Brachymeles wrighti is one of only two species in the genus Brachymeles to possess four fingers and four toes. The other known four-digit species is B. elerae, a considerably smaller species. It is a larger species with a very restricted known distribution in northern Luzon Island, Philippines. This species is known from only a few records worldwide. The genus Brachymeles represents a unique group of semi-burrowing (semi-fossorial) lizards in that the group possesses species with a full spectrum of body forms, from limbed species with five fingers and five toes, to fully limbless species. Researchers are interested in the process and patterns behind the evolution of these drastic changes in body form. With the exception of two species from Borneo (B. apus) and Thailand (B. miriamae), all species of Brachymeles are endemic to the Philippines. This means they are found among the more than 7,000 Philippine islands and nowhere else in the world.
We have evaluated this species against the IUCN criteria for classification, and find that it qualifies for the status of Vulnerable, VU, based on the following criteria: VU B2ab(iii); D2 (IUCN, 2010).
Brachymeles wrighti can be distinguished from congeners by the following combination of characters: (1) body size moderately robust, long; (2) limbs tetradactyl; (3) limb length moderate; (4) supralabials six or seven; (5) infralabials seven; (6) midbody scale rows 28; (7) axilla–groin scale rows 85; (8) paravertebral scale rows 106 to 112; (9) pineal eye spot present; (10) supranasals separated; (11) prefrontals contact or separated; (12) frontoparietals contact; (13) single preocular; (14) postnasals absent; (15) enlarged chin shields in two pairs; (16) nuchal scales differentiated; (17) fourth and fifth supralabial subocular; (18) auricular opening completely covered by undifferentiated scales; (19) Toe-IV lamellae 4 or 5; and (20) scale spots covering body present.
Coloration in life remains unrecorded; however, because Brachymeles specimens do not change significantly during preservation (CDS, personal observation). Coloration in preservative: The ground color of the body is medium brown, with each dorsal scale having a dark, chocolate-brown blotch covering the center one-third of the scale. Each blotch does not correspond to the scale boundary, but extends to the anterior edge of the next most posterior scale. The blotches are present around the entire body, and gradually reduce in size laterally. Ventral scales have smaller blotches restricted to the posterior third of each scale. Caudal and subcaudal blotches are less well defined, giving the appearance of a homogeneous, medium brown tail color. Dark brown blotches on the body range from irregular spots of dark colors (ventrally) to irregular streaks and spots (dorsally), and give the appearance of longitudinal rows of spots that run down the body. Dorsally, these longitudinal rows appear more continuous, with the dark brown streaks and spots creating discontinuous dorsal stripes. Limb scales are mottled light and medium brown and do not possess the spotted pattern observed on the body. Precloacal scales each have a large, dark brown blotch covering most of the scale. Head scales lack spotting, and are nearly homogeneous medium brown. The rostral, nasals, supranasals, first supralabials, first infralabials, and mental scales have a light brown to cream coloration; lighter in color than the body.
Brachymeles wrighti is known only from the Municipality of La Trinidad in the southern portion of the Cordillera Mountain Range, northern Luzon Island, Philippines.
Similar to B. elerae, B. wrighti is among the few species of Brachymeles known to occur at higher elevations. Recent surveys in the northern Cordilleras resulted in the rediscovery of B. elerae, with two specimens found within rotting logs in dry secondary growth forest (Siler, 2010). It is presumed that B. wrighti prefers similar habitat. The only other squamate species observed to be sympatric with Brachymeles wrighti is Calamaria gervaisi, Eutropis bontocensis, Ophiophagus hannah, and Oxyrhabdium leporinum. Whether this species possesses a wider geographical distribution on northern Luzon Island is unknown.
Luzon Pleistocene Aggregate Island Complex (PAIC; Brown and Diesmos, 2002).
No original forest remains in the Municipalities of Baguio and La Trinidad, Luzon Island, but it is assumed that the species once occurred in primary-growth pine forest at mid- to high elevations. Although no observations have been made of the preferred microhabitat of B. wrighti, nearly all species of Brachymeles are known to live within the rotting material of fallen logs.
Brachymeles wrighti most closely resembles B. elerae, the only other known tetradactyl species within the genus, but differs from B. elerae by having a much larger body, longer limbs, six or seven supralabials, seven infralabials, six supraciliaries, five supraoculars, the presence of a pineal eyespot, the absence of a third pair of enlarged chin shields, and a greater number of Toe-IV lamellae, mibody scale rows, axilla–groin scale rows, and paravertebral scales rows.
SVL 113.0, 125.8 mm (only two adult specimens known from museum collections)
Although the communities around La Trinidad have maintained and protected these small hillside preserves, the habitat is regenerated at best from complete deforestation (CDS pers. observ.).
Three separate focused surveys of the type region have been conducted by CDS over the last three years, all resulting in no new observations of B. wrighti. All that remains of potentially suitable habitat are small slivers of hillside designated as community gardens for the distinct barangays of La Trinidad.
Wright's short-legged skink (Brachymeles wrighti) is a species of skink endemic to the Philippines.[2]
Wright's short-legged skink (Brachymeles wrighti) is a species of skink endemic to the Philippines.
