Taxonomic status of the arboreal Skink Lizard Dasia halianus (Haly & Nevill, 1887) in Sri Lanka and the redescription of Dasia subcaeruleum (Boulenger, 1891) from India

Author Contribution: The first author designed and carried out the study, while the co-authors, contributed with the preparation of the manuscript, literature survey and reference works in the corresponding museums. Abstract: A comparative study of Dasia halianus in India and Sri Lanka is discussed. Indian specimens of “D. halianus” are in fact referable to D. subcaeruleum. D. halianus is again considered a Sri Lankan endemic.


INTRODUCTION
By 2001 a total of 84 species of scincid lizards belonging to 19 genera were recognized in South Asia, 62 in India and 27 in Sri Lanka, with seven species common to both (Das 2001).Since then four new species have been described, a new range extension of Chalcides cf.ocellatus from Sri Lanka and a new genus described from India, increasing the total number of species to 89 (Batuwita & Pethiyagoda 2007;Wickramasinghe et al. 2007;Das et al. 2008;Karunarathna et al. 2008), and the genera to 20 (Eremchenko & Das 2004).Also, the genus Mabuya in the region was changed to Eutropis, keeping the genus and species count without any change (Mausfeld & Schmitz 2003).Two species from Sri Lanka, Sphenomorphus rufogularis Taylor, 1950, andS. striatopunktatus Ahei, 1856, were synonymised with Lankaskincus fallax (Peters, 1860), and L. taprobanensis (Kelaart, 1854), respectively, reducing the total number of species to 86 (Greer 1991;Wickramasinghe et al. 2007).
Although there are seven species said to be found in both these countries there has not been a proper comparative study done so far, amongst these species.In our present study we have provided a comparison between D. halianus found in India and Sri Lanka.

MATERIAL AND METHODS
The following 22 measurements were taken with a Mitutoyo digital Vernier calliper (to the nearest 0.01mm) axilla to groin (AG, distance between axilla and groin), distance between back of eye (DBE, measured between the posterior edge of eyes), distance between front of eye (DFE, measured between the anterior edges of eyes), ear length (EL, the greatest vertical length of ear), ear width (EaW, the widest horizontal distance of ear), ear to ear distance (EE, distance between ears), eye to nostril distance (EN, distance between the anterior most point of eyes and nostrils), eye width (EW, measured between the anterior and posterior edges of eye), forearm length (FL, distance between the palm and elbow), head depth (HD, the maximum height of head, from the occiput to throat), head length (HL, distance between posterior edge of the last supralabial and the snout tip), head width (HW, measured at angle of jaws), internarial distance (IN, distance between nares), nostril to ear distance (NE, the distance between the posterior point of nostril and the anterior point of ear), snout to ear distance (SED, distance between the tip of snout and the anterior point of ear), snout to eye distance (SE, distance between the tip of snout and the anterior most point of eyes), snout to nostril (SN, distance between the tip of snout and the anterior point of nostril), snout to vent length (SVL, from the tip of snout to vent), tibia length (TBL, the greatest length of tibia, between knee and sole), tail depth (TD, the highest depth of tail base), tail length (TL, from vent to the tip of tail end), and tail width (TW, measured at the base of tail), Infralabials at end of gape (IL), Lamellae of Finger 1 (LF1), Lamellae of Finger 2 (LF2), Lamellae of Finger 3 (LF3), Lamellae of Finger 4 (LF4), Lamellae of Finger 5 (LF5), Lamellae of toe 1 (LT1), Lamellae of toe 2 (LT2), Lamellae of toe 3 (LT3), Lamellae of toe 4 (LT4), Lamellae of toe 5 (LT5), Paravertibral (PV), Scale around mid body (SMB), Subcaudals (SC), Supralabials at end of gape (SLG), Supralabials at mid orbit (SLO), Ventrals (V).
Preserved specimens were examined in the Colombo National Museum of Sri Lanka (NMSL), (The specimen in the best condition was selected for the description), Bombay Natural History Society collection (BNHS) and The Natural History Museum, London, UK (BMNH), as part of a study carried out, by the Sri Lankan Herpetological Foundation, for the non-endemic Saurian species in Sri Lanka.
The locations pertaining to the collection points of specimens according to previous literature were obtained using a Garmin E-trex venture GPS.
