci-
mens on Dog Island, and considered
its occurrenceprobable on Congo and Lovango
Keys
between
St. John and
St. Thomas, (1932e)
noted
A. antillensis
on Salt
and
Peter Islands and
considered
it
very
rare
on Tortola, (1936) reported a series
of
twelve
A.
antillensis
from
Jost van Dyke,
and
(1937)
considered
A.
antillensis
extinct
on St. Thomas, reporting the species
as
still occurring
on Water Island,
183
(Little)
Saba
Island, Savana Island, Cockroach
Island
-
all islets
associated
with
St. Thomas,
-
and
on Salt
Island
(off of Tortola)
and Virgin Gorda.
GRANT also
mentioned taking two A. anegadae on Anegada.
In the latter paper GRANT (1937, p. 516)
described Alsophis nicholsi
on the basis
of three specimens from Buck
Island
off St.
Thomas.
This species
was diagnosed
as "a pale form with the squamation of antillensis but the pattern of portoricensis,
namely differingfrom typical antillensis" in having the lateral stripe on scale rows 4
and
5 faintly indicated
only on the neck,
dorsal longitudinal band obscured,
and
chin, throat, and anterior portion of body immaculate without any trace of mottling
or spotting.
The ventral
scales
varied
between
181
and
185,
and
all
snakes
had
incomplete tails; the scale rows
are presumably 19, although this
is not expressly
stated. The
coloration
was pale olive
green
in life, which faded
to pale brown
in
alcohol.
GRANT stated also (loc. cit.) that nicholsi
varied
more from
antillensis
than
did variegatus from portoricensis.
After the publication of BRONGERSMA'S
paper
(1937) concerning the allocation
of the cotypes of A. antillensis, GRANT (1946) again reported on the Alsophis of the
Virgin Islands.
Since SCHLEGEL apparently had not used specimens from the north-
ern Virgin Islands in his description of antillensis, this left nameless the populations
which previously had been
called antillensis. GRANT showed,
however,
that one of
the cotypes of A. antillensis, labeled
as having come from St. Thomas, had
very
likely indeed
come from that island, but since BRONGERSMA had already restricted
the name A.
antillensis
to the species occurring
on Guadeloupe by selection
of
a
lectotype from the cotypical series,
this name was no longer available
for Virgin
Islands
snakes. GRANT
then proceeded to
describe Alsophis nicholsi richardi
from
St.
Thomas, this form having a distribution
of the Virgin Islands except Anegada
and St. Croix, and occurring also on the islands and islets east of Puerto Rico except
Vieques.
At the same time
GRANT
commented
on the resemblances
between antillensis
(= nicholsi)
and anegadae, but
made no nomenclatorial
changes. He
mentioned
as
well
the great diversity of pattern of A. nicholsi
richardi
on St. Thomas (the type
locality)
and regarded
this
form
as
a subspecies
of the previously
described
A.
nicholsi
on the basis of the occurrence of a nicholsi- patterned snake
on St. Thomas,
and the finding of a snake on Water Island (immediately south of, and adjacent to,
St. Thomas) which approached A. nicholsi in general appearance.
The St. Thomas
race richardi was considered closest to anegadae, which is smaller and paler and has
reduced
dorsal scale pores,
and differs from n. nicholsi
in having a lateral pattern,
and from A. portoricensis in lacking a reticulate pattern.
More recently,
UNDERWOOD
(1962, p.
105) has confused
the issue somewhat, by
returning to the
old
nomenclature
and attributing
A.
antillensis
to Puerto
Rico,
Vieques, Culebra, and the Virgin Islands and later (p. 121) stating that A. antillensis
occurs on St. Thomas,
Water Island, St.
John, Dog Island, Tortola, Peter Island,
Salt Island, Virgin Gorda,
and Anegada, and
A. sancticrucis
(!)
on Culebra, St.
Thomas,
St. John, Jost van Dyke, Tortola, and Anegada (although on the
earlier
page he correctly assigned A. sancticrucis to St. Croix only). I am disregardingthese
allocations.
184
VARIATION
I
have
examined
252
Alsophis
from
the
Puerto
Rico-Virgin
Islands
area,
as
follows:
MONA,
9 <J,
10$,
1 unsexed; DESECHEO,
1 $;
PUERTO RICO,
25 $, 35$,
including one specimen from CAYO
SANTIAGO; CAJA
DE MUERTOS,
4 (J,
15 $; ISLA
PINEROS,
3
<J, 4$;
VIEQUES,
2 <J,
1 $;
CULEBRA,
21 $, 23$;
ST.
THOMAS,
17 $,
14$; WATER ISLAND,
3 $, 2$;
HANS LOLLICK ISLAND,
3$; SABA ISLAND,
1 $;
SAVANA ISLAND. 2 <J; DOG ISLAND,
2 (J; GREAT ST.
JAMES,
1 $; LITTLE ST. JAMES,
1
LOVANGO CAY, 2$; BUCK ISLAND,
3 (J;
GUANA ISLAND,
1 $; PETER
ISLAND,
7 $; SALT ISLAND,
1 $; VIRGIN GORDA, 13 $,
14 $; NECKER ISLAND,
1 $; ANEGADA,
1 <?,
3 $; ST. CROIX,
6 $.
For convenience, hereinafter the islands
of Saba, Savana, Dog, Great and Little
St. James, and Lovango will
be grouped together and referred to as the St. Thomas
satellite
islands; all are closely associated with St. Thomas or lie between that island
and St. John. Hans Lollick, Water and Buck are likewise associated with St. Thomas,
but for various
reasons these three islets will be
discussed
separately.
Since
A.
sancticrucis
is
so very distinctive, it
will not
be treated in the present
context of variation.
Scale
rows.
The basic
differences between Puerto Rican and
Virgin Islands snakes has always been considered to be, in addition
to colorationand pattern, the possession of 17 scale rows at midbody
by Puerto Rican Alsophis and 19 scale rows at midbody by Virgin
Islands
snakes.
Thus the former comprise
the species
portoricensis
and the latter the species
nicholsi.
The modal condition of dorsal
scale row formula for snakes from Mona (andDesecheo ?) is 17-17-15;
no other population
has almost all snakes with this formula, and all
but
one (17-19-15)
of the Mona snakes examined have
counts of
17-17-15. On Puerto Rico and Caja de Muertos, the modal count is
17-17-14. Puerto Rican snakes have the following
dorsal counts,
with incidence in parentheses in each case: 17-17-14 (36); 17-17-15
(15);
17-17-13(6);
17-19-15 (1); and
18-19-15 (1). The same data
for Caja
de Muertos Alsophis
are:
17-17-14 (13);
17-17-15 (4);
17-15-13
(1);
and
19-17-14
(1).
Note
that
two
Puerto
Rican
snakes and
one
Mona snake have
19 scale
rows
at midbody,
and
one Caja de Muertos snake has
19 scale rows
on the neck.
On Culebra, St. Thomas, Water, Buck, Hans Lollick, St. Thomas
satellites, Guana, Peter, Salt, Virgin Gorda, and Anegada, the modal
dorsal scale
formula is
19-19-15 (or may be
one
of two formulae
with the same frequency). However,
this count is far from constant
on each island. Two examples
will suffice. On Culebra,
the dorsal
formulae vary as follows: 19-19-15(25);
17-19-15(9); 20-19-15 (2);
185
19-17-15 (2);
17-17-15 (1);
19-19-16 (1);
19-19-17 (1);
18-19-15
(1); on Peterand Salt islands combined, the formulae are: 19-19-15
(2);
17-19-15 (2);
17-19-14 (1);
19-17-13 (1);
17-17-14 (1).
Note
that there is
one specimen
from Culebra and
another from Peter
and Salt which have "typical" portoricensis counts of 17-17-14or 15.
Snakes from other of these eastern islands show the
same sort of
variations about
a
theme
(19-19-15
or
17-17-15)
with various
combinations of these modal conditions,
especially
on the neck and
at midbody.
Specimens
from Isla Pineros,
just off
the east
coast of Puerto
Rico, and Vieques, between Puerto Rico and Culebra but farther to
the south,
show
still
another situation.
The modal
condition
on
Isla Pineros,
despite
its
very
close proximity
to
Puerto Rico,
is
19-19-15
(5
specimens),
whereas
19-19-14 and
17-19-15 each
occurs
in
a single
snake.
On Vieques,
two snakes have counts of
18-19-15, and the other
17-17-15.
From the above, it is obvious that midbody
scale
rows
or dorsal
scale row formulae, while suggestive,
are by
no means absolute, and
to regard
a snake as either portoricensis
or nicholsi simply because
of its having
17 or
19 scale
rows at midbody
may
be extremely
misleading.
Ventrals. Ventrals have been counted in the manner proposed
by
DOWLING (1951). Despite statements to the contrary (SCHMIDT
1928, p.
146), there are differences between the means of numberof
ventrals in
the
two
sexes,
females regularly having
a
few
more
ventral
scales
than males,
both
in extremes
and
means.
These
differences,
however,
are
indeed slight.
Considering
snakes
from
all islands involved,
the ventrals in males vary from
163 (Puerto
Rico)
to
184 (Buck,
St.
Thomas satellites, Virgin Gorda),
and in
females from
166 (Puerto Rico)
to
187 (Vieques).
Considering
the
wide
geographic
range
occupied
by
these
snakes
in
this region,
the
relative
lack
of
extreme
variation in
ventrals
is
striking;
thus, in twenty-five males from Puerto Rico, the ventrals vary by
only
14 scales,
and in a series of fifteen females from Virgin Gorda,
they vary by only 9 scales.
The highest
mean for males (181.7)
is for the small series from
186
Buck Island;
this
mean is outstanding
among all
series of males.
The lowest
mean
for
males (170.0)
is for
Puerto
Rican
snakes.
Considering
males
from Culebra east to Anegada
(and
with
the
exception of Buck Island), there is a very gradual increase in mean
numberof ventrals. There is, on the other hand a rather sharp break
between Puerto Rican males and Culebra males.
The highest
mean for females (182.7)
is for the small series from
Anegada.
The lowest
mean for females (174.3)
is
once again from
Puerto Rico. The general trend in ventrals in females from Puerto
Rico eastward is low in Puerto Rico,
higher
in
Isla Pineros,
de-
creasing to the St. Thomas satellites, and then increasing to Anegada
A sharp break in number of ventrals in females occurs between Salt
and
Peter islands (176.5)
and
Virgin
Gorda-Anegada
(182.5
and
182.7).
Subcaudals. As in
so many long-tailed
snakes,
specimens
of
Alsophis
with complete
tails
are
few.
When these
few
are
once
again
divided into two groups by sexes,
it is hardly practicable
to
compare data between various series.
Of the entire Puerto Rican
series,
for example,
only thirty
one
snakes
have complete
tails
(11
males,
20 females).
In
the
series
from Culebra,
only
sixteen
(8
males,
8 females)
have complete
tails.
In general,
males have
longer tails than females. In general, there seems to be
an increase
in number of subcaudals from west to east; thus Mona males have
from 115 to 125 subcaudals and Mona females 113 to 122 subcaudals,
whereas Virgin Gorda males have from
132 to
138 subcaudals and
Virgin
Gorda
females
from
124
to
132
subcaudals. Populations
which are geographically intermediate between these two extremes
have roughly intermediate ranges of subcaudals. The lowest count
(106) is from a female from Caja de Muertos, and the highest count
(143)
is for
a St. Thomas male.
Coloration
and
pattern.
Perhaps
the most subjective
-
and therefore most
difficult
-
aspect
of the present problem
is
a
discussion of coloration and pattern.
Preserved Alsophis, like many
other colubrids, have a strong tendency to lose epidermis whenbeing
handled. GRANT (1946,
p.
121,
and errata sheet insert) has shown
187
quite
clearly
that
SCHMIDT'S
illustration
(1928,
p.
145)
of
A.
variegatus
is misleading
since the artist
depicted
a section of the
snake
upon which
the epidermis
was
missing
from many scales,
thus giving
the impression
of
a false "pattern"
on
the
dorsum.
With loss of scales,
the entire dorsum achieves a much lighter hue.
However,
the basic
pattern
of
these
snakes
is
not
lost by
such
epidermal sloughing, and even in snakes which presently lack most
of their dorsal scales,
the pattern is quite clearly discernible. What
is lost is any
concrete notion
as to depth of
dorsal pigmentation;
what
may
have
been
a
rather
dark
brown
snake
is
currently
rendered much paler by loss of scales.
