PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON 113(4):871-886. 2000. A new species of Mabuya (Sauria: Scincidae) from the British Virgin Islands Gregory C. Mayer and James Lazell (GCM) Department of Biological Sciences, University of Wisconsin-Parkside, Kenosha, WI 53141, U.S.A.; (XL) The Conservation Agency, 6 Swinburne Street, Jamestown, RI 02835, U.S.A. Abstract. — Mabuya macleani, new species, is a pallid, drab, almost pattern-less skink which is abundant on Carrot Rock, British Virgin Islands. Mabuya sloanii shows character divergence in pattern from the new species concordant with geographic approach to within 400 m. On Puerto Rico, M. sloanii has a broad middorsal bronzy area on the anterior dorsum. On most of the smaller islands of the Puerto Rico Bank, as well as the Mona and Desecheo Banks to the west, this middorsal area is much narrowed by the presence of well-de-veloped dark dorsolateral stripes stretching from the head to behind the fore-limbs. These two pattern types, which apparently intergrade in the vicinity of northeastemmost Puerto Rico, are recognized as M. s. nitida Garman and M. s. sloanii Daudin, respectively. The specific name "mabouya" Lacepede, for-merly applied to Antillean skinks, is shown to be unavailable. The presence of M. macleani and another endemic lizard (Anolis emestwilliamsi) on such a small (1.3 ha), poorly isolated, and young (<3000 y) island as Carrot Rock may be a striking case of rapid divergence of insular populations. "The coloration is highly interesting . . . several insular forms may be distinguishable when adequate series become available." Karl P. Schmidt (1928) The scincid lizards of the genus Mabuya are nearly tropicopolitan in distribution. We have collected or examined them in num-bers from the Antilles, South America, tropical Asia, and Africa. Throughout this vast range, most species are brown with near-black stripes extending the length of the body. A striking exception is on Carrot Rock, a very small (1.3 ha), steep-sided is-land off the southeast end of Peter Island in the British Virgin Islands (Fig. 1). On 13 July 1985, while one of us (GCM) climbed the biggest tree on the island in search of anoles, the other (JL) toiled in the dust in the little gully on the windward side of Carrot Rock in which the tree grew, looking for Sphaerodactylus geckos. A far larger, drab, pale lizard was turned out, and ran up his sleeve. Although this initial spec-imen was distinctive, we at first referred to it as Mabuya mabouya sloanii (Mayer & Lazell 1988), the common skink of the Vir-gin Islands (MacLean 1982, Lazell 1983), pending collection of further specimens. Over the next several years JL returned to Carrot Rock occasionally, and found an area where these peculiar pallid lizards were abundant, and succeeded in capturing five more individuals (of dozens seen). These specimens, as well as comparison with Mabuya from throughout the islands of the Puerto Rican Bank, have abundantly confirmed the distinctiveness of this popu-lation, and also brought into sharp focus a most intriguing evolutionary phenomenon. We here describe this distinctive Mabuya as: Mabuya macleani, new species Mabuya mabouya sloanii. — Mayer & La-zell, 1988:23 (in part).