Blythia hmuifang, Vogel & Lalremsanga, 2017

Vogel, Gernot & Lalremsanga, Hmar Tlawmte, 2017, A second species of the genus Blythia Theobald, 1868 (Squamata: Colubridae) from Mizoram, India, Zootaxa 4276 (4), pp. 569-581 : 570-576

Blythia hmuifang sp. nov.

( Figs. 1–8 )

Holotype. MZMU 714 , male, from Hmuifang Community forest , Aizawl District, Mizoram, India , 23o27'13.5"N; 92o45'09.5"E, elevation 1,442 m asl., collected by H.T. Lalremsanga and Zodinliana Fanai on 14th April 2015.

Paratypes (n=3). MZMU 715 , female, the same locality as the holotype, 23o47'52.7"N; 92o 43'40.8"E, elevation 1,458 m asl, collected by Mr. R. Lalthlengliana on 22nd April 2015 ; MZMU 716 (male) and MZMU 717 (female), both collected by C. Siamkima near Lungkawlh village , Serchhip district, Mizoram, India on 4th and 8th April 2016, respectively.

Diagnosis. A species of the genus Blythia characterized by the combination of: (1) 114–117 ventrals; (2) 18– 21 subcaudals; (3) a long tail in females (TaL/TL 0.109–0.116); (4) light upper labials with dark upper margins (5) venter bright orange-red or cream in life.

Description of holotype. In a good state of preservation, hemipenes everted. Body cylindrical and elongate; head elongate, bluntly pointed, distinct from neck; snout long, nearly twice as long as eye diameter; small, round nostril piercing between two small nasals, touching the first supralabial below; eye moderate, its diameter slightly smaller than its distance to the nostril, round pupil; scales smooth without apical pits; tail short, tapering progressively and pointed.

Measurements. SVL: 154 mm; TaL: 21 mm; TL: 175 mm; ratio of TaL/TL: 0.120; HL: 4.84 mm; SnL: 2.30 mm.

Dentition. As these specimens are quite small, we did not examine the teeth in detail. However the maxillary teeth in the middle are larger than anterior and posterior ones as described in the definition of the genus according to Smith (1943).

Hemipenis. Simple, cylindrical organ extending up to the 5th subcaudal scales, not forked; sparsely spinous proximally and calyculate distally throughout, the spines increase in size from the proximal region to the distal region of hemipenial core; apical lobes terminate flat, surrounded by strong and exposed calyculate spines; sulcus spermaticus simple or undivided; the spine line on the either side of the sulcus spermaticus is very weak; the base of the hemipenes is nude (see Fig. 5 ).

Body scalation. DSR: 13–13–13, all smooth; 114 Ve (+ 2 preventrals); 21 Sc, all paired; anal divided; terminal caudal scale pointing.

Head scalation. Upper head scalation complete, including 2 internasals, 2 prefrontals, 2 supraoculars, 1 frontal, and 2 parietals. Rostral wider than high, hardly visible from above; 2 small, triangular nasals, the nostril in between; internasals trapezoid, much wider than long, less than half as long as prefrontals; the short suture between internasals about two thirds as long as the suture between prefrontals; prefrontals large, much wider than long, their suture about one third as long as frontal, touching the 2nd and 3rd supralabials on each side; supraoculars quadrangular, narrow, more than twice as long as broad; frontal, large, hexagonal, long and wide, about 1.4 times longer than wide; parietals very large, extending on about 45% of HL, longer than wide, about 1.5 times longer than frontal; a small nuchal scale behind parietal; no loreal scale; 6 / 6 SL, 1st in contact with both nasals, 2nd in contact with posterior nasal, 2nd and 3rd in contact with prefrontal, 3rd and 4th SL entering orbit, 6th SL largest; no preoculars, prefrontal entering orbit; no suboculars; 1 / 1 postocular; 1 / 1 large temporal, followed by a paraparietal and an enlarged dorsal scale, temporal touching the 5th and 6th supralabials; 6 / 6 IL, 1st IL broadly in contact each with the other, 1st–4th IL in contact with anterior chin shields; mental small; anterior chin shields more than twice as long as the short posterior ones.

Colour and pattern. Body and tail dark brown, dorsal scales with fine speckling and a mixture of cream, pale orange and bright orange upon closer examination; this speckling becomes darker posteriorly resulting in a slightly darker appearance of the tail. Dorsal scales edged in darker colour; a faint longitudinal dark ventrolateral line between the 2nd and 3rd dorsal scale rows, extending from the neck region to the tail tip; two more indistinct ventrolateral lines also present between the 1st and 2nd dorsal scale rows as well as between the 4th and 5th; the ventrolateral line between the 1st and 2nd scale rows disappearing beyond the vent while that between the 4th and 5th scale rows extending indistinctly to the tail tip; a pale orange, complete crossband on the neck, from the first ventral to the parietals and extending across the temporal up to the corner of the mouth. Lower part of supralabials cream, upper part dark, forming a dark stripe, extending posteriorly to the anterior half of the temporal and 6th supralabial. The interscales between 5th supralabial, temporal and 6th supralabial mottled with cream colour. Internasals dark with irregular light marbling, the remaining part of the head coloured like the dorsal part of the body.

