Rhinophis lineatus Gower & Maduwage, 2011, sp. nov.
Creators: name: Gower, David J.
name: Maduwage, Kalana
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Uropeltidae
Rhinophis
Rhinophis lineatus

description: Rhinophis lineatus sp. nov.
(Figs. 1–5; Table 1; Appendix)
Rhinophis drummondhayi Wall, 1921: de Silva (1990: plate 1F) Rhinophis sp. 1: Cadle et al. (1990)
Holotype. CAS 226024, female, Harasbedda (07°03’N, 80°52’ E, alt. 1,460 m, Fig. 1), near Ragala, Central Province, collected 26 – 30 October 1976 by Lalith Jayawickrama. Photographs presented in Figs. 2 – 4.
Paratypes. 18 specimens, all from the type locality: CAS 225806; CAS 226025 – 226035 (11 specimens); CAS 226042 – 226044 (all CAS specimens same dates and collector as holotype); WHT 5208 and 5218, males, collected by M. M. Bahir, 0 4 and10 November 2000, respectively; WHT 5788, male, collected by S. V. Nanayakkara, 20 November 2002.
Diagnosis. A Rhinophis distinguished from R. dorsimaculatus, R. oxyrhynchus, R. porrectus, R. punctatus and R. zigzag by having fewer than 200 ventral scales, and from the first four of these species by its middorsally transversely rounded rostral (vs a distinctly crested/carinate rostral). The new species differs from R. blythii, R. erangavirajei, R. travancoricus and R. tricolorata by having more than 170 ventral scales. The Indian R. fergusonianus and R. sanguineus differ from R. lineatus in having much larger tail shields, and rostrals that separate the prefrontals along less than half their length. In addition, R. lineatus lacks the conspicuous (but low) carinae on the distal ends of the scales on the underside of the tail of R. sanguineus, and is less attenuate than the only known specimen of R. fergusonianus (midbody width in length ca. 30 – 40 vs 42). Rhnophis philippinus has a much larger tail shield (longer than the shielded part of the head) than R. lineatus. In common scalation characters, R. lineatus resembles R. drummondhayi and R. homolepis most closely, but it differs from both these species substantially in its colour pattern; regular, narrow, longitudinal pale/dark stripes around and along almost the entire body (R. lineatus) vs striped venter but unstriped dorsum with short pale and middorsally incomplete cross bars (R. homolepis) or mottled venter and dark dorsum with lateral/dorsolateral yellow, dorsally tapering bars (R. drummondhayi). Indeed, R. lineatus is the only species in the genus characterised by a colour pattern of multiple, narrow longitudinal stripes around and along most of the body, a feature occurring in all known specimens.
Description of holotype. See Table 1 for morphometric and meristic data. Head small; snout pointed. Rostral pointed, trihedral anteriorly, longer than wide, dorsally rounded and slightly raised/arched (in lateral and anterior views), without sharp dorsal crest (though with rounded longitudinal ridge); rostral widest at level of anterior superior corner of first supralabials. Rostral several times longer (in dorsal view) than rostral-frontal gap. Frontal irregularly hexagonal, slightly wider than long, anterolateral (ocular) margins slightly converging posteriorly, posterolateral margin straight; anterolateral (ocular) margin shortest, anterior edges longest. Frontal shorter, wider than rostral. Paired nasals separated from each other by posterior half of rostral. External naris small, subcircular, slightly countersunk within small depression, located in anteroventral corner of nasal. Nasal contacts supralabials 1 and 2. Prefrontals briefly (for less than 25% of their length) in contact with each other along midline, separating frontal from rostral. Prefrontals wider than long, shorter than frontal. Supralabials four, first smallest, making the least contribution to margin of mouth; second larger but only slightly longer; fourth much the largest. Ocular contacts supralabials 3 and 4. Eye small but distinct, diameter less than one third length of ocular, located near anteroventral corner of ocular, bulging slightly from ocular surface, pupil appears subcircular. Paired parietals about as long as frontal, posteriorly broadly rounded (a little> 90°). Opposite parietals in brief midline contact, left overlapping right. Parietals substantially wider than long, wider than frontal and rostral. Each parietal contacts four scales other than head shields and infralabials. Three infralabials, first and third subequal in length, notably shorter than second. First infralabials very briefly in midline contact, separating small, slightly prominent mental from first midline ventral scale. First and second ventrals longer than wide, third about as long as wide, fourth and subsequent ventrals wider than long.
