Herpetological Monographs, 24, 2010, 1–54 E 2010 by The Herpetologists’ League, Inc. PHYLOGENY-BASED SPECIES DELIMITATION IN PHILIPPINE SLENDER SKINKS (REPTILIA: SQUAMATA: SCINCIDAE: BRACHYMELES): TAXONOMIC REVISION OF PENTADACTYL SPECIES GROUPS AND DESCRIPTION OF THREE NEW SPECIES 1 CAMERON D. SILER AND RAFE M. BROWN Biodiversity Institute and Department of Ecology and Evolutionary Biology, University of Kansas, 1345 Jayhawk Boulevard, Lawrence, KS 66045-7593, USA ABSTRACT: We use data from external morphology and mitochondrial gene sequences to provide the basis for a taxonomic revision of two polytypic, pentadactyl Philippine species of scincid lizards of the genus Brachymeles. Although previous studies have noted significant morphological variation among island populations, the similarities in body size and scale pigmentation and pattern have led to the continued recognition of these two ‘‘widespread species.’’ A third, widespread, pentadactyl species, Brachymeles talinis, is known from Jolo Island and the central and northern Philippine islands. We evaluate both morphological and genetic data to define species limits in B. boulengeri, B. schadenbergi, and B. talinis. Our molecular and morphological data indicate each of the four subspecies of B. boulengeri, and both subspecies of B. schadenbergi, are genetically distinct, with ranges biogeographically circumscribed, differ from their congeners by numerous external morphological features, and therefore should be recognized as full species. Our morphological and genetic data necessitate the recognition of northern populations of B. talinis (from Luzon Island) as a new species and also reveal an unanticipated new species from Masbate Island. Finally, morphological data require the recognition of the B. talinis population from Jolo Island as a unique, new species. These 10 taxa elevate the total known number of species of Brachymeles from 18 to 25. BUOD: Gamit ang datos mula sa panglabas na kaanyuan at mga gene sequence mula sa mitochondria nagsagawa kami ng rebisyon ng tatlong species ng reptilyanong nabibilang sa genus na Brachymeles. Sa kabila ng malaking pagkakaiba sa kaanyuan ng mga populasyon sa iba’t ibang isla, dalawang kalat na species— Brachymeles boulengeri at Brachymeles schadenbergi—ang patuloy na kinikilala dahil sa magkakatulad na laki ng katawan at pagkakahawig ng kulay at disenyo ng kanilang kaliskis. Ang ikatlong species, ang Brachymeles talinis, ay matatagpuan sa isla ng Jolo at sa gitna at hilagang bahagi ng Pilipinas. Ipinapakita ng aming datos na ang bawat isa sa apat na subspecies ng B. boulengeri at ang dalawang subspecies ng B. schadenbergi ay may natatanging kalamnang genetiko, may bukod-bukod na distribusyon, at naiiba sa ibang miyembro ng genus sa maraming aspekto ng panlabas na kaanyuan at samakatwid ay nararapat na kilalanin bilang ganap na species. Binibigyang katwiran ng aming datos genetiko ang pagkilala sa populasyon ng B. talinis mula sa Luzon bilang bagong species at ang pagtuklas ng isang di-anaasahang bagong species mula sa isla ng Masbate. Sa huli, kinakailangan ding makilala ang populasyon ng B. talinis mula sa isla ng Jolo bilang isang bago at ganap na species dahil sa kanilang namumukod na kaanyuan. Sa pamamagitan ng rebisyong ito, tumataas ang bilang ng species na nabibilang sa genus na Brachymeles mula sa Pilipinas sa 25. Key words: Biodiversity; Brachymeles boulengeri; Brachymeles schadenbergi; Brachymeles talinis; Endemism; Faunal region; Limb reduction; Philippines; Taxonomy THERE ARE ONLY four genera of scincid lengeri, B. gracilis, B. makusog, B. schaden- lizards possessing both fully limbed and bergi, and B. talinis); eight are nonpentadac- limbless species (Brachymeles, Chalcides, tyl, with reduced limbs and numbers of Lerista, and Scelotes; Brandley et al., 2008; digits (B. bonitae, B. cebuensis, B. elerae, B. Lande, 1978; Wiens and Slingluff, 2001). muntingkamay, B. pathfinderi, B. samarensis, Within the genus Brachymeles, all but one of B. tridactylus, and B. wrighti); and four are the 18 recognized species are endemic to the entirely limbless (B. apus, B. minimus, B. Philippines. The exception is B. apus from lukbani, and B. vermis). Within the nonpen- northern Borneo (Brown and Alcala, 1980; tadactyl species (Brown, 1956; Brown and Hikida, 1982; Siler et al., 2009, 2010a,b). Six Rabor, 1967; Dume´ril and Bibron, 1839; species are pentadactyl (B. bicolor, B. bou- Taylor, 1917, 1918, 1925) exist a wide range of limb- and digit-reduced states, from minute 1 CORRESPONDENCE: email, [email protected] limbs that lack full digits (B. bonitae, B. 1 2 HERPETOLOGICAL MONOGRAPHS [No. 24 cebuensis, B. muntingkamay, B. samarensis, and B. tridactylus) to moderately developed limbs with four to five digits on the hands and