Platyplectrurus trilineatus ( Beddome, 1867 )

Pyron, Robert Alexander, Ganesh, Sumaithangi Rajagopalan, Sayyed, Amit, Sharma, Vivek, Wallach, Van & Somaweera, Ruchira, 2016, A catalogue and systematic overview of the shield-tailed snakes (Serpentes: Uropeltidae), Zoosystema 38 (4), pp. 453-506 : 477

Platyplectrurus trilineatus ( Beddome, 1867)

Plectrurus trilineatus Beddome, 1867: 14 . Three syntypes: BMNH 1866.12.15.10 (= 1946.1.15.72) and MNHN-RA-1895.112-113. Type locality: Pollachi, Anamalai hills, Tamil Nadu state, India.

Platyplectrurus bilineatus Beddome, 1886: 33 . Three syntypes:BMNH 1883.1.12.60-61 (= 1946.1.23.54-55), MNHN-RA-1895.114. Type locality: “Madura hills”. Designated as a junior subjective synonym by Boulenger (1893a).

DISTRIBUTION. — India, in the Anaimalai and possibly Palni hills, at elevations> 1200 m (see Rajendran 1985; Ganesh 2011, 2015).

DESCRIPTION

Slender, maximum total length c. 390 mm, ventrals 163- 175, subcaudals 8-16 ( Smith 1943; Rajendran 1985; Ganesh 2011). Color pattern typically light brown to reddish-brown dorsal coloration with three rows of dark spots, one down the center of the back, and dorsolaterally on either side of the body (see Ganesh 2011).

REMARK

This species is rarely encountered (see Ganesh 2011). Although reportedly originating from Anaimalais (see Beddome 1867), field studies recorded this species from the Palnis, but surveys in the Anaimalais failed to uncover any specimens ( Roux 1928; Rajendran 1985).

Plectrurus Duméril & Bibron

in Duméril & Duméril, 1851

Plectrurus Duméril & Bibron in Duméril & Duméril, 1851: 224.

Maudia Gray, 1858a: 261 . It appears that Gray (1858a) intended to place Plectrurus perrotetii in Maudia , making it the type species

by monotypy, and rendering Maudia an objective junior synonym of Plectrurus .

TYPE SPECIES. — Plectrurus perrotetii Duméril & Bibron in Duméril & Duméril, 1851.

INCLUDED SPECIES. — Plectrurus aureus Beddome, 1880 , P. guentheri Beddome, 1863 , P. perrotetii .

DISTRIBUTION. — India, Wayanad Plateau and Nilgiri hills (see Beddome 1886; Wallach et al. 2014; Ganesh 2015).

DIAGNOSIS. — Plectrurus can be distinguished from all other amniotes by the characters given for the family, and oculars divided, nasals in contact, no temporal, no mental groove, dorsal scales in 15 rows at midbody, juxtaspedial process distinctly restricted by approximation of dorsal and ventral margin and fenestra pseudorotunda never exposed in lateral view ( P. perrotetii ) or juxtaspedial process wide open laterally and fenestra pseudorotunda may be exposed in lateral view ( P. aureus ; see Olori & Bell 2012), and Oberhäutchen cells 10-20 mm ( P. perrotetii ; Gower 2003).

DESCRIPTION

Tail is slightly compresssed with weakly multicarinate scales terminating in a scute with two bifid points. Between the one specimen of Plectrurus aureus and two of P.perrotetii dissected, no characteristic of visceral topology is significant in uniquely diagnosing the genus from other uropeltid genera. However, a number of characteristics of those specimens appear to be at or near the ranges of other genera. The first is the size of the left lung, which is smaller (mean of 0.85% SVL) compared to the other genera (2.55%). The second is a smaller heart (3.70%) compared to the other genera (4.38%). The third is a more posterior junction of the systemic arches (–0.48%) compared to the other genera (–2.16%). These should be examined in more specimens to determine if they are indeed diagnostic of the genus.

REMARKS

With the exception of Plectrurus perrotetii , which is common at several sites throughout its range ( Rajendran 1985; SRG pers. obs.), the other species are very rarely encountered and have been collected either not at all ( P. aureus ), or very rarely ( P. guentheri ) since their original description in the late 19th century. Gray (1858a) placed Plectrurus in a subgroup Plecturina, which is thus a valid name in the family series (e.g., subfamily Plectrurinae Gray, 1858 ). We do not recognize any subfamilies of Uropeltidae at present. Two specimens in the BMNH (1964.1678 & 1964.1713) have tags labeled “ Plectrurus undescribed sp., In bottle A? Ceylon ”. However, Plectrurus was historically much larger and included many species, including Rhinophis melanogaster (see Peters 1859). These specimens have a rostral separating the nasals, fused oculars, no temporal, and 17 dorsal scale rows, clearly allying them with Sri Lankan Rhinophis , and not Plectrurus or other uropeltid genera with nasals in contact, separated oculars or a temporal, and 15 dorsal scale rows. Positive identification of these specimens is difficult, but we suggest that Plectrurus should not be considered part of the Sri Lankan snake fauna.