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
Author
Mallik, Ashok Kumar
Author
Srikanthan, Achyuthan N.
0000-0003-0570-3330
peltopelor@gmail.com
Author
Pal, Saunak P.
0000-0002-8267-4708
herps.saunak@gmail.com
Author
D’Souza, Princia Margaret
0000-0002-2185-2611
princiadsouza777@gmail.com
Author
Shanker, Kartik
0000-0003-4856-0093
kshanker@gmail.com
Author
Ganesh, Sumaithangi Rajagopalan
0000-0002-1947-8093
snakeranglerr@gmail.com
text
Zootaxa
2020
2020-11-06
4874
1
1
62
journal article
8009
10.11646/zootaxa.4874.1.1
d04aa5ef-c604-457c-92e8-e8c9a88a1eef
1175-5326
4423512
8FF98990-0E47-4BB7-82BB-098F86771271
Ahaetulla pulverulenta
(
Duméril, Bibron & Duméril, 1854
)
Dryinus pulverulentus
Duméril, Bibron & Duméril, 1854
Dryinus fuscus
Duméril, Bibron & Duméril, 1854
—
Dumeril
et al.
1854
part
Dryophis pulverulentus
Jan, 1863
Passerita purpurascens
Günther, 1864
Ahaetulla pulverulenta xanthiscuta
Deraniyagala, 1955
Dryophis pulverulentus
—
Wall 1921
;
Smith 1943
part;
Ahaetulla pulverulenta
—
Das & de Silva 2005
;
Wallach
et al
. 2014
part
Comments:
David & Dubois (2005)
elaborated on the taxonomic and nomenclatural history of this species, besides redescribing its
holotype
. As currently understood, this species has four subjective junior synonyms. One of them
Dryophis pulverulentus
Jan, 1863
is, in addition, also a secondary homonym of
Dryinus pulverulentus
Duméril, Bibron & Duméril, 1854
(see
David & Dubois, 2005
).
Type Material and Type Locality.
Holotype
(by monotypy),
MNHN 7565
coll.
Louis Theodore Leschenault
, collected from “Ceylan”, present day
Sri Lanka
.
Etymology.
Latin, named after its ‘ashy’ or ‘dusty’ greyish brown colouration.
Material examined.
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.
Diagnosis.
1. Phylogenetically,
Ahaetulla pulverulenta
(L8) is sister to the clade comprising
A. sahyadrensis
nom. nov.
(L7),
A. oxyrhyncha
comb. nov.
(L1) and
A. anomala
.
2.
A. pulverulenta
shows a moderate level (4.52 % in Cytb and 1.7 % in 16S) of genetic divergence from
A. sahyadrensis
nom. nov.
of the Western Ghats (see below).
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 Peninsular
India
Ahaetulla
spp., except
A. anomala
and
A. sahyadrensis
nom. nov.
); lacking white or yellow ventrolateral stripe (vs. present in all regional congeners except
A. sahyadrensis
nom. nov
.
); 8 pre-diastemal and 7 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.
& 7 and
6 in
A. sahyadrensis
nom. nov.
from
India
, dissected from BNHS 2010); differs from
A. sahyadrensis
nom. nov.
of
India
in ventral scale counts 179–193 [
182–186 in
BNHS specimens] (vs. 182–203 [
186–202 in
our study] in
A. sahyadrensis
nom. nov.
) and subcaudal scale counts 151–178 [
158–159 in
BNHS specimens] (vs. 169–208 [
175–208 in
our study] in
A. sahyadrensis
nom. nov.
); lower posterior dorsal scale rows count 10–11 (vs.
12–13 in
A. sahyadrensis
nom. nov.
) (
Fig. 11
&
12
,
Table 2
).
4.
Ahaetulla pulverulenta
is an insular endemic species, restricted to the island of
Sri Lanka
and separated by geographic barriers—the Palk Strait and the Indian dry zone—from
A. sahyadrensis
nom. nov.
of the Western Ghats.
Description and Variation.
Adult specimens very slender, partially laterally compressed body with a maximum snout to vent length
827 mm
; tail length (
253 mm
for specimen of SVL
454 mm
; other specimens with broken or damaged tails); ventrals 182–186 notched with keels; subcaudals 158–161 divided; 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, supralabials 8 (both left and right) with 5
th
& 6
th
supralabial being the largest, 5
th
in contact with the eye; 4
th
supralabial divided; infralabials 7 (both left and right);1
st
, 2
nd
, 3
rd
and 4
th
infralabials in contact with the anterior genials; 4
th
, 5
th
and 6
th
infralabials in contact with the posterior genials; mental scale wedged in between 1st pair of infralabials; nasal 1 (both left and right); loreals absent; pre-subocular 1 (both left and right); pre-ocular 1 (both left and right); post-oculars 2; sub-oculars absent; temporal 2+3 (both left and right); prefrontal scale in contact with pre-oculars; preventrals 2; rostral appendage comprised of numerous smaller scales.
FIGURE 11.
Images of
Ahaetulla sahyadrensis
nom. nov.
Images of BNHS2015. (a) Head dorsal. (b) Head lateral. (c) Section of body and ventrals.
(
d–f) Everted Hemipenis. (g) Full specimen. Images of live, uncollected individuals, (h) Near Jog falls, Karnataka, (i) from Agumbe, (j) Kudhremukh, (k) from Agumbe (Images a & b; d, e & f to scale, other images not to scale).
Colour in preservative.
Specimens with light brown to grey dorsum with speckles of dark brown in the light coloured scales; anterior part of the body with hints of black to dark brown cross oblique bands facing backwards; venter light brown to grey with dark brown speckles, uniform throughout the venter, extending till the tip of the tail; head with dark brown markings on the dorsum, prominent pre-ocular and post-ocular stripe in dark brown, dotted with light grey; pre-ocular stripe extends till the nape and abruptly ends.
FIGURE 12.
Images of
Ahaetulla pulverulenta
,
Sri Lanka. (a) Head dorsal, (b) Head lateral, (c) Whole animal (images not to scale).
Maxillary arch dentition (dissected from BNHS 2010).
Arched with a dip towards diastema; 15 teeth perpendicular to maxilla, curving inwards; prediastemal teeth 8, postdiastemal teeth 7, observable gradual tooth size increase in prediastemal tooth set with the largest teeth precursing diastema; diastema smaller, about 3 tooth-sockets wide, suffixed with a set of 5 uniform, smaller teeth followed by the last grooved pair of large teeth (
Fig. 6
).
Distribution and habitat.
Ahaetulla pulverulenta
is endemic to
Sri Lanka
, where it occurs almost throughout the island except the high (>
1200 m
AMSL) elevations (see
Wall 1921
;
Das & de Silva 2005
).