Except the snakes from Buck Island (nicholsi ), which were said
to be pale olive green (GRANT
1937, p. 516) in life and some snakes
from Puerto Rico, all Alsophis from the Puerto Rico-Virgin
Islands
area are some shade of brown in life. I have not seen living specimens
from Mona or Desecheo,
but have seen living material from Puerto
Rico
and
several
of the Virgin
Islands (including
Water,
Hans
Lollick,
Guana,
Peter, Virgin
Gorda,
and Anegada).
The shade of
brown involved varies from a pale sandy-brown
on Cajade Muertos
and Hans Lollick,
to a rich dark purplish-brown
on Puerto Rico.
Specimens from Virgin Gorda and Anegada
are dark brown as well.
Patternwise,
there
are
two distinct
types
of pattern
involved.
1) On most of Puerto Rico,
the snakes
are
dark with all dorsal
scales outlined posteriorly with black,
and with the ventrals having
their posterior margins usually
very heavily
outlined with black
or dark brown. There is a faint dorsolateral dark line indicated on
scale
rows
4 and 5, although
this is not obvious.
Some specimens
also
are
transversely
banded with
dark and slightly
paler
zones;
this
condition appears
more
often
on
young
or subadult snakes.
The supra-
and
infralabials
are unicolor
reddish-brown
without
stippling
or
dark markings;
the chin
and throat
are
also mostly
unmarked,
although
there may
be
dark pigment
in this region,
usually
more as blotching
or clouding rather than discrete and bold
spots.
COCHRAN (1941, p. 348) noted that members of the genus Alsophis
may have a groovealong the upperborder of the posterior supralabi-
als, and that this groove may be pigmented. Along with the above-
188
mentioned pattern
is associated a diffusely
and darkly pigmented
supralabial
groove; this is not to be confused with
a dark mask
which occurs with the following pattern. The remainder of the head
is reddish-brown to brown, and usually
without dorsal pattern of
any sort. On the neck there is an inconspicuous
median dark streak
which soon disappears posteriorly.
2)
The
second
basic
pattern
occurs
on
the
Virgin
Islands,
southern PuertoRico, and Caja
de Muertos. In this pattern, every
third
or fourth scale in the fifth dorsal scale
row is
more
or
less
particolored,
the upper half being
pale and the
lower half dark
brown
to black.
There may
or
may
not
be
a prominent
lateral
dark neck line; if present, it may be fragmented
or entire. There is
a black face mask over the canthal area and posteriorly
along the
supralabial
groove.
The
ventrals
usually
have
dark
posterior
margins, but these markings
are not black
or dark brown and
are
not boldly conspicuous
as in Puerto Rican snakes. Additionally,
the
belly is stippled with brown, and there are a series of longitudinal
dashes
on the sides of the
ventrals corresponding
to the angle of
these scales when the snake is alive.
The supra- and infralabials,
as well
as the chin and throat,
are heavily
marked with discrete
and bold flecks
or spots
of
dark brown.
The top
of the head is
usually
marbled or flecked with dark, and there is
a dark median
neck line which cuts off between itself
and the lateral dark neck
lines
a pair of roughly
triangular pale blotches behind the head.
I
have discussed these
two patterns
as if they
were completely
separable.
In actualiy,
this
is not
so.
Thus specimens
from Mona
have
a dorsal pattern
which is roughly like that of Puerto Rican
snakes (although highly modified from that condition),
while they
have a bold black mask. On Culebra, both patterns
occur, although
pattern
(2)
is by
far
the
commoner. Finally,
there
are
all
sorts
of intermediate conditions in any large sample. These intermediates
and variants defy any sort of rational analysis
into the above two
patterns, and are intermediate in the sense that they seem randomly
to combine features from both pattern types.
Structural
and
scale
differences. Treating
the
whole
series
of Alsophis
as
a single
unit,
I
am
unable to
differentiate
189
between the
various populations
on
any
single
scale
feature
or
combination of
features. The
head scalation in all
is usually
1/1
loreals,
1/1 preoculars, 2/2 postoculars, the lower
such smaller than
the
upper,
and
1
■+• 2
temporals.
The
temporals
are
especially
subject
to variation,
due to additional partition
of the temporals
themselves (for instance,
the first temporal may divide vertically
to give two temporals instead of one)
or fusings, especially between
the upper of the second row of temporals with neck scales above it.
All these variants are uncorrelatedwith geography. The supralabials
are usually 8 and the infralabials
10; again, counts of 11 infralabials
are not uncommon, either unilaterally
or
on both sides, and
some
snakes have 9 supralabials.
This is likewise uncorrelated geographi-
cally.
One
feature is
suggestive;
the
snakes
with pattern
(1)
above
seem to have the head shorter and blunter than those with pattern
(2).
I cannot determine if this is a real difference,
a condition due
to preservation techniques,
or an illusion due to the pigmentation
associated with snakes with pattern (2).
This is a tenuous difference
at best, and one which cannot be really determined.
Hemipenis.
The hemipenes
are extruded on many males from
various localities, including
Puerto Rico
and Caja
de Muertos
on
the
west and Virgin
Gorda
on the
east. Specimens
from Puerto
Rico
and Virgin
Gorda
are
identical. The hemipenis
may
be
de-
scribed as follows (based
on ASFS V3853, Virgin Gorda): the hemi-
penis
is moderately long,
extending to the level of the eighth
or
ninth subcaudal, distinctly bilobed,
and has the sulcus very deeply
forked, each fork ending in a tear-shaped
zone of papillate
flounces
with some calyces.
The sulcate surface is covered with tiny spines.
The non-sulcate surface is likewise coveredwith tiny spines (although
it appears naked in gross examination), and there are four rows of
seven to nine large spines, increasing in size distally, and proximally
becoming
lost in an
area of spinelets
and papillae
on the pedicel.
A specimen from Puerto Rico (ASFS X7530) shows the same struc-
ture precisely; these two snakes represent the two color patterns as
described above.
190
Apical
pits. All dorsal scales, with exception of the lowermost
row
on each side, have from one to three (usually two) apical pits.
On the tail, the usual condition is three apical pits per scale, except
on the lowermost row on each side which may have less or even none
on some scales. The lowermost body row may have a few scales with
one or two pits, although generally this row lacks pits entirely. There is
no difference in distribution of pits
between specimens
from
the
extremes of the region under discussion.
In summary then,
considering
the entire series
of
snakes
from
Mona to
Anegada,
there
seem either to be
no differences between
snakes
from
the
two
extremes
in
some
characters
(hemipenis,
apical pits)
or
a more
or less graded series of characters (ventrals,
subcaudals,
dorsal scales)
or a situationwhere the character appears
in a random, although geographically correlated, manner (coloration
and pattern).
I
have
striven
to find
even
one
single
all-or-none
character
which will
divide these snakes into the two time-honored species,
and have failed. Although
various populations
are quite distinct in
coloration
and
pattern
from
other
populations,
and
although
various populations differ from one another on the basis of average
number of ventrals or modal dorsal scale formulae,
on
the other
hand there are regions
where
these characters intergrade.
Under
these circumstances there can be little justification for maintaining
these populations underfour specific names (portoricensis,
variegatus,
nicholsi, anegadae).
Perhaps the
crux of the entire matter lies in the two specimens
cited by
SCHMIDT
(1928,
p.
141)
as
A.
antillensis from
Coamo
Springs,
Puerto Rico.
I have examined these two snakes (AMNH
13305-06); both
are females rather than a pair
as SCHMIDT stated.
They
are
without
a
doubt very
different from the majority
of
Puerto Rican specimens in dorsal and ventral pattern (both repre-
sent pattern type
(2)
as
described above),
and show
no approach
to pattern
type
(1)
which is usual for
Puerto Rican
snakes.
The
ventrals (182,
185)
are slightly
above other Puerto Rican
females
(166-181).
The dorsal scale formulae
are
17-17-15 and
17-19-15.
The
question
is
whether these
two
snakes
(1)
really
represent
a
191
Puerto Rican population
of the otherwise Virgin
Islands nicholsi,
and thus portoricensis
and
nicholsi
are
two
distinct
species
with
the latter having a somewhat peculiar distribution, or (2) represent
a peculiar
variant or,
at
best,
a subspecies
of
portoricensis
on
Puerto Rico.
Evidence for the latter alternative is two-fold. During tne course
of the present investigation
I have examined,
in addition to these
Coamo Springs specimens, three other specimens from Puerto Rico
with the same sort of coloration and pattern, all with 17 midbody
scale rows, and all from southern localities (Guanica, Guanica Insular
Forest, and Maricao).
From Maricao and Adjuntas there are addi-
tional specimens which show at least ventral patterns intermediate
between portoricensis
and
the paler
southern form; these will
be
discussed in detail later. It thus seems that there is in xeric southern
Puerto Rico
a subspecies of portoricensis, presently represented by
a very few specimens,
which intergrades with portoricensis
farther
north.
Secondly, Cajade
Muertos, which lies off Ponce off the southern
coast of Puerto Rico,
has
a population
which to varying
degrees
includes individuals which are primarily like the southern mainland
specimens noted above and others which are more like portoricensis,
the one category blending gradually and almost imperceptibly into
the other. Thus,
although
the
extremes
of the Caja
de Muertos
series might be separated into pale, nicholsi- like specimens and other
more
portoricensis- like
snakes,
the
majority
are
intermediate
between these two, and all are quite different as
a group from the
northern Puerto Rican snakes.
In these
two
cases,
it is
perhaps
arguable
that
the supposed
intergrades at Maricao and Adjuntas,
as well as the Caja de Muertos
conglomerate,
are hybrids betweentwo species. To anyone with this
inclination,
I can only say that it is impossible to reach any sort of
logical arrangement of the various forms involved by presupposing
the
occurrence
in
this
assemblage
of
two (or
more)
full
species.
One quickly encounters such a non-concordance of characters, such
a variety
of patterns,
such
a host of intermediates between what
are assumed at the outset to be distinctive patterns, that the whole
picture
becomes
confused
and
unreasonable. With
a
very
few
192
specimens,
the picture
can be simply resolved. With more adequate
series,
the situation increases in complexity.
In
some
ways
I
am
not satisfied
with the arrangement
as
proposed
below,
but,
con-
sidering the fact that I have had access
to far more material than
any previous
worker
on these snakes,
it
is the only
arrangement
which does not violate too many concepts at the same time.
SYSTEMATIC TREATMENT
Alsophis portoricensis Reinhardt & Lutken,
1863
Alsophis portoricensis REINHARDT &
LUTKEN,
1863, Vid.
Meddel.
Naturh.
Foren.
Copenhagen 1862, p. 221.
Alsophis anegadae BARBOUR,
1917, Proc. Biol.
Soc. Washington 30,
p.
102.
Dromicus variegatus SCHMIDT,
1926, Publ. Field
Mus. Nat. Hist., Zool.
12, p.
160.
Alsophis nicholsi GRANT,
1937, Jour. Dept. Agri. Puerto Rico 21, p.
516.
Type
locality:
PUERTO
RICO.
Description:
A large (males
to 794 mm, females to 923
mm
snout-vent length) colubrid snake with either
17 or
19 scale rows
(occasionally
15 or
18) at midbody;
163 to
184 ventrals in males,
166 to 187 ventrals in females; dorsal scales smooth with from one
to three apical pits;
anal divided;
head scalation of the normal
unspecialized
colubrid type
with
1/1
loreals,
1/1
preoculars,
2/2
postoculars,
and
usually
1 +2/1 +2
temporals;
supralabials
usually
8/8,
infralabials
10/10;
subcaudals paired,
114 to
143 in
males,
106 to
140 in females;
pattern
various, ranging
from dark
purplish-brown
dorsum and pale venter with each dorsal scale and
each ventral scale edged in dark brown to black,
to a pale brown
dorsum and creamy venter with heavy stippling and traces of dark
ventral
margins,
and with
an
at least
indicated line
on the fifth
scale row, made up every third
or fourth scale with its upper half
pale and its lower half dark brown to black; hemipenis as previously
described;
head and neck
pattern
various
and
as
described for
each subspecies below.
Alsophis portoricensis portoricensis Reinhardt & Lutken,
1863
Type locality:
PUERTO Rico.
