Uropeltis tricuspida Gower 2023, sp. nov.

Uropeltis tricuspida sp. nov.

Figs. 4–6; Tables 2–3

urn:lsid:zoobank.org.act: 3BFE988E-B0D4-4E52-BEAF-6B2DEFD3B6C3

Uropeltis petersi (Beddome, 1878): Boulenger 1890, 1893 in part; Wall 1923, in part; Smith 1943, in part; Gans 1966, in part; Wallach et al. 2014, in part; Pyron et al. 2016, in part; Sampaio et al. 2023, in part

Holotype. CAS 244452 (Fig. 5), adult female based on large size, and relatively high ventral and low subcaudal count. Collected by C. Gans, C. Rajasundaram and R. A. Bonhoure on 11 June 1990 from Sevenmalai (also spelled Sevenmallay or Sivanmalai, a tea estate), 4 km West of Munnar, Idukki District, Kerala, India, 2,100 m (ca. 10.075°N, 77.0417°E, from Google Earth and Rajendran (1985: map 3), though land here is ca. 1,600 m elevation versus the reported 2,100 m).

Paratypes (n = 7). CAS 244451 (male), 244453 (female), 244454 (male), 244455 (female) and 244456 (male), same data as for the holotype. CAS 244441 and 244442 (both male) collected by C. Gans, C. Rajasundaram and R. A. Bonhoure on 10 June 1990 from Sevenmalai Estate, 2 km East of Munnar, Idukki District, Kerala, India, 2,000 m. Whole-specimen photographs of these specimens are presented in Fig. 6.

Referred specimens (n = 30). CAS 244407 (male), 244408 (male), 244409 (female), 244411 (female), 244413 (male), 244414 (female), 244415 (male), 244416 (male), and 244417 (male) collected by C. Gans, C. Rajasundaram and R. A. Bonhoure on 9 June 1990 from Sevenmalai Estate, 2 km East of Munnar, 2,000 m. CAS 244421 (female), 244422 (female), 244424 (male), 244425 (female), 244426 (female), 244427 (male), 244443 (female), and 244444 (male) collected by C. Gans, C. Rajasundaram and R. A. Bonhoure on 9 June 1990 from Parvathi (Parvathy) Division, Sevenmalai Estate, 4 km East of Munnar, 2,000 m. CAS 244450 (male) collected by C. Gans, C. Rajasundaram and R. A. Bonhoure on 11 June 1990 from Parvati Division, Sevenmalai Estate, 4 km West of Munnar, 2,100 m. CAS 244447 (female) and 244436 (male) collected by C. Gans, C. Rajasundaram and R. A. Bonhoure on 10 June 1990 from Sevenmalai Estate, 2 km East of Munnar, 5,500 feet (= 1,676 m). CAS 244437 (male); CAS 244438 (female), 244439 (male), and 244440 (male) collected by C. Gans, C. Rajasundaram and R. A. Bonhoure on 10 June 1990 from Sevenmalai Estate, 2 km East of Munnar, 2,000 m. CAS 244886, 244888 and 244889 (three females) from Sevenmalai, 20 April 1972. MNHN 1897.249 (male) from Peermad, N. Travancore, 4,000 feet; BNHS 3621 (male: voucher specimen reported as UK MW 2228 by Sampaio et al. 2023) from near Munnar collected by O. V. Oommen and colleagues October 2001; BMNH 1946.1.17.8 (male), Anamallays, 4,000 feet, R.H. Beddome.

