Oligodon churahensis, Mirza & Bhardwaj & Patel, 2021
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publication ID |
https://dx.doi.org/10.3897/evolsyst.5.72564 |
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publication LSID |
lsid:zoobank.org:pub:CA45E262-22CD-463E-9B8A-13B324319E87 |
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persistent identifier |
https://treatment.plazi.org/id/E7D48769-300F-43B4-8F8B-45E0A8ED414B |
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taxon LSID |
lsid:zoobank.org:act:E7D48769-300F-43B4-8F8B-45E0A8ED414B |
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treatment provided by |
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scientific name |
Oligodon churahensis |
| status |
sp. nov. |
Oligodon churahensis sp. nov.
Figs 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6
Holotype.
female NCBS NRC-AA-019 from near Thanei Kothi village, Churah Valley, Chamba District, Himachal Pradesh, India (32.835467, 76.119381, elevation 1864 m) collected by Virendar Kumar on 22nd June 2020.
Paratype.
male BNHS 3657 collected on 25 June 2020, same data as for the holotype.
Etymology.
The specific epithet refers to the Churah Valley where the new species was collected.
Suggested common name.
Churah Valley Kukri
Diagnosis.
A medium sized Oligodon (SVL 275 mm) with 17 dorsal scale rows at midbody. Seven supralabials, 3rd and 4th in contact with the eye. Loreal present. 170-175 ventrals, 46-47 subcaudals. Palatine and pterygoid teeth absent. Dorsal patterns consist of 1-2 dorsal scales wide black bands edged with yellow. Ventral scales white with brown smear along the width of each scale, the smear is darker on the lateral edges forming a blotch on each side. 48 to 54 bands in total on the body. Hemipenis forked and spinose throughout.
Comparison.
Morphologically Oligodon churahensis sp. nov. differs from all South Asian congeners, except O. affinis Günther, 1862, O. arnensis , O. cinereus ( Günther, 1864), O. erythrogaster Boulenger, 1907, O. melanozonatus Wall, 1922, O. theobaldi ( Günther, 1868), O. travancoricus Beddome, 1877, O. venustus (Jerdon, 1853) and O. woodmasoni (Sclater, 1891), by having 17 dorsal scale rows at midbody. The new species differs from O. affinis in having higher (170-175) number of ventral scales (vs. 128-133), higher (46-47) number of subcaudal scales (vs. 23-36) and loreal present (vs. absent) ( Smith 1943; Whitaker and Captain 2004). It differs from O. cinereus in having higher (46-47) number of subcaudal scales (vs. 29-42), 7 supralabials (vs. 8), hemipenis forked and spinose (vs. hemipenis not forked, lack spines) ( Smith 1943). It differs from O. erythrogaster by having a loreal present (vs. absent), hemipenis forked and spinose (vs. hemipenis not forked, lack spines) and dorsum with darker bands (vs. dorsum with stripes, bands absent) ( Smith 1943). The new species differs from O. melanozonatus in having 7 supralabials (vs. 6), higher (46-47) number of subcaudal scales (vs. 42-45) and loreal present (vs. absent) ( Smith 1943). It differs from O. theobaldi in having 7 supralabials (vs. 8), higher (46-47) number of subcaudal scales (vs. 30-42), hemipenis forked and spinose (vs. hemipenis not forked, lack spines) ( Smith 1943). The new species differs from O. travancoricus in having higher (170-175) number of ventral scales (vs. 150-155), higher (46-47) number of subcaudal scales (vs. 31-39), loreal present (vs. absent) and hemipenis forked (vs. not forked) ( Smith 1943; Ganesh et al. 2009). It differs from O. venustus in having higher (170-175) number of ventral scales (vs. 138-165), higher (46-47) number of subcaudal scales (vs. 27-36), loreal present (vs. absent) and hemipenis forked (vs. not forked) ( Smith 1943). It differs from O. woodmasoni in having 7 supralabials (vs. 6), hemipenis forked and spinose (vs. hemipenis not forked, lack spines) and dorsum with darker bands (vs. dorsum with stripes, bands absent) ( Smith 1943; Vijayakumar and David 2006). See Table 3 View Table 3 for a summary of comparison with south Asian species.
The new species is most similar to O. arnensis in bearing a banded dorsum, 17 mid-dorsal scale rows and in shape of the Hemipenis. However, differs from O. arnensis sensu stricto (see Discussion) in bearing a loreal shield (vs. absent in O. arnensis ); palatine and pterygoid teeth absent (vs, present in O. arnensis , Fig. 4d-f View Figure 4 ); maxillary teeth gradually increase in size posteriorly (vs. posterior most teeth enlarged abruptly, in O. arnensis ); ventral scales white with brown smear along the width of each scale, the smear is darker on the lateral edges forming a blotch on each side (vs. ventral scales white, lacking markings in O. arnensis ); 48 to 54 bands in total on the body (vs. ≤40 in O. arnensis ).
Description of female holotype NCBS NRC-AA-0019 (Figure 2 View Figure 2 ):
The specimen is in good condition preserved in a coil with its head resting outside the coil. The specimen bears a single longitudinal incision (spanning over nine ventral scales) (Fig. 2a, b View Figure 2 ).
