A New Genus and Species of Moist Closed Canopy Forest Skinks from the Philippines

Abstract

-Parvoscincus is described as a new genus of small skinks inhabiting the litter in closed canopy forests on two islands in the centralwestem part of the Philippine Islands archipelago. The genus consists of two species, one of which, Parvoscincus sisoni sp nov., is described here from seven specimens from the Mt Madia-as region of the Visayan island of Panay. Until recently, the higher elevations of the west coast of the island of Panay, in the central, or Visayan, region of the Philippine Archipelago, have been unexplored by scientists (Gonzales and Kennedy, 1990). A joint expedition of the National Museum of the Philippines (PNM) and the Cincinnati Museum of Natural History (CMNH) visited Mt. Madia-as on the border of Antique and Aklan Provinces, Panay from 4 April 1992 through 1 May 1992. Among the specimens collected were six individuals of a cryptozoic skink that appear to be an undescribed species. A seventh specimen was collected in the same area on 29 November 1992 by Arvin C. Diesmos of the University of the Philippines at Los Banos (UPLB). This new species is closely related to Lygosoma (Sphenomorphus) palawanensis Brown and Alcala, 1961, known from only three specimens (California Academy of Sciences-Stanford University Register no. 23122-holotype, and CAS-SU 23124 and CAS 91205 paratypes) from Palawan Island in the Philippines. Together the two species appear to constitute a lineage of skinks worthy of generic rank. Parvoscincus New Genus The new genus is a member of the Sphenomorphus Group of lygosomine skinks (Greer, 1979). It may be distinguished from all other taxa in this group by the following combination of derived characters. The polarity of the character states is inferred relative to Eumeces, the generally primitive scincid genus, and to the the southeast Asian species of Mabuya, the most generally primitive lygosomines. Diagnosis.-Supranasals absent; prefrontals, when present, moderately to widely separated; * This is contribution number 11 of the National Museum of the Philippines/Cincinnati Museum of Natural History Philippine Biodiversity Inventory. supraciliaries nine; upper half of lower eyelid formed by single row of deep scales; subocular row complete; supralabials six, fourth subocular; external ear opening absent. Body scales smooth, in 26 or fewer longitudinal rows at midbody. Supradigital scales in single row; phalangeal formula of manus 2.3.4.4.3; subdigital lamellae of fourth toe <12. Left oviduct absent; brood size =1. Abdominal fat bodies absent. Size small (maximum SVL ?34 mm). Lacrimal absent; postorbital absent; supratemporal fenestra a small slit; post-temporal fenestrae obliterated by close apposition between parietal and supraoccipitals; quadratal conch absent; vomers fused; pterygoid teeth absent; palatal rami of pterygoids medially expanded with posteromedial recurved process. Skull osteology was observed only in Parvoscincus sisoni new species (PNM 2309). Radiographs showing clearly the details of the postcranial skeleton were available for both P palawanensis (CAS-SU 23122; CAS 91205) and P sisoni (CNHM 3797-98; PNM 2308). Type Species.-Parvoscincus sisoni new species (below), by present designation. Species.-P palawanensis (Brown and Alcala, 1961; Fig. 4); P sisoni new species (Figs. 1, 3). Distribution.-Philippines (Fig. 2). Altitudinal range: 100-1125 m. Habitat.-In leaf litter and beneath surface cover in moist closed-canopy forest. Reproduction.-The holotype of Parvoscincus palawanensis (CAS-SU 23122) is a gravid female with a single large ovarian follicle or oviducal egg on the right side. The new species P sisoni also has a brood size of one (below). A brood size of one is usual in skink taxa with only a single oviduct (Greer, 1977, 1989; Greer and Mys, 1987). Unfortunately, an inference as to the mode of reproduction in the genus is not posThis content downloaded from 157.55.39.254 on Mon, 05 Sep 2016 03:59:49 UTC All use subject to http://about.jstor.org/terms