Diagnosis. A species of Uropeltis that differs from all congeners except U. liura, U. maculata and U. petersi in having 17 rows of dorsal scales at midbody, nasals that make contact along the midline posterior to the rostral, and that lack a flattened or mildly longitudinally convex tail shield composed of matt scales with substantial keels— instead having a strongly longitudinally convex tail tip with scales bearing low, inconspicuous ridges. Differs from U. petersi in having more ventral scales in females (178–185 versus 156–162) and more subcaudal scales (6–10 and 10–13 versus 5–6 and 10–11 in males and females, respectively), and in having a tricuspid versus bicuspid terminal scute. Differs from U. maculata in lacking large yellow spots or blotches laterally on the anterior end of the body, in having typically two versus three small, non-subcaudal scales overlapped by each anal shield, and in having a tricuspid versus bicuspid terminal scute. Differs from U. liura in having fewer ventral scales (156–174 versus 173 to>195, respectively), in having typically two versus three small, non-subcaudal scales overlapped by each anal shield, lacking yellow dots on most of the body scales on the dorsum, and in having a tricuspid versus bicuspid terminal scute. Uropeltis tricuspida sp. nov. is distinct from these three phenotypically superficially similar congeners (and all other species) also in DNA sequence data (Sampaio et al. 2023).

Description of holotype. Some meristic and morphometric data presented in Table 2. Female, based on relatively high number of ventrals, relatively short tail and relatively few subcaudals (see paratype variation section below). Good condition, preserved in a tight but flexible U-shape.

Body subcylindrical, slightly wider anteriorly than posteriorly, venter slightly flattened, perhaps somewhat artefactually; tapering over c. 15 mm immediately behind head; very gently tapering posteriorly up to vent and onto tail until final c. 5 mm when tapering more strongly. Head strongly tapering in dorsal view, sides straight to slightly convex to just behind nostrils, rounded anteriorly; tapering also in lateral view, gently with straight to slightly convex edges up to level with nostrils.

Rostral rounded anteriorly, wider than long in dorsal view, much deeper than long in lateral view; dorsally without longitudinal ridge or crest; at widest slightly in front of and below nostril. Rostral shorter (in dorsal view) than rostral-frontal gap. Frontal six-sided, lateralmost edges in contact with oculars diverging anteriorly. Frontal much longer, wider than rostral. Paired nasals in brief contact behind rostral. Midline contact between nasals and between prefrontals (left overlapping right in both cases) subequal in length; midline sutures not parallel with long axis, left prefrontal contacts right nasal but not vice versa. External naris small, subcircular, slightly countersunk within small depression, located towards anteroventral corner of undivided nasal shield. Nasal contacts first and second supralabials (SLs). Prefrontal (as nasal) wider than long, shorter than frontal, contacts SL2 and SL3. Supralabials four, SL1 smallest, making least contribution to margin of mouth; SL2 larger than SL1, smaller than SL3; SL4 much the largest and longest. Ocular contacts SL3 and SL4; posterodorsal margin slightly concave. Eye small but distinct, diameter less than one half and more than one third length of ocular shield, located near anteroventral corner of ocular; bulges slightly from ocular surface, pupil appears subcircular; eyes directed anterolaterally and slightly dorsally.

Paired parietals each about as long as frontal, posteriorly broadly rounded. Opposite parietals in brief midline contact, left overlapping right. Parietals slightly longer than wide, wider than frontal and rostral. Each parietal contacts four scales other than head shields. Three infralabials (ILs) on each side, IL1 and IL3 subequal in length, notably shorter than IL2. Left and right first infralabials in midline contact, separating small, slightly prominent mental from first midline ventral scale. First four ventrals longer than wide, fifth and subsequent ventrals wider than long. Six maxillary and eight mandibular teeth on each side. Teeth simple, pointed, distinctly retrorse, straight to slightly recurved, evenly spaced, smallest posteriorly.