193
Diagnosis:
A subspecies
of A. portoricensis
characterized by
a combination of large size (males to 794 mm, females to 923 mm
snout-vent length),
dorsum unicolor dark purplish-brown
to olive,
each scale edged with black to dark brown (Fig. 44);
venter pale,
each ventral scale edged posteriorly
with dark brown to black in
strong
contrast to the rest
of the scale which is immaculate;
top
of
head reddish-brown to brown;
supra- and
infralabials usually
immaculate pale reddish-brown (Fig. 52), chin and throat usually
immaculate, but if marked, only with diffuse dark to dusky blotches;
ventral scales
few in number,
163 to
176 in males (mean
170.1),
166 to
181 in females (mean 174.3); subcaudals 114 to 134 in males,
115 to
133 in females; dorsal scales most often 17-17-14.
Distribution:
Puerto
Rico,
except
the
southern
section;
known in the south from Maricao, Adjuntas, and Cayey
(Fig. 56).
Variation
and
discussion:
The black-edged
dorsals and
ventrals
are
a
common recognition
feature of A.
p. portoricensis.
The ventral black edging is variable in intensity and may
be extremely dark
and
contrasting (MCZ 58805)
or may
be reduced
to
a very
few
dark
discrete
dots
or
dashes
on the posterior ventral edges (MCZ 61487). The
usual condition
is heavy
ventral markings, however, and only one snake (MCZ 6140) lacks these marks entirely.
The
ventral ground color varies (notes in life from four specimens from Bosque de
Rio Abajo, ASFS X7530-32, RT 555)
from white anteriorly to grayish posteriorly,
or white to yellowish or pinkish posteriorly in subadult specimens. The dorsal ground
color varies from olivaceous to rich purplish-brown, and all dorsal scales have black
posterior margins. This latter feature is somewhatvariable, however, with a resulting
dorsal dark
reticulum
(much like
that which distinguishes the Mona subspecies);
MCZ
6140
from Bayam6n has this condition.
Usually the
dark
scale edges on the
fourth and fifth scale rows are more extensive than those elsewhere, and these then
form
a diffuse lateral
band, especially
on the
neck (UMMZ 74383)
but
at times
extending the length of the
entire body (UMMZ 74367).
The dorsum
in juveniles
and
some
subadults
is
rather
inconspicuously
transversely
banded
with
wide
(3 to 4 scales)
dark and narrow (1 to 2 scales)
whitish lines
which give the snake
an
obscurely
banded
appearance.
This
condition
is apparently lost with
adulthood
since it occurs in no large snakes. The dark dorsal and ventral scale edgingcontinues
onto both the dorsal and ventral surfaces of the tail,
so that on the tail each scale is
outlined by dark
brown
or black.
The
head is regularly reddish-brown
to brown, without pattern. A dark median
line, involving as many
as three adjacent scale rows, proceeds posteriorly from the
parietals for
a short
distance along the neck; if lateral scale
rows 4 and
5 are con-
spicuously darker, a slightly paler
area is thus enclosed
between the
dark
median
and dark lateral
lines. In many specimens,
due to the dark hue of the dorsal scales,
the median nuchal line is not apparent. The labials, chin and throat are all usually
unmarked; if there is any dark pigment present, it is a brownish
to dusky clouding
194
and
is confined
to the chin
and throat. Such
dark pigmentation is
not a constant
feature ofthe series, and most specimens have the throats immaculate. There is some
dark pigment in the supralabial groove, but
this
is almost restricted to the groove
itself and in no way approaches the formation of a mask or a dark
canthal line.
There are two juveniles (MCZ 57898-99); the smaller (snout-vent length 322 mm)
is
so discolored
dorsally that it
is presently
an entirely dark
brown
snake
with
faintly indicated posterior pale crossbands; ventrally the scutes
are dark gray
and
there is a suggestion of lateral angle-following longitudinal dashes on the ventrals.
The
ventrals
lack
posterior dark
margins.
The
second specimen
is considerably
larger (snout-vent length 444 mm) and is colored like the adults, although anteriorly
this particular
individual
has
a
more than
usual
reticulate pattern; if there
were
pale crossbands
on this small snake, they are no longer apparent.
The
modal
dorsal
scale
row
formula
is
17-17-14, although
as indicated
in the
introduction, there are several
others variants. Only a single snake (CM 28126) has
19
scale
rows
at midbody.
Except for
this individual, all other specimens have
formulae of 17-17-13,—14,
or -15. The supralabials are 8/8 in all but one snake which
has
8/9. The infralabials
are
10/10, with 9/10
as
the most
common variant
(six
specimens),
and 9/9 (three), 10/11 (three), and
11/11 (one) also occurring.
One snake
has
1/2 postoculars instead
of the customary 2/2.
The temporals
are especially
variable; the normal arrangement of
1 +2/1 +
2 is varied to
1 +
1 unilaterally in
fifteen
specimens,
and
four
snakes
have
1 +
1/1 +
1.
Other
conditions
include
1 + 3
on both
sides (two specimens), 1+3/1 +
1
(one),
and
1 + 3
unilaterally
(one).
I cannot detect any geographic variation in colorationor scalation
in the material
before
me.
To
the south there are
indications of
influence of the pale and more heavily and distinctly marked south-
ern subspecies;
these intergradient
specimens
are
discussed later.
Specimens
examined:
PUERTO RICO,
no other
locality,
4
(USNM
12447); 4 km
SE Isabela,
1 (ASFS V3241); 2 mi.
S Pueblito
de Ponce,
Bosque de Guajataca,
1 (ASFS V3239); Bosque de Rio Abajo, 2.5 mi. SW
Dos Bocas, 4 (ASFS X7530-32, RT 555); Utuado,
1 (CM 1332); Adjuntas,
3 (CM
1333, AMNH 8434-35; see discussion beyond); Maricao, 2 (UMMZ
74366, MCZ 37328; see
discussion beyond);
2.3
mi. W Dorado,
1
(ASFS
X7702);
Bayam6n,
1
(MCZ 6140);
San Juan,
1
(MCZ 6144);
10
mi.
S
Canovanas,
1 (UMMZ 74367); headwaters, Rio
Mameyes,
1 (MCZ 37329);
3 mi. N Playa de Humacao,
1 (MCZ 37327); Playa Santiago ( = Playa de
Humacao), 23 (MCZ 58773-74, 59796-97, 58799-16, 61487); Cayo Santiago,
1
(MCZ 58798); Humacao, 3
(UMMZ 74365,
USNM 27766-67); District
of
Humacao,
1
(CM
28126);
Cayey,
5
(UMMZ 74368,
UMMZ
74383,
USNM 86521, MCZ 37301, MCZ 37332).
Alsophis portoricensis prymnus, new subspecies
Holotype: MCZ 77226, CAJA
DE MUERTOS, PUERTO RICO, one of a series taken
13 May 1961 by David C. Leber and Albert Schwartz. Original number 12509.
195
Paratypes (all from Caja de Muertos except as indicated): ASFS 12511-
17, same data
as type; UMMZ 74369-70, 20 August
1931
and
November
1931,
C. Grant;
UMMZ
125569,
10 December
1960, H.
Heatwole; MCZ
37330-31, 20 August 1931, C. Grant; MCZ 66422, 27-30 May 1959, Jordan
and Martorell; MCZ 37302, May 1932, C. Grant; AMNH 32986, May-June
1926, Anthony and Goodwin; UMMZ 74381, islet south of Caja de Muertos,
May 1932, C. Grant.
Associated
specimens (all
from
PUERTO RICO):
AMNH
13305-06,
Coamo
Springs;
MCZ
61486,
Gu&nica
Insular
Forest;
ANSP
19622,
Guanica; MCZ 61488, Maricao.
Diagnosis:
A subspecies of A. portoricensis
characterized by
moderate size (males
to 555 mm, females
to 580
mm
snout-vent
length), dorsum tan to light brown;
dorsal scales with dark edging
much reduced to almost absent (Fig. 4); ventrals without conspicu-
ous dark edges but usually with longitudinal dashes at the region of
the ventral angle and occasionally
with some general tan stippling;
top of head variegated;
supra-
and infralabials, chin,
throat and
even
first
eight
ventrals
with
heavy
and
conspicuous
discrete
markings (Fig. 53); ventrals averaging higher
than p. portoricensis,
172.8 in
males
and
177.8 in
females;
subcaudals
122 to
129 in
males,
106 to
132 in females;
dorsal scales
most often
17-17-14.
Distribution:
Known only
from Caja
de
Muertos (and
its
associated islet)
and
the southern portion
of
Puerto Rico,
from
Guanica east
to
Coamo
Springs,
and
inland to
the
vicinity
of
Maricao and Adjuntas (Fig. 56).
Description
of
type:
An
adult
male, snout-vent length
542 mm, tail length 269 mm, not quite complete; ventral scales
179;
anal
divided; subcaudals in
131 -(-pairs; supralabials
8/8;
infra-
labials 10/10; loreals 1/1; preoculars
1/1; postoculars 2/2; temporals
1
-(- 3/1 +
1; dorsal scale rows
17-17-14.
The dorsal coloration is a pale tannish-brown; many scales have
dark brown to blackish edging, although this is not conspicuous
nor
constant for every
dorsal
scale.
The result
is
that
the anterior
portion of the body especially
is almost reticulate with
a fine dark
network which additionally
gives the appearance of zigzag
cross-
banding, the faint darker bands two scales in width, the pale bands
involving
only
one scale.
About every third, fourth or fifth scale
of
the
fourth
scale
row
is particolored,
dark
brown below and
196
slightly
paler
than the ground
color above.
Both this particolor
row and the transverse bands are slightly
more conspicuous
poste-
riorly
than anteriorly.
The ventral surface
was white in life, each
ventral having
only
the
faintest remnant of
the
dark
marginal
edging;
the
same
condition holds for
the
subcaudals.
Whatever
edging is present is brownish and not dark brown and conspicuous.
The head is brown, with
some black smudging
which is indistinct,
and the median neck line is rather bold and extends posteriorly
about the first six median dorsals. There is an ill-defined but none-
theless definite mask remnant from the rostral through the eye and
onto the temporals, blending thence into a faint lateral neck stripe
on scale
row 4,
which continues posteriorly
and is ultimately lost
in the dark scale edgings
on the body. The supralabials
are unicolor
reddish-brown with only very
faint indications of markings;
the
infralabials, chin shields and throat, including the first nine ventrals,
have brown markings,
those
on
the chin shields
and infralabials
being the darkest. The hemipenes
are extruded.
Variation:
The paratypes
include
five
males
and eighteen
females.
The largest male measures 555
mm in snout-vent length, and the largest female
580
mm. The ventrals
range from
169 to
179 (mean 172.8) in males, and from
173
to
185
(mean
177.8) in
females.
Two males
with complete tails
have
122
and
129
subcaudals, and four females have from 106 to 132. The scale row formulae are 17-17-
14 modally, but
counts
of
17-17-15
(five snakes), 17-15-13(one), 17-19-15 (one),
and
19-17—14
(one)
occur. Variation in
head
scales
includes
one snake
with
8/9
supralabials, one snake each with
10/11 and 9/10 infralabials, and one snake which
has only one postocular on one side (the other side has been destroyed). The type
is unique in its temporal formula; aside
from the usual
formula of
1 +
2
on both
sides (16 specimens),
counts of
1 +
1 (unilaterally)
occur in five
snakes and
2 +
2
unilaterally in two snakes.
The entire lot of specimens from Caja de Muertos and its associated
islet presents
a bewildering
array
of patterns,
as
noted
in
the
introduction.
Some specimens
(MCZ 66423, ASFS 12516) at least dorsally resemble p. portoricensis to a great extent,
but such specimens ventrally have the scale margins not so dark or regular as does
the northern mainland race. These snakes also have the hps, chin and throat heavily
marked with
dark brown
to black. At the other extreme
are specimens which
are
virtually patternless and pale dorsally (UMMZ 74381, ASFS
12513 )but which have
mottled lips,
chin
and throat, faint indication
of a dark lateral stripe on scale row
four, and longitudinalmarkings at the angulate portion of the ventrals. The major
portion of the series is intermediate
between the two pattern extremes, but
inter-
mediate in varying degrees, so that the gap between the two extreme color patterns
is rather nicely bridged by
the material.
A single juvenile male (UMMZ
125569) is
197
distinctly
crossbanded
with
wide dark
and
narrow pale bands, and
the
venter
is
dark gray.
The five mainland specimens vary in no significant way from the Caja de Muertos
series;
the pale dorsal ground color, the reduced
dorsal and
ventral
scale edging,
the stippled venters,
the dark
mask stripe follwoing the supralabial groove
and
continuing onto the neck, the prominent median neck stripe, the heavily marked
labials, chins, and throats (in all except the two juveniles -
MCZ 61488
and
ANSP
19630), all align
these
snakes
with
the Caja
de Muertos
series and
not with the
balance
of material from the remainder
of Puerto Rico.
