University of Colorado, Boulder
CU Scholar
Series in Biology
Ecology & Evolutionary Biology
Winter 2-1-1963
Notes on a collection of herpetozoa from the
Yucatan Peninsula of Mexico ; Reptiles -- Yucatán
Peninsula
T. Paul Maslin
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Recommended Citation
Maslin, T. Paul, "Notes on a collection of herpetozoa from the Yucatan Peninsula of Mexico ; Reptiles -- Yucatán Peninsula" (1963).
Series in Biology. 22.
http://scholar.colorado.edu/sbio/22
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U N I V E R S I T Y OF C O L O R A D O S T UD I E S
Series in Biology
No. 9
U
niversity
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of
o uld er
F
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olorado
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ebruary
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, 196]
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N O T E S ON A C O L L E C T I O N OF H E R P E T O Z O A
FROM T H E Y U C A T A N PENINSULA
OF M E X I C O
By
T.
P a u l M a s l in 1
T he U niversity o f C olorado M useum and the Thorne E cological Research
Station sponsored an expedition to the Y ucatan Peninsula for the purpose
o f collecting certain endem ic races of the teiid lizard genus, Cnemidophorus.
Incidental to collecting these lizards a num ber of other species were collected.
These are reported on in this paper. A few snakes were also acquired, hut
these and the am phibian larvae which were collected will be reported on in
separate papers.
I
am indebted to the U niversity o f C olorado M useum , the C ouncil on
Research and Creative' W ork of the University o f C olorado, the T horne
E cological Research Station, and the N ational Science Foundation (grant
num ber (1 1(5244 in part) for financial assistance.
1 Curator of H erpetology, U niv ersity o f Colorado M useum .
1
2
U N I V K H S I T Y OF C O L O R A D O S T U D I K S
T he expedition left Boulder, C olorado, Juno 19, 19")!), and returned on
July 12. C ollecting times and sites on the Peninsula consisted o f tw o short
trips to 9 km. north of Alerida, Y ucatan, on the 25th and 2(>th o f June; five
days on Isla de Cozum el, Quintana R oo, and fou r days in the vicinity of Piste
and Chichen Itza, Y ucatan. On C ozum el we encountered rain and cou ld
collect p rofitably for tw o days only. T he party consisted of Air. and Airs.
H erbert Beargie, Air. Christopher Smith, a N ational Science Foundation
undergraduate participating scholar, and m yself. A total o f 439 specimens
representing 25 species were collected on the Peninsula. These specimens,
with the exception o f a representative series which has been sent to the
A lexican N ational M useum , are housed in the University o f C olorado Aluseum.
Leptodactylus labialis (C ope)
Seven males, three females, and seven juveniles were collected in the
vicinity of Piste, Y ucatan, on the evening of July 4. It had rained fairly
heavily the evening before and was overcast on the night o f the 4 th, w ith a
very light drizzle. W e heard a weak, high-pitched, upw ardly inflected peep or
bleat, nearly whistle-like, lasting abou t j>2 second and given at long and
irregular intervals. Finally a male labialis was located crouching betw een tw o
small stones near the edge o f a m anure-polluted mud wallow in the center o f a
road. There was no free water at the time, but p robably there had been some
the night before. There were numerous small rocks around the wallow and
in the mud o f the wallow itself. Three froth nests were found, each lying
beneath a rock near the periphery o f the wallow. T he nests consisted of
pockets in the mud about 2 ^ inches in diam eter com pletely filled with a
gleam ing white froth o f the appearance o f half-beaten egg white but more
viscous. Each nest had an exit point consisting o f a small crevasse below the
lip o f the rock above. Eggs o f varying stages of developm ent were found in
all these nests. T he freshly laid eggs are a bright yellow and are scattered
haphazardly through the froth but tend to occu r in small aggregations.
A second breeding site was located later in the evening. Here the bulk of
the specimens were collected. T he site consisted o f a series of small waterfilled basins in an exposed mass of limestone. T he area is partly overgrow n
with small trees, and one o f the basins was partly filled with wet mud. Here
also small rocks lay in and on the mud, and, under these, froth nests were
found. A group o f some ten frogs were collected here, m ost o f them males.
T he head o f one frog was seen through a small l 4-inch hole beneath a rock
well above the water level but still in wet mud. W hen the rock was lifted
slow ly it was obvious that the frog was constructing a brooding cham ber.
Judging from the position o f the frog and the marks in the walls o f the chain-
H E R P E T O ZO A F R O M T H E YUCATAN PEN INSULA
3
her, this construction was achieved b y pushing against the m ud and slow ly
expanding the cham ber b y internal pressure. N o traces o f excavated waste
could be detected. T he cham ber was nearly 2j^> inches in diam eter and hence
must have been near com pletion. T he specim en was collected but was in­
ad verten tly placed in a bag with other specim ens so that its sex was not
determ ined. I am under the impression, how ever, that it was a female. W ithin
an area o f three square feet, fou r other com pleted, froth-filled nests were
found, and in this same small area were located the bulk o f the specimens
collected. These were all on the ground, in the open, or crouched between
stones. T he males sang in the same fashion as those heard previously, the
calls being uttered at sporadic and irregular intervals. T w o juvenile specimens
were fou n d here, and others were located on w et bare m ud in the area.
T here is considerable variation in the color patterns o f these frogs. T he
general effect is of a m ottled dark- and light-brow n pattern interspersed with
gray. T h e m ottling is m ade up o f dark-brow n irregular blotches of varying
size, the larger o f which tend to be specifically located. One b lotch, roughly
triangular, is located on the eyelids and betw een the eyes, its apex extending
posteriorly. T his b lotch is follow ed b y a smaller m edian b lotch w hich in turn
is follow ed b y a brilliant orange-red spot betw een the scapulae. T he orange
spot is follow ed b y a large m edian brow n b lotch located at m id b od y . On
either side of the orange sp ot is fou n d an elongated dark blotch . Other marks
are less regularly arranged. T he dark blotches often have darker edges and
are surrounded b y light-gray borders. In alcohol, the orange marks have
turned a crim son magenta, and the same color in some specim ens occurs
extensively betw een the dark blotches ov er m ost o f the dorsum including the
head. This red pigm entation was m ore conspicuous after fixation and preserva­
tion in eth yl a lcoh ol than it was in the live specimens.
T he adult males measure, from snout to vent, 36.9, 39.8, 36.7, 36.3, 36.1,
36.8, and 39.9 m m ; females, 39.0, 38.7, and 39.3; juveniles, 13.6, 13.0, 14.0,
12.9, 13.0, 13.0, and 14.3. A ll three females are gravid with eggs o f all sizes.