Head and body scales macroscopically smooth, lacking keels, except on far posterior of body and tail. 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, posteriormost ventral with V-shaped posterior margin (straight to gently rounded in most preceding ventrals). Ventrals 181, at midbody approximately 1.6 times as broad as exposed part of adjacent first dorsal scale row. Dorsal scale rows 19 anteriorly (by two head lengths behind head), reducing to 17 by level with 32 nd ventral up to level with vent. At level of 52 nd (left) and 53 rd (right) ventral the fourth dorsal-row scale is noticeably enlarged (“b”) and the fifth-row scale notably small (“s”: represented in square brackets in formula below):

4+5 (32) [b4, s5: 53]

19 --------------- 17 ----------------- 17

4+5 (32) [b4, s5: 52]

Dorsal scale rows 15 at base of tail. Paired anal scales (right overlying left) considerably larger than posteriormost ventrals and subcaudals. Distal margin of each anal overlaps two other scales in addition to anteriormost subcaudals. Seven subcaudals on each side. Last few dorsal scale row scales on body, but not ventrals, anals or subcaudals with multiple (typically 3 to 5, see Fig. 5) short and very low subparallel ridges, increasingly prominent posteriorly and dorsally. Very inconspicuous other than on approximately last four scales anterior to terminal scute.

Tail ‘shield’ not clearly demarcated, distinctly convex both longitudinally and transversely; most closely matching Type III among Smith’s (1943) states for Uropeltis tails (also type III of Pyron et al. 2016). Terminal scute prominent, approximately as wide as long, surrounded by nine scales including last subcaudals; ventrally smooth and convex both longitudinally and transversely; dorsally somewhat flat centrally, strongly upturned posteriorly, with irregular (though subparallel, anteriorly diverging) short, tubercles, more prominent on anterior half. Posterior upturned edge of terminal scute ends in thin tricuspid subhorizontal ridge with paramedian cusps (0.5 mm apart) flanking more prominent midline cusp.

In alcohol, background dorsal body colour uniform brown; edges of distal tips of dorsal body scales translucent and narrow edges of bases of scales off-white to pale dull yellow, such that most of the dorsum (the nine central dorsal scale rows; except for posteriormost c. 30 mm of specimen) bears very narrow, longitudinal (zigzag) pale lines between darker scales. Scales on dorsum mostly unblemished though some (especially anteriorly) with pale yellow flecks. Body scales slightly iridescent. Head brownish, about as dark as anterior of body; fairly uniform above except for slightly paler orange-brown tip of rostral and pale-yellow upper lips and most of SL4. Underside of head with more and more-irregular pale flecking. An irregular, lateral, pale-yellow line extends posteriorly from SL4, diminishing and becoming increasingly wavy and irregular over anteriormost quarter or so of body. Ventral aspect of specimen with more pale-yellow markings than dorsally, mostly confined to first three dorsal scale rows; ventrals mostly brown, except over anteriormost c. 25 mm where mostly with at least some pale yellow. Most scales with pale-yellow on dorsal rows 1–3 have pale blotches rather than being entirely pale.

Subcaudals brown with pale-yellow lateral edges that, along with pale markings on medial edges of first dorsal scale row on tail, form a pair of tapering, gradually converging pale stripes on ventrolateral surface of tail. Anterior ends of these stripes merge with broad transverse pale-yellow band that covers both anals and most of the posteriormost ventral. Upper surface of tail brown-grey except for increasingly pale posterior end of terminal scute.

Variation in paratypes. Seven more or less U-shaped specimens (Fig. 6), in generally good condition. CAS 244454 close to ecdysis when fixed, with broken spine at approximately midbody, and small piece of viscera protruding though midventral hole into coelom, with patch of outer layer of scales missing anterior and posterior of this hole. CAS 244441 slightly macerated; CAS 244442 with outer scale layer missing in some patches.

Some meristic and morphometric data presented in Table 2; scale-reduction formulae presented in Appendix 1. Generally similar to holotype. Rostral slightly longer or shorter or subequal to gap between rostral and frontal. Lateralmost edges of frontal barely diverge in CAS 244456. Right prefrontal contacts left nasal in CAS 244451. Parietals generally notably slightly shorter than frontal. Parietals slightly wider than long in CAS 244456. CAS 244454 has seven rather than six maxillary teeth on each side.

