X. r. sanmanmatrinensis formal description

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Posted by 59herps on February 26, 2003 at 19:02:48:

In Reply to: Re: Xenosaurus grandis and former X. rackhami taxon questio posted by paalexan on February 22, 2003 at 19:43:41:

Here is the formal description. There is a X. r. rackhami, my mistake. Here is the subspecies description excerpt.

Formal Species Description Excerpt From Two New Lizards (Genera Abronia and Xenosaurus) from the Los Tuxtlas Range of Veracruz, Mexico) by John E. Werler and Frederick A. Shannon 1961

Xenosaurus rackhami sanmartinensis, new subspecies

Holotype. Frederick A. Shannon Collection No. 10540, an adult female from the crater of Volcan San Martin, Veracruz, Mexico, eleva�tion 5,000 feet; collected by Jack Reid and John E. Werler on January 25,1954.

Paratypes. FAS No's. 10532-47, same locality and data as for the holotype.

Diagnosis. Similar to Xenosaurus r. rackhami but with longitudinal ventrals in 18-21 rows at midbody (24 in X. r. rackhami) and lamellae under fourth toe of forelimb 20-23 (24�25 in X. r. rackhami). In sanmartinensis the tubercles on dorsum of tibia are more conical and less numerous, spaces between adjacent enlarged tubercles generally as great as or greater than diameter of tubercle base. Otherwise, the differences between X. .r. sanmartinensis and other Xenosaurus are the same as between them and X. r. rackhami.

Description of holotype. Head triangular; snout, - from rostral to interorbitals, covered with slightly differentiated conical scales; rostral and mental of approximately equal length; three distinct rows of carinate interorbital scales, a few posterior ones conical; five transversely elongated medial supraoculars surrounded by smaller scales and finally by larger granules; remaining dorsal head scales mostly subconical and of diverse sizes; a row of large, nearly flat scales from orbit to back of head, marking the lateral-posterior edge of dorsal head scutes. Nostril in a single nasal; supralabials 10-10, separated from sub-oculars by a row of large scales; infralabials 9-10; scales in temporal region high and distinctly conical, separated from one another by num�erous granular scales; anterior border of tympanum with an irregular series of conical and subconical scales. A V-shaped skin fold on throat, followed by two transverse gular folds; about thirty-three rows of gular scales from anterior gular fold to postmentals; a discrete lateral dermal fold from axilla nearly to groin; venter with mostly flat, quadrangular plates arranged in 34 transverse rows from axilla to groin; 20 scales, in the widest row across belly. Body covered with enlarged round or ovoid conical scutes, separated by numerous small granular scales; enlarged scales on lateral surfaces seemingly arranged in parallel rows; middorsal scales in two parallel rows, somewhat, larger than laterals, decidedly ovoid and separated from �one another by about 10 rows of granular and small oval scales.

Variation. The sixteen paratypes show the following variation in scutellation, figures in brackets indicating averages: longitudinal ventrals, 18-21 [20.3]; gulars, 27-34 [31.9]; fourth toe lamellae, 20-23 [21.]; scale rows, axilla to groin, 32-36 [34.2]; supralabials, 9-12 [10.7]; infralabials, 9-12 [10.3]. Four individuals possess markings similar to those of the holotype, except that in two specimens the light colored dorsal body bands are interrupted middorsally. In one example most of the bands are inter�rupted down the middle of the back by a wide middorsal band of black and white spots. Another has a speckled dorsum and four possess a mottled pattern, all of them with little or no indication of transverse banding. One individual is uniformly dark with no pattern. Ventral markings may be present or nearly absent; some specimens are distinctly banded on venter, others show indistinct markings, and a few have only a trace of pigment on these surfaces. In one specimen the limbs are light colored and the dark tail bands are light-centered.

Remarks. It is not improbable that X. r. sanmartinensis, X. r. rackhami and X. grandis may ultimately prove to be subspecies of one species. On the basis of overall similarities and allopatric ranges, grandis might be regarded as a valley population with two mountain subspecies, sanmartinensis and rackhami. However, for the present we prefer to regard the San Martin population as a subspecies of rackhami, which it strongly resembles.

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Habitat. Sanmartinensis apparently is a cloud forest form, speci�mens having been collected only from within the volcano crater of San Martin. Several were taken from fractures in huge rock masses not more than one hundred feet below the crater lip, the remainder from under large rocks lying on the crater floor. Never was more than one lizard observed beneath a single rock. All were caught with little difficulty; the low temperatures at the time (55-60 degrees F.) rendered them almost immobile.

Acknowledgements. We gratefully extend our appreciation to Dr. Harold Dundee for providing certain scale data from the type speci�men of Xenosaurus rackhami in the collection of the University, of Michigan Museum of Zoology, to Ellen Shannon for the line drawings of Abronia reidi, to Donald M. Darling for the habitat photos, to Dr. Ralph D. Axtell for reading the manuscript and for making helpful criticisms, and to the following individuals for the loan of comparative material from their respective institutions: Dr. Hobart M. Smith, Uni�versity of Illinois Museum of Natural History; Dr. George Lowery, Louisiana State University Museum of Zoology; Drs. Remington Kellogg and Doris M. Cochran, United States National Museum.

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