One subadult male measuring 20.3 m m from snout to vent was collected at
“ T he L a g oon ” , 9 km. south o f San M iguel, C ozum el Island. This specimen
was fou n d abou t 3 :0 0 p.m . foraging in dam p grass some 30 feet from the
lagoon, and constitutes a record for the island.
Triprion petasatus (C op e)
Nine specim ens o f this hylid were1 collected on the nights o f the 3rd and 6 lh
o f July just northeast o f Piste, Y ucatan. Promising water-filled limestone
basins had been fou n d in the afternoon o f the 3rd preceding a heavy rain, and
after dark these were visited. Srnilisca were found here and collected ; but
4
U N I V K R S I T Y OF C O L O R A D O S T U D I E S
in the distance, a different call was heard, consisting o f a clear, resonant,
upw ardly inflected hornlike bleat. A n individual call was approxim ately
second in duration w ith a pause o f approxim ately \
seconds between calls.
W e traced these calls to a small but deep lim estone basin fairly high up on a
limestone dom e heavily overgrow n with trees and cactus. T he basin itself
was nearly overgrow n with bushes and a large m any-branched colum nar
cactus. In the flutings of this cactus, 2 )^ to ;j feet above the ground, a chorus
of petasatus was found. Lender the circum stances, w ithout tongs, collecting
was difficult, but we m anaged to collect a few before disrupting the chorus
com pletely. Flashlights did not overly disturb them, but after the hylids
had been displaced b y our collecting efforts th ey did not resume singing.
Tadpoles were collected from the basin below . These seem abou t half-grow n.
Smaller choruses in similar locations in the area yielded a few m ore specimens.
T he single voca l sack with tw o large lateral buccal openings is extrem ely
thick-skinned and unpigm ented. A ll o f the specimens, during fixation, d e­
veloped a strong flexure in the neck so that the heads are bent, dow n, making
total length measurements difficult. A llow ing for the inevitable inaccuracies
resulting from this flexure, the specim ens measure 4(5.6, 52.4, 44.3, 42.9, '>0.3,
52.9, 49.8, and 54.(5 m m from snout to vent. These specim ens are very much
smaller than the ty p e which measures, according to K ellogg (1932: 139),
72.5 mm . T he color pattern in life is m uch as B arbour and Cole (190(5: 154)
describe it, except for the arms and legs, on which the dorsal blotches tend to
form transverse bars.
Smilisca baudini baudini (D um eril and B ibron)
T h irty-tw o males and fou r females were collected on the nights o f July 2,
3, and (5, in the vicinity o f Piste and from an area 3 km. east o f Chichen Itza.
An additional immature fem ale, collected on June 3, 1955, from Chichen
Itza, was donated to us b y E. C. W elling.
Four males were collected at about 8 :3 0 p.m . in the vicinity o f a large
filled-in cenote 3 km . east and abou t % km . north o f Chichen Itza. Small
choruses could be heard all through the area scattered at considerable dis­
tances from each other. W e forced our w ay through the thorn forest to one of
these and found a small water-filled basin abou t 2 feet wide and (5 inches deep
in a limestone ou tcrop. T he vegetation was more sparse here and overhung
the basin. T he song consisted of tw o rapidly em itted horn-like bleats of
alternating pitch. T he calls are not shrill, but resonant, though giving the
impression o f being slightly muffled. Kach bleat lasts a little less than l 5
second with a shorter tim e interval between. A m otif of a higher-pitched
“ A h ” follow ed by “ A h ” o f abou t a half-tone lower is rapidly repeated about
H E R PE T O ZO A FR O M TH E Y U CATAN PEN INSULA
fou r or five times. A fter approxim ately 6 seconds another stanza repeating the
m otif the same num ber o f times is sung again. This is repeated for from a few
minutes to as m uch as 15 or 20 minutes, after which a long rest occurs of
varying duration. W e discovered that in these small aggregations tw o frogs
constitute a chorus. If the first v oice o f a singing pair is disturbed, the chorus
ceases; but if the second voice is disturbed, the first will continue to try to
initiate a song b y bleating in the same pitch at the correct intervals for his
share o f a stanza, leaving pauses of appropriate length for his colleague.
A n incom plete stanza o f this sort is follow ed b y a pause o f m uch greater
duration than the 6 seconds norm ally occurring betw een stanzas. T his effort
to initiate a song is repeated at od d intervals for a minute or tw o. A t a later
tim e and in a different locality, we collected the second voice o f a chorus first
and it later to o k us abou t 15 minutes to locate the first m em ber. In this case
as m uch as 5 minutes w ould elapse before the frog attem pted to initiate a
song again. A ctiv e but more distant choruses seemed to stim ulate attem pts to
initiate another song o f stanzas.
On tw o occasions a male, after trying to initiate a song b y calling his share
o f a stanza at appropriate intervals, uttered a low er-pitched coarse roar of
possibly Vi second duration. I interpret this roar as a more dem anding call
for a response in a d u et; but further observation would be necessary to estab­
lish this for a fact.
It rained in the early part o f the evening of July 3. T h a t night num erous
choruses cou ld be heard in the area around Piste. W o searched ou t a num ber
o f these and fou n d the habitats essentially similar in all instances. O ccasionally
clusters o f w ater-filled lim estone basins would be found. Here the hylids were
more abundant, and it was more difficult to recognize that a song was a duet
consisting o f a series o f m otifs in canonic style. Usually the hylids were perched
2 to 5 feet a b ove the ground in twigs or in the crotches o f small branches
a b ove or near the water, b u t occasionally in larger breeding areas th ey would
be found in the open on the bare lim estone. One pair was found in amplexis,
but breeding must have started m uch earlier because alm ost every basin
contained tadpoles in large num bers and of varying sizes. A t one place both
Leptodactylus labialis and T riprion petasatus were found together with
Smilisca.
T he color pattern o f the dorsum is extrem ely variable, but a basic design
is evident. T he ground color is a light brow n, anteriorly changing to an olivegreenish color, upon which is superim posed a bold pattern of dark olive-brow n
markings. From a large, dark, triangular area in the occipital region tw o arms
extend up on to the eyelids, and one broad, posteriorly extending arm fuses
with tw o large, irregular, diagonal marks which diverge posteriorly. The
(>
U N I V E R S I T Y 01" C O L O R A D O S T U D I E S
sides are speckled with smaller spots of a light to deep dark brow n. B oth the
arms and legs arc crossbarred dorsally. A brow n band extends from the lips
up and over the nares, through the eye, across the tym pan u m , and posteriorly
a bove the arm, where it is abru ptly truncated. T he posterior part o f this
band is a deep, m ottled brow n. A short brow n bar extends from the eye to
the lip. B oth upper and lower lips are narrow ly margined w ith light brow n.
