Additions to Philippine Slender Skinks of the Brachymeles bonitae Complex (Reptilia: Squamata: Scincidae) III: a new species from Tablas Island

Abstract

Studies of the diversity of Philippine amphibians and reptiles have resulted in the continued description of cryptic species. Species formerly thought to range across multiple recognized faunal regions are now considered to be assemblages of multiple unique species, each restricted to a single faunal region. This pattern continues to hold true when considering Philippine skinks of the genus Brachymeles. Recent studies have resulted in the description of numerous unique species with many exhibiting various degrees of digit loss or limb reduction, as well as suggesting that unique lineages are still present in the B. bonitae Complex. In this paper, we describe a new species of fossorial skink within this species complex from Tablas Island based on collections made nearly 50 years ago. Although no genetic data are available for the new species, examinations of morphological data (qualitative traits, meristic counts, and mensural measurements) support its distinction from all other members of the genus. Brachymeles dalawangdaliri sp. nov. is differentiated from other members of the genus based on a suite of unique phenotypic characteristics, including a small body size (SVL 66.0-80.9 mm), bidactyl fore-limbs, digitless, unidactyl, or bidactyl hind limbs, a high number of presacral vertebrae (49), the absence of auricular openings, and distinct dorsal head scale patterns. The description of the new species increases the diversity of endemic vertebrates recognized to occur in the Romblon Island Group in the central Philippines.

Are there general laws for digit evolution in squamates? The loss and re‐evolution of digits in a clade of fossorial lizards (Brachymeles, Scincinae)

“…We sampled 39 individuals, representing all but two of the 41 species of Brachymeles currently recognized for our ingroup (Figure ; supporting information Table S1; Davis et al, ; Siler et al, ). Our outgroup sampling included 30 individuals, representing 30 outgroup species sampled across squamata, which include 22 species in the family Scincidae.…”

“…There are several clades of lizards that comprise a broad diversity of limb morphologies that range from limbless, to limbed but non‐pentadactyl, to pentadactyl. Among them, the genera Brachymeles and Lerista possess the greatest diversity of digit and limb states (and have 41 and 95 species recognized, respectively; Couper et al, ; Davis et al, ; Skinner, ; Skinner et al, ; Skinner & Lee, ; Siler et al, ). For example, among the 41 Brachymeles species so far described, the genus encompasses at least 18 limbed but non‐pentadactyl species (representing a spectrum of different digit state combinations on the forelimb and hind limbs), and five externally limbless species (Couper et al, ; Davis et al, ; Siler et al, ).…”

“…Among them, the genera Brachymeles and Lerista possess the greatest diversity of digit and limb states (and have 41 and 95 species recognized, respectively; Couper et al, ; Davis et al, ; Skinner, ; Skinner et al, ; Skinner & Lee, ; Siler et al, ). For example, among the 41 Brachymeles species so far described, the genus encompasses at least 18 limbed but non‐pentadactyl species (representing a spectrum of different digit state combinations on the forelimb and hind limbs), and five externally limbless species (Couper et al, ; Davis et al, ; Siler et al, ). Brachymeles is found almost exclusively in the Philippines, with the exception of two limbless species known from Borneo and Thailand (Davis et al, ; Heyer, ; Hikida, ; Siler et al, ).…”

“…For example, among the 41 Brachymeles species so far described, the genus encompasses at least 18 limbed but non‐pentadactyl species (representing a spectrum of different digit state combinations on the forelimb and hind limbs), and five externally limbless species (Couper et al, ; Davis et al, ; Siler et al, ). Brachymeles is found almost exclusively in the Philippines, with the exception of two limbless species known from Borneo and Thailand (Davis et al, ; Heyer, ; Hikida, ; Siler et al, ).…”

A new species of Pseudogekko (Squamata: Gekkonidae) from the Romblon Island Group, Central Philippines

“…In fact, the northwest peninsula of Panay Island (Buruanga Peninsula: now part of the central Philippine islands), Carabao Island, southwest Mindoro Island and the Romblon Island Group are now believed to have been part of the North Palawan geologic terrane, which paleomigrated with the Palawan microcontinental block following its separation from Asia (Zamoros & Matsuoka 2004;Zamoros et al 2008). Regardless of historical or recent connectivity, few would argue against the isolated nature of the Romblon Island Group, particularly considering this island group harbors numerous other endemic species of amphibians and reptiles (e.g., Platymantis lawtoni Brown & Alcala, P. levigatus Brown & Alcala, Gekko romblon Brown & Alcala, G. coi Brown, Siler, Oliveros, Diesmos & Alcala, Brachymeles dalawangdaliri Davis, Geheber, Watters, Penrod, Feller, Ashford, Kouri, Nguyen, Shauberger, Sheatsley, Winfrey, Wong, Sanguila, Brown & Siler;Brown et al 2011;Siler et al 2012;Davis et al 2016). The presence of additional species of endemic vertebrates in the Romblon Island Group underscores the importance of this small island assemblage as a center of biological endemism (Goodman et al 1995;Rickart et al 2005;Esselstyn & Goodman 2010).…”