Brachyorrhos gastrotaenius (Bleeker, 1860) Murphy & Mumpuni & Lang & Gower & Sanders, 2012

Murphy, John C., Mumpuni, Lang, Ruud de, Gower, David J. & Sanders, Kate L., 2012, The Moluccan Short-Tailed Snakes Of The Genus Brachyorrhos Kuhl (Squamata: Serpentes: Homalopsidae), And The Status Of Calamophis Meyer, Raffles Bulletin of Zoology 60 (2), pp. 501-514 : 508-509

Brachyorrhos gastrotaenius (Bleeker, 1860) new combination

( Fig. 4b )

Rabdion gastrotaenia Bleeker, 1860a: 286

Oxyorrhos fusiformis Fischer, 1879: 89

Type locality. — Buru

Syntypes. — SMNS 1327 (3) lost in WWII (fide Schluter & Hallermann, 1997)

Brachyorrhos albus Boulenger, 1893: 305

Material examined. — Holotype. BMNH 6312425 . Note that RMNH 3977 ( Leiden ) from “O-I Archipel” (= East Indies Archipelago ) is described as a “co-type” for this species. It has been skinned and scale count data is therefore not available. Type Locality. “Amboina” (= Ambon), in error. Buru – Fakal: ZMA 13.044 (3); Rana – ZMA 12.844 (3); no specific locality – RMNH 572 .

Diagnosis. — Six upper labials, fourth (rarely 3+4) are in the orbit, the fifth is the tallest; a mid-ventral stripe is often present. This combination will separate this species from all other members of the genus.

Redescription of the Holotype. — BMNH 631242 is a juvenile, presumably female, 194 mm in total length (173 mm + 21 mm). Ventrals 180; subcaudals 27; dorsal scales in 19 rows throughout; two postoculars; six upper labials, fourth enters the orbit on the right side, 3+ 4 in the orbit on the left; upper labials 2-3 contact the PLP shield on the left, 2-3-4 contact the PLP shield on the right; the tallest upper labial is five; seven lower labials, the first four contact the anterior chin shields. There are two primary temporal scales on both sides.

Description. — Rostral is visible from above, separates nasals; nasals are divided or semi-divided with the nostril in the anterior portion of the scale, posterior lobe wedges between second upper labial and prefrontal; prefrontal, preocular, and loreal fuse into a large shield; two postoculars; internasal divided; primary temporal scales may be one or two; large occipital scales contact the primary temporal(s). Upper labials six, 2-3 make contact with the fused lorealprefrontal shield, usually the fourth (or 3 + 4) enter orbit (note that in the type specimen the third and fourth are in the orbit on the left, and the fourth enters the orbit on the right), the fifth is the tallest. Lower labials seven, rarely six; the first pair make contact on the midline of the chin posterior to the mental; first four contact the only pair of chin shields. Dorsal scales on the body are smooth and in 19 rows, and there is no posterior reduction in scale row numbers. In alcohol, a uniform brown-grey dorsum; the upper and lower labials are lighter in colour than the crown of the head. A mid ventral stripe is often present. In the type specimen (a juvenile) there is a light coloured occipital band followed by three indistinct bands. Four males have 177–193 ventrals, three males have 34–38 subcaudals, and tails are 12.3–17.6% of the SVL. Females have 187–195 ventrals, 18–29 subcaudals (N = 5, = 24.8, SD = 4.43) tails are 5.7–9.4% of SVL. Two sample t-tests found the ventrals (p <0.05) were not sexually dimorphic but subcaudals (p> 0.05) were dimorphic in this species.

Size. — Two adult Brachyorrhos gastrotaenius males have SVLs of 342 and 415 mm and 42 and 73 mm tails, with tail/ body ratios of 12.3 and 17.6%. Females had SVLs ranging from 338–595 mm (N = 5, = 470.8, SD = 118.3); tails ranged from 30–48 mm (N = 5, = 36.8, SD = 7.04); and tail/body ratios of 5.7–9.4% (N = 5, = 8.04, SD = 1.55).

Notes. — (1) While Bleeker’s type specimen of Rhabdion gastrotaenius matches the other Buru specimens quite closely, there is one inconsistency, the subcaudal count and the tail/body ratio. The type specimen is a juvenile; it has 27 subcaudals and a tail/body ratio of 12.1. The subcaudal count would suggest it is a female, while the tail/body ratio suggests it is a male when compared with other Buru specimens. Bleeker’ type associates with Buru specimens in both our PCA and cluster analysis, thus pending evidence to the contrary we are tentatively assigning Bleeker’s name to the Buru population. (2) Kopstein (1926) described four specimens of Brachyorrhos from Buru that had 163–174 ventrals; 25–32 subcaudals; six upper labials, the 4 th in the orbit; and three lower labials contacting the chin shields. His ventral counts extend ours downward, and we have not seen any specimens with only 3 lower labials contacting the chin shields, our sample has 4 lower labials contacting the chin shields. The specimens examined here, collected by Toxopeus in 1921, came from Fakal (southwest Buru) and from Lake Rana in the center of the island. Both locations are at relatively high elevations, at 1451 m and 773 m respectively. Kopstein’s specimens may represent a different population or a different species than the one under discussion. However, the drawings by Fischer (1879) and scale count data for Oxyorrhos fusiformis are in close agreement with the specimens examined for this study.

Distribution. — Buru

Etymology. — The epithet gastrotaenius is derived from the Greek gaster, pertaining to the belly, and the Latin taenia referring to a ribbon, in reference to the mid-line stripe on the venter of this snake. We have changed the suffix of Bleeker’s gastrotaenia so that the gender of the epithet is in agreement with the gender of the genus.

Figures

Fig. 4. A comparison of the labial architecture for four species of Brachyorrhos: (A) B. albus (FMNH 134323) Ambon; (B) B. gastrotaenius (BMNH 6312425) Buru holotype; (C) B. raffrayi (MNHN 5174) Ternate, holotype; (D) B. wallacei (MZB 3463) Halmahera holotype. Labials are numbered, T denotes tallest labial; P = preocular; PFL = prefrontal-loreal shield; PLP = preocular-loreal-prefrontal shield.