REVALIDATION OF Lycodon hypsirhinoides (THEOBALD, 1868) FROM ANDAMAN ISLANDS (SQUAMATA: SERPENTES: COLUBRIDAE)

The Andaman population of the genus Lycodon is compared to Lycodon capucinus Boie, 1827 and Lycodon aulicus (Linnaeus, 1758) occurring on the eastern and western parts of the range of this species complex. The population was found to be distinct and the species name Lycodon hypsirhinoides (Theobald, 1868) is revalidated for this population. It differs from both species in the size, proportions and colouration of adults and juveniles.


Introduction
The genus Lycodon Boie, 1826 currently comprises 36 species (Uetz, 2012). This genus is characterized by the following combination of characters: head depressed dorsoventrally, barely set off from body; a relatively small eye with a vertically elliptic pupil; large nostril; an upper maxillary bone both strongly arched and bent inwards anteriorly; anterior maxillary teeth curved, with a gap between the very large anterior teeth and the subsequent ones; dorsal scales smooth or feebly keeled in 17, 19, or 21 rows at mid-body, and the ventrals rounded (Malkmus et al., 2002). Species of this genus are small to medium sized, crepuscular to nocturnal ground dwellers with a good ability to climb. They feed mainly on lizards, frogs, and snakes. Juveniles usually possess more intense colours and more contrasting patterns. All species are oviparous (de Lang & Vogel, 2005). Some are anthropophilous species, living close to human settlings, making dispersal by humans likely. of the genus, Lycodon capucinus Boie, 1827, is known to be easily introduced to non-native areas and is increasing its range (Smith, 1988;Fritts, 1993). Considering the issues surrounding invasive species such as Lycodon capucinus (Cogger, 2006), it is important to know the biogeographic patterns of members of the Lycodon aulicus-capucinus complex. The constant delay of these tasks will lead to problems in reconstruction of the original distribution area and might lead to unnoticed extinction of similar species, especially of the same genus. The introduction of an invasive species might be disguised. The disastrous results of the introduction of invasive snake species are well known (Rodda & Fritts, 1992;Rodda et al., 1999, Cogger, 2006. The long and confusing history of the genus name is discussed by Adler & Zhao (1995). The history of the species names Lycodon aulicus and L. capucinus has a similar complex past. It is beyond the scope of this paper to discuss the taxonomic history of these names in detail. Since Taylor (1965), both taxa are usually treated as full species (but see Lanza 1999). In 2007, another species of this group was described from South India as Lycodon flavicollis Mukherjee & Bhupathy, 2007. In 1868, Theobald described Tytleria hypsirhinoides based on a single specimen collected by R. C. Tytler from the 'Andamans, in the Bay of Bengal'. He created the new genus by monotypy and compared this genus only with the genus Hypsirhina (now a synonym of Enhydris). The species was synonymized with Lycodon aulicus (including L. capucinus), by Theobald in 1876. Since then, it was treated as a subjective synonym of Lycodon aulicus or later Lycodon capucinus by others (Boulenger, 1893;Smith 1943) without being discussed. Das et al. (1998) listed the holotype in the collection of ZSI (ZSI 8145) (Figs. 1, 2). We show that the population from Andaman Islands warrant species status based on the biological species concept, i.e., a diagnosable, reproductively isolated population that does not naturally interbreed with other populations. The insularity of this population means it has an evolutionary history distinct from other Lycodon populations elsewhere, and we resurrect its species status as Lycodon hypsirhinoides (Theobald, 1868).

Material & Methods
We compared 13 preserved and 26 live and uncollected specimens (for colour in life) of L. hypsirhinoides from different islands of the Andamans with 15 preserved and about 10 live specimens of Lycodon capucinus and 16 preserved and a larger number of live specimens of Lycodon aulicus. The preserved specimens were examined for external morphological characters and dentition (Appendix I). Twenty nine morphological and colouration characters were recorded for each specimen (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 useful for further taxonomic actions.
Measurements, except body and tail lengths, were taken with a slide-caliper to the nearest 0.1 mm; all body measurements were made to the nearest millimeter. The number of ventral scales was counted according to Dowling (1951). Half ventrals were counted as one. The first scale under the tail meeting its opposite was regarded as the first subcaudal, the terminal scute was not included in the number of subcaudals. The dorsal scale rows were counted at one head length behind head, at midbody (i.e., at the level of the ventral plate corresponding to a half of the total number of ventrals), and at one head length before vent.
We considered sublabials being those shields that were completely below a supralabial. Values for paired head characters are given in left / right order. The sex was determined by dissection of the ventral tail base when possible or by everting the hemipenes in male specimens.

