A NEW MONTANE SPECIES OF THE GENUS Pareas WAGLER, 1830 (SQUAMATA: PAREATIDAE) FROM NORTHERN MYANMAR

A new species of the genus Pareas is described from northern Myanmar. It differs from all other known species of the genus by coloration, which is mainly uniform, and its size (one of the largest species in the genus). Furthermore it is characterized by a low number of supralabials (six), a loreal that touches the orbit, presence of a presubocular and absence of a preocular. The new species was found at an elevation of 1890 m a.s.l. and is regarded as an inhabitant of high elevation mountainous areas.


Introduction
The genus Pareas Wagler, 1830 is widely distributed in the Oriental region. Since the description of Pareas nigriceps Guo & Deng, 2009 and the revalidation of Pareas chinensis (Barbour, 1912) by Guo et al. (2011) the genus currently comprised 11 species. Although there have been several revisions (Rao & Yang 1992, Ota et al. 1997, Guo & Deng 2009, Guo et al. 2011, its phylogeny is only partially known (Guo et al. 2011). Several species groups of the genus await clarification of their systematics and an increase in the species number can be expected. Astonishingly, little is known about the natural history of the members of this genus, despite the fact that in some areas, species of this genus are quite common. Together with the monotypic genus Aplopeltura A. Duméril, 1853, and Asthenodipsas Boie, 1827, with five species (Loredo et al. 2013), Pareas is included in the family Pareatidae (Pyron et al. 2011). Snakes of the genus Pareas are mainly arboreal, nocturnal, and feed generally on slugs and snails (Götz, 2002).
In 1999, the National Science Foundation funded a joint three-year collaboration between the Nature and Wildlife Conservation Division, Forestry Department of Myanmar, the California Academy of Sciences, and the Smithsonian Institution, to catalogue the amphibian and reptile species of Myanmar. The core of the project was specimen-based surveys conducted primarily by a trained field team chosen from employees of the Nature and Wildlife Conservation Division, Forestry Department. In the course of this project, a large unusual specimen of the genus Pareas was collected and deposited in the collection of the CAS, which subsequently herein is described as a new species.

Materials and Methods
The specimen of the undescribed species was compared with a total of 128 preserved specimens of all known species of the genera Pareas, Asthenodipsas and Aplopeltura with the exception of Pareas iwasakii from Japan. The external morphological characters and coloration of all the specimens were examined in detail, and the examined materials are listed in Appendix 1.
A total of 40 morphological characters were recorded for each specimen (see Appendix 2). Not all of these characters were useful to distinguish between species in this study, but all of them were compared because they may be of use for further taxonomic studies.
Measurements were taken with a slide-caliper to the nearest 0.1 mm, except body and tail lengths, which were measured to the nearest of one millimeter with a measuring tape. The number of ventral scales was counted according to Dowling (1951). Half ventrals were counted as one. The first enlarged shield anterior to the ventrals was regarded as a preventral and was present in all examined specimens. The first scale under the tail meeting its opposite was regarded as the first subcaudal, and the terminal scute was not included in the number of subcaudals. The dorsal scale rows were counted at one head length behind head, at mid-body, and at one head length before vent. In the number of supralabials touching the subocular, those only touching the presubocular were not included. Infralabials were considered being those shields that were completely below a supralabial and bordering the mouth gap. Usually the last supralabial shield was a very large shield, much larger than other supralabials. Smaller shields behind this enlarged shield do not border the mouth gap (only the connecting muscle) and were excluded in the sublabial scales count, despite the fact that they were covered by the supralabials. The first sublabial was defined as the scale that starts between the posterior chin shield and the infralabials and that borders the infralabials. Values for paired head characters were recorded on both sides of the head, and were reported in a left / right order. The sex was determined by dissection of the ventral tail base.

Diagnosis:
A species of the genus Pareas characterized by a large size (in the single known specimen 657 mm); loreal widely touching orbit; vertebral scales smooth and not enlarged; dorsal scales smooth; 178 ventrals in the single known female, males unknown; 61 subcaudals in the single known female; relative TL 0.198 in the single known female; 6 supralabials with SL 3-4 touching the subocular; 6 infralabials, first ones touching behind the mental shield; no pre-or postocular, one presubocular; 2 anterior temporals; body pattern uniform and no markings on the head, no collar. The new species can be diagnosed by its large size, low number of supralabials and infralabials, and unusual uniform pattern for this genus.
Etymology: This species is named in honour of Jens Vindum (CAS, San Francisco, USA), for his enormous contributions to the CAS expeditions to Myanmar. I suggest the following common names: Vindum's Slug Eater (English), Vindums Schneckenfresser (German).

