Ahaetulla sahyadrensis, Mallik & Srikanthan & Pal & D’Souza & Shanker & Ganesh, 2020

Mallik, Ashok Kumar, Srikanthan, Achyuthan N., Pal, Saunak P., D’Souza, Princia Margaret, Shanker, Kartik & Ganesh, Sumaithangi Rajagopalan, 2020, Disentangling vines: a study of morphological crypsis and genetic divergence in vine snakes (Squamata: Colubridae: Ahaetulla) with the description of five new species from Peninsular India, Zootaxa 4874 (1), pp. 1-62 : 25-26

publication ID	https://doi.org/ 10.11646/zootaxa.4874.1.1
publication LSID	lsid:zoobank.org:pub:8FF98990-0E47-4BB7-82BB-098F86771271
DOI	https://doi.org/10.5281/zenodo.4567189
persistent identifier	https://treatment.plazi.org/id/353C523C-141F-2623-FF50-95C9FE62F8D7
treatment provided by	Plazi
scientific name	Ahaetulla sahyadrensis
status	nom. nov.

Treatment

Ahaetulla sahyadrensis nom. nov.

Passerita mycterizans var. fuscus (not of Duméril, Bibron & Duméril, 1854)— Günther, 1858; Beddome, 1862

Dryophis pulverulentus View in CoL (not of Duméril, Bibron & Duméril, 1854)— Wall, 1919: 574

Dryophis pulverulenta indica Deraniyagala, 1955 (non Dryophis prasinus indicus Mell, 1931 )

Ahaetulla indica ( Deraniyagala, 1955) —nomen praoeccupatum pro Ahaetulla indica ( Mell, 1931)

Ahaetulla sahyadrensis nom. nov. —nomen substitutum

Nomenclatural remarks. As the Western Ghats population of A. pulverulenta sensu lato is diagnosed to be distinct at species rank from the Sri Lankan population, the available subspecific nomen Dryophis pulverulenta indica Deraniyagala, 1955 listed as a subjective synonym, should be conferred on it. However, in the Ahaetulla prasina group, there is an available subspecific nomen Dryophis prasinus indicus Mell, 1931 . These nomina are available names and represent taxa that are currently considered congeneric ( Wallach et al. 2014). Thus, Dryophis pulverulenta indica Deraniyagala, 1955 becomes a primary junior homonym of Dryophis prasinus indicus Mell, 1931 . As Deraniyagala’s (1955) nomen is junior to Mell’s (1931) nomen and is thus permanently invalid, and as both these nomina were originally erected at the same taxonomic rank (as subspecific nomina), we consider these nomina as congeneric. As no other subjective synonym is available for the preoccupied nomen (see Wallach et al. 2014), according to Art. 57.2, 59.1 and 60.3 of the Code, we herein erect a new replacement name Ahaetulla sahyadrensis nom. nov. to resolve this case of primary homonymy.

Type material and type locality. As per Recommendation 60A of the Code, the new objective replacement nomen Ahaetulla sahyadrensis nom. nov. takes the same type material and type locality as that of the preoccupied nomen Dryophis pulverulenta indica Deraniyagala, 1955 . Since no type specimen information has been given and the type locality is implied as India ( de Silva 1969), here we designate a neotype and neoparatypes from the collections of BNHS from Peninsular India. As per Art. 75.3 of the Code ( ICZN 1999), since we clarify the status of this available nomen and since its name-bearing types are lost ( Wallach et al. 2014), we designate a neotype that is consistent with the original description ( Deraniyagala 1955) and is in morphological and geographical conformity with the original publication.

Neotype. BNHS 2015 View Materials ; Castle Rock, Karnataka; Coll. Gerhardt P., Year Unknown.

Neoparatypes. BNHS 2012; Nelliyampathy hills; Coll. Kinloch A. M, 1911.

BNHS 2016; Karwar, Karnataka; Coll. McMann C., 1940.