Guidelines to evaluate the conservation status of species were taken from the IUCN Red List Categories and Criteria (version 3.1;IUCN 2001)
Rostral concave; supranasal present; no postnasal; frontonasal larger than the prefrontals along the longitudinal axis, lateral border touching first loreal and supranasal; prefrontals is slightly separated, lower border touching both loreal scales, but touching the posterior loreal more than half, the posterior border touching the first supraocular, and frontal; frontal slightly longer or equal in its distance to tip of snout, and approximately shorter or slightly equal in frontoparietals and interparietal combined; seven or eight supraciliaris; four supraoculars, first one longer than wide, second wider than long, first three in contact with frontal, third in contact with frontal and frontoparietal, fourth in contact with frontoparietal, parietal and upper pretemporal; frontoparietals distinct, slightly smaller than interparietal length; posterior tip of interparietal barely in point-contact with primary nuchal scales, parietal touching upper and lower pretemporal scales laterally, primary nuchal and three small scales touching parietal post laterally (Image 2A); non fused nasal and in contact with 1 st supralabial; two loreal scales, anterior loreal touching nasal, supranasal, frontonasal, prefrontal, 1 st and 2 nd supralabials or 1 st , 2 nd , and 3 rd supralabial scales.Posterior loreal longer, and wider than the anterior loreal, posterior loreal Image 1.The dorsolateral view of uncatalogued specimen of Dasia halianus in NMSL collection touching prefrontal, 1 st supraciliaries, upper and lower preocular scales.Lower border touching 2 nd and 3 rd supralabials or third; two preocular scales, lower ones lager than the others; eight supraciliaries, in a row, the first one is lager than the others; seven supralabials, the last supralabial single, 5 th at the mid orbit point; 12 subocular scales, smaller than the supraciliaries scales; the subocular row touching 5 th to the 6 th supralabial scales and primary temporal scale, the first subocular scale touching the presubocular, and 5 th supralabial scale, the last subocular scale touching the primary temporal scale; presubocular scale touching lower preocular, 4 th and 5 th supralabial scales; Lower eye lid scaly, six large scales on window eye lid touching the upper edge of window, two scales on either side smaller than the once in the centre, and small scales filling the gaps at the upper edge between larger scales, lower edge has two scale rows; two small scale rows between window eyelid and subocular scales; four anterior and three posterior postocular scales, anterior postoculars smaller than the posterior postocular scales; two pretemporal scale, smaller than the primary temporal scale, upper pretemporal scale touched by parietal, lower pretemporal scale, upper and lower postoculars and last supraciliaries scale; single primary temporal, primary temporal touching 6 th and 7 th supralabial scales; tow secondary temporal scales, the lower secondary temporal touching 7 th supralabial and primary temporal scale, the upper secondary temporal touching parietal, lower pretemporal, and primary temporal scale, the secondary temporal larger than the primary temporal scale; seven infralabials, the sixth one being the largest (Image 2B); mental wider than postmental, transverse axis but shorter than longitudinal axis, postmental touching first and second infralabial only; two pairs of chinshields behind postmental, the first pair meeting in midline, the first chinshield in contact with second and third infralabial scales, the second pair in contact with third and forth infralabials, the second pair of chinshields separated by a single scale (Image 2C); dorsal body scales with three to five obtuse ridges, and lateral and ventral mid body scales smooth, the two vertebral series of scales feebly widened, 24 rows around body; 46 paravertebral scales; 54 scales between the mental and vent; the median preanals enlarged, outer preanals overlap with inner; dorsal tail scales with three obtuse ridges but some scales with four or five obtuse ridges, 67 smooth subcaudals scale; three ridges on each dorsal scale on fore and hind limbs, ridges more prominent on hind limbs, scales on underside of limbs smooth; the fourth finger and fourth toe longer than others; the fourth finger having 14 smooth lamellae; the fourth toe having 16 smooth lamellae; the lamellar formulae for fingers and toes, respectively: 4>3>2>5>1 (Image 2D) and 4>3>5>2>1 (Image 2E).Digits having single row of scales dorsolaterally; scales of palm and sole elevated, six large, prominent "heel" scales, which can easily be separated from those of sole.
