LIBRARY OF THE UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN 590.5 FI V.39 cop. 3 NATURAL HISTORV, SURVEY ^ 9' ♦ t. ^>"' . FIELDIANA • ZOOLOGY ^ Published by CHICAGO NATURAL HISTORY MUSEUM Volume 39 October 31, 1957 No. 9 NOTES ON LIZARDS OF THE GENUS DICRODON Karl P. Schmidt* Chief Curator Emeritus, Department of Zoology At the request of Dr. Doris M. Cochran, Curator of Reptiles and Amphibians at the United States National Museum, I engaged to identify certain lizards collected by Dr. Allan R. Holmberg in the course of his ethnological investigations in Peru in 1947. His specimens came from the Chao Valley, just south of the Viru Valley, in the Department of Libertad, in which latter valley archaeological studies have been made for Chicago Natural History Museum by Dr. Donald Collier. Considerable collections of reptiles from the desert segment of Peru have accumulated in Chicago Natural History Museum. Some are from Talara, collected by my friend of many years, Dr. Axel Olsson, while he was stationed as geologist at the north Peruvian oil field, and by Colin C. Sanborn, formerly Curator, Division of Mammals, during his stay there as naval attach^ during World War II; others are from the Hacienda Chiclin, obtained through the courtesy of Senor Constante Larco Hoyle when I was entertained at the Hacienda in 1939; and still others are from southern Peru, obtained by myself in the course of the Museum's Magellanic Expedition of 1939. I had reported upon the snakes of the Peruvian coastal region (with Warren F. Walker) in 1943, and it was probably for this reason that Dr. Cochran turned to me for the identification of the Holmberg lizards. It did not occur to either of us that this might require anything more than the routine comparison with specimens already identified in the reference collection. When the five well-preserved specimens of lizards arrived, they were at once recognized as belonging to the genus Dicrodon, of the family Teidae. Dicrodon is characteristic of and confined to the coastal regions of Peru and southwestern Ecuador. There are two * Deceased September 26, 1957. Library of Congress Catalog Card Number: 57-H.89S No. 828 65 THE UBRARY OF THE NOV 2 1 IQVn NATURAL ^'"^' ^ HISTORY SURVEY >; f ^ rfitsscsr?*.. Fig. 10. Upper: Adult specimen of Dicrodon holmbergi on branch of algar- robo tree. Lower: Male, right, and female, left, of Dicrodon holmbergi. Photo- graphs by A. Guillen. 67 68 FIELDIANA: ZOOLOGY, VOLUME 39 Diagnosis. — A species of Dicrodon with small granular scales on the posterior part of the back, and with a ring of small scales com- pletely surrounding the supraoculars (fig. 11). Description of type. — Habitus of a lacertiform teid, tail 70 per cent of the total length; head large, snout not elongate; limbs well- FiG. 11. Dorsal views of heads of Dicrodon guttulatum, CNHM 41576 (left), and Dicrodon holmbergi, USNM 127823 (right), showing the distinctive difference in the circlets of scales bordering the supraoculars. developed, fingers five, toes five; fingers and toes with long com- pressed claws. Viewed from above, the rostral about three times as long as the internasal suture; a single post-internasal, slightly longer than broad; suture between prefrontals shorter than that between inter- nasals; anterior loreal half as large as the posterior, with a portion on the upper surface of the snout reaching the post-internasal; a large anterior frontal, with an enlarged scute, perhaps the first supraocular, wedged between frontal, prefrontal, superciliaries, and circumsupraoculars on each side; a ring of circumsupraoculars in a single row of enlarged scales (3 to 5) at the anterior inner border SCHMIDT: LIZARDS OF THE GENUS DICRODON 69 followed by about 5 scales in two rows adjacent to the frontals and with smaller scales in three rows adjacent to the superciliaries; superciliaries 8; supraoculars 3; the posterior frontal in contact with the occipital and two post-frontals; enlarged parietals relatively small, widely separated by the occipital, with a row of enlarged scales behind parietals and occipital, behind which are two additional transverse rows of slightly enlarged scales; enlarged upper labials 6-6 to a point beneath the middle of the eye; lower labials 5-5 to same level; sub-labials 9-9; lower eyelid with a row of 4 enlarged scales in the middle. Dorsum with small granular scales, about 106 across mid-body; ventral plates in regular series, in 8 longitudinal and 40 transverse rows; gulars on mid-line about 46; 4 rows of enlarged scales on the forearm; 6-8 rows of enlarged scales on the upper arm; 7-8 rows of enlarged scales across thigh; 4-5 across tibia; 36 lamellae beneath fourth toe; the small lateral row of scales on the posterior side of the toes angulate and projecting. Coloration. — Color pattern much faded in preservative, dull greenish-gray above; belly brownish; a light stripe along sides extending from ear-opening to groin and along base of tail; dorsum with scattered small light spots, tending to form obscure dorsolateral lines; top of head and gular region light brown. Measurements. — Total length 477 mm., tail 340 mm., arm 46 mm., leg 90 mm., snout to