J)
Of the two other Maricao specimens (UMMZ 74366, MCZ 37328), both
are much
closer to p. portoricensis than
to prymnus ; however, both have
one feature which is
unusual
in
the former subspecies
and
characteristic
of the latter
-
the
occurrence
of dark
dashes at the angle of the ventrals, especially anteriorly. One
also has the
labial
and chin spotting
more prominent and
evident than
is customary for the
northern race. Finally, of three specimens from Adjuntas,
one (CM 1333) has a very
heavily marked
venter (although the ventrals have the dark marginalborder much
reduced) and prominent angulate markings. An Adjuntas juvenile (AMNH 8434)
has the venter gray
and heavily stippled and likewise has angulate markings very
well developed. The final Adjuntas specimen is typical of portoricensis.
From
these data it
appears that portoricensis
intergrades
with
prymnus
in the vicinity of Maricao, and some prymnus characters
are
still
evident
in
the region
of Adjuntas,
although
Adjuntas
appears to be north of the actual area of direct prymnus
influence.
Remarks: The
occurrence
of two
races
of A. portoricensis
on
Puerto Rico
was predicted
by SCHMIDT (1928, p.
144)
who stated
that
"It
is
not unlikely
that
a pale
form of
true portoricensis
formerly occurred in the arid district
of southwestern Puerto Rico,
and the Muertos Island specimen is evidence to this effect." On the
mainland, A. p. prymnus
seems to be rather rare,
since there are
very few specimens of Alsophis available from the southern section
of the island. On Caja de Muertos, on the other hand,
the race
is
x)
Since
the
present
paper
was
submitted for
publication, additional specimens of
A. p. prymnus
were
collected during the spring of
1965 in Puerto
Rico by DONALD
W.
BUDEN,
RICHARD
THOMAS
and myself. These include
a series
of eleven specimens from
Caja de Muertos (ASFS V4803-12, ASFS V5849), and two snakes from the southwestern
Puerto
Rican mainland: ASFS V5728, 7.0 km
E Gu&nica, and ASFS V5754, 8.5 km
SE
Gu&nica. All these specimens agree very well with my concept of A. p. prymnus,j and the
mainland snakes reinforce
my interpretationof the differences existing between the Caja
de Muertos
snakes, along with those
from southwestern Puerto Rico,
and A. p.
porto-
ricensis. New localities for the latter subspecies include: ASFS V4520,
17.7 km NE Utua-
do, Hacienda Roses,
1100 feet; ASFS V5439, Ramey Air Force Base, Rifle Range Beach;
V5874, 4 mi. W Las Llanadas, 600 feet; and ASFS V5931-32, 1 mi. SW Regadura. None
of
the
new localities for portoricensis
and prymnus
is
shown
on
Fig.
56,
and
all new
localities
are enclosed within the known
ranges of the two subspecies.
198
extremely common; Mr. LEBER and I secured the series of type and
paratypes
in about eight
hours
general
collecting
on
the island
and without any special search for snakes.
Alsophis
p. portoricensis
and A.
p. prymnus require
little
com-
parison;
the former is
a dark, well marked snake with bold dark
margins to the ventrals, whereas prymnus is much paler with much
reduced
dorsal and ventral markings.
In contrast to portoricensis,
bellies
of prymnus
were
noted
as being
white to
tan anteriorly,
becoming more reddish posteriorly. In scalation, both subspecies have
17-17-14
as
the
modal
dorsal
formula,
but
in
both
sexes
the
extremes and means of ventrals are higher in prymnus.
Alsophis
portoricensis
variegatus Schmidt,
1926
Type locality:
MONA
ISLAND.
Diagnosis:
A
subspecies
of
A.
portoricensis
characterized
by small size
(males
to 535 mm,
females to 510 mm
snout-vent
length),
dorsum medium to dark brown, with
some
dorsal scales
edged in black, giving
a reticulate appearance, especially prominent
on
the neck and anterior part of the body which is usually
very
darkly
marked (Fig.
46);
venter pale
and with
dark margins of
ventrals much reduced or absent and usually
some additional dark
stippling; top of head variegated with black; supra- and infralabials
usually heavily flecked with dark brown, as are chin and throat and
anterior ventrals;
dark canthal-ocular-temporal
mask
prominent
and black in most specimens;
ventrals moderate in number,
171 to
177 in
males (mean
173.4),
174 to
179 (mean
177.2)
in females;
subcaudals
115 to
125 in males,
113
to
125 in
females;
dorsal
scales almost always
17-17-15.
Distribution:
Isla
Mona (and doubtfully
Isla Desecheo)
off
of western Puerto Rico (Fig. 46).
Variation
and
discussion:
The
characteristics
which
most readily
distinguish
variegatus from portoricensis
and prymnus
are the dorsal and ventral patterns,
as well as the almost constant
17-17-15 formula (one exception in seventeen specimens examined).
The irregular dark edging to the dorsal scales gives a distinctly reticulate
appear-
ance; this is especially true on the neck and anterior body. In UMMZ 74373F, which
199
displays this condition,
the neck
scales are heavily marked with black, so much
so
that the neck
immediately behind
the parietals is
almost black, with two lateral
patches
of ground color cut off by the very
dark
median
neck line, and
the black
pigment extensively
deposited above the fourth
scale
row.
More posteriorly
this
snake has
a black median
dorsal line
and black lines
on the sides
on the fourth and
fifth rows,
all of which become slightly less
bold
even more posteriorly. Although
this snake
is exceptionally dark anteriorly, all specimens from Mona have the same
sort
of pattern, with
dark
scale edgings
more prominent on the lower
sides
and
middorsum. The pair of lateral neck blotches behind the parietals is always present
and obvious,
even in snakes with
a paler ground color
and somewhat
less
intense
black pigmentation(AMNH 31909). Ventrallythe series varies frombeing completely
patternless, to having the ventrals heavily stippled and with longitudinalangulate
markings,
to
moderately heavy but
interrupted dark
posterior ventral margins.
In the latter case,
the ventrals
are marked only on the posterior two-thirds of the
body, the
anterior third lacking this pattern. A black mask is present, its intensity
correlated
with the intensity of the
black
dorsal markings. In all specimens except
a small juvenile, the labials, chin and throat scales,
as well
as the anterior ventrals,
are heavily and clearly marked with dark
brown to black,
so much so that in one
individual(UMMZ 74372) the whole area shows more very dark brown than paleareas.
There is one juvenile (UMMZ 74371) with a snout-vent length of 218 mm. Except
for the
absence
of labial, chin and throat markings,
this
small snake
is patterned
much
like the
adults; anteriorly the dark dorsal
scale edges form
a series of four
laterally almost
ovate blotches,
which blend
gradually into
more obscure
dorsal
dark markings. The small snake is not crossbanded
in the fashion of portoricensis or
prymnus juveniles. The apparently larger size reached by males rather than
females
is presumed to be an artifact of the sample.
All
but
one specimen (UMMZ 74372) have
a dorsal scale
formula
of 17-17-15;
the exception has
17-19-15. One snake has 8/9 supralabials, and all others have 8/8
supra- and 10/10 infralabials.
Only two snakes
are exceptional as regards temporals;
these
two snakes have
1 -\-
1 unilaterally.
The heavy
anterior
dorsal markings
and reticulate
pattern
of
variegatus will distinguish it at once from portoricensis
and prymnus.
In dorsal ground color it seems intermediate between the other two
races,
but
closer
to prymnus
than to portoricensis.
The reduced
ventral
pattern
distinguishes
variegatus
from
portoricensis
; both
variegatus and prymnus
are comparable in ventral pattern reduction.
The heavy
black
mask separates
variegatus
from the other
two
races, and the heavily marked labials, chin, and throat distinguish
the
Mona
race
from
portoricensis.
In scalation,
prymnus
and
variegatus are comparable, and both average higher than portoricen-
sis in number of ventrals. Although both portoricensis
and prymnus
have snakes with dorsal formulae of 17-17-15, this is not the modal
condition in these two subspecies.
200
There is
a single specimen
(USNM 29356) from Isla
Desecheo
available
to
me.
This is a female with
181 ventrals
and
17-17-15 dorsal rows. The number of ventrals
is higher than that of variegatus females, but within the range of ventrals
of female
prymnus.
The specimen is
old and
much faded; the pattern is
much
more similar
to prymnus than to variegatus, since it is reduced, there being very little
black. The
ventrals
lack posterior dark
margins, but
do
have
lateral angulate longitudinal
dashes. For want of a better name for this specimen, I am groupingit with variegatus,
although this assignment is
almost surely incorrect.
I suppose that Isla
Desecheo
is
inhabited
by
another subspecies, characterized
by high number of ventrals
and
pallid
coloration
with
little
or no dorsal markings. Only
additional
material will
solve
the problem.
Specimens
examined:
Isla
MONA,
19
(UMMZ
74371
(3),
UMMZ
74372 (5), UMMZ 74373
(6), USNM
12086, ANSP 24607, AMNH
13773-74,
AMNH 31909); Isla DESECHEO,
1 (USNM 29356).
Alsophis portoricensis aphantus,
new subspecies
Holotype: BMNH RR1964.944, VIEQUES,
taken
before April
1890 by
A.
H.
Riise.
Paratypes : BMNH RR1964.943, RR1964.945, same data
as type.
Diagnosis:
A subspecies
of A. portoricensis
characterized by
moderate size
(males
to
634 mm, females to 670
mm
snout-vent
length), dorsum tan to light brown;
dorsal scales with dark edging
prominent but somewhat irregular although not giving a reticulate
appearance; a moderately to very prominent
dark lateral stripe
on
scale
rows
four
and five,
each
particolored
scale
in
this stripe
subtending
above it a pale rosette of from two to four scales (Fig.
47);
ventrals
with
dark
posterior
margins
reduced
but
usually
present and moderately dark, and dark longitudinal dashes present
at the ventral angle, at least anteriorly; top of head plain to varie-
gated; supra- and infralabials, chin and throat heavily marked, the
markings rather diffuse and not especially clear-cut; ventrals very
high in the single
female (187)
and high
in the
two males (177);
subcaudals
130 in
the single
specimen
(a male)
with
a complete
tail;
dorsal scale counts variable, two specimens
having
18-19-15,
and one 17-17-15.
201
Distribution: Known only from Isla Vieques, off the eastern
end
of
Puerto Rico;
presumed
to
be presently
extinct
(Fig.
56).
Description
of
type:
An adult female,
snout-vent length
670
mm,
tail
not
complete;
ventral
scales
187,
anal
divided;
subcaudals 98 + pairs; supralabials 8/8; infralabials
10/10; loreals
1/1; preoculars
1/1; postoculars 2/2; temporals
1 +2/1 +2; dorsal
scale rows
17-17-15.
The dorsal colorationis brown, most scales having
a narrow dark
brown
to black margin,
thereby giving
a
more
or
less uniformly
marked dorsum. Starting
on scale rows
four and five
on the neck,
a black lateral line proceeds posteriorly,
breaking
gradually
into
a series of particolored
scales
on the anterior trunk. These scales
at first
are
separated
from each other by
one
or two scales, but
more posteriorly all scales in the fourthand fifth rows are particolor-
ed, giving
a somewhat zigzag
black lateral line. Most particolored
scales in the fourth row subtend small
but very conspicuous
white
rosettes of three to four scales which are most obvious on the poste-
rior two-thirds
of the body,
and continue onto the top of the tail
as a series of white scales on the second scale row.
The top of the
head is suffused with dusky,
and there is
a moderately prominent
median dark nuchal line,
one scale in width, which, in conjunction
with
a
dark patch
laterally
behind the temporals,
cuts off
two
rather
triangular
patches
of
brown ground
color
on
the
neck.
The ventral scales have their posterior margins outlined in medium
brown, but the edgings
are irregular and often broken; these ventral
scale
edges
are
fainter
on
the anterior
quarter of the body.
The
lateral angulate markings on the ventrals are restricted to occasional
dark dots. The supra-, infralabials,
chin, and throat are
diffusely
marbled with darker,
the markings
on the chin and throat being
the
more
discrete. There are
some brown vague markings
on
the
first
ten
ventrals. The
subcaudals
are
irregularly
margined
with
brown. The dark face mask is limited to a short dark canthal line,
a black supralabial groove line, and a rather large black posttempo-
ral patch which blends into the dark lateral neck lines mentioned
above.