The chin and throat cream, with few dark brown irregular blotches, especially along the margins of the first three lower labials and anterior chin shields. The tongue dark with a cream tip in life.

The venter bright orange-red in life ( Fig. 2 ), cream in preservative, ventrals uniformly dark mottled at their lateral parts. A few tiny scattered brown spots on the venter. Posterior margin of the ventrals lighter. In life, ventral surface of the tail heavily mottled with dark spots, paler anteriorly than posteriorly, with a few scattered red parts.

Variation. The new species is known only from the male holotype and three paratypes (one male and two females). Morphologically, the three paratypes agreed well with the holotype, except in the following characters (characters of the holotype in brackets): maximal known SVL: 176 mm (154 mm); TaL: 23 mm (21 mm); TL: 195 mm (175 mm); ratio TaL/TL: 0.109–0.120 (0.120); Ve 114–117 (114), Sc 19–21 (21); the absence of a pale band on the neck region and cream colouration of the venter in MZMU 716 which is the largest specimen ( Fig. 4 ). The reason for this could be an ontogenetic shift (see Table 1 for a detailed comparison). There is not enough material available for a detailed analysis of a sexual dimorphism, but a comparison of the four specimens show that females obviously have a shorter tail, fewer Sc and more Ve, and the variation is usually found in colubrid snakes ( Kopstein 1941).

Comparisons. Blythia hmuifang spec. nov. differs from B. reticulata , the only known species of the genus in the number of ventral scales (114–117 vs. 129–149), the number of subcaudal scales in males (20–21 vs. 22–32), the proportion of tail length/total length in females (0.109–0.116 vs. 0.076–0.098), the colour of the venter (bright orange-red in smaller specimens, cream in the largest specimen vs. black in all ages), the colouration of the supralabials (lower part of the supralabials pale vs. totally dark) and other smaller differences in the colouration ( Smith, 1943 and examined specimens [Appendix]). The hemipenis of the new species also differs from that of Blythia reticulata (sparsely spinous vs. uniformly spinose; longitudinal folds absent vs. present; terminate with blunt vs. lobe, see Fig. 5 ).

Blythia hmuifang spec. nov. differs from the holotype of Aproaspidops antecursorum Annadale, 1912 , which is a juvenile female, most notably by the number of ventral scales (114–117 vs. 149) and by the colour of the belly (bright orange red in smaller specimens, cream in the largest specimen vs. dark olive with paler border). For the present time we regard Aproaspidops antecursorum as a synonym of Blythia reticulata .

Blythia hmuifang spec. nov. differs from members of the superficially similar genus Trachischium by the absence of a loreal and a preocular scale, from the genus Calamaria by the presence of internasals and one temporal scale, and from the genus Xylophis by the absence of a loreal scale.

Three specimens of B. hmuifang spec. nov., MZMU 714, MZMU 715 and MZMU 717 may still have juvenile coloration with the light collar in the neck, which is also present in juveniles of B. reticulata ( Fig. 6 ).

Etymology. The new species is named in honour of the people of the Hmuifang village who have gone to great lengths to preserve their natural landscape. As common names, we suggest Mizoram Ground Snake (English), Mizoram Bodennatter (German) and Lunghnuairul (Mizo).

Distribution. Blythia hmuifang sp. nov. is known only from the two following localities, both in Mizoram, India: Hmuifang, Aizawl District (type locality) and near Lungkawlh village, Serchhip District. It may be expected in neighbouring states of Manipur and Nagaland, and in Myanmar. It may have been overlooked due to its small size or most probably due to its secretive habits.

Natural history. The type locality located between 92°45'21''E–92°46'01''E and 23°26'19''N–23°27'26''N with elevations from 1,430 to 1,619 m asl. The annual precipitation is approximately 3,100 mm. It is located at a distance of ca. 50 km to the south of Aizawl city, the capital of Mizoram. The area is covered with moist tropical montane forests which have been preserved since the days of the Mizo chiefs during the early 19th century. Small perennial streams originate below the virgin forest that surrounds a natural lawn. Undergrowth within the forest contains largely herbaceous plants and fern species. The most common trees present in the area are

