A New Species of Cnemidophorus (Sauria: Teiidae) from the Llanos of Colombia and Venezuela

Abstract

-A new species of whiptail lizard is described from the Llanos of Colombia and Venezuela. Cnemidophorus gramivagus is a member of the lemniscatus species group. It is most similar to C. lemniscatus, but differs in color and pattern in all age classes of both sexes, and attains a much larger size than C. lemniscatus. Additionally, female C. gramivagus become reproductively mature at a larger size than C. lemniscatus. A description of both juvenile and adult color patterns is provided along with an analysis of ontogenetic color pattern change. Comparative meristic data are provided for both taxa. In the early 1970's, in the Venezuelan Llanos, J.R.D. observed and collected a large series of Cnemidophorus, which he tentatively assigned to C. lemniscatus. He noted that these specimens differed from what is known as typical C. lemniscatus in color, pattern, size, and behavior. These bright green lizards readily climbed trees and fence posts (Dixon and Staton, 1977). Such climbing behavior is rarely observed in C. lemniscatus or other Cnemidophorus species in general. At present five species of whiptails are recognized on mainland South America (Maslin and Secoy, 1986). Two of these (C. lemniscatus and C. ocellifer) are recognized as members of the lemniscatus species group (Lowe et al., 1970). All occur south of the Rio Amazonas except C. lemniscatus and the new taxon described herein. Cnemidophorus lemniscatus occurs along the Rio Amazonas (to at least Manaus) and throughout northern South America and Central America. A careful comparison was made of the Llanos population with C. lemniscatus from adjacent Venezuelan populations as well as several other localities throughout its range. Data were collected on 23 meristic characters and four morphometric characters from both the new taxon and C. lemniscatus. These characters and their acronyms are defined in Appendix 1. A numbering sys1 Present address: Arizona-Sonora Desert Museum, Route 9, Box 900, Tucson, Arizona 85743, USA. tem was developed for all observed color patterns and each recognizable pattern was coded. Females were dissected and their ovaries were examined to determine at what size they become reproductively mature. One hundred forty of the new taxon and 310 C. lemniscatus were examined. The new taxon's color patterns were distinctly different from those of C. lemniscatus in all age classes of both sexes. It attains a much larger snout-vent length (SVL; x = 92 mm vs. 67 mm) than C. lemniscatus. Additionally, it becomes reproductively mature at a much greater size. While the two forms were not observed sympatrically by us, C. lemniscatus was observed in the northern floodplain of the Llanos, 63 airline km from the type locality of the new taxon. Although it appears that the two forms may be sympatric, further collecting is needed to ascertain precisely their boundaries. After reviewing the taxonomic history and examining the available type specimens of C. lemniscatus, and observing the aforementioned differences in color, pattern, length, and size at reproductive maturity, we propose that this large whiptail lizard of the Llanos grasslands be known