T he pair of v oca l sacs are pigm ented, but the strip o f non-distensible skin
betw een them is not.
H yla staufferi (C ope)
T w o males and three fem ales were collected at the Casa San Juan, 4 km.
north of San M iguel 011 C ozum el Island. T h e y were collected after dark from
1 to 6 feet ab ove the ground off the trunks o f cocon u t palm trees and stum ps
adjacent to an elevated rain w ater cistern. In the males the v o ca l sac is ap­
parent but n ot pigm ented nor highly vascularized. It is single and opens into
the buccal ca v ity b y tw o large, elongated slits. N one was heard singing during
the five days we stayed at the Casa, but the females are gravid w ith fully
m ature pigm ented eggs. From these facts I assume the breeding season o f
these form s was close at hand. T he rainy season was just getting underw ay.
X o ponds or puddles occu r in the v icin ity o f this sandy spot, b u t limestone
basins were found farther inland in the thorn forest.
In life the specim ens were vagu ely m ottled, w ith a d irty gray-green above
and white below . In alcohol a pattern o f stripes is more conspicuous. A m ottled,
melanistic, subtriangular b lotch extends across the interorbital area, tw o
m ottled stripes arch from behind the eyes over the scapular region to abou t a
third o f the w ay dow n the b o d y . A similar stripe starts at the eye, passes
a bove the tym panum , widens, and extends halfw ay dow n the b o d y . P o s­
teriorly, the dorsum is sparingly marked with m ottled blotches o f darker
pigm ent. A n elongated, blue-black spot occurs on either side o f the p u b oischial prom inence. T he arms and legs are vaguely crossbarred dorsally.
T he males measure ‘2 5.8 and 25.7 m m from snout to vent and the fem ales
26.1, 26.0, and 25.2.
Rana pipiens (Schreber)
F our specim ens were collected in a large cenote 3 km. east of Chichen Itza.
T w o o f these, a male and a fem ale, are marked with a few large, dark blotches
between the dorso-lateral folds and possess a bold , banded pattern on the
hind legs. T he other tw o, also a male and fem ale, are com p letely devoid o f a
dorsal pattern and bars on the legs. T he largest o f these, an unm arked fem ale,
measures 100.0 mm from snout to vent.
H E R P E T O Z O A FR O M T H E Y U C A T A N PEN INSULA
Thecadactylus rapicaudus (H ou ttu yn )
Three specim ens, tw o males and one fem ale, were given us b y K C. W elling.
A ll three, according to M r. W elling, were collected in Chichen Itza on or in
the thatch of dwellings in the area. T h e y are apparently m uch feared. This is
n ot surprising considering their size and their ferocious appearance accen ­
tuated b y the large eyes, m outh, swollen tem poral region, and sturdy legs.
T he fem ale resembles the males in color patterns and form except for the
tail, w hich is smaller. T he swollen area just posterior to the ven t which is so
conspicuous in the males is also smaller. In the males there is a spur consisting
o f tw o or three enlarged and protuberant scales directed upwards on either
side o f this post-anal swollen area. T he same structure occurs in the female,
bu t it is smaller and m ade up o f smaller and m ore numerous scales.
In all three specim ens the color pattern is a com plicated system o f irregular
transverse bars, spots, and longitudinal lines o f dark brow n on a beige b a ck ­
ground. A dark line begins on the rostrum , passes back through the eye, con ­
tinues posteriorly through the ear and on. It is interrupted b y the arm but
continues indistinctly down to the inguen. A series of paired dark blotches
begins in the parietal region and extends back to the base of the swollen
portion of the tail. T he tail itself is streaked w ith longitudinal fine lines, but
cross bands o f brow n on beige are also evident. T he ventrum is beige and
m inutely speckled with dark brown.
T he vertical pupil is like that o f Perc/pus mutilatus. If the tw o edges should
meet, four small, rh om boidic orifices w ould remain open. T he large eyes are
deeply set back from the lips and are invisible from the ventral surface in
spite of their large size. T he eye is one half as long as its distance to the snout.
Four or five supraorbital scales a b ove the postero-dorsal corner of the eye are
tentacled.
T he fingers and toes are heavily w ebbed so that on ly the distal half o f each
digit is free. T he term inal claw and phalanx o f each o f the outer digits is
com pletely retracted betw een the lamellae into scale-covered sheaths opening
ventrallv betw een the tw o rows of lamellae and raised on the back o f the
finger into a high ridge. T he claw is absent from the first digit of the manus
and vestigial on the first o f the pes.
Aristelliger georgeensis (B ocou rt)
Seven specim ens were collected on C ozum el Island, one adult in San
M iguel, tw o juveniles and four adults at the Casa San Juan, 4 km. north of
San M iguel. T he juveniles were found about 5 :0 0 p .m ., June 2(5, beneath the
trash and leaves at the bases o f cocon u t palm s. Later, abou t 9 :0 0 p.m ., a
large male was collected b y hand off the trunk o f a cocon u t palm in the garden
8
U N IV E R S IT Y OF C O L O R A D O ST U D IE S
of the M a y a Luum H otel. A larger specim en escaped b y clim bing high up
tow ards the crown. Later in the evening one m ore specim en was collected b y
searching the boles o f palm s b y flashlight, and tw o more were seen b u t es­
caped. This represented approxim ately an h ou r’s collecting on som e 40-odd
palm trees. T h e y were easily spotted b y flashlight abou t 8 feet a b ove the
ground. Light, how ever, disturbed them and caused them to clim b higher in
the trees. T he follow ing nights tw o were successfully sw ept to the ground with
snake sticks, but one escaped. A third specim en was caught b y hand on the
screening of our house. These larger specim ens were pugnacious and would
bite. A nother adult specim en was fou n d beneath a pile o f driftw ood and trash
in a sheltered spot on the beach.
There has been little change in color pattern subsequent to preservation.
