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UNIVERSITY OF

ZOOLOGICAL SERIES

OF
FIELD MUSEUM OF NATURAL HISTORY

Volume 24 CHICAGO, OCTOBER 20, 1943 No. 30

THE WHITE SANDS EARLESS LIZARD

BY HOB ART M. SMITH

DEPARTMENT OF ZOOLOGY, UNIVERSITY OP ROCHESTER

Holbrookia maculata flavilenta Cope is a name that, for the past
twenty years or so, has generally been associated with the peculiar,
bleached population of earless lizards that inhabit the unique White
Sands of southern New Mexico. This association has been incorrect,
as the following discussion will demonstrate.

The White Sands Holbrookia has not been long known. In fact,
as far as I am aware, the first mention of it was made by Ruthven,
in 1907, who applied Cope's name of flavilenta and described in
some detail the specimens he collected on the dunes. It is true that
the history of the name flavilenta goes back much farther, and that
many from elsewhere in New Mexico had been collected before 1907,
but in spite of these facts Ruthven's specimens seem to have been
the first known from the famous area about the dunes. No others
were reported in the literature until 1942, with Bugbee's brief notes
on the fauna of the area. This extraordinary paucity of published
accounts does not necessarily imply a rarity of specimens — they
are common enough on the dunes — or a general lack of knowledge
of the existence of specimens. I have no doubt that after 1907
many more specimens found their way into various collections than
published accounts would indicate. In fact, in 1931 I collected a
series, the present location of which I unfortunately do not know,
and a few collections I have examined contain others.

The responses of organisms to the extraordinary environment
afforded by the White Sands have received the attention of many
naturalists. In spite of the unique nature of the environment,
however, relatively few endemic forms are known from there.
Only two of the twenty mammals known are considered distinct
(Perognathus apache gypsi Dice and Geomys arenarius brevirostris
Hall). Among the reptiles only one, the earless lizard, has been

No. 536 339

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

considered distinct. The evolutionary problems are discussed by
Benson (1933).

Three species of lizards, exclusive of Holbrookia maculata, occur
commonly on the dunes: Uta stansburiana stejnegeri, Sceloporus
undulatus consobrinus, and Cnemidophorus perplexus. Specimens
of any of these species from the dunes are lighter than those from
the surrounding plains, yet the differences are perhaps not so marked
as in the case of Holbrookia. Circumstances indicate that perhaps
the lighter colors of the other lizards are directly affected not so
much by genetic as by environmental factors. The dunes form of
Holbrookia, however, appears to owe its lighter color to genetic
changes, rather than to direct environmental effect, as Atsatt
(1939) suggests. That this is the case is indicated by failure of the pat-
tern and color to change under laboratory conditions; Dr. L. C.
Stuart has informed me that specimens kept more than a year and
observed under various environmental conditions did not change
appreciably. I examined his experimental animals after they had
been preserved, and certainly they were not different in appearance
from specimens preserved when collected.

The distinctive features of the White Sands specimens are (1)
great reduction in size and prominence of the dorsal blotches, and
(2) absence of the brown pigment. The gray pigment is present or
absent; when absent the lizard is uniform cream yellow above, and
even under the microscope no pigment granules can be discerned.
In its greatest concentration, in the darkest specimen examined
(Field Museum No. 28571), the gray pigment is rather extensively
distributed over the dorsal surfaces, but is absent in small scattered
particularly prominent areas on the sides of the body; the mid-dorsal
area may be more or less uniform light gray; on either side of the
mid-dorsum are some ten small, faint, poorly defined, more or less
crescentic blotches.

Normal specimens of the presumed parent race (m. approximans)
possess fairly well-defined dorsal blotches, and are provided with
brown as well as black (gray) pigment. In almost all races of
maculata the dorsal blotches may be absent or reduced in a small
percentage of specimens; but in none is this the usual condition,
and in none, so far as I am aware, is the brown pigment absent even
as an anomaly. From these statements it might be assumed that
the White Sands specimens could be positively identified in all
cases. I am not certain this is true, for probably intergradation in

3 °

1943 WHITE SANDS EARLESS LIZARD — SMITH 341

these characters occurs in the territory surrounding the dunes,
where m. approximans occurs.