Colour in alcohol: Six dark brown cross bands from neck to base of tail, fourth bifurcated; there are twelve dark brown bands upon the tail; simultaneously rows of dark brown bands seen upon limbs.Four, broad, dark brown longitudinal bands upon head, starting from close to the ear.Band interspaces and venter off white (Image 1).
Colour in life: The colour pattern is the same with brighter colours.Colour changes from dark brown to black and off white to white.
Variation: The following differences were observed apart from the general description for D. halianus.Specimen NMSL R.S.K II has a small interparietal; frontoparietals larger than the interparietal length; parietals touching each other behind interparietal.A specimen deposited in 1906, collected from Elehara (North Central Province) has the first two supraoculars in contact with frontal and the third supraocular in contact with frontoparietals.Body moderately elongate.Head depressed and narrow (HD/HW ratio 0.53 and HD/HL ratio 0.37); elongated and (HD/NE ratio 0.47 and HL/SVL ratio 0.22); distinct from the neck; snout long (SE/HW ratio 0.58); longer than the eye width (EW/SE ratio 0.48); eye relatively lager than the ear (EW/EL ratio 3.22 and EW/EaW ratio 9.67); ear opening small (EL/HL ratio 0.06); snout to eye distance greater than the width of eye (SE/EW ratio 2.09).Body length equal in tail length (SVL/TL ratio 1.00), and round in cross section (TD/TW ratio 0.97).
Rostral slightly concave; supranasal present; no postnasal; frontonasal larger than the prefrontals along the longitudinal axis, lateral border touching first loreal and supranasal; prefrontals is separated, lower border touching both loreal scales, but touching the posterior loreal more than half, the posterior border touching the first supraocular, and frontal; frontal longer than its distance to tip of snout, and shorter than frontoparietals and interparietal combined; seven supraciliaris; four supraoculars, first one longer than wide, second one wider than long, first two in contact with frontal, third in contact with frontoparietal, fourth in contact with frontoparietal, parietal and upper pretemporal; frontoparietals distinct, its equal in interparietal length; parietals touching each other behind interparietal, parietal touching upper and lower pretemporal scales laterally, primary nuchal and two small scales touching parietal post laterally (Image 4A); non fused nasal and in contact with 1 st supralabial; two loreal scales, anterior loreal touching nasal, supranasal, frontonasal, prefrontal, 1 st and 2 nd supralabial scales.Posterior loreal longer, and wider than the anterior loreal, posterior loreal touching prefrontal, 1 st supraciliaries, upper and lower preocular scales.Lower border touching 2 nd , 3 rd , and 4 th supralabials; two preocular scales, lower ones lager than the others; seven supraciliaries, in a row, the first one is lager than the others; seven supralabials, the last supralabial single, 5 th at the mid orbit point; 10 subocular scales, smaller than the supraciliaries scales; the subocular row touching 5 th to the 6 th supralabial scales and primary temporal scale, the first subocular scale touching the presubocular and 5 th supralabial scale, the last subocular scale touching the primary temporal scale; presubocular scale touching lower preocular, 4 th and 5 th supralabial scales; Lower eye lid scaly, four large scales on window eye lid, lower edge has two scale rows; two small scale rows between window of eyelid and subocular scales; five anterior and four posterior postocular scales, anterior postoculars smaller than the posterior postocular scales; two pretemporal scales, smaller than the primary temporal scale; upper pretemporal scale touched by parietal lower pretemporal scale, upper and lower postoculars and last supraciliaries scale; single primary temporal, primary temporal touching 6 th and 7 th supralabial scales; two secondary temporal scales, the lower secondary temporal touching 7 th supralabial and primary temporal scale, the upper secondary temporal touching parietal, lower pretemporal, and primary temporal scale, the secondary temporal larger than the primary temporal scale; seven infralabials, the fifth one being the largest (Image 4B); mental shorter than postmental in transverse axis but wider in longitudinal axis, touching first, second and third infralabials; two pairs of chinshields behind postmental, the first pair meeting in midline, the first chinshield in contact with third and forth infralabial scales, the second pair in contact with forth and fifth infralabials, the second pair of chinshields separated by a single scale (Image 4C); dorsal mid body scales smooth but dorsal back body scales with three obtuse ridges, lateral and ventral body scales smooth, the two vertebral series of scales feebly widened, 24 rows around mid body; 52 paravertebral scales; 56 scales between the mental and vent; the median preanals enlarged, outer preanals overlap with inner; dorsal tail scales with three obtuse ridges, 71 smooth subcaudals scale; three ridges on each dorsal scale on fore and hind limbs, ridges more prominent on hind limbs, scales on underside of limbs smooth; the fourth finger and fourth toe longer than others; the fourth finger having 15 smooth lamellae; the fourth toe having 18 smooth lamellae; the lamellar formulae for fingers and toes, respectively: 4>3>2>5>1 (Image 4D) and 4>3>5>2>1 (Image 4E).Digits having single row of scales dorsolaterally; scales of palm and sole elevated, eight pallets which look much the same as those of sole around heel.
