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UNIVERSITY OF
ZOOLOGICAL SERIES

OF

FIELD MUSEUM OF NATURAL HISTORY

Volume 24 CHICAGO, AUGUST 30, 1941 No. 23

A NEW SUBSPECIES OF SCELOPORUS JARROVII
FROM MEXICO

BY HOBART M. SMITH1
AND

BRYCE C. BROWN

In late fall (November 15) of 1938, the senior author and his
wife collected a large series of a striking black-and-orange Sceloporus,
immediately recognized as a form different from any described
species, on the vertical, rock slopes of a road-cut on Mount
Zapaliname', near Saltillo, Coahuila. All were found near the top
of Diamond Pass, at about 7,800 feet elevation, where they were
extremely abundant and associated with S. m. disparilis and 'S. poin-
settii. At lower elevations on the same mountain they were not
seen, although apparently suitable rock cliffs are available. The
form does occur at lower elevations, however, for two were found on
eroded cliffs near Arteaga (some nine miles southeast of Saltillo),
but little above the elevation of the plains.

Prior to this date, the junior author had encountered the same
form, also at Diamond Pass, on April 30, 1937. Three adults were
then secured and were kept alive for about three months. On
December 25, 1940, the mountain was again visited. There was a
thin layer of snow on the ground near the top of the pass, covering
the peaks of the mountain. It was very cold and a strong wind was
blowing, but in spite of this a number of half-grown and juvenile
lizards were seen sunning themselves in protected places, about three
hundred feet from the snow line. No adults were seen at that time.

Sceloporus jarrovii oberon subsp. nov.

Type from Arteaga, Coahuila. No. 105823 United States
National Museum. Male. Collected November 15, 1938, by
Hobart M. and Rozella Smith.

Paratypes. — One hundred and seventy-four; one, F.M.N.H. No.
37772, from the type locality; all the remainder from Diamond

1 Walter Rathbone Bacon Scholar, Smithsonian Institution.
No. 501 253

Natural Hlntory

254 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. 24

Pass, 7,800 feet, Mount Zapaliname', near Saltillo, Coahuila
(U.S.N.M. Nos. 105606-107744; F.M.N.H. Nos. 37753-71; E. H.
Taylor-H. M. Smith Nos. 26916-39; B. C. Brown Nos. 52-54, 99-105).

Diagnosis. — Supraoculars essentially in two rows; median lateral
body scales subequal to mid-dorsal scales in size; adult males nearly
entirely black above and below, with spots of orange on sides of
head, belly and tail; light borders of nuchal collar very poorly denned
in specimens of all ages and in both sexes, almost or quite obsolete
in adult males; throat orange or pale blue, sides of belly pale blue
or orange in males, becoming orange in large specimens.

Description of type. — Interparietal three times as large as a
parietal; one frontoparietal on each side, separated medially by a
small azygous scale; frontal transversely divided, anterior section
nearly twice as large as posterior; two pref rentals, in contact
medially; three frontonasals, the median transversely divided
(abnormal); internasals irregular, separated from rostral by two
scales; a subnasal; two canthals; a very elongate loreal; preoculars
1-2; one subocular; two postoculars; two rows of lorilabials, reduced
to one below orbit; outer row of labiomentals not reaching mental;
gular scales smooth, with a single apical notch.

Temporal scales keeled, strongly mucronate; three large auricular
lobules, upper largest, rounded; scales between ear and lateral gular
pouch subequal in size to posterior temporal scales, keeled, very
strongly mucronate, denticulate; these scales in turn subequal in
size to scales between gular pouch and insertion of foreleg; latter
weakly keeled and flatter than scales about ear, but strongly mucro-
nate and denticulate; the median scales in all these areas little smaller
than corresponding mid-dorsal scales.

Dorsals very feebly keeled, not or very weakly mucronate, with
numerous lateral denticulations and notches, especially in nuchal
region; lateral body scales subequal to or somewhat larger than
dorsal scales, about three times as large as median ventral scales;
38 dorsals; 40 scales around middle of body.

All scales on foreleg except ventrals and those on anterior surface
of lower foreleg keeled; dorsals on upper foreleg larger than those on
lower foreleg, a little smaller than mid-dorsals on body; dorsal scales
on foreleg strongly mucronate, especially toward insertion of limb.

Dorsal scales of hind leg strongly keeled, strongly mucronate,
those on shank very little larger than those on thigh, subequal to
median dorsals on body; scales on ventral surface of hind leg smooth,
rounded on shank, notched on thigh; scales on posterior surface of

FZ

1941

A NEW SCELOPORUS— SMITH AND BROWN

255

thigh very strongly mucronate; median scales a little larger than
median preanal scales; femoral pores 15-16; postanals enlarged;
subcaudals perfectly smooth, except toward tip of tail; scales at
base of tail (dorsally) rather strongly mucronate, feebly denticulate,

FIG. 24. Dorsal view of male, and ventral view of female, of Sceloporus
jarrovii oberon subsp. nov. Paratypes from Mount Zapaliname; both specimens
in the private collection of Bryce C. Brown.

becoming more strongly mucronate distally; scales on sides of base
of tail very strongly mucronate.