Variation : The two male paratypes (snout-vent lengths 560 mm
and 634 mm) both have 177 ventrals, and the smaller has a complete
202
tail
with
130
pairs
of
subcaudals.
The only
exceptional
head
scalation is
that
one snake
has
1 -f
3 temporals unilaterally;
all
other head scale
counts
are
as for
the species.
Both males
have
dorsal formulae of
18-19-15. On a population
level I imagine that
the Vieques
snakes
are
19-19-15 row snakes like the Virgin Islands
Alsophis.
The smaller male (BMNH RR 1964.945) resembles
the type very closely in most
pattern features; it
does lack, however,
a prominent dark lateral line, but
the pale
rosettes
are present. Ventrally, in addition to the brown
scale margins, the lateral
angular markings
are prominent and consistent the length of the body; lip and chin
markings are present. The larger male (BMNH RR 1964.943) lacks dark dorsal scale
edges or has
them at least much reduced anteriorly,
lacks
a lateral dark line, and
apparently lacks rosettes
as well.
The ventral markings likewise
are much reduced
and there are only very fine ventral scale edges and the very faintest oflateral angular
markings.
The throat
and chin
are, however, very profusely marked with
darker
and the labials
have suture-following dark
lines and smudges.
Remarks
: Alsophis p.
aphantus
is represented
by
only
three
specimens,
and thus comparison
of the meristic characters of this
subspecies with others is difficult and uncertain. The presence of 19
scale rows at midbody will differentiate aphantus from most speci-
mens
of portoricensis,
prymnus,
and
variegatus.
The
very
dark
lateral line (when present)
and the white rosettes are features which
aphantus shares with no other subspecies,
although variegatus
does
have
a dark
lateral line in
many specimens.
Absence of
a dark
mask separates
aphantus
from variegatus,
as
well
as
the
former
lacking
a reticulate dorsal pattern.
Ventrally,
aphantus
is much
like prymnus
and variegatus,
and quite
different
from the boldly
marked portoricensis.
The high
number of
ventrals in the single
female aphantus
is higher than that of any other specimen
of the
species. Of the described subspecies, it is most closely approached by
female prymnus.
The male
counts of
177 ventrals
are
within the
known ranges of ventrals in male prymnus
and variegatus,
and one
scale higher than the large series of male portoricensis.
Before leaving the environs of Puerto Rico, there is a short series of seven snakes
from Isla Pineros (UMMZ 74380 (4), MCZ 37306-08) which requires some comment.
These
are the specimens about which GRANT (1932C, p. 149) said that they "seemed
at first to be slightly aberrant
A. portoricensis,
but they were A. antillensis.” They
are indeed
a confusing lot. There
are three males
and four females; all are adult.
The
ventrals in the
males
range from
174 to
175 (mean 174.4) and in the
females
203
from
173 to
185 (mean 179.5). The dorsal scale formulae are 19-19-15 in five snakes,
19-19-14
in
one,
and
17-19-15
in
another.
All
thus
have
19 scales
at midbody.
Only
one specimen,
a female, has
a complete tail, with
131 pairs of subcaudals.
These
snakes
as
a group
are distinctly unlike
any
other Puerto
Rican
specimens
in having
19 scale
rows at midbody. The four specimens from the University of
Michigan could
very easily be regarded as aberrant A. p. portoricensis in pattern,
since they have the ventral markings reduced
or absent, two have angular longi-
tudinal dashes, the dorsal scales have reduced dark edges, the tops of the heads are
variegated, and lips, chin, and throats
are very heavily marbled
with dark brown.
The three Harvard specimens on the other hand are much paler in dorsal coloration,
have prominentparticolored scales in the fifth row, have somewhat stippled venters,
and lack almost completely any indication
of ventral dark scale edging.
Here
is
a
particular
instance
where
the
investigator
is
really
beset
with
confusion.
Do
these
two
series
represent two
species
which
differ
in
the
time-
honored
dorsal
and
ventral patterns ?
If
so,
we must then assume that the por-
toricensis-like
individuals
differ
from
their
mainland
relatives by
19 rather than
17
midbody
scale
rows.
At
the
same time,
the
pale snakes with distinct parti-
colored
fifth scale
rows
are much
like
specimens to the
east
on Culebra
and
the
Virgins. Another possibility
is that these
snakes represent
an intergradient popu-
lation between two subspecies -;portoricensis and the race next to the
east. Geograph-
ically this seems implausible, since Isla
Pineros lies only about
1 kilometer
off the
shore
of Puerto Rico,
but some 45 kilometers from Culebra
and about
12 kilometers
from Vieques; the
Isla
Pineros
snakes
are not aphantus. Since
there
is
a certain
amount of "intergradation" in the sample between
the
two
extreme conditions,
I prefer to regard these snakes
as very
aberrant A. p. portoricensis, at least for the
moment,
while admitting at the same time that they may represent a distinct
race
from Isla Pineros.
Alsophis portoricensis richardi Grant,
1946
Alsophis nicholsi richardi
GRANT,
1946, Jour. Agri. Univ.
Puerto Rico jo(2), p.
124.
Type locality :
ST. THOMAS, American Virgin Islands.
Diagnosis:A
subspecies of A. portoricensis
characterized by
a
combination of large
size (males
to 648 mm, females to 790
mm
snout-vent
length),
dorsum
sandy
to
dark
brown,
with usually
every
two
to four scales in
the fifth scale
row particolored
pale
above and dark brown below (Fig. 48); venter heavily stippled with
brown, but ventral scales usually
without conspicuous
dark
pos-
terior margins; longitudinal
dashes on
ventrals at angle regularly
present; top of head variegated; supra- and infralabials,
chin and
throat spotted
or marked with dark brown, this pattern extending
onto the first few ventrals;
a dark brown mask present
or at least
204
indicated;
ventrals
moderate
in
number,
172
to
179
in
males
(mean
175.4),
175 to
183 in females (mean
179.0)
-
data from St.
Thomas material only; subcaudals
135 to 143 in males,
130 to 135
in females (St. Thomas);
dorsal scales most often
19-19-15.
Distribution: Known from the islands of Culebra, St. Thomas
(and
its
satellites,
except
Buck),
Peter
and Salt
Islands in
the
British Virgin
Islands (Figs.
56
and 57);
doubtless occurring
on
many smaller islands and
islets in the American Virgins and the
western British Virgins,
but unknown to
me (by specimens)
from
St. John or Jost van Dyke (whence it has been recorded by GRANT
1936, p. 9-11).
Variation
and
discussion:
Perhaps
the
best
way
of
attacking
A.
p.
richardi
is
to
discuss
variation
on
the
various
islands
which
it
inhabits.
There
are
long
series
available
from
Culebra and St.
Thomas,
and
less adequate
material from other
islands.
1) St
Thomas. In
the
series
of
30
snakes
from St. Thomas, the
ventrals in
males
vary
between
172 and
179 (mean 175.4) and between
175 and
183 in females
(mean 179.0). Subcaudals
vary
in males
(three)
from
135 to
143 and
in females
(three)
from
130
to
135.
The
dorsal
coloration
is extremely variable, including
specimens which
are presently
at least
very pale sandy (USNM
66523) to those
which are very dark brown (MCZ 5429). The modal coloration seems to be medium
brown.
The particolored fifth scale
row is always present, and, by inclusion
of the
fourth scale row
as well, may make up a dark lateral line (BMNH 60.4.18.3). A dark
brown
mask, often hollowed centrally, is always present and
is more prominent in
paler individuals.
Dorsal scales
may be outlined
with dark brown, especially
pos-
teriorly (MCZ 5426), or all body scales
may
lack
this
condition
(USNM
12403).
The ventrals always have
some brown stippling, which may be very dense (BMNH
60.4.18.1) or may
be
almost
absent (USNM
13857). A few specimens (MCZ 5426)
have remnants
of dark
brown posterior margins on the
ventrals,
but this
is the
exception rather than
the regular condition. The modal
dorsal scale formula is
19-
19-15 (25 individuals), but
formulae of
19-19-14
(2),
19-19-17
(2),
17-19-15
(1),
and
19-18-15 (1)
also occur.
Five juveniles are all light sandy in color, lack lip or chin markings, and
show the
particolored scale
row rather
clearly;
their
bellies
are all stippled with
grayish-
brown, for the most part heavily so.
2)
Culebra.
In 44 snakes from Culebra, the ventrals in males vary from
170 to
181
(mean 174.6) and in females from
174 to
185 (mean 179.8). Subcaudals
vary in
males (eight) from 125 to 135, and in females (eight) between 127 and
132. The dorsal
205
coloration
and
its variants
are much
as described
for St. Thomas; the same can be
said
about the pattern. Attention
should
be
called to two
snakes (MCZ 37310
and
UMMZ 74378) which resemble A. p. portoricensis in most features, and were at first
regarded by
me as evidence for the occurrenceof two species on Culebra. Once again,
however, these two portoricensis-like
snakes are imperceptibly joined by a series of
intermediates
to
snakes which
are typical of richardi
at the other extreme.
Unless
it is
assumed that Culebra
is populated principally by hybrids, the conclusion that
this portoricensis-like pattern
and
the richardi pattern are
but
extremes
of
an
insensibly grading series
is
inescapable. The
modal
dorsal
formula
is
19-19-15
(25 specimens),
with
other
counts
of
17-19-15
(9),
20-19-15
(2),
19-17-15
(2)
17-17-15
(1),
19-19-16 (1),
19-19-17
(1)
and
18-19-15
(1). The
presence
of three
snakes with midbody counts of 17 (in contrast to nonefrom St. Thomas) is of special
interest; whether
these
three
snakes represent residual
genetic influence
from the
mainland of Puerto Rico is of course unknown.
3)
Water
Island. Water Island is
a satellite of St. Thomas and lies just west
of the harbor of Charlotte Amalie; the maximum width of the channel separating
Water from St. Thomas is
0.5
kilometers
and
the maximum depth is
8 fathoms.
Ventrals in three
males range between
175 and 177 (mean 175.7) and intwo females
between
175 and
180 (mean 177.5); no snake has
a completetail. In coloration these
individuals
as a group
seem somewhat darker than St. Thomas specimens but
show
the
same sort of variation in dorsal pattern.
4)
St. Thomas
satellites.
The
islands
ofSavana,
Dog,
Saba, and
Great
and Little
St.
James
are all satellites
of St. Thomas;
of them, Dog
and the
St.
James's are arranged in a series off the southeastern tip of St. Thomas with
a
maximum
depth of 8 fathoms between them. Savana and Saba
are western
and the
channel between them and
St. Thomas is
16 fathoms in the former case and
14 in
the latter. Saba is the farther removed from St. Thomas at a distance of 4 kilometers.
Lovango,
on the other hand,
is
closer to St. John, and
is one of a linear
group
of
islands
(Thatch, Grass, Mingo,
and Lovango) which
cross the northern
reaches
of
Pillsbury
Sound. Lovango is
2 kilometers
off the northwest corner of St. John and
is separated from it by a maximum depth of 13 fathoms. Since noneof these islands
is represented by more than two specimens, they are grouped together.
Six males (Savana, Saba, Little St. James, Dog) have from 173 to
184 (mean 177.0)
ventrals and three females (Great St. James, Lovango) have between
177 and
179
(mean 178.3). One male (Saba) has
125 paired subcaudals, and one female (Lovango)
has
128 paired subcaudals.
The modal
dorsal scale
formula
is
19-19-15; only one
specimen (Savana) is exceptional in having 19-19-14. The only outstanding variants
in pattern and coloration
are two specimens (KU 45669, Lovango, and
KU 45672,
Little
St.
James) which
are unusually heavily stippled ventrally,
and
also have
dark brown ventral scale margins.
5)
Hans
Lollick.
This island
lies
off the northeastern
shore of St. Thomas,
at
a distance of 2.5 kilometers
and with a maximum channel depth of
16 fathoms.
Three females are known, of which
one, the only full adult, is damaged and a ventral
count cannot
be taken.
The remaining two females both
have
178 ventrals. Two
have complete tails with
125 and
140 subcaudals.
All are rather pale dorsally, and
two
have prominent and continuous dark
brown
lateral lines.
The
adult
has
re-
markably unmarked labials, chin and throat.
6)
Salt and
Peter.