Colour in alcohol: thin irregular dark brown cross bands with intermittent white spots from forelimbs to end of tail.Dark brown spots, seen on limbs.Four, thin, dark brown longitudinal bands beginning close to forelimbs moving towards head.Band interspaces and venter off white (Image 3).

Dasia halianus was introduced to science as
Euprepes halianus Haly & Nevill, 1887(in Nevill 1887), from the type localities Henarathgoda and Anuradhapura, Ceylon (Sri Lanka) and type material deposited in the NMSL (Haly & Nevill 1887) (Appendix 1).But the types are suspected to have been lost or misplaced during the upheavals of World War II (Kandamby 1997;Das et al. 1998).From its initial discovery till the year 1984, this species was considered to be endemic to the island (Haly 1893;Annandale 1906;Deraniyagala 1931;Smith 1935 and1937;Taylor 1950;Deraniyagala 1953;Taylor 1953;Greer 1970;Inger 1980), until Joshua & Sekar on the 18 th August 1984 reported D. halianus for the first time from the Thambiraparani River, Mundanthurai Wild Life Sanctuary, Tirunelveli District, Tamil Nadu, India.Joshua & Sekar (1984) provided a text figure (black and white) of the specimen they found, but no mention of the specimen being deposited in a Museum or a relevant Institute.Although there were three species of Dasia described from India by that time, Joshua & Sekar mention that "The skink was strikingly different in colour and pattern from species so far known in India and was identified as D. halianus."Also in this short discussion they do not provide any comparison between other congeners in the country.After this publication, however, there had been quite a number of sightings of this same species from the country (Karthikeyan 1991;Das 1994Das , 1997Das , 2001;;Kumar et al. 2001).Such a specimen from the BNHS 1391, was critically examined, and compared with the Sri Lankan D. halianus specimens from NMSL, and from our results the following combination of characters clearly distinguished the Indian "D.halianus", from that of the Sri Lankan D. halianus.
Sri Lankan D. halianus differs from the Indian specimen by the following combination of characters (the characters within brackets are of Indian D. halianus): primary nuchal and three small scales touching parietal post laterally (primary nuchal and two small scales touching parietal post laterally); Lower border of posterior loreal touching 2 nd and 3 rd supralabials or third (Lower border of posterior loreal touching 2 nd , 3 rd , and 4 th supralabials); eight supraciliaries (seven supraciliaries); 12 subocular scales (10 subocular scales); six large scales on window of eyelid (four large scales on window of eyelid); and small scales filling the gaps at the upper edge between larger scales (no small scales filing the gaps); four anterior postoculars (five anterior postoculars); three posterior postoculars (four posterior postoculars); sixth infralabial is largest (fifth infralabial is largest); mental wider than postmental in transverse axis (mental shorter than postmental in transverse axis); mental shorter than longitudinal axis (mental wider in longitudinal axis); postmental touching first and second infralabial (postmental touching first, second and third infralabials); first chinshield pair in contact with second and third infralabial scales (first chinshield pair in contact with third and forth infralabial scales); second chinshield pair in contact with third and forth infralabials (the second chinshield pair in contact with forth and fifth infralabials); dorsal body scales with three to five obtuse ridges (dorsal mid body scales smooth but dorsal back body scales with three obtuse ridges); six large, prominent "heel" scales (eight "heel" scales which look much the same as those of sole).