In alcoh ol th ey are dorsally gray and ventrally white. D iffuse white spots
occu r on the sutures o f the labials, and single white granules occu r scattered
over the head and neck. T he axillary region is darker than the dorsum and is
marked b y white, vertically orientated spots and streaks. A m uch larger similar
area, b u t paler, occurs in the inguen and on the flanks. D orsally the tail is
blotched with dark brow n. Clusters o f these blotches suggest cross-banding
anteriorly. In m ost o f the specim ens a few dark flecks or spots occu r on the
back as well.
A nolis limifrons rodriguezi (B ocou rt)
Fifteen specim ens o f this lizard were collected, eight from Isla de Cozum el
near San M iguel and seven from Piste, Y ucatan. T he specim ens show co n ­
siderable variation and p oorly fit what published descriptions are available.
T he keeled dorsal scales, distin ctly smaller than the ventrals, the nearly sm ooth
chest scales, vaguely keeled nearer the hum erus, the sm ooth m idventral
scales, the unicarinate m edian head scales, m oderately long lower leg, round
tail, and enlarged post-anal scales in males all indicate that the specim ens o f
this small series are A . 1. rodriguezi. Several females had a bright m iddorsal
yellow -green median band running from the occip ital region to the proxim al
base of the tail. This has faded in a lcoh ol and now consists of a white stripe
abou t four scales wide bordered laterally b y tan stripes abou t three to four
scales wide. T he tan stripes are in turn bordered laterally b y a narrow, onescale-wide stripe and then a black stripe four to five scales wide. This peculiar
banded pattern flares slightly on the neck and over the pelvic region. Smith
and Iversten (1955) and Pianka and Smith (1959) report a similar phenom enon
in A nolis crassulus, and Stuart (1955) has observed it in the Guatem alan
A . /. rodriguezi. T he single fem ale collected on C ozum el vaguely shows the
same pattern. T he specim ens from Isla C ozum el do not differ conspicuously
H EUPETOZOA F R O M TH E Y U C A TA N PEN INSULA
9
from the m ainland specim ens, but a fairly distinct double row of slightly
enlarged scales does run dow n the m iddle o f the back. This is replaced b y a
median row o f m uch larger scales on the tail. In three males a fleshy raised
nuchal crest is apparent.
A ll the specim ens collected b y the p a rty were found in tw iggy brush close
to the ground. Specim ens were seen on a vine-covered wall and on rocks
beneath bushes. O nly one specim en was seen in a small tree approxim ately
six feet a bove the ground. T h e y were extrem ely abundant in brush piles along
a strip being cleared for a road south o f San M iguel. These we were unable to
snare or catch b y hand. O vercast and rainy w eather did not seem to hamper
their a ctiv ity appreciably.
Laemanctus serratus (C op e)
Three specim ens, measuring 53, 64, and 46 m m respectively, wrere collected.
T w o specim ens were found in open w oodland in the v icin ity of Chichen Itza
b y E . C. W elling on O ctober 16, 1954, and F ebruary 17, 3956. T he other
specim en was collected ju st east o f Piste am ong brush and w-eeds b y the side
o f a forest road. This specim en still shows an um bilical scar. A num ber of
juvenile Ctenosaurus were collected in the same area and were initially m is­
taken for Laemanctus. Superficially they are m uch alike.
T h e dorsal surface o f the head o f the juvenile is a gray-green. The, anterior
edges o f the prenasal, the scale im m ediately m edial to it (outer internasal),
the single canthal, the anteriorm ost superciliary, and the frontal are black. A
slightly raised ridge occurs on the supraorbital sem icircles; this is dusky in
color. T he tem pero-occip ita l ridge is encircled b y a row o f keeled scales
con spicu ou sly different from the scales on either side, but these scales are not
p roduced into p rojectin g serrated scales as th ey are in adults. A gray-green
band, five scales wide, starting at a point on the nape, extends to the base of
the tail, where it expands to contribute in the form ation o f the ground color
of the entire tail. This is crossed b y chevron-like dark-brow n marks about five
scales long. Laterally these marks are continuous, with faint extensions giving
an im pression o f cross-banding.
Beginning at a dark-brow n spot on the m iddle superciliary scale, a lightbrow n band extends diagonally dowm over the eyelids, crosses the tym panum ,
passes to the shoulder, where it expands considerably, and then continues down
the flank, where it is fou r or five scales wide. It again expands a bove the hind
leg, continues on to the tail, and here merges with the dorsal stripe. T he edges
of this band tend to be darker than its center. A b o v e the tym panum and
above the dark band on the neck are white spots. A white band begins below'
the eye and extends to the shoulder. T his band resumes at the axilla and
10
U N I V E R S I T Y OF C O L O R A D O S T U D I E S
extends to the inguen. Here on the flank the upper edge is undulant and is
bordered b y a dusky edge. T he last dorsal undulation in the inguinal region
is the largest and is in con tact with the dark lateral band. This area could
easily be isolated as a spot. Posterior to the hind leg a spot-like rem nant of
this band appears again. T he long delicate tail is banded with grey-green and
brow n. T he entire ventrum (exclusive o f the tail) is green, as is the ground
color betw een the longitudinal dark and light stripes.
The remaining tw o specim ens were n ot seen alive. T he green areas in them
now appear to be a light reddish-brow n. T he remaining elements o f the p a t­
tern, however, are essentially the same.
T he scales o f the occip ital ridge in the smallest specim en are partially
produced, while those o f the largest form a conspicuous serrated crow n. T he
circum orbital scale counts are 54, 56, and 59 respectively.
Basiliscus vittatus (W iegm ann)
T en specim ens of this m agnificent lizard were collected on the Isla de
Cozum el, five males and five females. One o f the latter is a juvenile measuring
46 m m from snout to vent. T he species is quite com m on along the coast of
the island. W e saw m any more individuals than were actually collected. A
male and fem ale were fou n d foraging around a tem porary pond located in an
open glade some 30 yards from the sea. T h ey b oth ran b ipedally abou t 30
feet tow ards a th icket o f dense brush, but halted and froze before reaching it.