These two islands
are part of the British Virgin Islands,
and lie to the southeast, 7 and
6 kilometers respectively, of Tortola. They represent
206
a string of islets which
extends to the southwest from Virgin Gorda and historically
are likely more closely associated with Virgin Gorda than with Tortola, from which
they
are separated by
the
Sir Francis
Drake
Channel
which reaches
a maximum
depth of
27 fathoms
between Tortola and Peter. All eight specimens are females,
with ventrals varying between
175 and
181 (mean 176.5); four with complete tails
have from
126 to
136 subcaudals. The dorsal scale formulae are extremely variable
for such a small series, with both
19-19-15
and
17-19-15 each represented by two
specimens,
and
17-19-14,
17-17-13,
and
17-17-14 by
one snake
each.
The high
incidence
of
17 rows on the neck is noteworthy, and two snakes have
17 scale rows
at midbody.
In color and pattern, these snakes
are not unusual; Grant (1932e) noted that the
specimens from Peter were peculiarly marked, and that the
three specimens he
had
seen from Salt and
Peter had straw-yellow throats in life. A juvenile and
subadult
which
were collected in 1964 on Peter indeed did have the throat and both supra- and
infralabials yellow. This condition occurs elsewhere (Virgin Gorda; Culebra
- Grant,
1932c, p. 150), and I do not attach undue importance to it.
Treating all specimens
of A.
p. richardi
as
a unit, it is at
once
obvious that this
race
is especially
variable. Aside from more
or
less constant features of
dorsal scale row formulae (although Peter
and Salt specimens are exceptional in having such a high incidence of
17 scale
row snakes),
and certain pattern
and coloration features,
there is little to ally all these islands populations
with one another.
I do so principally
on the very close ventral means of both sexes
on
the various islands. As will be seen shortly, there is a distinct break
in numberof ventrals to the northeast on Virgin Gorda and Anegada.
The specimens from Hans Lollick are especially interesting because
of
their pale
coloration
and
conspicuous
dark lateral
line,
but
it is likely that even
these features would vanish in larger
series
from that islet. Another fact of note, since it is important in reference
to the following subspecies,
is that of all
the specimens
from St.
Thomas and its satellites
and Culebra (46 individuals),
only
one
male (from Dog Island)
has
ventrals
as high
as
184; Culebra has
the next highest
counts of
181.
Exceptions
to the normal
head scalation are
as follows:
supra-
labials 9/9
(1
snake), 8/9 (4); infralabials, 8/9 (1), 9/9 (1), 9/10 (4),
10/11 (7),
11/11 (2); preoculars
1/2 (1); postoculars,
1/2 (2),
1/3 (1),
2/3
(3);
temporals
1 +3
(unilaterally
)(15),
1+3/1+3
(2),
2 + 2 (unilaterally)
(1);
1 + l(uni laterally)
(13),
1 +
1/1 + 1(2).
None of the above head scale irregularities
shows any correlation
with a particular island.
207
The absence of
specimens
of
A.
portoricensis
from
St.
John is
most
unusual;
although
these
snakes
have
been reported
from
there
(BOULENGER
1893),
there
seem to be
no
readily
available
specimens in any of the larger collections. I have also been unable
to locate the series of twelve specimens from Jost van Dyke reported
upon by
GRANT (1936);
although
these
were
stated
to be in the
Museum of Zoology of the University
of Michigan,
they
are
not
there
now.
Unfortunately,
GRANT
gave
no
ventral
or subcaudal
counts or any detailed color descriptions,
so at present I
am unable
to say whether Jost van Dyke specimens
are richardi or not. Since
this large island is 6 kilometers to the northwest of Tortola (another
island which is unrepresented by specimens) and 7 kilometers north
of St. John (likewise unrepresented) and stands on its own platform,
separated by channels with maximum depth of
17 fathoms from the
adjacent large islands, it is possible that the subspecies
there is not
richardi. Geographically
Jost
van Dyke
seems more closely related
to Tortola, and it is possible
that the postulated
occurrence
of the
more western race on Tortola applies equally well to Jost van Dyke.
Comparison
of
A.
p.
richardi with
the remaining
races
of A.
portoricensis
is hampered somewhat by the rather extensive
color
and pattern
variation in the former. From the
races portoricensis
and
variegatus,
richardi
differs
in
lacking
the
regularly
black
margined
dorsals and
ventrals of the
former and
the reticulate
dorsum of the latter. From prymnus, richardi may be differentiated
by having
a more heavily stippled
venter. From these three
sub-
species, richardi differsin having the modal dorsal formula 19-19-15,
rather
than
17-17-14
or
15.
From
aphantus,
richardi
differs
in
lacking white lateral rosettes and in having less ventrals, at least
in
the females. Only
a single
specimen
from Culebra,
of
all
the
richardi examined, has the peculiar modal dorsal formula of 18-19-
15 shown by aphantus.
Specimens examined
: CULEBRA, 44 (UMMZ 74374
(5), UMMZ 74375
(3), UMMZ
74377
(7), UMMZ
74378
(2), USNM 25554-57, USNM 26102,
USNM 56438, MCZ 37309-26, AMNH 32983-85); ST. THOMAS, 31 (USNM
13857, USNM 75866, USNM
115831, USNM
12403 (2), USNM 66522-25,
BMNH
57.6.4.6, BMNH
60.4.19.1-.7, BMNH
65.3.31.1-.2, ANSP 5577,
MCZ 3297, MCZ 5426,
MCZ 5427, MCZ
5428
(4),
MCZ
5429 (4);
WATER
ISLAND,
east side,
1
(ASFS V7423); no other locality, 4 (UMMZ 74379,
208
UMMZ
80644,
USNM 52547,
MCZ 37305);
HANS
LOIXICK
Island,
east
side, 2 (ASFS V7459-60); no other locality,
1
(CM 23779); SAVANA Island,
2
(UMMZ 80646,
MCZ
42363);
SABA
Island,
1
(UMMZ
80642);
DOG
Island,
2
(UMMZ 74376);
GREAT
ST.
JAMES,
west
end,
1
(KU45671);
LITTLE ST.
JAMES, south end,
1 (KU45672);LOVANGO Cay, northeast end,
2 (KU45669-70);
PETER Island, Little Harbour,
3
(ASFS V7870-72);
no other locality, 4 (UMMZ 74412,
UMMZ 80645,
MCZ 37303-04); SALT
Island,
1 (UMMZ 74382).
Alsophis portoricensis nicholsi Grant,
1937
Type locality:
BUCK
ISLAND
(of Capella Islands),
off southern
coast of St.
Thomas, American Virgin Islands.
Diagnosis:
A subspecies
of A. portoricensis
characterized by
a combination of large
size (males to 795
mm snout-vent length),
dorsum pale olive green (fide GRANT
1937, p. 516) in life but
very
pale tan in preservative; black or dark dorsal scale edgings
almost
or completely absent (Fig. 49)
; venter pale, practically immaculate,
without either
extensive
stippling
or
dark
ventral margins;
top
of
head tan,
with
very
limited
dusky
variegations;
supra- and
infralabials
pale
tan,
without
conspicuous
markings,
chin
and
throat
almost
immaculate;
dark mask absent (Fig.
54);
ventrals
(in males)
high in number,
180 to
184 (mean
181.7);
subcaudals
unknown;
dorsal scales
19-19-15.
Distribution:
Known only
from
Buck
Island,
the
north-
westernmost
of
two
islands
jointly
called
Capella
Islands,
3.5
kilometers off the south-central coast of St. Thomas, and separated
by
a channel of
16 fathoms maximum depth (Fig. 57).
Variation
and
discussion
:
The only specimens of A.
p.
nicholsi
are those available to GRANT at the time of the description,
the type
(UMMZ
80648)
and
two paratypes
(UMMZ
80641
and
MCZ 46503).
All are males, with ventrals varying between 180 and
184;
none has a complete tail, the longest being
that of the type
with 95 -)- pairs of subcaudals. All specimens have
19-19-15 dorsal
scale rows, and
none has any variants of the head scales.
If GRANT'S annotation of "pale olive green" coloration is correct,
209
this
alone will
serve
to distinguish
nicholsi from any
other
race
except
portoricensis,
which has
some individuals which
are
olive.
An attempt to collect
more material of nicholsi in the summer of
1964 failed,
and further attempts
on Major
GRANT'S part
did not
succeed
as well; apparently
these snakes
are not common on Buck
Island.
The
island itself,
although
rather easily
accessible
from
Charlotte Amalie, is somewhat inhospitable,
and except for partial
fringes of sea-grapes along the limited lower coastal areas, is almost
completely
covered with tall grass enclosing small copses of dwarf
trees and shrubs
- altogether
not a very easy place to collect fast-
moving snakes.
The separation
of nicholsi from richardi
rests primarily
on two
characters:
1) the much reduced and pale dorsal markings, lip, chin,
and throat mottling, and ventral pigmentation,
and 2) the higher
ventral
scale
counts.
As
for
the former,
such
common
richardi
features as the dark mask and the particolored
fifth scale
row
are
completely suppressed
in nicholsi; the same is true of head mottling
and dark lip spotting. The higher ventrals of nicholsi are also appar-
ent
upon comparison
with richardi.
As noted previously, only
one
male richardi has
a count of
184 (the high count for nicholsi),
and
no specimen of: richardi from St. Thomas has a count which overlaps
that of the
three specimens of nicholsi.
Interestingly,
the single
high-count male richardi is from Dog Island, which is a St. Thomas
satellite 8
kilometers
east
of
Buck
Island.
This
snake
shows
no
tendencies toward reduced pigmentation
and pattern,
and should
not be interpreted
as intergradient.
Surely additional specimens of
nicholsi
will
show
ventral overlap
between it
and richardi,
but
almost certainly
the
mean
for
nicholsi
ventrals will remain
con-
sistently higher than that of richardi.
GRANT (1937, p.
124) noted that a specimen he collected on Water
Island approached
nicholsi in general appearance; examination of
a larger
series (five)
shows that snakes from this island are in
no
way
closer to nicholsi than are
some other occasional specimens of
richardi
from Culebra
or
Hans
Lollick,
for
example,
which
are
pale.
Certainly
the extreme reduction of
the lateral
dark line in
nicholsi
can hardly be matched by any richardi.
Comparison
with
the other
races
of A.
portoricensis
is
rather
210
simple.
From the nominate form, variegatus
and prymnus,
nicholsi
differs
not only
in
extreme reduction of
pattern
but
in having
19-19-15 scale
rows.
From aphantus it differs in reduced pigmen-
tation and
in
19-19-15 rather
than
18-19-15 or
17-17-15 scale
rows.
The high counts of male aphantus ventrals (177 in two speci-
mens)
surely
would
overlap
the
counts
of
nicholsi,
if
adequate
series of both forms ever become available.
Specimens examined: BUCK Island, 3 (UMMZ 80641, UMMZ
80648,
MCZ 46503).
Alsophis portoricensis anegadae
Barbour,
1917
Type locality: ANEGADA, British Virgin Islands.
Diagnosis:
A subspecies of A. portoricensis
characterized by
a
combination of moderate size (males to 645 mm, females to 605 mm
snout-vent length),
dorsum brown to very dark brown, dark scale
edging
much
reduced
(Fig.
50);
venter
moderately
to
heavily
pigmented with dark brown stippling and margins of ventrals with
a heavy
dark brown border; top of head brown, variegated
with
darker brown;
supra- and infralabials pale, moderately
to heavily
marked with brown,
chin and throat usually
heavily marked with
dark brown, extending
onto the first
eight
ventrals;
dark mask
present
but obscured because of dark dorsal coloration (Fig.
55);
fifth scale
row
particolored
but
not especially
conspicuous
since
the upper halves of these scales
are brown,
the lower halves dark
brown, the whole blending into the dark dorsal coloration; ventrals
high in number, in males between 174 and
184 (mean
177.5) and in
females between 178 and
186 (mean
182.5)
on Virgin Gorda;
dorsal
scales usually
19-19-15.
Distribution:
Anegada,
Virgin
Gorda,
Necker,
and Guana
islands in the British Virgin Islands, and very probably Tortola as
well (Fig. 57).
Variation
and
discussion:
Alsophis
anegadae
was
described by BARBOUR (1917, p.
102)
on the basis of two specimens
(MCZ
12083 and 12098)
as differing from A.
“antillensis” by "being
pale ashy
gray in color, the fifth scale
row not parti-colored, but
211
with a median streak of black. The upper lips are immaculate white,
unspotted."
I have examined these two specimens,
and although
they are presently very pale (through loss of most of their epidermis)
and although
the lips
are indeed unspotted
white,
the fifth scale
row
is
strongly
particolored.
Both
are
young snakes,
and
this
doubtless
accounts
for
the immaculate
labials.