The Sri Lankan D. halianus can also be clearly separated from its Indian congener by the following combination of colour pattern features.Four broad, dark brown longitudinal bands upon head, starting from close to the ear (vs Four thin, dark brown longitudinal bands beginning close to forelimbs moving towards head); six dark brown cross bands from neck to base of tail; there are twelve dark brown bands upon the tail (vs thin irregular dark brown cross bands with intermittent white spots from forelimbs to end of tail).
From the above results, we were able to conclude that the Indian D. halianus, in fact, matches the morphological characters of D. subcaeruleum.Type specimens of D. subcaeruleum, are found at the BMNH, under the following numbers 1946.8.15.55 (Image 5), and 1949.1.8.51 (Greer, 1970).Due to the incorrect identification in 1984, the mistake had been repeated until now that the species in India is D. halianus.As the Indian species can be confidently placed as D. subcaeruleum, D. halianus is indeed endemic to Sri Lanka.
Since there are quite a lot of recorded sightings of D. halianus from India after 1984, these sightings can now be considered as sightings of D. subcaeruleum, and thereby a distribution pattern of this species can be derived from earlier publications [(Kalakkad Hills, Tirunelveli, Tamil Nadu, Thambiraparani River, Mundanthurai Wildlife Sanctuary, Tirunelveli District, Tamil Nadu (Joshua & Sekar 1984), Kalakad-Mundanthurai Tiger Reserve (Johnsingh 2001;Kumar et al. 2001), Mundanthurai Wildlife Sanctuary, Tamil Nadu (Karthikeyan 1991)].At present the conservation status in India for D. subcaeruleum is Data Deficient (Molur & Walker 1998), and D. halianus is Critically Endangered.Hence according to IUCN criteria, for D. subcaeruleum, the species requires reassessment.The present conservation status for D. halianus in Sri Lanka is Near Threatened (IUCN & MENR 2007).
Although the type localities of D. halianus are mentioned as Henarathgoda (07 0 04'N & 80 0 01'E) and Anuradhapura (08 0 21'N & 80 0 23'E), this species could only be found in the latter locality but not in the former, based on our field studies.However, Henarathgoda remains its type locality in most of the literature (Annandale 1906;Deraniyagala 1931;Smith 1935;Taylor 1950;Deraniyagala 1953;Das & de Silva 2005;Somaweera & Somaweera 2009), in spite of the fact that there remains no valid record after the initial sighting.Henarathgoda, is an area situated close to the present Gampaha Town (07 0 05'N & 79 0 59'E), located in the lowland wet zone.Therefore, the initial statement of distribution of D. halianus, in this locality could in fact be a mistake, which can very well be justified by the description of the type locality by Haly as "the hot and dry districts of Ceylon", where Gampaha on the contrary belongs to the wet zone.Regardless, our field studies confirm that D. halianus does not exist at the Gampaha locality today.
According to Anandale, there exists a third specimen (half grown) from Horana collected and deposited on the 08 November 1901 by G.H. Swayne at the NMSL (Annandale 1906), without any mention of a district nor a province to relate this locality to.But according to our field studies and findings D. halianus is a species found only in the dry and intermediate zones of the country.P.E.P. Deraniyagala, in 1931 mentions that this species was found in "Horana", in the North Central Province (Deraniyagala 1931).But he himself later in 1953, states that the species was found in "Horana", in the Western Province (Deraniyagala 1953).According to our field studies carried out so far, we have not been able to find D. halianus in the western province locality (wet zone), and there were no records from the Horana locality of the western province in the NMSL inventory.But D. halianus is found in the north central province, and there are records from the north central province in the NMSL inventory.Hence according to our studies we can confidently state that there is no evidence that D. halianus is found in the Horana (06 0 43'N & 08 0 03'E), nor anywhere in the wet zone of the western province.After re-evaluating its conservation status of D. halianus remains Near Threatened due to its area of occurrence extending to more than 30,000km 2 , and its occupancy having a score of >60 points from available distribution data.
According to the museum inventory, there were ten specimens of D. halianus deposited in the NMSL.We were able to sort out four D. halianus specimens from the mixed up collection.Three specimens were recognized, and were in accordance to the inventory.The remaining specimen was totally dried out and the labels were also destroyed, and was in an unrecognizable state (Image 6).Another specimen which could not be examined was found in the collection of exhibits.