Colour in preservative:
Head and body chocolate-brown with very fine dark and pale specklings, only visible in close-up view; no markings or bands on the body and head; head the same colour as body, paler in the temporal region, whitish-cream on upper and lower labials, head sides with fine speckles, more intense on the sutures of the upper labials and in the temporal region; lower labials also speckled but less intensively than supralabials; eye black; underside of head coloured like ventral side of the body, also with fine speckles. Venter whitish-cream with fine specklings, more concentrated to the base of the ventrals. Tail coloured like body, ventrally heavily speckled.
Distribution and natural history: Pareas vindumi sp. nov. is currently only known by an unique specimen from the Chipwi Township region of Kachin State, Myanmar. It should be expected in the surrounding mountainous areas and in neighboring Republic of China. The holotype was found at an elevation of 1,890 m a.s.l., at about 9.00 PM. Nothing else was recorded, but obviously this is a species living at high elevations. No further information is known on the biology of this species.

Discussion
In Guo & Deng (2009), the new species keys out as P. monticola (Cantor, 1839). The pholidosis is most similar to P. boulengeri (Angel, 1920). However both species have a banded pattern and distinct neck-and head markings as well as more supralabials and more infralabials (Figs. 4 & 5). I refrain from providing a new key, due to the fact that several publications on this genus are about to be published and the key would be outdated shortly after it is printed.
Pareas vindumi sp. nov. can be distinguished from the other members of the genus Pareas as follows (values of P. vindumi sp. nov. vs. the compared species in brackets). Only the most diagnostic differences are listed. The data of the compared species were taken from specimens listed in Appendix 1 and for P. iwasakii from Guo & Deng (2009) From P. boulengeri (Fig. 4) it differs by the lower number of supralabials (6 vs. 7-8), by the fact that only two supralabials touch the sublabial (versus usually 4 rarely 3); by the presence of a presubocular (vs. none) and by the lower number of infralabials (6 vs. 8 or rarely 7 or 9). P. boulengeri has a totally different colouration. In Pareas vindumi sp. nov., there are no postocular stripes (against 2), there is no mask like mark in the neck (against such a mark present) and there are no bands on the body (against 38-48 bands in the three types of P. boulengeri). The subcaudals are heavily mottled in Pareas vindumi sp. nov. (against a few scattered spots). There is considerable confusion in the literature about the determination of the species P. boulengeri, P. chinensis, P. monticola and P. formosensis. So the new species was explicitly compared to the syntypes of P. boulengeri.
From P. monticola (Fig. 5) it differs by the lower number of Ve (178 vs 182-189) and Sc (61 vs. 69-72, 84 in the holotype of Amblycephalus monticola [Boulenger, 1896]), by the lower number of supralabials (6 vs. 7), by the lower number of infralabials (6 vs. 7-9), and by the absence of a postocular (vs. presence). P. monticola has a totally different colouration. In Pareas vindumi sp. nov., there are no postocular stripes (against 2), there is no mask like mark in the neck (against such a mark present) and there are no bands on the body (against 48-60 bands in three females of P. monticola). The subcaudals are heavily mottled in Pareas vindumi sp. nov. (against a few scattered spots ).
From the P. chinensis / formosensis-complex it differs by its larger size, by the lower number of Sc (61 vs. 65-80), by the lower number of supralabials (6 vs. 7-8), by the lower number of infralabials (6 vs. 7-9), by the Lo touching the eye (vs. not touching) and by the presence of a presubocular (vs. none).
From P. nigriceps it differs by the lower number of supralabials (6 vs.7), by the lower number of infralabials (6 vs. 7), by the smooth dorsal scales (vs. keeled in the 9 median rows) and by the not enlarged vertebral scales (vs. enlarged). P. nigriceps furthermore has a very characteristic coloration.
From P. stanleyi (Boulenger, 1914) it differs by the higher number of Ve (178 vs. 151-160), by the smooth dorsal scales (vs. keeled in the 13 median rows), by the not enlarged vertebral scales (vs. enlarged), by the presence of a subocular (vs. absent) and by the lower number of infralabials (6 vs. 7-9).
Currently Pareas vindumi sp. nov. cannot be assigned to any species group in this genus, and based on the pholidosis it seems to be an isolated species. Very surprising is the high elevation of 1890 m a.s.l. at which the specimen was found. Only few snake species are known from such high elevations in Myanmar.
The discovery of several new species is not surprising considering the isolated geographical situation of the area, located between the Irrawaddi River and the Hengduan mountains area and the paucity of collections. More new species can be expected when the collected material has been worked through. Four more new snake species were described as a result of the CAS expeditions to Myanmar: Naja madalayensis Slowinski & Wüster, 2000, Lycodon zawi Slowinski, Pawar, Win, Thin, Gyi, Oo & Tun, 2001, Python kyaiktiyo Zug, Gotte & Jacobs, 2011