feet (B. elerae, B. pathfinderi,andB. wrighti: Brown and Alcala, 1980; Hikida, 1982; Siler et al., 2009, 2010b). All species are semifossorial and typically found in dry, rotting material inside decaying logs or in loose soil and leaf litter. Shared body plans and similar external morphological features among populations of Brachymeles has proven problematic for diagnosing species (Brown and Alcala, 1980; Siler et al., 2009, 2010a,b). In addition, several rare, mid- to high-elevation species have long been represented by only a few specimens, in some cases without knowledge of their exact type locality (e.g., B. bicolor, B. elerae, B. wrighti, and B. pathfinderi). Three species are polytypic: B. boulengeri contains four subspe- cies and B. gracilis and B. schadenbergi each contain two subspecies (Brown, 1956; Brown and Rabor, 1967; Brown and Alcala, 1980). Several other species are recognized as having widespread distributions that span historical faunal demarcations in the Philippines (Brown FIG. 1.—Map of the Philippine islands, with island and Diesmos, 2002; Brown and Guttman, labels provided for islands with representative samples 2002; Heaney, 1985, 1986), including B. used for this study. The five recognized major Pleistocene aggregate island complexes (PAICs), major island groups, talinis, B. samarensis,andB. bonitae (Brown, and additional deep-water islands are labeled for refer- 1956; Brown and Alcala, 1980; Brown and ence. Islands of the Romblon Island group are designated Rabor, 1967). by the first letter of the island name (T, Tablas Island; R, Romblon Island; and S, Sibuyan Island). Current islands in the Philippines are shown in medium gray; light gray TAXONOMIC HISTORY areas enclosed in black 120-m bathymetric contours The genus Brachymeles was first described indicate the hypothesized maximum extent of land during the mid- to late Pleistocene. by Dume´ril and Bibron (1839) for the small, limb-reduced species B. bonitae. Three addi- tional species (Senira bicolor, Gray, 1845; gros islands as representatives of the species Eumeces (Riopa) gracilis, Fischer, 1885; and (Fig. 1). Thirty years later, Brown (1956) E.(R.) schadenbergi, Fischer, 1885) were described B. gracilis taylori and included transferred to the genus by Boettger (1886) B. boulengeri as one of three subspecies of and Boulenger (1887). These four species the polytypic species B. gracilis. Brown and represented the known diversity in the genus Rabor’s (1967) description of B. gracilis for 30 yr, until Taylor published a series of boholensis and B. g. mindorensis brought the herpetofaunal descriptions in the early 1900s. number of subspecies within B. gracilis to In Taylor’s (1917) review of the genus, he five. It was not until 1980 that Brown and revised B. gracilis to not only include popu- Alcala (1980) resurrected the polytypic spe- lations in the Mindanao Faunal Region but cies B. boulengeri and included four subspe- also populations on Negros and Mindoro cies (B. b. boulengeri, B. b. boholensis, B. b. islands (Fig. 1). A few years later, Taylor mindorensis, and B. b. taylori), all believed to (1922b) described B. boulengeri, based on be distinct from B. gracilis. This view material from Polillo Island, and included characterized the taxonomy of B. boulengeri populations from Luzon, Mindoro, and Ne- for the next 30 yr. Numerous studies have 2010] HERPETOLOGICAL MONOGRAPHS 3 mentioned the morphological variation among talinis have been available, the recognition of island populations of B. boulengeri and other this widespread species has continued for species (Brown, 1956; Brown and Alcala, .40 yr (Brown and Alcala, 1980; Siler et al., 1980; Brown and Rabor, 1967; Taylor, 2009, 2010a,b). 1922b), but all refrained from elevating these Following the separation of B. talinis from subspecies to full species. Brachymeles bou- the B. schadenbergi complex, Brown and lengeri boulengeri and B. b. taylori have larger Rabor (1967) recognized two subspecies of geographic distributions across multiple is- B. schadenbergi: one subspecies from western lands within a single faunal region (Brown and south central Mindanao Island and and Alcala, 1980; Brown and Rabor, 1967; Basilan Island (B. s. schadenbergi), and the Taylor, 1922b), whereas B. b. boholensis and other subspecies from eastern Mindanao, B. b. mindorensis are single-island endemics Camiguin Sur, Bohol, and Leyte islands (B. (Brown, 1956; Brown and Alcala, 1980; Brown s. orientalis). Fischer (1885) had previously and Rabor, 1967). designated the type locality for B. schaden- Although B. talinis was described originally bergi as southern Mindanao Island, and as B. schadenbergi talinis (Brown, 1956), and specimens from south central Mindanao considered part of the widespread B. scha- Island