The
venters
are
heavily stippled with brown but lack dark posterior margins;
the
angulate markings
are obvious.
GRANT (1937,
p.
521) reported the
taking of two small specimens,
one of which was
a gravid female;
GRANT (1946, p.
123) later noted that these two snakes
were light
tan rather than gray, and that they too had particolored fifth scale
rows.
GRANT also (1937, p. 521) stated that
one of his anegadae had
only one smallobscure scale pit on the dorsals, whereas the other had
two large scale pits. From this he deduced that "Anegada may be
a point of intergradation between these two genera"
- i.e., Alsophis
and Dromicus,
since these genera are in part differentiated by the
number of apical pits.
Collection of two fresh specimens
on Anegada
in the summer of
1964 indicates that A.
anegadae
is in
no
way
different
from A.
portoricensis,
and
is
closely
related,
as may
be
imagined,
to the
Virgin Islands
race richardi. The use by
BARBOUR (1937,
p.
160) of
the combination Dromicus anegadae
is
indefensible;
these
snakes
are
only
subspecifically
differentiable from
the
balance
of
the
Virgin
Islands snakes, and in no way represent
an isolated species
of the genus Dromicus.
Specimens
from Anegada
and Virgin
Gorda appear to
be
in-
distinguishable;
the
following
data
are
based
on
the
far
more
adequate series available from the latter island, but comments will
be made on the short Anegada series.
The dark brown dorsal coloration is a common character of anegadae. The dorsal
scales
lack
extensive dark
dorsal scale edging. The fifth scale
row
is particolored
(brown below
and
buff above), but
this condition
is obscured by the depth of the
dorsal pigmentation;
old
specimens, however,
show
the
condition
quite clearly,
both onVirgin Gorda
and Anegada. Ventrally these
snakes are very
dark
- darker
than most specimens of richardi
- due to the heavy brown stippling and the dark
brown margins to the ventrals.
This
ventral coloration is
somewhat variable, and
two fresh specimens from Anegada are slightly less dark ventrally than are most of
the Virgin Gorda
specimens. The lateral angulate line is bold and conspicuous and
often forms a continuous
line down each side ofthe ventral scutes. Inlife, the ventral
212
coloration
of
a Virgin Gorda specimen
was noted
as white anteriorly becoming
browner posteriorly
with
some pink
and
orange added; a juvenile
was noted
as
having a yellow throat. Two specimens from Anegada had the bellies cream anterior-
ly grading to pale orange
on the posterior two thirds; the labials
and
throats were
white with brown flecks.
The head is brown with
some darker suffusions; the labials, chin
and throat are
always heavily marked
with very
dark brown in adults, but this feature is lacking
in the type and paratype (both juveniles) of anegadae.
There is
a pair of diagonal
paler spots
on the neck which are bordered medially by a dark brown
nuchal line
and laterally by the post-temporal extension of the dark brown mask.
These spots
are the homologuesof pale areas noted in specimens of most other races,
and which
are especially prominent in
variegatus. The
two Anegada specimens have
a series
of pale chevronate
markings on the
neck which
are not so apparent in the Virgin
Gorda specimens.
The
modal dorsal scale row formula
is 19-19-15, with variants
of
19-19-17
and
18-19-15
(one specimen each). The ventral scales range in males (Virgin Gorda and
Necker Island) from
174 to
181
(mean 177.5) and in females from
178 to
186 (mean
182.5). A male from Anegada has
176 ventrals,
and three females
from Anegada
have
182 to
184 ventrals (mean 182.7). Four Virgin Gorda males have between
132
and
138 paired subcaudals
and
four females
from the same island have
between
124
and
132 subcaudals.
The single Anegada female with
a complete tail
has
118
subcaudals.
Two snakes have 8/9 supralabials; infralabials may be 9/10 (2), 10/11 (6),
or
11/11 (4), in
addition
to the
usual
count.
Variation
in temporals includes
one
snake with
1 +
1
on both sides,
one snake with
1 -f
1 unilaterally, four snakes with
1 -f
3 unilaterally, and one snake with 2 +
2 unilaterally. The apparently large size
reached
by
males
rather
than
females
may
well
be real, considering the
large
sample. Only in anegadae and variegatus (which is represented by a smaller sample),
does this condition
occur.
The single
specimen
(a male) from Guana Island,
which lies off
the northeast tip of Tortola,
is just
as dark dorsally
and ventrally
as are snakes from Anegada
and Virgin
Gorda. I assign it for this
reason
to anegadae,
although
because
of its
ventral count
(178)
it might with equal propriety be considered a specimen of richardi.
The
single
individual from
Tortola
which
I
examined
casually
while in Roadtown
was
likewise
very
dark;
from these
meagre
data I
suspect that Tortola is inhabited by anegadae
rather than
richardi.
Additional specimens
may
well
prove
this
assumption
incorrect.
Anegada,
which lies about 24 kilometers to the north of Virgin
Gorda across
a channel which is
13 fathoms deep at its maximum
depth, is quite
different geologically from the balance of the Virgin
Islands;
Anegada is low and flat (maximum elevation
10 meters)
and much of it is inundated. It does however lie
on the same bank
213
as the other Virgins. The fauna is Puerto Rican,
and only two forms
are
known
to be
endemic,
Cyclura
pinguis
Barbour (although
it
may
be
related
to the
extinct
C.
mattea
of
St.
Thomas)
and
Typhlops richardi
catapontus
Thomas. The fact that both Anegada
and Virgin Gorda are both inhabited by the same
race of A.
porto-
ricensis
may
indicate that this snake is a relatively
recent invader
from the south, and that it has not differentiated on Anegada from
its more southern relative.
Alsophis portoricensis
anegadae differs from the races portoricensis,
variegatus,
and prymnus
in having
19-19-15 rather than
17-17-14
or
15 dorsal scale
rows.
Its style
of
coloration is quite
different
from that of p.
portoricensis,
although
its
depth of pigmentation
is
similar to that of the Puerto Rican race.
From variegatus
and
prymnus, anegadae differs in much darker coloration and in lacking
the reticulated dorsum of the former. From the Virgin Island races
richardi
and
nicholsi,
anegadae
differs in much
darker coloration
dorsally
and in
a
more heavily
pigmented
venter;
nicholsi
and
anegadae
represent
two
extremes
of
coloration
in
the
Virgins.
The higher average ventral counts in both sexes help in separating
anegadae
from richardi ;
as noted previously,
the break in average
number of ventrals falls between Peter and Salt
on
one hand and
Virgin
Gorda
on the other. The race aphantus is larger in size and
much
more differently patterned dorsally;
the bellies of anegadae
are consistently
darker than are
those of the Vieques
subspecies.
Specimens
examined:
ANEGADA,
vicinity
of
The
Settlement,
2
(ASFS V3944—45) ;
no other
locality,
2
(MCZ
12083, 12098); VIRGIN
GORDA,
north
of Pond
Bay,
2
(ASFS
V3665,
RT 944)
;
hillside
above
Pond Bay,
3 (ASFS V3695-96, V3738) ;
Pond Bay
to Mahoe Bay, 3 (ASFS
V3752-54) ;
Mahoe Bay,
2 (ASFS V3811, DRP 3201); above Mahoe Bay,
1
(ASFS
V3810); between
Little Dix
Bay
and
Savana
Bay,
1
(ASFS
V3697) ;
just north of
Garden
Rock,
4 (ASFS V3733, ASFS V3791-93);
inland
margin
of Salt
Pond
back
of St.
Thomas Bay,
5
(ASFS V3755,
ASFS V3853-56) ;
no other locality,
7
(UMMZ 80643, UMMZ
80647
(3),
MCZ
12094-96); NECKER
ISLAND,
1
(AMNH
90517);
GUANA
ISLAND,
White Bay,
1 (ASFS V4005).
214
Alsophis
sancticrucis Cope,
1862
Alsophis sancticrucis COPE,
1862, Proc. Acad. Nat. Sci. Philadelphia, p.
76.
Type locality: ST. CROIX, American Virgin Islands.
Description:
A
very large
(females
to
1025
mm snout-vent
length)
colubrid
snake
with
17
scale
rows
at midbody;
191
to
198 ventrals infemales, male unknown (two males citedby Boulenger,
1894, p.
122,
are
females);
dorsal
scales smooth with
two apical
pits,
two
or three on
dorsal caudal scales;
anal single
or divided;
head scalation of the normal unspecialized
colubrid type with
1 /1
loreals,
1/1
preoculars,
2/2
postoculars,
and
1+2
(or
1 +
1)
temporals;
supralabials
8/8,
infralabials
10/10;
subcaudals
140 to
145 in two
females,
unknown in males;
dorsum (in preservative)
very
dark bluish-black with
a series of
15 to 20
transverse pale
bars, less than one scale in width, on the neck, the remainder of the
body with pale flecking
or pale anterior scale edges, giving
a rather
regularly mottled or marked appearance (Fig. 51); venter pale with
the margins
of the
ventrals heavily
marked with blue-black,
the
remainder of each scale with
some smudges
connected to the dark
ventral margins,
and with
some
indication of the lateral
angular
marking
on ends of each ventral, at times forming
a rather distinct
line down each side of the ventrals; hemipenis
undescribed; head
dark with snout and
lores pale (yellowish),
thereby making
even
more conspicuous
the black mask which is also outlined above by
clear yellow postocular stripe.
Distribution :
Known
only
from
the
island
of
St.
Croix,
American Virgin Islands (Fig. 51).
Variation
and
discussion:
The blue-black dorsum and
pale venter easily distinguish A. sancticrucis from A. portoricensis.
The dorsum is usually marked with
a series of pale transverse
bands anteriorly,
sharply
set off from the ground color. Posteriorly, these bands persist but become
more obscure,
finally being indicated
by
transverse
series
of small pale H-shaped
markings, each
H being composed
of the adjacent pale portions
of three
scales
(BMNH 59.3.14.22). In another specimen, there is
a wide, pale, diffuse dorsolateral
band, separating dark below and
a rather dark-and-light mottled middorsal
band
in which remnants
of the pale crossbars
are still discernible.
Some specimens (i.e.,
ANSP 5542) have the dorsalscale slightly flecked with paler so that they are diffusely
215
salt-and-pepper in aspect. In this same specimen the fifth scale row is particolored,
its lower half black and its upper pale, although the pale sections
are isolated from
one another by
the black ground and form only the vaguest of lateral lines.
The
ventral ground color is pale, with very heavy
and prominent black scale margins;
the subcaudals
are similarly marked. The margins may be clearcut or may be
smud-
ged anteriorly on each ventral, especially in the lateral angular area, giving at times
almost
a complete ventrolateral
dark
line.
The
black ventral margins are absent
anteriorly, and
may even be incomplete posteriorly (BMNH 59.3.14.24), although
each margin is still at least partially and boldly represented. The top of the head is
black,
and the
snout pale; there is invariably a black mask,
more or
less
outlined
above from the eye posteriorly by a bold yellow stripe which disappears behind
the
temporals.
All
specimens
have
17-17-15
scale
rows,
8/8
supralabials,
10/10 infralabials,
1/1 loreals,
1/1 preoculars, and 2/2 postoculars. One snake has
1 +
1/1 +
1 tempo-
rals, and two have
1 +
1 unilaterally. The anal is
divided in four snakes and entire
in three;
the ventrals
vary from
191 to
198, including counts made from the type
(ANSP 5404) by
Mr.
EDMOND
V. MALNATE
-
the type having
the count
of
198.
Two females with complete tails have
140 and
145 subcaudals.
A. sancticrucis is the only Alsophis
which has ever been reported
from St. Croix.
The British Museum has two snakes (1922.6.16.28-
.29)
which are ostensibly
from
St. Croix,
and were
received from
the Christiana Museum. These snakes are A. portoricensis
richardi,
having
19-19-15 scale
rows.
I
do not
regard
these Alsophis
as
representing
a record
for this
species
on
St. Croix;
doubtless the
specimens
were originally carelessly
labeled. They orginated
else-
where in the Virgin Islands.
St. Croix lies 58 kilometers south of St. Thomas, separated by the
southwestern
end
of
the
Anegada
Passage,
with
a
maximum
intervening depth of 2040 fathoms.
SCHUCHERT (1935,
p.
475—481)
suggested that St. Croix was at one time part of the Puerto Rico-Vir-
gin Islands land mass, but that its separation
through "profound
block
faulting"
took
place
in
the
Pliocene. Certainly its present
fauna includes a number of endemics (Ameiva polops Cope, Sphaero-
dactylus
beattyi
Grant,
Anolis acutus Hallowell)
none of which
is
closely related to the present fauna of the Virgin Islands or Puerto
Rico.