The most common trees present in the area are Callophyllum polyanthum Wall. ex Planch. & Triana (family Calophyllaceae ), Elaeocarpus rugosus Roxb. ex G.Don (family Elaeocarpaceae ), Engelhardtia spicata Lechen ex Blume (family Juglandaceae ), Quercus leucotrichophora A.Camus 1935 (family Fagaceae ), Quercus polystachyus (Wall. ex A.DC.) Rehder (family Fagaceae ), Rubia cordifolia L. (family Rubiaceae ), Syzygium claviflorum (Roxb.) Wall. ex. A.M.Cowan & Cowan (family Myrtaceae ), Syzygium cumini (L.) Skeels (family Myrtaceae ), Wendlandia budleioides Wall. ex. Wight & Arn. (family Rubiaceae ), etc. Three species of bamboo, Chimonocalamus griffithianus (Munro) Hsueh & T.P.Yi (family Poaceae ), Cephalostachyum latifolium Munro (family Poaceae ) and Pseudostachyum polymorphum Munro (family Poaceae ) and other vegetations, like Ageratina adenophora (Spreng.) R.M.King & H.Rob. (family Compositae ), Amomum dealbatum Roxb. (family Zingiberaceae ), Amorphophallus sp. (family Araceae ), Aneoctochilus brevilabris Lindl. (family Orchidaceae ), Begonia palmata D.Don (family Begoniaceae ), Cinnamomum tamala (Buch.-Ham.) T.Nees & Eberm. (family Lauraceae ), Calocasia sp. (family Araceae ), Urena lobata L. (family Malvaceae ), etc. are also identified.

The holotype was encountered and collected under wet bolders from the intermittent stream that seeps from crevices of rocky bed under the forested area (23o 27'13.5" N; 92o 45'0.9.5"E; 1442 m asl) at around 03:45 PM on 14th April 2015 ( Fig. 7 ). The paratype, MZMU 715 was collected from the foot path just in front of the tourist lodge (23o 47'52.7" N; 92o 43'40. 8"E; 1458 m asl, about 300 m away from the holotype collection site) at around 06:30 AM on the 22nd April 2015. Two other paratypes, MZMU 716 and MZMU 717, were collected underneath rocks during day time by workers while constructing the road, near Lungkawlh village which is very close to the Myanmar border ( Fig. 8 ).

The new species seems to be semi-aquatic and crepuscular rather than diurnal or nocturnal. The species is seeminly very rare and / or highly secretive; a thorough day and night survey on the herpetofauna of this area conducted since the year 2010 to date has yielded only these four individuals of the species. Sympatric snake species found during the surveys were Blythia reticulata, Trimeresurus popeiorum Smith, T. erythrurus (Cantor) , Pareas monticola (Cantor) , Oligodon albocinctus (Cantor) , Boiga ochracea (Theobald) and Rhabdophis subminiatus (Schlegel) . Other herpetofauna of this type locality include the following amphibians: Rhacophorus maximus Günther , Rhacophorus bipunctatus Ahl , Rhacophorus suffry Bordoloi, Bortamuli & Ohler , Kurixalus sp., Xenophrys serchhipii Mathew & Sen , Fejervarya limnocharis (Gravenhorst) , Duttaphrynus melanostictus (Schneider) , Duttaphrynus chandai Das, Chetia, Dutta & Sengupta , Odorrana mawphlangensis (Pillai & Chanda) , Amolops afghanus (Günther) , Philautus sp., Polypedates himalayensis (Annandale) and unidentified rhacophorid species, and lizards including Japalura otai Mahony , Calotes versicolor (Daudin) , Oriocalotes paulus (Smith) and Cyrtodactylus sp. All handled specimens were very timid, gentle, and inoffensive in disposition. The holotype was kept in captivity for 22 days and provided with tadpoles, froglets, earthworms and insects. The snake did not feed on these provided food items. Water was accepted. It did not bite when handled.

Figures

FIGURE 1. Holotype of Blythia hmuifang sp. nov. (MZMU 714): General view (A) and lateral view of head (B), left side.

FIGURE 2. Holotype of Blythia hmuifang sp. nov. (MZMU 714, male): Ventral view, freshly preserved.

FIGURE 3. Holotype of Blythia hmuifang sp. nov. (MZMU 714) in life.

FIGURE 4. Comparison of the heads of (A) the holotype of Blythia hmuifang sp. nov. (MZMU 714), (B) a paratype of Blythia hmuifang sp. nov. (MZMU 716) and (C) B. reticulata (MZU 802).

FIGURE 5. Hemipenes of Blythia reticulata (A) and the holotype of B. hmuifang sp. nov. MZMU 714 (B).

FIGURE 6. Comparison of the paratype of Blythia hmuifang sp. nov. left (MZMU 715, female) with a juvenile of Blythia reticulata (Blyth, 1854) right.

FIGURE 7. Habitat of the holotype of Blythia hmuifang sp. nov. at Hmuifang Community Reserved Forest.

FIGURE 8. Map showing the distribution of Blythia hmuifang sp. nov. and the known distribution of B. reticulata: 1. Htingnam; 2. Sumprabum; 3. Gandhigram; 4. Renging, Janakmukh and Rotung; 5. Dejoo, of North Lakhimpur; 6. Dafla Hill; 7. Itanagar; 8. Chessa; 9. Orang National Park; 10. Upper Shillong; 11. Shillong; 12. Cherrapunji; 13. Samagooting; 14. Kohima; 15. Ukhrul; 16. Lawachara Reserve; 17. Sawleng; 18. Sihphir; 19. Sihhmui; 20. Durtlang and Aizawl; 21. Hmuifang; 22. Lungkawlh; 23. Fort White; 24. Hakka.