Head short, measuring 10.1 mm from snout to the posterior tip to the parietal scale, comprising 3.6% of total length; high, 5 mm, with steeply domed snout in lateral view; upper jaw visible from ventral side. Head of the same width as the neck (width 6.8 mm). Snout gradually tapering to blunt, rounded tip in dorsal view (Fig. 3a View Figure 3 ). Rostral subtriangular, slightly visible when viewed from top; wider (2.5 mm) than deep (1.6 mm). Nostrils small, elliptical shaped, present in the posterior border of the anterior nasal. The posterior nasal borders the nostrils. Paired internasals, wider (2 mm) than long (1.1 mm); smaller than prefrontals. Prefrontals, wider (2.5 mm) than long (1.7 mm). Frontal roughly hexagonal, bell shaped, 2.7 mm at the widest anterior border, median length 3.8 mm. Parietals 4.2 mm long, 3.2 mm at its widest anterior border. Temporals 1+2, anterior temporal 2.2 mm long and 0.9 mm wide, posterior upper temporal 2.3 mm long and 0.9 mm wide and the lower posterior temporal 1.6 mm and 1 mm long and wide respectively. Six nuchal scales, slightly larger than adjacent dorsal scales, bordering parietals. Supraocular larger than preocular; preocular large, deeper (2.5 mm) than wide (1.5 mm). Loreal roughly pentagonal, longer (1 mm) than high (0.6 mm). Two postoculars, subequal. Eye circular, 1.9 mm diameter of the eye with a circular pupil. Seven supralabials, third and fourth in contact with eye (Fig. 3c, d View Figure 3 ). Supralabial increase in size gradually, fifth and seventh larger than the rest. Second supralabial in contact with posterior nasal, loreal and first + third supralabials. Sixth supralabial deeply embedded between fifth and seventh supralabial, remotely making contact with the upper jawline on the right lateral side of the head (Fig. 3c View Figure 3 ). The sixth supralabial makes broad contact with the jawline on the left side of the head (Fig. 3d View Figure 3 ).
Mental short, triangular, wider (1.9) than long (1.2). Infralabials 7, first really long, II to VI infralabials short and thin, fifth onwards larger (Fig. 3b View Figure 3 ). First four infralabials in contact with the genials. Anterior genials almost one and a half times as long (2.5 mm) as wide (1.7 mm); posterior genials as long as wide (1.2 mm) (Fig. 3b View Figure 3 ). The right genials are fused.
Body rounded, compressed, ventral surface distinctly flattened. Dorsal scales in 17-17-15 rows. First lateral reduction observed after the 10th ventral is at 50% of the ventrals where third and fourth DSR are involved in reduction from 17 DSR to 16 at ventral 85, thereafter from 16 DSR to 15 at the 90th ventral, row 2 +3 involved (52.9%). Dorsal scales imbricate, regularly arranged, vertebral scales not enlarged. All body scales smooth and glossy, without apical pit. Ventral scales 175 in number excluding two preventrals. Anal shield divided, slightly larger than last ventral scale. Subcaudals paired, 46 in number. Tail terminates in a sharp, tapering apical spine. Total length 335 mm, tail length 60 mm, tail/total length ratio 0.18.
Colouration.
'In preservative’ Overall in a shade of pale brown with broad dark brown to black bands throughout the body. Each dorsal scale bears dark brown mottling. The first band is thin that runs across the internasals, the second in shape of a chevron that runs from fourth supralabial along the eye on the either side of the head and joins at the prefrontals. The third one, runs from the posterior of the angle of the jaw along the posterior temporals and further along the parietal and meets the frontal. The fourth broad chevron mark (4-5 scales wide) meets at the posterior portion of the parietal. The dorsal broad black bands are 1-2 scale wide edged with cream colour. The bands in the anterior 1/3rd of the SVL are not connected at the vertebral scale row. Each dorsal band is spaced by 3-4 dorsal scales. Forty-five bands on the dorsum from the nape to the vent and nine bands on the tail. Ventral scales white with brown smear along the width of each scale, the smear is darker on the lateral edges forming a blotch on each side.
Skull features: A complete and robust skull typical of members of the family Colubridae ( Cundall and Irish 2008). Maxilla with 8-10 functional teeth, gradually increasing in size posteriorly (Fig. 4b View Figure 4 ). The palatine bone is slender, lacking teeth so is the pterygoid (Fig. 4c View Figure 4 ). Postorbital bone slender, conical, directed downwards, not making contact with the maxillary bone.
Hemipenial morphology of paratype male BNHS 3657 (everted organs, N=2):
The hemipenis is fully everted and expanded. The organ is stout, slightly bilobed, and semicapitate; lobes extend to about 20% of the hemipenis. The organ is spinous throughout; the spines are larger near the base and mid body and gradually decreases in size distally; sulcus spermaticus deep, bifurcating on the terminal fifth of the hemipenial body, with centrolineal orientation; the spine line on either side of the sulcus spermaticus is weak; hemipenial base is nude, with few spinnules.
Natural history notes.
The holotype and the paratype were found actively moving along a mud road around 20:00 hours (Fig. 6b View Figure 6 ). Additionally, five more individuals (uncollected) of the species were encountered at the same locality between the last weeks of May to late June 2020. All the individuals were found near the village after dusk. Sympatric reptile species recorded at the locality include Cyrtodactylus chamba Agarwal, Khandekar & Bauer, 2018, Asymblepharus sp., Lycodon mackinnoni Wall, 1906, Gloydius himalayanus ( Günther, 1864), Orthriophis hodgsonii ( Günther, 1864), Laudakia sp. and Liopeltis sp. None of the observed individuals showed any sign of aggression nor did they try to bite except for the male paratype, which bit one of us upon capture.
Variation.
The paratype male agrees with the description of the female holotype except for differences listed here: V 170 (+2 preventrals) Sc 47, first 8 subcaudals undivided thereafter the 9th subcaudal is divided followed by three undivided subcaudals and the rest are divided (13th onwards). The colouration of the male is much darker in comparison with the holotype. The number of dark bands on the dorsum in the paratype male is 37 bands from nape to the vent and 11 on the tail. Variation in the scale reduction formula is presented in Table 1 View Table 1 (Suppl. material 3).
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