Bachia, Thomas, 1965

Murphy, John C., Salvi, Daniele, Santos, Joana L., Braswell, Alvin L., Charles, Stevland P., Borzée, Amaél & Jowers, Michael J., 2019, The reduced limbed lizards of the genus Bachia (Reptilia, Squamata, Gymnophthalmidae); biogeography, cryptic diversity, and morphological convergence in the eastern Caribbean, Organisms Diversity & Evolution (New York, N. Y.) 19 (2), pp. 321-340 : 329-330

The hex-scaled Bachia from Grenada and the Grenada Bank

The morphological and molecular results suggest that Bachia alleni is restricted to Grenada and the Grenadines and is not conspecific with the hex-scaled Bachia present on Trinidad, Tobago, or Little Tobago.

Diagnosis A Bachia with (1) prefrontal scales in medial contact; (2) the second supraocular the longest; (3) the frontonasal is pentagonal; (4) four digits on the manus and pe s (phalange formulas: manus 2–3–3–2–0, pes 4–4–2–2–0); (5) a band of eight (7–11) hexagonal scales on the dorsum; (6) scales around mid-body 27–31; (7) transverse dorsal rows 38–41; (8) the fifth upper labial may or may not contact the last supraocular; (9) eight rows of gulars; (10) the second pair of chin shields is not in contact; (11) an interparietal scale is present.

The status of the Bequia Island Bachia Thomas (1965) noted that two specimens of Bachia from Bequia Island (12° 58′ N, 61° 14′W) have prefrontals in apical contact and suggests that they may represent a distinct species. We have examined one of them (AMNH 90516). The scale counts fall within the ranges of Grenada B. alleni ( Table 2). However, the prefrontals are triangular (pentagonal in Grenada B. alleni ), the fourth supraocular is the smallest (first and fourth about the same size in Grenada B. alleni ), and the posterior edge of the interparietal is rounded (squared off in Grenada B. alleni ). Most remarkably, the limbs are long, the forelimbs are 0.166 of the SVL, and the hind limbs are 0.195 of the SVL. The Grenada B. alleni has forelimbs that are 0.09–0.118 (x = 0.099, n = 4) and legs that are 0.100 –0.133 (x = 0.120, n = 4) of the SVL. The Bequia specimen also has an elongated head, 0.242 of the SVL. In Grenada, B. alleni has a head that is 0.149 –0.159 of the SVL. Given the small size of this specimen (21 mm SVL), we suspect that it is a hatchling, although no umbilical scar was noted. We cannot rule out the possibility that the long head and limbs are a product of allometry. Thus, the status of Bequia Island Bachia remains uncertain but worthy of future investigation; it is the most northern population of B. alleni .

Similar species Bachia alleni has four digits on each limb and usually eight rows of hexagonal scales on the dorsum, two traits that will separate it from Bachia trinitatis (five digits on the manus and usually 10 rows of hexagonal scales). It has prefrontal scales that make medial contact a trait that will separate it from B. heteropa and B. beebei sp. nov. (both lack prefrontal scales). It can be distinguished from B. whitei sp. nov. by the band of hexagonal scales. To separate B. alleni from other former members of the B. heteropa group, see Table 2.

Material examined Bachia alleni (n = 34) GRENADA –Albert A. Schwartz collection AAS6847–48, 6998, 7144–7155, 7158, 7175, 7197–99, 7368; AMNH 38968; KU 315771– 76; USNM 43219, 67219 – 20, 79190, 286940. GRENADINES –Bequia Island AMNH 90516; Canouan Island MCZ 32345.