Seven maxillary and eight mandibular teeth on each side. Teeth simple, pointed, distinctly retrorse, straight, evenly spaced. Mandibular teeth hidden deeper in gingivae. Anteriormost maxillary tooth aligned approximately with halfway along lower margin of second supralabial, posteriormost maxillary tooth close to posterior edge of lower margin of third supralabial; mandibular row similar in length and alignment, with anteriormost member a little further forward than maxillary row.
Body subcylindrical to slightly dorsoventrally compressed. Head and body scales macroscopically smooth, lacking keels. Body scales generally evenly sized on dorsum and along body except for those involved in dorsal scale row reductions. Midline ventral scales between mental and anal of even size though anterior- and posteriormost ones gradually narrow. Ventrals 186, at midbody approximately 1.1 times as broad as exposed part of adjacent first dorsal scale row. Dorsal scale rows 19 anteriorly, reducing to 17 along most of body.
4+5 (45) +5 (52) 3+4 (64)
Scale reduction: 19 ------------------- 17 ------------- 19 ---------------- 17
4+5 (40) +5 (49) 3+4 (62)
Dorsal scale rows 13 at base of tail. Paired anal scales (right overlying left) considerably larger than posteriormost ventrals and subcaudals. Distal margin of each anal overlaps three other scales in addition to anteriormost subcaudals. Subcaudals 7 (left), 6 (right), all but posteriormost paired/divided. Tail scales macroscopically smooth though with two to six inconspicuous keels on posterior portion of posteriormost subcaudals (increasingly prominent posteriorly). Caudal 'shield' conical, forming tip of tail, about as long as wide in dorsal view, distinctly shorter than shielded part of head, visible from below and especially above, base (not as wide as base of tail) surrounded by last (unpaired) subcaudal and 12 other scales. In posterior view shield broad oval to slightly egg-shaped, wider ventrally than dorsally, widest point about halfway up. Shield surface covered with small spines in approximately radial distribution, generally subequal though perhaps slightly larger close to midline. In parts, a thin halo around base of shield glossy and without spines.
In alcohol, background body colour yellowish to pale tan. A darker (pale brown) longitudinal line present on each dorsal scale row, collectively forming multiple stripes along length of body, interrupted only at scale reductions. Stripes widest dorsally; brown stripes darker and background tan paler posteriorly so that contrast between stripe and background colour weakest anteriorly; stripes very wide anteriorly on dorsum, almost merging, but ventrally much thinner and more intermittent. Ventrals with darker blotches mostly restricted to proximal part of scale, together forming broken additional stripe. Head brownish, about as dark as anterior of body; fairly uniform except for paler posteroventral part of fourth supralabial and slightly paler, more orange rostral. Anals yellowish with mottled brown posteromedial margins. Subcaudals brown with small yellowish flecks medially; dorsalmost 7+ scale rows and ventralmost row on tail brown; irregular yellowish lateral stripe one to three scales wide. Tail shield matt brown with yellowish apex.
Variation. See Table 1 for meristic and morphometric details. Supra- and infralabials always as holotype except four infralabials on right of CAS 226043. Relative size and shape of dorsal shields of head somewhat variable; for example, frontal notably small relative to parietals and prefrontals in CAS 226026; rostral and frontal in contact in CAS226028; second of four (from midline) scales contacting each parietal generally does so more briefly than in holotype, so that in some specimens (e.g. CAS 226026, 226028) each parietal superficially appears to contact only three non-head-shield scales. Mental generally narrowly separated from first ventral; very briefly in contact in CAS 226029, 226034. Ventrals 180 – 195; subcaudals 4 to 7 on each side, between one (always the posteriormost) and four of which are undivided/single. Left anal overlaps right only in CAS 225806, 226026, 226033, and WHT 5218. Dorsal scale rows always 19 anteriorly, 17 at midbody and immediately in front of anus (perhaps 16 rows here in CAS 226044); however, considerable variation in scale-row reductions although pattern seen in holotype seemingly average (see Appendix). Shield shape variable in posterior view; much wider ventrally than dorsally in CAS 226025, little wider ventrally than dorsally in CAS 226026, little wider dorsally than ventrally in CAS 226028 and 226044. Not all specimens were dissected to determine sex but available data do not indicate clear sexual size dimorphism (Table 1). Males perhaps tend to have longer tails, but number of subcaudals is not a reliable indicator of sex.