CESS 159 adult female Bhagavathi, Kudremukh National Park , Karnataka, Coll. Ashok Kumar Mallik , 2010.

Comparative material. Ahaetulla pulverulenta : SRI LANKA: BNHS 2009; adult (sex unknown); Ceylon (present day Sri Lanka); Coll. E.E. Green, Year unknown.

BNHS 2010; adult (sex unknown); Matugama, Ceylon (present day Sri Lanka); Coll. Col. Frank Wall, Year unknown.

BNHS 2011; adult (sex unknown); Ceylon (present day Sri Lanka); Coll. W.W.A Phillip., Year unknown.

Type locality (by virtue of neotype designation). Castle Rock (15.393 N, 74.332 E), in Northern Western Ghats , Peninsular India GoogleMaps .

Etymology. Latin, toponym, alluding to its distribution in the Western Ghats or Sahyadri hills.

Diagnosis.

1. Phylogenetically, Ahaetulla sahyadrensis nom. nov. (L7) is nested with the clade comprising A. pulverulenta (L8), A. oxyrhyncha comb. nov. (L1) and A. anomala . It is sister to the clade comprising A. oxyrhyncha comb. nov. and A. anomala .

2. There is a low level (3.2 % in Cytb & 0.4 % in 16S) of genetic divergence between A. sahyadrensis nom. nov. and members (CESS211, CESS244, CESS506, CESS521 & CESS528) of Ahaetulla oxyrhyncha ( Bell, 1825) comb. nov. Ahaetulla anomala also differs from A. sahyadrensis nom. nov. with a low (3.2 % in Cytb and 0.8 % in 16S) level of genetic distance. In addition, A. sahyadrensis nom. nov. shows a moderate level (4.52 % in Cytb and 1.7 % in 16S) of genetic divergence from Sri Lankan A. pulverulenta . Also, A. sahyadrensis nom. nov. differs from the superficially similar, brown coloured A. laudankia as the latter belongs to a separate clade that clusters with Southeast Asian rather than South Asian taxa.

3. This is a species of usually grey-brown coloured Ahaetulla having an elongate multi-scaled rostral appendage and a rhomboid crown marking (vs. rostral scale not multi-scaled in all other sympatric Ahaetulla spp.; except A. anomala and A. pulverulenta ); lacking white or yellow ventrolateral stripe (vs. present in all regional congeners except A. pulverulenta ,); 7 pre-diastemal and 6 post-diastemal maxillary teeth (vs. 7 and 9 in A. isabellina comb. nov., 6 and 7 in A. malabarica sp. nov., vs. 6 and 11 in A. farnsworthi sp. nov., vs. 6 and 8 in A. borealis sp. nov., vs. 7 and 7 in A. oxyrhyncha comb. nov. & 8 and 7 in A. pulverulenta from Sri Lanka, dissected from BNHS 2010); differs from the northern Indian A. laudankia in having much lower ventral scale counts (vs. never less than 192 in A. laudankia ), higher subcaudal scale counts (vs. never more than 185 in A. laudankia ); differs from A. pulverulenta s. str. (of Sri Lanka) in ventral scale counts 182–203 [186–202 in our study] (vs. 179–193 [182–186 in BNHS specimens] in A. pulverulenta s. str.) and subcaudal scale counts 169–208 [175–208 in our study] (vs. 151–178 [158–159 in BNHS specimens] in A. pulverulenta s. str.). The Sri Lankan A. pulverulenta specimens from BNHS also have 10–11 scale rows near the vent whereas A. sahyadrensis has 12–13 rows near the vent ( Fig. 11 View FIGURE 11 & 12 View FIGURE 12 , Table 2 View TABLE 2 ).

4. Being distributed in the Western Ghats, it is separated by a geographic barrier from Sri Lankan A. pulverulenta and is also separated from the lowland species Ahaetulla oxyrhyncha ( Bell, 1825) comb. nov. and A. anomala by occupying a range in the wet hill-forest habitats.