A. sancticrucis
does not differ structurally
from A. portoricensis
in any
obvious way,
with the possible
exception
of having in
a
fairly
regular
manner
an
entire,
rather
than
double,
anal.
In
dorsal scale rows,
its
formula of 17-17-15 occurs
as the
norm in
p.
variegatus,
and
occurs
with
some regularity
in p. portoricensis
216
and p. prymnus.
On the other hand,
the coloration and pattern of
sancticrucis are very different from that of any race of A. portoricen-
sis; features in common are the black mask (which is much more pro-
minent
and
outlined above
with
pale
in
sancticrucis )
and
the
presence of a particolored fifth
scale
row (the
net effect of which
is practically
lost in sancticrucis,
due to the black ground
color,
rather than forming
a prominent part of the dorsal pattern
as in
portoricensis).
Likewise,
the dark-margined ventrals
occur in both
species.
It may be profitable to compare sancticrucis with members of the
genus
Alsophis
from
islands
on
the
south
side of
the Anegada
Passage
-
i.e., the northern Lesser Antilles. Of these,
the Anguilla
Bank
islands
are
occupied
by A. rijgersmai
Cope,
the
St. Kitts
Bank and Saba by A. rufiventris Dumeril & Bibron,
and the islands
between Montserrat and Dominica,
and including
Antigua, by A.
antillensis Schlegel.
BRONGERSMA
(1959),
in his
excellent summary of two of these
species,
recorded
23-21-19
or
17
for
specimens
of
rijgersmai;
PARKER (1936, p.
230) noted 21-21-17 and 21-23-19 for the
same
species. In any event, A. rijgersmai has 21 or 23 scale rows at midbody.
BRONGERSMA (1959, p. 55) reported rufiventris
as having scale row
formulae of 23
or 25
-
21
or 23
-
17 to
19 (the
modal condition
being
23-23-19).
PARKER
([loc.
cit.
)
noted that rufiventris
has
21-23-17 or
23-23-19 dorsal rows.
A. rufiventris
is thus another
species
with typically
23 scale
rows
at midbody.
The ventrals
in
both rijgersmai
and rufiventris
are high,
198 to 207 in the former
and
204 to 220 in the latter (PARKER,
loc. cit.). Finally,
PARKER
considered all
the
races
of
A.
antillensis
as
19
scale
row
snakes,
although
the
races
manselli
Parker
(Montserrat)
and
antiguae
Parker (Antigua)
may have
21 scales
at midbody.
None of
these
three species is thus a 17 row snake as is A. sancticrucis. The ventrals
in the races
of A. antillensis range from
191 to 209; in these counts
the species antillensis is comparable to A. sancticrucis.
In
coloration
and pattern,
neither rijgersmai
nor
rufiventris
bear
special
resemblances
to
sancticrucis;
both
for example
are
brown (rather
than black) snakes. A. rufiventris
is sexually
dichro-
matic and females do not particularly resemble female A. sancticru-
217
cis.
Of
the races
of A.
antillensis,
at least
manselli
and
sibonius
Cope
are dark brown to black.
Of these two, manselli is black with
a yellow pattern
consisting
of rather large pale blotches
grading
into yellow H-shaped spots, all
on the anterior half of the body.
The posterior dorsum is solid black. The sides are variously marbled
or marked with yellow
or yellowish.
The yellow ventrals
are splot-
ched with black, and there is a tendency to have the ventral margins
black also. On the posterior half of the belly, the ventrals are usually
solid black. Although manselli and sancticrucis
are similar in having
a combination of
black and yellow
in the pattern,
they differ in
many details. I do not consider them to beclosely related. Thepattern
of sibonius bears little detailedresemblance to that of sancticrucis.
Considering
the history of St. Croix, and considering the features
which sancticrucis
and portoricensis
(especially
the nominate race)
have in common, it
seems most likely that sancticrucis represents
a
derivative
of
A.
portoricensis,
derived directly
from
the
Puerto
Rican mainland (rather than via the Virgin Islands)
in the distant
past,
and
has
had a
very
long
and independent
history
on
St.
Croix. The degree of divergence from the basic stock is of so much
greater magnitude than that of the other subspecies of A. portoricen-
sis
that
I
regard
sancticrucis
as
a separate
species,
although
its
portoricensis affinities
are acknowledged.
Specimens examined:
ST. CROIX,
6 (BMNH 59.3.14.22-.24, BMNH
RR 1964.946, ANSP 5541-42).
TAXONOMIC ARRANGEMENTS
There may still be those who will feel that the oldand time-honored
arrangement
of the Alsophis
of the
Puerto Rico-Virgin
Islands
region into two species (exclusive of A. sancticrucis)
on the basis of
midbody scale rows either 17 or
19 is more to their liking than the
one
which I have proposed.
Now that
the snakes
from this area
have been discussed in detail, it
seems appropriate
to make
some
defense of the present
arrangement;
the reader is referred to the
systematic
treatments for details.
If two species
are accepted,
the names
are A. portoricensis
with
218
17
scale
rows
at
midbody
and A.
anegadae
(this
name having
priority
over
any other based
on Virgin
Islands
snakes)
with
19
rows at midbody. On the basis of midbody scale rows, portoricensis,
variegatus, and prymnus would be associated as races of A. portori-
censis, and aphantus,
richardi, nicholsi, and anegadae
as races
of A.
anegadae. The most trenchant criticism of this system is the obvious
pattern
similarity
between variegatus,
prymnus,
and richardi,
for
instance,
despite
differences in midbody
counts.
In
such
an
ar-
rangement,
aphantus would be placed with anegadae although it is
more closely related to portoricensis.
Another possibility
is the association of variegatus and prymnus
as
one species
(variegatus),
portoricensis
and aphantus
as another
(portoricensis), ,
and
richardi,
nicholsi,
and
anegadae
as
a
third
(anegadae).
This system
then would have
one species
characterized
by 17 scale rows (ivariegatus ) , a second with 19 (anegadae), and a third
with either 17 or
19 (portoricensis).
The problem of the intergrades
between prymnus
and
portoricensis
might
be
answered by
con-
sidering
these few specimens
as hybrids.
Such a course of arrange-
ment
has something
to
recommend it, but it
seems to multiply
basic entities to an unnecessary degree.
Still
a third possibility
is to regard A. portoricensis
as monotypic,
and all other forms as races of A. anegadae;; I originally subscribed
to this system.
This arrangement
groups together both
17 and
19
row snakes
as does mine, and separates the two species principally
on the basis of coloration and pattern. Objections
to this arrange-
ment are the presence of specimens in southern Puerto Rico which
are
intermediate
between
portoricensis
and
prymnus,
and
the
occurrence
on various islands of individual snakes
which resemble
portoricensis
but which
can be
observed to be
one
extreme of
a
series of intermediates,
at the other extreme of which
are snakes
resembling
anegadae.
Thus there seems to be no real advantage
to
separating
portoricensis
from
the
balance
of
the
assemblage,
considering the very close affinities of the snakes involved.
When all
material
is assembled,
and these
various hypotheses
are
tested,
it
becomes gradually
clear
that
the
only
reasonable
arrangement
of these snakes
is
as
races
of
a single
species.
Any
other system quickly
runs afoul of the material itself. Unless
addi-
219
tional material demonstrates to the contrary,
the present
solution
to the problem
seems the most rational and
the most consistent.
REFERENCES
BARBOUR, THOMAS,
1917.
Notes
on the herpetology of the
Virgin Islands.
Proc.
Biol.
Soc.
Washington 30, p.
97-104.
—
1937. Third list of Antillean
reptiles and amphibians. Bull. Mus. Comp. Zool.
82 (2),
p. 77-166.
BOULENGER,
GEORGE
A.,
1894.
Catalogue of
the
snakes
in
the
British
Museum
(Natural History), vol. 2. London, xi +
382 pp.,
20 pis. (repr.
1961, Germany).
BRONGERSMA,
L.
D.,
1937.
The
types
of Psammophis
antillensis
Schlegel.
Zool.
Meded. Leiden
20, p.
1-5.
—
1959.
Some snakes from the Lesser Antilles.
Studies Fauna Curacao
and
other
Carib. Islands 9, p. 50-60, fig. 83, pi. 4-5.
COCHRAN, DORIS M.,
1941. The herpetology of Hispaniola. Bull.
U.S. Nat. Mus. *77,
vii + 398
pp.,
12 pis.
120 figs.
DOWLING,
HERNDON
G..
1951. A proposed standard
system
of counting ventrals
in snakes. Brit. Jour. Herpetology 1 (5), p. 97-99,
1 fig.
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—
1932a. The herpetology of Vieques
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16
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—
1932b.
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—
1932c. The
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—
1932d.
The herpetology of St.
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—
1932e. Herpetology of Tortola; notes
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—
1936. Two new reptile records from Jost van Dyke, B.V.I., with notes ondistri-
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—
1937. Herpetological notes with new species from
the American
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1936. Jour. Dept. Agri.
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21 (4), p. 503-522, 4 pis.
—
1946. A
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Jour. Agri.
Univ.
Puerto
Rico
30
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Herpeto-
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220
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H. W.,
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-
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Reptiles of
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221
Fig.
45.
Alsophis portoricensis prymnus,
midbody pattern
(type,
MCZ
77226),
CAJA
DE MUERTOS, P.R.
Fig.
44.
Alsophis portoricensis portoricensis,
midbody pattern
(ASFS
X
7702),
2.3 mi. W. Dorado, PUERTO RICO.
222
Fig.
47. Alsophis portoricensis aphantus, midbody pattern (type,
BMNH
RR1964.
944), Isla VIEQUES.
Fig. 46. Alsophis portoricensis variegatus, midbodypattern (UMMZ 74373), IslaMONA.
223
Fig.
49.
Alsophis portoricensis
nicholsi,
midbody pattern (type,
UMMZ
80648),
BUCK ISLAND, V.I.
Fig.
48.
Alsophis
portoricensis
richardi,
midbody
pattern
(BMNH
60.4.18.3),
ST. THOMAS.
224
Fig.
51. Alsophis sancticrucis,
midbody pattern (BMNH
59.3.14.22), ST.
CROIX.
Fig.
50.
Alsophis portoricensis anegadae, midbody pattern (ASFS V3810),
above
Mahoe Bay,
VIRGIN GORDA.
225
Fig. 55. Alsophis portoricensis anegadae, lateral view of head (ASFS V3810), VIRGIN
GORDA.
Fig.
52. Alsophis portoricensis portoricensis,
lateral view
of head
(ASFS X7702),
PUERTO
RICO.
Fig.
53.
Alsophis portoricensis
prymnus, lateral
view
of head
(MCZ 77226), CAJA
DE MUERTOS.
Fig.
54. Alsophis portoricensis nicholsi, lateral
view of head (UMMZ 80648), BUCK
ISLAND.
Fig.
56.
PUERTO
RICO
and
associated
islands.
—
Subspecies
of
Alsophis
portoricensis
as
folows:
1)
vertical
lines,
portoricensis;
2)
horizontal
lines,
prymus
(overlap
of
symbols
of
portoricensis
and
prymnus
indicates
intergradation;
arrow
indicates
ocurence
of
prymnus
both
on
Caja
de
Muertos
and
Puerto
Rico);
3)
diagonal
lines,
variegatus
(questioned
arrow
indicates
doubtful
ocurence
of
variegatus
5)
fine
stippling,
aphantus
;
on
Isla
Desecheo);
4)
heavy
stippling,
richardi
(arrow
indicates
ocurence
of
richardi
on
other
islands
to
the
east).
Lack
of
symbols
in
western
and
southeastern
Puerto
Rico
indicates
only
that
the
race(s)
inhabiting
these
areas
is
presently
unknown
by
specimens.
227
Fig. 57.
VIRGIN ISLANDS.
— Subspecies of Alsophis portoricensis as follows:
1)
fine
stippling, richardi
(arrow indicates occurrence of this subspecies
on Peter and Salt
islands
to the
east); 2)
nicholsi
;
3)
fine
vertical
lines, anegadae (arrows
indicate
occurrence of anegadae
on Virgin Gorda, Anegada, and
Guana Island). Jost
van
Dyke,
Tortola, and St. John are questioned, since none is presently represented by
specimens, although the
species
has
been reported from two
(St.
John, Jost van
Dyke)
and
a specimen
from Tortola
was
cursorily
examined.
4)
crosshatching,
A. sancticrucis.