Unlike other large lizards th ey are rem arkably easy to stalk. These tw o were
stalked and shot one after the other. Later specim ens were seen early in the
m orning and late in the afternoon sunning them selves on branches of small
trees close to dense thickets. T h ey are difficult to see, bu t once spotted are
easy to stalk and extrem ely easy to kill; a few pellets from the gun stops
them in their tracks. A b ou t eight individuals were seen around the banks and
shores of a lagoon 2 km. north o f San M iguel. W ell established runways within
a few feet of the water are apparent here. These are u ndou btedly used b y
other species than Basiliscus and Ctenosaurus, which were seen here also. T he
Basiliscus would run gracefully and rapidly dow n these runways. In the more
open areas bipedal locom otion was the rule, but over rock falls and o u t­
croppings the hands were used as well. A fter initially being startled, a lizard
w ould run for some 30 or 40 feet, then freeze and remain m otionless until
approached to within 7 or 10 feet. T h e y apparently rely heavily on their
disruptive color pattern to escape detection. One juvenile specim en, when
startled, instead o f running around the curve o f a 5-foot b a y , cut across the
water to the trail on the opposite side. L ocom otion in the water was still
bipedal, with the hind legs virtually entirely subm erged at the end o f each
H K R PE TO Z O A F R O M T H E Y U C A T A N PEN INSULA
11
thrust. T he b o d y and tail, how ever, remained a b ove the surface o f the water.
X o adults were seen in or on the wrater. Other specim ens were seen in open
glades in the thorn forest, frequently far from any sign o f a depressed marshy
area or tem porary pools.
T he color pattern o f the males and females is not too different. T he greatest
variation is on togen ctic. T he dark-browrn transverse bands o f the neck,
shoulders, and anterior p ortion o f the back are clear-cut and distinct in
juveniles, and the light-brow n ground color is relatively hom ogeneous. Juvenile
females are speckled w ith dark brow n, particularly on the flanks and abdom en.
In larger specim ens the pattern is less distinct and som ew hat disrupted. In
life the longitudinal facial stripe and shoulder stripe are bright-yellow , and
the chest and belly are a purplish rusty-red. T he second proxim al eighth of
the tail is o f the same color.
Ctenosaurus sim ilis sim ilis (G ray)
F our subadult specim ens were collected from Cozum el Island in the vicinity
o f San M igu el and eleven juveniles from Piste, Y ucatan. T he species is ex­
trem ely com m on at b oth localities, but particularly abundant in the cleared
zones on either side o f the road b oth north and south o f San M iguel. T he
piles o f cut trees and brush and the stum ps in the cleared area provide good
cover and g ood areas for basking. A large “ h erd” o f lizards grazes in the
grass-covered com m on ju st north o f the church in Piste. C. similis seems m uch
more prone to habituate open exposed areas than C. pectinata-, but it does
browse in trees as well. T h e juveniles from Piste varied in snout-vent length
from (j4 to 55 m m (av. 60.0). T h e y are bright-green dorsally and light-green
ventrally. T he b o d y is crossed transversely bj^ bands consisting o f dark-brow n
ov al spots on a white field. T he anterior edges o f these spots are clear-cut but
posteriorly fade to a lighter brow n and are hazy. T he white also fades pos­
teriorly and merges into the green betw een the bands. A b ou t six bands cross
the b od y betw een the legs; the anteriorm ost bands are wider, more distinct,
and farther apart. T he tail is banded b y abou t six dark-brow n bands separated
b y buff ban ds; the latter are a little narrower than the form er. T he stom achs
o f several juveniles exam ined are filled with insects, including fairly large
grasshoppers. M o st o f the juvenile specim ens were caught while th ey were
foraging in the brush and weeds beside the roads in the vicinity o f Piste. W hen
partially obscured b y such cover, th ey m ove and look like Laemanctus.
S celopom s lundelli gaigeae (Sm ith)
One subadult fem ale o f this tree lizard measuring 53 m m from snout to
vent was collected near Piste, Y ucatan. There is a nondescript pattern of
12
U N I V E R S I T Y OF C O L O R A D O S T U D I E S
vague streaks and bars on the back, and a p oorly developed black collar is
present. One other specim en o f this shy lizard was also seen high up on the
trunk o f a large tree in the village.
Sceloporus serrifer serrifer (C ope)
Three males and eight females, m ostly juvenile, o f this species were co l­
lected 9 km north o f M erida, Y ucatan, on the Progresso R oa d . These wary
lizards were found high on th e walls o f one o f a grou p o f roofless, abandoned
m asonry farm houses to the west o f the road. T he adults are extrem ely wary
and alert, and gave us little op p ortu n ity to shoot. W hen alarm ed they sought
shelter in the cracks o f the m asonry on the top s o f the crum bling walls or
beneath what plaster remained. T he you n g are less w ary and were relatively
easy to collect. T he startlingly brilliant yellow and black pattern o f spots and
bars on the crow n o f the heads o f the juveniles m ade them particularly easy
to recognize from considerable distances.
A s is the case in so m any species o f Sceloporus, the fem ales have a bolder
m elanistic pattern than the males, but the males are more conspicuously
ornam ented with other colors. In b oth sexes a conspicuous black collar is
present, bordered anteriorly and posteriorly w ith a w hite band either one of
which m ay be interrupted m edially. T he heads o f b oth sexes are b old ly marked
w ith light yellow and black. A conspicuous feature o f the pattern is the
crescent-shaped light mark starting at the posterior corner o f the eye and
arching up and over the tem porals tow ards the parietals. In juveniles the light
area o f the crow n is a bright yellow . T he tail is banded with white and black,
this banding being particularly conspicuous in the females. T he more p os­
teriorly located dorsal scales and especially the scales o f the tail are marked
with blue. T he black dorsal collar, w hich ends on the shoulder in fem ales,
broadens here in males, then extends across the throat as a narrow, black,
uninterrupted band. A nterior to this in males is a diffuse, pale, lavender-blue
area which in turn gives w ay peripherally to pink. T he pale-blue flank marks
o f males are very broadly bordered with black m edially, but th ey are separated
b y a narrow m edian white band. T he dorsal pattern o f the trunk region in
males is virtually nonexistent. In females, how ever, the back is clearly crossed
by about fo u r broad transverse dark bands bordered posteriorly w ith a narrow
light area. T he keels o f the darker scales are more heavily pigm ented, giving a
streaked effect.
Sceloporus cozumelae (Jones)
T hirty-six specim ens o f this distinctive small species were collected in the
v icin ity o f San M igu el on C ozum el Island. T h e series consists of six adult and
H E R PE T O ZO A FR O M TH E YU C A T A N PEN INSULA
13
seven juvenile males and nineteen adult or subadult and four juvenile females.
In life sexual dim orphism is obviou s but is less apparent in the preserved
specim ens. T he dorsal surface o f the head o f males is yellow -brow n spotted
with flecks o f dark brow n. T he largest flecks occu r on the supraoculars and the
interparietal. A n indistinct gray stripe, tw o scales wide, starts on the occip u t
and extends a short distance ou t on to the tail. On each side a white stripe
starts inconspicuously a b ove the auricular opening, crosses a bove the shoulder
where it is m ost conspicuous, and extends posteriorly past the hind legs.