That the marked color change in the White Sands Holbrookia is
an adaptation to the specific conditions of that small area is a reason-
able assumption. All facts bear out that assumption. As a corollary
it may be assumed that the same genetic form is not to be expected
elsewhere. Yet the type locality of flavilenta, the name usually
applied to the White Sands race, is Lake Valley, Sierra County,
about 175 miles west of the dunes. Cope (1883, p. 10) describes
the locality: "It is in the foot-hills of the Mimbres or Negretta
range. The region is rather arid, springs not being numerous; but
during July and August there are frequent rains. Vegetation is
abundant in the form of grass and herbaceous plants and shrubs."
This is not a habitat like that of the White Sands. It is much
more reasonable to assume that flavilenta is based merely upon
the spotless variant that occurs normally, but infrequently, in
approximans at any part of its range. As described, the cotypes
cannot be distinguished from approximans; I have not examined
them and do not know whether they are now extant.

Most of the references to flavilenta that have been included
under that name are actually referable to

Holbrookia maculata approximans Baird

Holbrookia propinqua Cope, Proc. Acad. Nat. Sci. Phila., 1866, p. 303 —
Navajo Springs; Fort Wingate; San Francisco Mountains; Colorado
Chiquito River; Zuni City.

Holbrookia maculata propinqua Coues, Wheeler's Surv. W. 100th Mer., 5,
p. 601, 1875 — New Mexico, Arizona.

Holbrookia maculata flavilenta Cope, Proc. Acad. Nat. Sci. Phila., 1883,
pp. 10-11 — orig. description; type locality Lake Valley, New Mexico;
Stejneger, N. Amer. Fauna, 3, pp. 109-110, 1890— western New
Mexico; Arizona, except extreme southern portion; Moencopie and Little
Colorado River, Painted Desert, Arizona; Cope, Ann. Rept. U. S. Nat.
Mus., 1898, p. 298, fig. 34, 1900 — copy of original description; Stone,
Proc. Acad. Nat. Sci. Phila., 1911, p. 225 — greasewood belt east of Alamo-
gordo, New Mexico.

Authors who have seen or dealt specifically with specimens of
maculata from the White Sands have considered them distinct from
those of adjacent areas. Van Denburgh, I believe, had not seen
specimens. This synonymy has been placed under the new sub-
species here described.

Since Ruthven was the first to discover the White Sands race
and to realize its distinctness, and has given more pertinent notes

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

on it than any other authority, it is appropriate that the race from
that locality be known as

Holbrookia macula ta ruthveni subsp. nov.

Holbrookia maculata flavilenta Ruthven, Bull. Amer. Mus. Nat. Hist., 23,
pp. 523-525, 1907 — color, habitat, food; Schmidt, Bull. Amer. Mus.
Nat. Hist., 46, pp. 720-721, 1922— taxonomic notes; Atsatt, Publ. Biol.
Sci. Univ. Calif. Los Angeles, 1, p. 253, 1939 — comment upon color;
subspecific name misspelled flavienta.

Holbrookia maculata approximans Van Denburgh, Proc. Calif. Acad. Sci.,
(4), 13, pp. 202-203, 1924 — all New Mexico records for maculata, sub-
species referred to approximans.

Holbrookia maculata subsp. Bugbee, Trans. Kans. Acad. Sci., 45, pp. 316,
317, 1942 — brief notes on habits.

Type from White Sands, about twelve miles southwest of Alamo-
gordo, New Mexico. No. 29452 Field Museum of Natural History.
Female. Collected May 26, 1938, by Wilfred H. Osgood.

Paratypes.—Ten, including F.M.N.H. Nos. 28571, 29450-29451,
same collector and date; U.M.M.Z. No. 64690, collected by S. C.
Whitlock, July 10, 1927; A.M.N.H. Nos. 334-339, collected by
Alexander Ruthven, A. F. Zimmer, and G. von Krockow, July 9 and
19, 1906; and A.M.N.H. No. 61764, collected by J. E. Hill,
October, 1938.