posterior border of ear 28 mm., greatest width of head 15 mm. Notes on paratypes. — Three specimens, USNM nos. 127822, 127824, and 127825, are from the same locality as the type. Two are adult males, and one is an adult female. A hatchling juvenile, no. 127826, received with the same lot, is a specimen of Dicrodon heterolepis. No. 127822 agrees exactly with the type in the ocular ring character. The two others have the ring narrowly interrupted anteriorly, but have the frontal separated from the supraoculars, and all have the distinctive feature of four rows of enlarged scales on the forearm. The female specimen, no. 127825, has the color pattern well preserved, with a bold black band enclosing small white spots between the lateral and the dorsolateral light stripes, with another black band below the lateral stripe. The ground color of the back is a little lighter, with numerous light spots. The female specimen measures 97 mm. from snout to vent; tail incomplete. Comparisons. — The new form is at once distinguished from Dicrodon heterolepis by its granular posterior dorsal scales. The 70 FIELDIANA: ZOOLOGY, VOLUME 39 distinction from guttulatum lies especially in the complete or nearly complete ring of scales around the supraoculars, which, if incomplete anteriorly, separates the frontal from the anterior supraocular in holmbergi, whereas this scale is in contact with the frontal in 47 out of 49 specimens from Piura, and in 18 of 19 from Manta, Ecuador. I am unable to find any characters that would make possible the maintenance of the distinction between Dicrodon lentiginosus Gar- man (from Ecuador) and Dicrodon barbouri Noble (from Piura, Peru). This distinction was dropped by Burt and Burt in their check list of South American lizards (1933). The difference between holmbergi and guttulatum in the presence of four rows of enlarged ante-brachial scales instead of two, though perhaps somewhat diffi- cult to define without both forms at hand, is quite as significant as the complete versus the incomplete ocular ring. Range. — Dicrodon holmbergi is known positively only from the Chao Valley, Department of Libertad, Peru. It may be presumed to be the common species also in the Viru Valley to the north. Whether it extends northward in the coastal valleys of Lambayeque to meet the species guttulatum in Piura is a remaining problem. It is not impossible that guttulatum and holmbergi may be allopatric forms of the same herbivorous species of lizard. The juvenile specimen of Dicrodon heterolepis received with the series of holmbergi is the only clue as to any actual overlap of habitat of the two species. In overall distribution, however, the range of heterolepis embraces that of both guttulatum and holmbergi, except that it is not yet recorded from Ecuador. Dicrodon heterolepis is known from the Department of lea, far to the south of the known range of holmbergi. Ecology. — Dr. Holmberg's interest in the use of lizards as food by the Indian population of the Viru and Chao Valleys led him to inquire in considerable detail concerning the habits of the species in question. These lizards are known locally as cananes. They have the very sharp distinction from Dicrodon heterolepis of being her- bivorous. The adults are said to be exclusively herbivorous, but it may be doubted that this applies to the juveniles. In fact, the stomach of a small specimen of guttulatum from Piura contains a large caterpillar. Perhaps the adults may take some insect food as well as algarrobo seeds and pods. Dicrodon heterolepis appears to be normally insectivorous. Reference should be made to Dr. Holmberg's paper in Fieldiana, Anthropology (in press) for his account of the habits and behavior SCHMIDT: LIZARDS OF THE GENUS DICRODON 71 of the species now named for him. The method of collecting the lizards for food is unique, and it is unusual to have so detailed an account of so remarkable a relation between a species of lizard and ancient and modern man.^ REFERENCES BOULENGER, G. A. 1885. Catalogue of the lizards in the British Museum (Natural History). 2: XIII + 497, pis. 1-24. Burt, Charles E., and Burt, May Danheim 1933. A preliminaj-y check list of the lizards of South America. Trans. Acad. Sci., St' Louis, 28 : V + 104. DuMERiL, A. M. C, and Bibron, G. 1839. Erpetologie generale ou histoire naturelle complete des reptiles. 5 [Lizards]: VIII + 854. Garman, Samuel 1892. On reptiles collected by Dr. Geo. Baur near Guayaquil, Ecuador. Bull. Essex Inst., 24: 1-8. Holmberg, Allan R. Lizard hunts on the north coast of Peru. Fieldiana, Anthropology (in press). Noble, G. Kingsley 1924. New lizards from northwestern Peru. Occ. Papers Boston Soc. Nat. Hist., 5: 107-113. Schmidt, K. P., and Walker, Warren F., Jr. 1943. Snakes of the Peruvian coastal region. Field Mus. Nat. Hist., Zool. Ser., 24: 297-324. TSCHUDI, JOHANN J. VON 1845. Reptilium conspectus .... Arch. Naturg., 11: 150-170. 1 Dr. Holmberg's mention of "iguanas" in the literature cited by him must be presumed to apply to the large teid lizard Tejovaranus flavipunctatus. The true iguana is not known from coastal Peru, but in popular language "iguana" is used in the sense of "large lizard." fe <