Posteriorly this stripe is partially interrupted b y the paravertebral marks.
These consist o f posteriorly b ow ed crescentic brow n marks, slightly diago­
nally disposed with the m edian corner lying farther posteriorly. E ach mark is
posteriorly bordered w ith w hite which tends to merge w ith the white lateral
lines and brightens these lines at this ju n ction . A nteriorly the brow n marks
are bordered with gray. This border, abou t tw o scales long, is as long as the
brow n marks. T he lateral lines are fainter opposite the dark marks. T he dark
crescents tend to be paired, there being abou t 12 pairs from the occip u t to just
posterior to the hind legs. Here the dorsal pattern condenses to a brow n, lightcentered m edian line from which short spurs, the remnants o f the semipaired
b od y crescents, extend. A b o v e the shoulder is a sm oky, black area in the
center of which there is a conspicuous yellow spot. A yellow ish-w hite process
extends dow n from the white lateral line tow ards this spot. T h e arms and legs
are conspicuously crossbarred. T he throat and gular region is speckled and
reticulated with gray. Flank marks are very faintly indicated b y an extrem ely
pale blue area with a median ventral white area between.
T he color pattern of the females is quite similar. T he darker areas are
m uch darker and narrower, and the light areas are weaker or absent, so that
the conspicuous lateral white lines o f the males m ay be lacking entirely or
merely indicated. T he yellow spot on the shoulder is present and conspicuous.
T he m ost distinctive feature o f the females is the bright-red “ hash” mark
extending dow n the posterior face of the post-auricular fold. T he auricular
region itself and the lips are also red but not as bright as the post-auricular
streak. T h e throat and gular region o f fem ales tends to be m ore conspicuously
spotted and reticulated with dark gray than in the males.
O f the 18 adult females collected, 12 are gravid with m oderate to large
eggs. In three o f these the eggs are uterine and have shells. T he largest uterine
egg measured from a 47 m m fem ale containing tw o eggs, was 12.7 x 7.1 mm.
T he average num ber o f eggs contained in these 12 females is 1.8, the num ber
varyin g from one to fou r with tw o the m ode.
T he species is alm ost com pletely confined to the shores o f the island. These
shores consist o f deeply eroded and fissured lim estone with a scanty cover of
14
U N I V E R S I T Y OF C O L O R A D O S T U D I E S
low shrubs and herbaceous plants grow ing in patches o f coral and limestone
sand or in the rocks. Beaches are virtually lacking. T he w idth o f the shore
varies from a few feet to 30 or 40 yards. Inland on higher ground the thorn
forest abru ptly begins. S. cozumelae occu pies this relatively open area. J u ve­
niles were extrem ely abundant, b u t exceptionally wary. T h e y were particu ­
larly com m on in sandy areas betw een rocks beneath the scanty vegetation
which grows here to abou t 8 inches in h e ig h t; b u t th ey were nearly as numerous
elsewhere along the shore. O ccasionally adults were fou n d occu p yin g stone
walls if such areas were close to the shore, but several abandoned houses near
the shore yielded no Sceloporus at all. D uring the tim e we were on the island
the species was active at all hours o f the day. B u t the weather, as has been
m entioned, was rainy, overcast, or partially overcast during m ost o f our stay.
Sceloporus chrysostictus (C op e)
F our males and four fem ales were collected 9 km. north o f M erida, Y ucatan,
beside the Progresso R o a d on the 25th and 26th o f June, and 20 males and 19
fem ales on the 3rd, 4 th, and 5th o f Ju ly in the vicinity o f Piste.
Usually small sceloperine species are n ot difficult to collect; but this species,
at this tim e o f year at least, proved to be unusually wary. N um erous speci­
mens were seen north o f M erid a; but in 24 m an hours o f collecting we were
able to acquire on ly eight. T h e y were m ost frequently seen along the low
lim estone walls bordering the fields and roads in fu lly exposed unshaded areas,
but th ey would also inhabit raised outcroppings or piled-up masses o f lim e ­
stone elsewhere. A cleared area in the im m ediate v icin ity o f such rocks or
walls seems highly desirable, b u t not essential. T he escape reaction is triggered
b y the sight o f even slow ly m oving people as far as 50 feet away. T he lizards
run to rocks if they are in the open, or slip into crevasses and spend an in­
ordinately long tim e in such retreats before emerging again. W hen th ey do
emerge it is often at a different place and shielded from the observer. T he
com m on sceloperine curiosity is not w ell-developed in this species.
T he m ost conspicuous feature o f the males is a bright-yellow ish line, about
tw o scales wide, beginning at the eye, extending well over the shoulder and
down the sides, where it is brightest, then on to the base o f the tail, where it
fades away. Between these tw o stripes is a broad brow n median band about
seven scales wide at m id body. In m ost specim ens this area is indistinctly
marked with tw o lateral rows o f darker-brow n spots diagonally disposed in
pairs. These pairs nearly form posteriorly-directed chevrons and occasionally
do. In the m ost distinctly marked specim ens nine or ten pairs can be counted.
T he yellow ish lines are subtended in the shoulder and axillary regions w ith a
black band. T his fades posteriorly and ventrally, m erging into light brow n,
H E R P E T O ZO A F R O M T H E YU C A T A N PEN IN SU LA
15
then buff, and finally into the w hite o f the ventrum . Gular and flank blotches
o f contrasting colors, such as blue, are lacking. A spot occurs in the black band
a bove the shoulder, and num erous whitish spots occu r on the flanks below the
lateral yellow line. T he lower lips and head are reddish-brow n speckled with
black. A narrow vertical black bar extends from the lower palpebral scales to
the upper lips; posterior to this is a less w ell-developed diagonal line also
reaching the lips. T h e tail is m arked dorsally w ith 11 or 12 indistinct dark
brow n saddle-like blotches.
In m ost fem ales the basic m elanistic pattern is the same as in the males,
but the lateral lines are m uch paler and often nearly lacking. T he dark band
below the lateral line is virtually the same brow n color o f the dorsal band
but is crossed b y vertical darker-brow n bars. T he dorsal diagonal spots and
tail blotches are darker and m ore distinct and posteriorly are bordered with a
lighter color. T h e m ost distinctive feature o f the females is the bright-red
lips, the lower lip being redder than the upper. O ccasionally this red extends
below the ear to the shoulder. In the less d istin ctly marked specim ens reddishbronze scales and marks are frequent, especially on the rum p.