Measurements. — Snout to vent 97.5; tail 129 (tip missing); tibia
16.5; snout to occiput 18.5; snout to posterior border of ear 22.

Color. — Adult male: head jet black above, sides in front of eyes
also black; subocular and lower half of temporal regions (including

256 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. 24

all auricular lobules) light orange; area between ear and lateral
gular pocket light blue, the tips of the scales orange. Entire dorsal
surface of body and forelegs jet black, except for a few faint light
marks (orange and blue) vaguely indicating the position of the
nuchal collar; these borders outline a collar about four scales wide.
Anterior half of dorsal surface of thigh, and anterior surface of tne
same member, black; posterior half of thigh (including posterior
surface) and dorsal surface of shank light, most of the scales tipped
with orange; base of tail bright orange on sides, this color changing
on dorsal surface to a mixture of orange and gray-blue; remainder
of dorsal surface of tail black, with narrow light (gray-blue) rings
one scale wide, spaced one to three whorls apart; distally these light
rings become less distinct and disappear completely. Throat and chin
light blue, mixed with orange, this color sharply differentiated from
the black that covers the entire ventral surfaces of the body
from the gular region to the anus; sides of belly vaguely lighter;
ventral surfaces of limbs also black, except hands and feet; subcaudal
surface light, with a bluish tinge.

Variation. — In 100 counts (50 of each sex) the dorsals vary from
34 to 41, average 37.5; in 200 counts (equally divided) the femoral
pores vary from 12 to 19, average 15.1. In 120 specimens, an
azygous scale (or pair of very small scales) separate the fronto-
parietals 104 times (86.6 per cent), the frontoparietals contact
medially 14 times, and the frontal is in contact with the interparietal
2 times. The supraoculars are regularly divided, rarely with one
or two scales in the outer row; in these cases the outer scales are as
large as the inner scales from which they have been separated.

In males the ventral coloration in adults is as in the type, except
that usually (all except some of the largest) the scales on the sides
of the belly are blue-centered. Specimens measuring about 60 mm.
snout to vent and over have the middle of the belly jet black (or
heavily suffused with black, in the smaller specimens) ; only in smaller
specimens is a black border visible about the edges of the lateral
belly patches. In dorsal coloration, even in the young, there is a
strong suffusion with black; the collar is poorly differentiated from
the dark dorsal color in all except a few which were preparing to
shed their scales.

In females also the dorsal coloration is very dark, as in the males,
and the nuchal collar likewise is nearly or quite indistinguishable,
especially in larger specimens; the chief difference between the dorsal
color of males and females is the lack in the latter of sharp differentia-

1941 A NEW SCELOPORUS— SMITH AND BROWN 257

tion of the light areas on the hind legs and tail, and the complete
absence of the orange color. The ventral surfaces are bluish-gray,
except in the largest specimen (84 mm. snout to vent), in which
they are generally suffused with black (not on throat); in a few of
the larger specimens a dark area extends across the gular region.

Comparisons. — Most characteristic of this species is its black
coloration. In males the light areas about the head, and especially
at the base of the tail and on the posterior portion of the hind
limbs, are strikingly well differentiated from the black body color.
In this subspecies only is the area of the belly between the lateral
belly patches entirely black in subadult as well as adult males;
this type of belly pattern occurs in other subspecies of jarrovii only
in occasional, extremely large specimens.

From j. jarrovii the present form is well differentiated by having
usually less than 40 dorsals (usually more in j. jarrovii) and two
rows of supraoculars (one row in j. jarrovii}. From j. immucronatus
it is also well differentiated by having the lateral scales (on neck,
posterior temporal region, sides of body) but little smaller than the
mid-dorsal scales on the same areas of the body (smaller in im-
mucronatus). From both of these forms, of course, it is well differenti-
ated in color pattern.

The closest relative of j. oberon is undoubtedly j. minor. In
scutellation the latter differs by having a higher average of dorsal
scales (40.6 as against 35.1 in j. oberon)', the dorsal scales also are
less mucronate, especially at the base of the tail, and generally less
visibly keeled, in j. minor. However, the chief difference between
these two subspecies rests upon pattern. In ;'. minor the ground
color is very light, and the nuchal collar well defined and broad; rarely
is the middle of the belly black, and never is the whole belly black.

Remarks. — Five specimens from Sierra Guadelupe, Coahuila
(U.S.N.M. Nos. 47493-5, 46700, 46702), appear to belong to this
subspecies (referred by Smith to j. minor, Kans. Univ. Sci. Bull.,
24, 1936 [1938 j, p. 637; see map, fig. 17, p. 622). They have slightly
higher dorsal counts (38, 40, 41, 41, 41) than the average, and one
adult male has the middle of the belly light. In the other two males
the middle of the belly is black. In all, the dorsal coloration is
nearly uniform black (except where the scales have shed). The
chief difference in color is the very dark blue throat color in the
three males. It is not impossible that these specimens are inter-
grades with ;'. minor, as indicated by the high dorsal counts and the
separation of the lateral belly patches in one of the adult males.

UNIVERSITY OF ILLINOIS-URBANA