Description of neotype. Adult of total length 1765 mm; dissected; very slender, partially laterally compressed body with snout to vent length 1054 mm; tail length 711 mm; ventrals 179 notched with keels; subcaudals 162 divid-ed; cloacal scale divided; relatively long and slender tail; dorsal scale rows in 15-15-11 rows of smooth, obliquely disposed scales; head very distinct from neck with head length 49.1 mm; transversely oval eyes with horizontal pupil, with a horizontal diameter of 3.4 mm and vertical diameter of 2.3 mm; distance from nostril to eye 11.1 mm; distance from snout tip to eye 18.3 mm; supralabials 8 (both left and right) with 5 th supralabial being the largest, in contact with the eye; 4 th supralabial divided; infralabials 7 (both left and right); 2 nd, 3 rd and 4 th infralabials in contact with the anterior genials; 4 th and 5 th infralabials in contact with the posterior genials; nasal 1 (both left and right); loreals absent; pre-subocular 2 (both left and right); pre-ocular 1 (both left and right); post-oculars 2; sub-oculars absent; temporal 3+3+1 (both left and right); prefrontal scale in contact with pre-oculars; preventrals 2; rostral appendage comprised of numerous smaller scales.

Variations shown by neoparatypes. Ventrals 186–202, subcaudals 175–208, scale rows near the head 13–15, mid body 14–15 and near the vent 11–12.

Colour in life. Dorsum with uniform light brown body with dark brown anteriorly-converging bars from nape till midbody; head with characteristic dark brown rhomboid markings, rostral appendage and eye stripe from the nostril to the nape dark brown; supralabials, infralabials and mentum white with brown spots of variable sizes; venter light brown, finely dotted with dark brown spots ( Fig. 11 View FIGURE 11 h–k).

Colour in preservative. Dorsum uniform light greyish brown body with anteriorly-converging brown bars from nape till midbody; head with dark brown rhomboid markings, rostral appendage and eye stripe from nostril to the nape brown; supralabials, infralabials and mentum white with faded brown spots of variable sizes; venter light brown, finely dotted with brown spots ( Fig. 11 View FIGURE 11 a–g).

Hemipenis (everted). Organ very short (5.7 mm long) and stout (4.9 mm wide); extending upto 2 subcaudal scales; unilobed, lobe head wide (5.3 mm), pedicel not quite narrow (pedicel length 3.4 mm), barely visible through the flounces; organ beset with large spiny flounces fairly densely throughout; length of largest spine 0.9 mm; spines largely erect and short while a few including some on proximal, distal and dorsal part of the organ curved and elongate; in asulcate view, spiny flounces cover the entire length of the pedicel, no plain smooth patch visible; in sulcate, view a mild patch of plain aspinose part visible, sulcus spermaticus mildly visible, like a groove, centripetal, turning to the right ( Fig. 11 View FIGURE 11 d–f).

Maxillary arch dentition (dissected from BNHS 2015). Arched with a dip towards diastema; 13 teeth perpendicular to maxilla, curving inwards; prediastemal teeth 7, postdiastemal teeth 6, observable gradual tooth size increase in prediastemal tooth set with the largest teeth precursing diastema; diastema smaller, about 4 tooth-sockets wide, suffixed with a set of 4 uniform, smaller teeth followed by the last grooved pair of large teeth ( Fig. 6g View FIGURE 6 ).

Distribution and habitat. Ahaetulla sahyadrensis nom. nov. is herein recorded from the Central Western Ghats. However, the actual distribution range will stretch across the Western Ghats ( McCann 1940; Das 2002; Whitaker & Captain 2004), possibly distributed in moist deciduous and evergreen forests from just above sea level till 1500 msl (metres above sea level). They are primarily arboreal, occasionally terrestrial and found in the vicinity of perennial streams.