Liopeltis tiomanica sp. nov.

Liopeltis tricolor (part): J.L. Grismer et al. 2004: 275; Grismer 2011: 203.

Liopeltis tricolour [sic] (part): Grismer et al. 2006: 178.

Holotype. LSUHC 5037, adult female (Figs. 2–4), Peninsular Malaysia, Pahang State, Pulau Tioman (= Tioman Island), Gunung Kajang trail, 2.77900°N 104.15703°E (Datum WGS84), 618 m elev., coll. 11 August 2002 by Jesse L. Grismer, Perry L. Wood, Jr., and L. Lee Grismer.

Etymology. The specific epithet refers to the new species’ type and only known locality on the island of Pulau Tioman. The specific epithet is feminine, in agreement with the gender of the genus (Poyarkov et al. 2019).

Diagnosis. A species of Liopeltis having the combination of the nasal scale fused with the internasal scale; preoculars two; ventrals 161; distinct black lateral cephalic stripe extending from rostral through eye to approximately 30 mm behind neck before fading; four longitudinal stripes on dorsum; and venter immaculate, without stripes.

Description of holotype (Figs. 2–3). Adult female; head slightly distinct from neck, triangular in dorsal view; snout weakly pointed in lateral view, projecting beyond lower jaw; eye large, pupil round; body slender; tail thin. Rostral wide, clearly visible from above; nasal partially divided, portion anterior to nostril continuous with internasal, portion posterior to nostril with horizontal suture; loreal absent; two preoculars, upper rectangular, approximately 25% size of lower, trapezoidal preocular; two postoculars, squarish or rounded, upper scale slightly larger than lower scale; eight supralabials, 4 th and 5 th in contact with eye, 2 nd– 4 th in contact with lower preocular, 5 th (right side) and 5 th– 6 th (left side) in contact with lower postocular, 7 th largest; eight infralabials, 5 th largest; one elongate anterior temporal; two subequal posterior temporals, shorter than anterior temporal; two internasals; two prefrontals; single frontal, approximately 63% length of parietals, with one supraocular on each side; two large, elongate parietals; anterior pair and posterior pairs of chin shields subequal in length, anterior pair broader; dorsal scales smooth, in rows 15:15:13, apical pits absent; 161 ventrals; cloacal plate divided; 119 paired subcaudals. Scale counts are summarized in Table 2.

*Data from Taylor (1922: 164, “No. 940, Bureau of Science Collection;” specimen destroyed during World War II).

Color of holotype in life (Fig. 2). Dorsal surface of head bronze-brown (Grayish Horn Color 268); chin, supralabials, and infralabials cream (Cream White 52); black stripe on lateral side of head and neck separates dorsal and ventral coloration, stripe slightly wider than one dorsal scale, extending from rostral though eye to approximately 30 mm posterior to neck, gradually fading; dorsum bronze (Grayish Horn Color 268) with four longitudinal brown (Olive-Brown 278) stripes, two dorsal stripes extending from neck to tail, two lateral stripes extending from area posterior of black head stripe to level of cloacal plate; venter uniform pale cream color (Cream White 52) with small dark spots on ventral scales.

Color of holotype in preservative (Fig. 3). Dorsum faded to grayish green (Olive Horn Color 16); dorsal stripes faded to light brown (Clay Color 18).

Molecular data. The standard deviation of split frequencies among the four Bayesian runs was 0.003717 and the Estimated Sample Sizes (ESS) of parameters were ≥ 3,390. The holotype of Liopeltis tiomanica sp. nov. was recovered with strong support (Bayesian posterior probability 1.00) to be the sister taxon of L. philippina (Fig. 4). The L. tiomanica sp. nov. + L. philippina clade was recovered with strong support (Bayesian posterior probability 1.00) to be nested within a clade containing L. tricolor and L. stoliczkae, although the relationships among L. tricolor, L. stoliczkae, and the L. tiomanica sp. nov. + L. philippina clade were not resolved (Fig. 4). Liopeltis tiomanica sp. nov. had uncorrected p -distances in cyt b of 9.6% from L. philippina and 12.9–13.3% from L. tricolor.

Distribution, natural history, and conservation. Liopeltis tiomanica sp. nov. is known only from the holotype specimen collected from Pulau Tioman (Fig. 1). The specimen was found in the afternoon while perched on a small tree branch 2 m above the ground in primary hill dipterocarp forest (J. Grismer et al. 2004, Fig. 5).

Comparisons. Liopeltis tiomanica sp. nov. differs from all other species of Liopeltis, except its sister taxon L. philippina (Fig. 4), by having the nasal fused with the internasal and four longitudinal stripes on the dorsum (Weinell et al. 2019). Liopeltis tiomanica sp. nov. differs from L. philippina by having 161 ventral scales (vs. 139–150 in L. philippina); two preocular scales (vs. one in L. philippina); and a distinct black lateral cephalic stripe (vs. indistinct in L. philippina; Fig. 5). Liopeltis tiomanica sp. nov. further differs from the sympatric (and possibly syntopic) L. tricolor by having the prefrontal in contact only with the second supralabial (vs. second and third supralabials in L. tricolor); and immaculate ventral scales (vs. three gray ventral stripes in most L. tricolor). Scalation differences among these three species are summarized in Tables 2 and 3.