Description of type. — Two rows of scales between occipital
and the one or two rows of granules surrounding the supraocular
area, except at one point, where two adjacent scales are fused;
frontal scales irregular, a pair of median scales bordered anteriorly
and posteriorly by an azygous scale; internasals in about three rows;
four scales bordering rostral behind, between anterior supralabials;
two large canthals; no subnasal; four loreal rows, one scale in upper
row, two rows between anterior canthal and supralabials; enlarged
supralabials in contact with subocular posteriorly; supralabials low,
elongate, overlapping about half their length. Dorsal scales small,
smooth, convex; lateral scales smaller, somewhat protruding;
ventral scales smooth, flat; scales on dorsal surfaces of limbs smooth;
only distal caudal scales keeled. Femoral pores 10-10.

Snout to vent, 49.5 mm.; tail 41 mm.

The dorsal color, which seems to be well preserved, is a light,
grayish cream, more yellowish on the sides. Extremely faint light
spots, covering some eight to ten granules, are barely visible in the
dorsolateral region; the mid-dorsal area of body, tail, and dorsal
surfaces of limbs are perfectly uniform. Under the microscope no

1943 WHITE SANDS EARLESS LIZARD— SMITH 343

pigment granules are discernible except on the sides of the belly,
where on each side two small, black spots are formed by a concentra-
tion of dark pigment granules; a point halfway between axilla and
groin is between the two dark spots; the anterior spot is slightly
posterior to the elbow.

Variation. — The darkest paratype examined (No. 28571) was
described briefly above. The lateroventral spots are large and dis-
tinct. This is a relatively large male with a broken tail, measuring
53 mm. snout to vent. The other paratypes have varying amounts of
pigment between these two extremes.

Ruthven describes the color in life of his specimens as follows:

"In one specimen the color of the dorsal surface is uniformly
grayish white, except for faint traces of dusky on the hind limbs,
sides of head, and base of tail, and numerous faint spots of orange
yellow that at a distance give a slightly pinkish appearance to the
body. The head is light golden yellow above. There is a faint
pinkish line extending from the outer canthus along the sides of the
body and base of the tail, and another from the angle of the mouth
to the groin, which is continued along the inner and outer sides of the
thigh and base of tail. Belly creamy white, immaculate.

"Two other specimens are almost identical in color with the
last, except that the dusky markings on the back are slightly increased
in amount, making the orange spots somewhat more distinct. In
[one] the upper surface of the head is also marked with darker.

"Three others, while also very pallid, are a little darker than those
described above. In the darkest individual the ground color is light
gray, with numerous small dark spots interspersed with orange-
colored ones; the dark spots distinct or obscure but without definite
arrangement. The amount of dark pigment is greatest on the upper
surface of the limbs and tail. The color of the head is light golden
yellow, that of the under surfaces the same as in the other two speci-
mens. The pinkish lateral line is not discernible."

REFERENCES

ATSATT, S. R.

1939. Color Changes as Controlled by Temperature and Light in the Lizards
of the Desert Regions of Southern California. Publ. Univ. Calif. Los Angeles,
Biol. Sci., 1, pp. 237-276, pis. 8-12, text figs. 1-9.

BENSON, S. B.

1933. Concealing Coloration among Some Desert Rodents of the Southwestern
United States. Univ. Calif. Publ. Zool., 40, pp. 1-70, pis. 1-2, text figs. 1-8.

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

BUGBEE, R. E.

1942. Notes on Animal Occurrence and Activity in the White Sands National
Monument, New Mexico. Trans. Kans. Acad. Sci., 45, pp. 315-321, 3 figs.

COPE, E. D.

1883. Notes on the Geographical Distribution of Batrachia and Reptilia in
Western North America. Proc. Acad. Nat. Sci. Phila., pp. 10-35.

RUTH YEN, A. G.

1907. A Collection of Reptiles and Amphibians from Southern New Mexico
and Arizona. Bull. Amer. Mus. Nat. Hist., 23, pp. 483-603, figs. 1-22.

SCHMIDT, K. P.

1922. A Review of the North American Genus of Lizards Holbrookia. Bull.
Amer. Mus. Nat. Hist., 46, pp. 709-725, figs. 1-5, pis. 58-60.

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