Four o f the fifteen largest adult fem ales are gravid. T he egg com plem ent is
rather low : tw o, three, three, and fou r eggs respectively. These are oviducal,
ov oid in shape, measure approxim ately 13.3 m m in length, and have nearly
com pletely form ed shell mem branes.
M abuya mabouya mabouya (L acepede)
One specim en was presented to us b y M r. E. C. W elling. H e collected it at
Chichen Itza on the 22nd of O ctober 1954. W e collected another at Piste on the
5 th o f Ju ly 1959, and an additional specim en from C ozum el Island on the
30th o f June 1959. T his latter specim en was found associated w ith Cnemidophorus cozumelus cozumelus 9 km. south o f San M igu el in open forest in the
v icin ity o f “ T h e L a g oon ” . It closely resembles the mainland form in scale
arrangem ent and color pattern. Its on ly peculiarity is the fusion o f the frontoparietals along their median suture to form a single scale.
Eum eces schwartzei (Fisher)
One adult fem ale, measuring 113 m m from snout to vent, was brought in
alive by one o f the children in Piste.
T he very broad nuchals are follow ed b y 12 pairs o f broad cervicals before
the median dorsal series com m ences. T he m edian dorsals in this specim en are
on ly fou r tim es as broad as they are long. Other points o f difference between
this specim en and the com posite description o f T a y lo r ’s (1 9 3 5 :9 5 -9 6 ) are as
follow s: T he rostral scale form s a median angle dorsoposteriorly between
1(5
U N I V E R S I T Y OF C O L O R A D O S T U D I E S
the supranasals. T he con tact betw een the supranasals is equal to their sutures
with the post-nasals. T he supranasal-frontonasal sutures are equal to the
supranasal-first loreal suture. T he frontal is obtu sely pointed anteriorly and
posteriorly. T he interparietal is slightly smaller than the frontoparietals and
is enclosed b y parietals posteriorly. T he lower labials num ber 8-0. T he chin
shields are follow ed posterolaterally b y norm al scales. There are .58 m edian
scales from the occip u t to a b ove the anus and three paired subcaudals p os­
terior to the vent. Aside from these differences, this specim en fits T a y lo r ’s
description very closely.
Arneiva undulata gaigeae (Sm ith and Laufe)
Six females and nine males o f this m agnificent lizard were collected, all
from the vicinity o f Piste except one male w hich was fou n d dead on a trail
9 km. north o f M erida. Like other races o f this species, this form prefers
shaded ground, heavily covered w ith organ ic debris and humus. M o st o f the
specimens wre collected were in dense thickets beside the roads and trails in
the vicinity o f the tow n. T h e y were rem arkably silent considering their size
and the nature o f the substrate over w hich th ey m oved and were difficult to
collect. T h ey were active m ost o f the m orning from abou t 8 :0 0 a.m . and again
were found late in the afternoon.
These specim ens closely fit the original description o f Smith and Laufe
(1949) except for the greater variation in the num ber o f paired and unpaired
median preanal scales. In on ly tw7o specim ens, b oth females, are all o f the
enlarged preanals paired. In the rest varying num bers are irregularly paired,
the few est num ber being tw o pairs. In one specim en, a fem ale, the pattern is
2 s .-lp r .-ls .-ls .
T he color pattern in life o f th e largest males is spectacular. T he dorsal
surface of the head and tail and the broad median stripe on the trunk are a
rich, warm brow n. T he dorsal surfaces of the appendages are similar but
lighter. T he arms are m arked with deep-brow n flecks and the legs with a
peculiar oscillated reticulum of the same color. Beginning at the m iddle o f
the back irregular dark-brow n spots appear, becom ing slightly larger posteri­
orly and extending ou t the tail. N ear the m iddle o f the tail these spots form
transverse bars edged with light blue, the posterior edging being lighter than
the anterior. T he bars extend dow n the sides o f the tail but do not extend on to
its ventral surface. T ow ards the tip o f the tail the banding becom es obsolete.
T he lower jaw s, gular region, throat and chest between the arms, and the
lower surface of the brachium are an intense, brilliant crim son. T he ventral
surface o f the antebrachium is lightly stained with the same color. In some
specimens, however, this red color is replaced with a bright lem on-yellow .
H E R PE T O ZO A FRO M T H E Y U C A T A N PEN INSULA
17
Further studies must be made to determ ine the basis o f this striking dim or­
phism. T he remaining portion of the chest, belly, and lower surfaces o f the
legs and tail are a clear, pale blue-green. T he light marks o f the lower lateral
dark stripe area, the light areas on the side o f the tail, and anterior and pos­
terior faces o f the hind leg are a clear greenish-blue. T he light areas form ing
vertical bars in the region o f the upper lateral dark line are m ore or less co n ­
tinuous with the light bars o f the lower lateral dark line but are a lighter blue.
T he dark vertical bars betw een these blue areas are a deep, rich brow n, with
black specks form ing a diffuse line superim posed on the broader brow n bars.
Cnemidophorus cozumelus cozumelus (G ad ow )
Inasm uch as the prim ary purpose o f the expedition was to collect Cnemidoph­
orus, more tim e was spent in habitats likely to yield specim ens o f this genus.
T he collecting o f other species was more or less incidental. A large series o f 78
specim ens of C. c. cozumelus was collected. U pon our return to the U niversity
o f C olorado it was discovered that these were all females. This sex ratio dis­
crepancy has already been reported upon (M aslin, 1962).
W e arrived at C ozum el at 2 :1 5 p.m . of the 26th o f June; shortly thereafter
it rained, b u t b y 5 :0 0 p.m . we were able to do some collecting. C onditions
were p oor that afternoon and all o f the next day. N o Cnemidophorus were
collected until the m orning o f the 28th, which was m uch sunnier, but still
partly overcast. W e also collected on the 29th and 30th. These lizards were
active virtually any tim e o f the d ay as long as it was neither raining nor too
h eavily overcast. T h e y seem to prefer a sem i-open w oodland and avoid dry,
barren, open areas. Large num bers were collected b y walking along the roads
and spotting the specim ens b y sound beneath the low herbaceous cover beside
the road on the humus o f the partly shaded thorn-forest floor. A large popula­
tion was discovered am ong weeds around an abandoned house. Here num erous
individuals were spotted foraging beneath the weeds, which were from one to
three feet tall. T he floor of the thorn forest has little vegetation during this
season but is h eavy with hum us and twigs. Individuals were frequently co l­
lected in open shaded glades on this forest floor n ot far from the shores. N o
specim ens were found deep in the forest. This h abitat is quite different from
that selected b y C. d. deppi, which prefer a m uch more open area.