Midbody ventrals 1.5–1.9 times width of adjacent dorsal-scale row scales. Dorsal scale rows reduce to 16 shortly anterior to vent in CAS 244456, and 14 instead of 15 rows at base of tail in 244455 and 244456. Low longitudinal ridges on posteriormost tail scales most noticeable on four to six (CAS 244451, 244455 and 244456) to seven to nine (CAS 244441, 244442) scales anterior to terminal scute. Posterior end of terminal scute tricuspid in all paratypes except CAS 244441, in which it is asymmetrical and somewhat more bicuspid.

Dorsum generally lacks pale flecks. Anterolateral pale stripe more or less well developed and extensive. Venter in some paratypes with incomplete, pale transverse bars one scale long with two darker scales between each pale bar, most notably in CAS 244455 and 244456. More pale blotches on dorsal surface of head in CAS 244456. CAS 244442 lacks pale, narrow, longitudinal zigzag lines on anterior of dorsum. Ventrolateral pale stripes on tail broken on one side in CAS 244451, 244453 (anals brown rather than pale), 244454, 244455 (anals partly brown), and 244456 (small brown blotches on anals; pale ventrolateral marks meet midventrally on posterior half of tail).

Variation in referred specimens. Some meristic and morphometric data presented in Table 3. Scale-reduction formula for one aberrant specimen with many fluctuations in scale rows on right side of body presented in Appendix 1. Each anal overlaps three rather than two small scales (in addition to subcaudals) in MNHN 1897.249 and on one side in CAS 244436.

Sexual dimorphism. The type and non-type material is together strongly sexually dimorphic in that (as in many other uropeltids) females have more ventrals (176–185 versus 170–178), fewer subcaudals (7–9 versus 11–13), and relative shorter tails (3.1–4.4 versus 4.4–6.3 % of total length) (Tables 2, 3).

Etymology. The name is in reference to the species having typically three cusps on the posterior end of the terminal shield. For nomenclatural purposes, the species epithet is a noun in apposition.

Suggested vernacular names. Three-cusped uropeltis or Three-cusped shieldtail (English).

Distribution, habitat and conservation. One of the early (<1900) specimens is from an imprecise locality (Anamalai hills). The other (MNHN 1897.249), according to the catalogue, is from Peermad, which is likely Peermed (also spelled Peerumedu, Peerumade, Peermade), Idukki District, Kerala, ca. 50 km due South of the type locality (ca. 1,000 m elevation). The 35 CAS specimens and the only other known specimen with a reasonably precise locality (BNHS 3621) were collected in 1972 (three specimens), 1990 (32 specimens over three days) and 2001 (one specimen), respectively, and are from a radius of within a few kilometres of Munnar in the Anamalai hills of the Western Ghats of peninsular India. The CAS catalogue records seven specimens from West of Munnar and 25 from East of Munnar. Some of the latter are recorded as from Parvathi Division, which is seemingly West of Munnar (10.0778°N, 77.0389°E, from Google Earth). Thus, perhaps some or all of the “East of Munnar” records are recorded in error and were actually from West of Munnar. The CAS specimens are recorded as from 1,676 m (two specimens) and 2,000 –2,100 m (29 specimens) but elevations immediately to the West of Munnar are typically in the region of 1,500 m and certainly below 1,800 m.

According to the catalogue, nine of the CAS specimens that have associated habitat data were “dug up from very wet turf” and eight were “dug up in garden patches, wet soil”. BNHS 3621 was also dug from moist soil, while searching for caecilian amphibians in a low-intensity agricultural habitat (O.V. Oommen, pers. comm.). Although the new species thus appears to tolerate at least some human disturbance and was locally abundant, at least, in 1990, little else is known of its natural history, and it has been recorded only from a very small area. Thus, it likely qualifies as Data Deficient conservation status based on IUCN Red List criteria (IUCN Species Survival Commission 2012).