Colour pattern generally constant and matching holotype. Intensity/brightness of orange tinge of rostral somewhat variable (bright in e.g., CAS 226043). Paler lower part of posterior supralabials extends further forwards in some specimens (e.g., onto second supralabial of CAS 226025).
Hemipenes (based on everted organs of WHT 5208, Fig. 5) moderately long (ca. 4 mm), slender, deeply forked: a single, subcylindrical organ, densely ornamented with large, curved, closely spaced spines on their distal one-third; proximal two-thirds smooth. Sulcus spermaticus shallow, its walls smooth and free of spines along distal third of hemipenis.
Colour in life. A colour photograph presented by de Silva (1990: plate 1f) depicts the species in life, identified as R. drummondhayi. The background body colour appears to be orange-brown, and the longitudinal stripes dark brown. The same photograph, also labeled as R. drummondhayi, appears on a 2001 poster “Snakes of Sri Lanka ” authored by de Silva, though here the background body colour appears a paler and less reddish brown.
Etymology. The species name is an allusion to the distinctive multiple longitudinal stripes. The specific epithet is considered a noun in apposition.
Suggested common name. Striped Rhinophis (English).
Distribution, natural history and conservation. Rhinophis lineatus is known only from the type locality, Harasbedda, in the Wet Zone of the central hills of Sri Lanka. As far as we are aware, all known specimens were collected from soils in agricultural habitats. Although the exact range of the species is unknown it is unlikely to be large (e.g. across a substantial part of the central hills) based on its absence in reasonably large collections of uropeltids from across the region (BMNH, CAS, WHT). Given its small probable range and very few known localities (not known to include protected areas), R. lineatus is likely to fall into one of the IUCN’s threatened categories.
Remarks. In terms of common scale counts, Rhinophis lineatus resembles R. drummondhayi (and R. homolepis) most closely among Sri Lankan snakes, and this probably led Carl Gans to refer specimens of R. lineatus to R. drummondhayi in his photographic (de Silva, 1990: plate 1F) and specimen collection (CAS electronic catalogue, accessed February, 2009) records. However, there are profound colour pattern differences (narrow, regular pale/ dark longitudinal stripes in R. lineatus; dark dorsum, ventral mottles, and pale dorsolateral bands anteriorly in R. drummondhayi), and we expect more extensive studies of R. drummondhayi to further reveal morphometric and meristic differences. Carl Gans later recognized that R. lineatus was an undescribed species (“ Rhinophis sp. 1”, Cadle et al., 1990)
Based on reliable locality records and morphological and molecular analyses (e.g. Cadle et al., 1990; Bossuyt et al. 2004; unpublished data) Sri Lankan species of Uropeltidae do not occur in India or vice versa. Rhinophis lineatus is readily distinguished from the three congeneric Indian species. The new species also differs clearly from the non- Rhinophis Sri Lankan uropeltids that, although currently classified in other genera (Pseudotyphlops, Uropeltis, e.g., McDiarmid et al., 1999), possibly form part of the Sri Lankan uropeltid radiation together with Sri Lankan Rhinophis (Cadle et al., 1990; Bossuyt et al., 2004). Rhinophis lineatus differs (beyond in its distinctive colour pattern) from Pseudotyohlops philippinus and Uropeltis melanogaster in having more than 170 ventrals, and from U. phillipsi in having fewer than 197 ventrals. Additionally, compared with R. lineatus, P. philippinus has a substantially larger, almost flat tail shield, and U. melanogaster and U. phillipsi smaller, narrower tail shields that are shorter (vs longer) than the part of the head anterior to the frontal. Uropeltis ruhunae has keels rather than spines on its tail shield.
description: Published as part of Gower, David J. & Maduwage, Kalana, 2011, Two new species of Rhinophis Hemprich (Serpentes: Uropeltidae) from Sri Lanka, pp. 51-68 in Zootaxa 2881 on pages 53-59, DOI: 10.5281/zenodo.201615