According to the type description, two type specimens were deposited out of which one is a young individual and the other is an adult.Although there is a mention of Fig. 1, 2, and 3 of Plate 1, in the type description these were not present in the journal.The figures would no doubt have been good evidence to clarify the type specimens.Due to the absence of any figures the following from the adult type description will be good evidence in the identification of the adult type specimen, "White back with ten black bands, one on the nape one between the forelimbs; three on the back, one between the hind limbs, and four on the tail with remains of a fifth".
In the inventory there were two specimens deposited under registry no.R.S.K II, but no mention of collection date and there locality.We were able to find one specimen of an adult which (Image 7), has a SVL of 74.65mm, in a labeled bottle under R.S.K. II.Six body bands, which matches the type description, were seen on this specimen, but tail bands were very difficult to recognize in the regenerated tail because of discolouration.R.S.K II also has the following characters, a small interparietal, frontoparietals are larger than the interparietal length, parietals touching each other behind interparietal.All these characters of R.S.K II, can be seen in the drawing done by Deraniyagala (Deraniyagala 1931(Deraniyagala , 1953)).The short tail length compared to its body length in the drawing, matches that of the regenerated tail of R.S.K II.Hence, we believe that this specimen was selected by Deraniyagala for his drawing.The two rupee note (Image 8) printed in the nineteen seventies, has a drawing of D. halianus, because of its shape, proportion and the scales on the head, we feel that the artist (Mr. Lucky Senanayake) had taken the same drawing by Deraniyagala with minor changes.This drawing is good evidence to confirm that R.S.K II, is a specimen belonging to Deraniyagala's time hence is ruled out from any doubts of being any of the type specimens.
A specimen in the British Museum under BMNH 1908.3.19.3 (Image 9) from Ceylon presented by Prof. Graham Kerr, accessioned on the 19 March 1908, having SVL 68mm and a tail length of 57mm (pers. comm. Colin McCarthy 2007), and the body bands, along with the tail matches well with the adult type description, and hence can be confidently placed as that of the adult type specimen, and we thus place this specimen of BMNH as the lectotype of D. halianus.
In the Ceylon Administration Report 1893, prepared by Mr. Haly, he mentions "A third specimen of Lygosoma halianus was purchased from the Southern Province.The rarity of this species is accounted for by the fact that it lives on tops of high trees".In contrast Annandale in 1906, mentions that he used a third half grown specimen deposited in the NMSL, a specimen collected and presented by G.H. Swayne, 08 November 1901, for his description.This specimen which Annandale mentions should actually be the fourth, and is clearly evident from its location and date that this was not the specimen which Haly purchased.Hence it can be concluded that Annandale was not aware of the third specimen which Haly mentions in his report.Annandale had used a separate specimen, from that of his description for his drawing.The drawing in Annandale's description is captioned as "young Thyconyx halianus" (Image 10), which was three times enlarged, and matches with the juvenile type description "sixteen black bands, one in front and one behind the fore limbs" hence the drawing is the only sketch currently available of the missing juvenile paralectotype.
Another specimen also exists in the Zoological Survey of India under ZSI 15977 (Das et al. 1998), the handwritten label attached to the specimen states "Thyconyx halianus (Nevill) Annandale".The next label states that this is a "co-type", hence we feel that this specimen could have been what Annandale had selected to measure in his paper, which happens to be the fourth specimen, and is ruled out of being any of the type specimens.
From our studies in a fully grown tail there should be 10 to 12 black bands, hence according to the type description we can infer that the tail of the adult type specimen was regenerated.Also an important comment to be made on the type description is, "the single prefrontal touches both rostral and vertical."which could well be the fronto nasal and not the prefrontal, because there are two prefrontals and this never touches the rostral.The specimen collected by P.E.P. Deraniyagala, from Galatabendiyawa Estate (there is a mention about another specimen collected in 1935, which we were not able to locate in the NMSL collection) and another from Wilpattu collected in 1967, and donated by Mr. Aditya were the other two recognized specimens.Two specimens apart from those in the inventory were also found (see Table 1 & 2
).None of the specimens at the NMSL matched the figures (Fig. 2 & Fig. 3) in the publication by Anandale 1906.Finally this work has taxonomically established the status of D. halianus in Sri Lanka (Image 11), and has redescribed the Indian species D. subcaeruleum.