Results
Theobald's original description of the type is brief (Theobald, 1868), and we quote below the description of the genus and species verbatim. Page 66: "TYTLERIA, Theobald. Aspect of Hipsirhina. Scales, smooth, in seventeen rows. Nostril lateral, almost dividing a smallish oblong nasal: frontals two pair: three upper labials enter the orbit. Loreal elongate: anal and subcaudals bifid: eye small; pupil vertical. T. hypsirhinoides, Theobald. Habit moderate, aspect of the Enhydrinae. Head shield normal. Anterior frontals slightly pentagonal, half as large as posterior. Nasal a trifle less than loreal. Ante-ocular one, reaching to the vertical. Postoculars two, small. Vertical straight in front, sides rapidly converging behind. Superciliaries moderate, broad behind. Occipitals moderate. Upper labials nine, 3rd, 4th and 6th enter the orbit. Two pairs of chin shields touching one another. Sixth lower labial largest, touches the middle of second chin shield. Color uniform reddish brown above. Belly yellowish white, length 21.00, tail injured 1.00 = 22.00 inches. a. type specimen. Andamans. Lt.-Col. Tytler." Diagnosis: A relatively large species of Lycodon (max. total length 717 mm) with stout body; juveniles with a speckled brown/white pattern on body and a dark brown head with white collar; adults uniform dark brown; collar band absent or very faint in younger specimens; body scales in 17:17:15, ventrals 188-210, divided anal, subcaudals 61-75.

Redescription of the holotype of Tytleria hypsirhinoides (ZSI 8145):
Holotype: ZSI 8145: unknown sex; Andamans (in the Bay of Bengal, India); Coll. R. C. Tytler; Date. Unknown (The holoype is a relatively large individual of unknown sex. Sex determination was not possible since we could not dissect the unique specimen but due to the number of ventrals we assume that it is a female. The specimen was soft to touch and very flexible). Body stout; snout-vent length 525 mm: most of the tail missing; total length 550 mm; head depressed, dorso-ventrally flattened, widest at the temporal region; 9/9 supralabials, 3rd to 5th in contact with the eye; rostral broader than high; anterior and posterior nasals of similar size, nostril in the division of the two; single elongated loreal; loreal in broad contact with internasal and second and third supralabials; 1/1 preocular, in contact with the frontal; 2/2 post-oculars; temporals 2+3, subequal in size; internasals about half as long as prefrontals; prefrontals wider than internasals; frontal large, as long as the combined length of internasals and prefrontals; supraoculars about half as wide as frontal; parietals about 1.5 times as long as frontal; mental triangular, narrower than rostral; 10/10 infralabials, first pair in contact with each other, sixth largest; anterior genials a little longer than posterior; scales in 17:17:15 rows; 210 ventrals, with a notch on either side; divided anal; 13+ subcauduals (tail incomplete).

Colour in alcohol:
The entire specimen is pale buff coloured, a little lighter on the ventrals. Natural history: Lycodon hypsirhinoides is a common snake, occurring in many of the islands in the Andaman Islands. Though it is often found close to human habitation, it is also common in evergreen and semi-evergreen forests. Individuals were found in leaf-litter, under tree bark, tree holes, and inside rotting logs and lianas. All active individuals were found at night. It is a shy snake that rarely bites when captured.
Despite the fact that the main differences between the Andaman population and the other species are the total length and the colouration of juveniles and adults, there can be no doubt that this population is specifically different from L. capucinus, L. aulicus and L. flavicollis. The differences from L. aulicus, and L. flavicollis are obvious and need no further explanation (see the discussion).
At the moment, L. hypsirhinoides is regarded as an objective synonym of L. capucinus. L. capucinus is a species with a wide distribution in Asia. It is known from Australia (Cook  Islands) (David & Vogel, 1996;How et al., 1996;Uetz, 2012). For comparison, we used specimens of populations from localities being distributed all over the species range as: Java, Borneo, Flores, Lombok, Timor, Thailand, Vietnam and Philippines (Samar). These localities were chosen to get a wide range of variation and to determine whether populations differ from each other in a way the Andaman population differs from them. It was quite astonishing to see that there was hardly any variation in the colouration of the specimens of L. capucinus. This was already noted for this species by Leviton on the Philippines (1965), where it is widely distributed and by Mertens (1930) and How et al. (1996) for the Lesser Sunda Islands. How et al. (1996) especially noted that there is no variation in colour or pattern by the studied specimens.