T he color pattern o f the specim ens seen or collected is rem arkably uniform .
T he ventral surface o f the tail is shrim p-pink and that o f the hind legs a
lighter pink. T he throat, chest, and belly are white. A broad brow n band
extends dow n the back and continues, more grayish, ou t the tail. This band
is bordered laterally b y a series o f greenish undulating stripes separated b y
deep russet brow n stripes, the broadest o f which is the third, lying between
18
U N I V E R S I T Y OF C O L O R A D O S T U D I E S
the third and fourth light lines (counting d orso-ven trally). T he light lines are
broken and som ew hat reticulated betw een the shoulder and the ear. T he
broadest dark band and the light band beneath it extend well ou t on to the
tail, where th ey becom e fainter and finally disappear. T he juveniles, measuring
33 and 35 mm respectively from snout to vent, have essentially the same
pattern. T he pink o f the tail and hind legs is lacking, the dorsal band is gray
buff, the undulating light lines nearly white, and the intervening dark bands
a dark brow n, nearly black.
Fourteen o f the specim ens had very large, nearly m ature eggs, bu t still
w ithout shells. T w elve others had enlarged eggs, the largest o f w hich measured
approxim ately 3 m m in diam eter, and the rem ainder o f the specim ens had
im m ature ovaries. T his variation in ovarian m aturity is correlated w ith the
variation in size of the specim ens caught, and strongly suggests that several
brood s are produced in a season.
Cnemidophorus angusticeps (C ope)
A good series was collected in the v icin ity o f Piste and Chichen Itza. This
series consists o f 62 males and 60 females. M o st o f the specim ens were co l­
lected in open bare areas adjacen t to low -grow ing brush or brush piles. T he
chief requisite seems to be a nearly barren d ry flat area. T h ey were n ot fou n d
in open areas where too m uch herbaceous cover existed. B y far the largest
num ber o f specim ens wrere collected in well-cleared cornfields. T he piled brush
p rovided b y the weeding sufficed fo r cover, but the brush around the fields
and the inevitable stone walls were also used. Specim ens were also collected
along the m otor roads, in the tow n o f Piste itself, and in the cleared areas
adjacen t to brush am ong the ruins o f Chichen Itza. On warm er days in d ivid ­
uals appeared at abou t 9 :0 0 a.m . and remained active until abou t 1 :3 0 p.m .
One o f the m ost striking features o f this race is the existence o f unusually
w ell-developed chrom atic sexual dim orphism . In the field, the sexes cou ld be
easily recognized even writh fleeting glimpses. T he entire throat o f the males
is a pinkish-buff. Posterior to the gular fold the chest is a deep blue-black.
In extreme cases this color extends posteriorly over the whole belly and out
the antero-ventral surface o f the thighs. U sually, how ever, the edges o f the
scales becom e increasingly lighter posterior to the chest with a still lighter
m edian zone extending as a widening band to the hind legs. This light median
area m ay be nearly white, but more often it is a pale blue. T he light areas of
the more laterally disposed ventral scales are rich cob a lt blue. T he total effect
is of a black-chested, blue-bellied lizard. T he ventral surfaces o f the arms,
legs, and tail are cream . D orsally the males are less v iv id ly marked than the
females. T he dorsal, dorso-lateral lines are buff, with the dorsolateral line
H E R P E T O Z O A FR O M T H E Y U C A TA N PEN INSULA
19
being a little wider than the other tw o. There is also present a median dusky
light line with ill-defined edges. T he tw o dark-brow n bands on either side
between the light lines are haphazardly speckled with num erous small buff
spots; the flanks below the lateral line and a b ove the ventral plates are usually
tesselated with black and buff. T he dorsal surface of the hind legs is brown,
freely speckled with small light-buff spots. T he tail is brow n and unm arked,
fading distally to a pinkish-buff.
In contrast to the males the fem ales have a white to light-blue throat and
no black on the chest or belly, which is usually whitish but occasionally is pale
blue. T he ventral surface o f the tail is a bright dark shrim p-pink, the sides a
reddish m aroon, and the top a rich brow n. In the field the total impression is
of a red tail. T he ventral surface o f the legs is also shrim p-pink and the dorsal
surface a dark d ried -blood red. T he white stripes o f the dorsum are whiter
and the dark bands betw een darker. In m ost individuals these dark bands
com pletely lack the speckling so characteristic o f costatus, but occasionally in
large specim ens diffuse spots are present. T he dorso-lateral light stripe ex­
tends well out on to the tail and the lateral stripe ou t onto th e anterior face of
the upper leg. T he dorsal surface o f the hind legs m ay be spotted, m ottled, or
barred with pink spots. T he flank tesselation is diffuse or absent. Duellm an
and Zweifel (19(j2) have figured a sample of this series to dem onstrate the
variation which occurs.
Five adult specim ens, four males and one fem ale, were collected 9 km. N
o f M erida on the Progresso R oad. T he female and one o f the males closely
resemble the Piste series. In the remaining three males, how ever, the light
specks in the dark fields are larger and encroach on the light lines so that the
lined pattern is less distinct. In one specim en the lined pattern is nearly co m ­
pletely disrupted. This same pattern disruption is seen in some Piste specimens,
but infrequently and not so extensively.
In the entire series there are on ly tw o juvenile specim ens, a male and a
female. These measure, from snout to vent, 41.3 and 38.7 m m respectively.
T he color pattern o f the male resembles that o f adult females. T he stripes are
sharply contrasting white and b la c k ; no spots are evident, either in the dark
stripes or on the legs. T he legs, however, are m ottled posterior to the stripe
on the thigh, which is a continuation o f the lateral stripe. T he pinks and reds
o f the tail and legs are not as bright as they are in adult females. T he juvenile
fem ale, except for the greater brilliance o f the stripes, also resembles adult
females. There is, how ever, a considerable am ount o f black pigm ent on the
ventral plates, particularly in the lateral abdom inal area.
T he sexes also differ in size. T he mean sn out-vent length of the largest 20 %
of each sex (51 and 53 m easured) is 91.3 m m for the males and 79.6 m m for the
females. T he largest specim en, a male, measures 100 mm from snout to vent.
20
U N I V E R S I T Y OF C O L O R A D O S T U D I E S
L IT E R A T U R E C IT E D
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