Discussion
Lycodon hypsirhinoides differs from L. aulicus in colouration (dark-brown against middle/reddish brown), pattern (uniform against banded anteriorly), the missing light collar (present in L. aulicus) and a larger body size in males. Further, colouration and pattern of juveniles is different. Juvenile L. aulicus resemble adults in colour and pattern, and there is no ontogenic shift in colouration. Juvenile L. hypsirhinoides have a speckled dark brown and white appearance (Fig. 3 & 4), which fades and becomes uniform dark brown or nearly black in adults (Fig. 5 & 6).      (Theobald, 1868) from Wandoor, South Andaman Island.

A B C D
From L. capucinus it differs in colouration (dark-brown against middle brown or purplishbrown) pattern (uniform against reticulate), the faint/absent light collar and a larger body size in males. The upper labials of L. capucinus usually have dark centres (Fig. 5, 7); these are missing in L. hypsirhinoides. The colouration and pattern of juveniles is also different. The males are larger than the females in L. hypsirhinoides, in L. capucinus the size of the sexes is more or less the same (How et al. 1996). There is no or nearly no ontogenetic shift in colour in L. capucinus, while it is distinct in L. hypsirhinoides (see also Smith 1943 and Fig. 3, 7). The populations of L. capucinus bear a striking resemblance to each other (Fig. 8). This suggests a recent colonisation of at least part of the distribution area, most probably by anthropogenic effects. Nevertheless without doubt a part of the investigated populations stem from the original distribution area.
There are two other species of Lycodon reported from Andaman and Nicobar Islands. These are Lycodon tiwarii Biswas & Sanyal, 1965 and Lycodon subcinctus Boie, 1827(Biswas & Sanyal, 1965Das, 1999;Vijayakumar & David, 2005;Harikrishnan et al., 2010). The holotype of Lycodon tiwarii is from Mayabunder in Middle Andaman, a locality within the range of Lycodon hypsirhinoides. All subsequent records of L. tiwarii including the paratype are from Nicobar Islands. L. subcinctus is also known only from Great Nicobar Island and not in the Andaman Islands. If one considers the possibility of erroneous type locality for L. tiwarii, the three species of wolfsnakes in the Andaman Islands will have mutually exclusive distribution ranges ie. L. hypsirhinoides in the Andaman Islands, L. tiwarii in the Car Nicobar and Nancowry group of islands and L. subcinctus in the Great Nicobar Island (Fig. 9).
In 1827 F. Boie described Lycodon unicolor based on the manuscript of H. Boie and Russell´s plate 39 (1810). The manuscript of H.
Boie was never published. The accompanying text of Russell gives for the specimen on plate 39 the following data: 265 ventrals + 67 subcaudals, length 4 feet 10 inches. Of the subcaudals apparently 36 are divided, 28 entire and the last 3 divided again. The locality is Bengal and the specimen was received from Alexander Russell of Calcutta in June 1788. The identity of this specimen cannot be resolved at this moment, but due to the high ventral count, it cannot belong to one of the three species treated.
It is important to note the distinctness of the population from the Andamans. It cannot be ruled out, that in near future L. capucinus might reach the Andamans and even displace the population of L. hypsirhinoides. Perhaps it is already there, but unnoticed due to limited collection or taxonomic confusions. It is the main concern of this paper to work against this.
TAPROBANICA VOL. 05: NO. 01 Figure 9: The distribution of three Lycodon species known from Andaman and Nicobar Islands. The type locality of Lycodon hypsirhinoides is "Andamans, in the Bay of Bengal". The holotype of L. tiwarii is from Mayabunder (indicated by a red dot), North Andaman, Andaman Islands, while the paratype is from Car Nicobar Island in the Nicobar Islands.