Monilesaurus ellioti ( Günther, 1864 ) Pal & Vijayakumar & Shanker & Jayarajan & Deepak, 2018

Pal, Saunak, Vijayakumar, S. P., Shanker, Kartik, Jayarajan, Aditi & Deepak, V., 2018, A systematic revision of Calotes Cuvier, 1817 (Squamata: Agamidae) from the Western Ghats adds two genera and reveals two new species, Zootaxa 4482 (3), pp. 401-450 : 429-431

Monilesaurus ellioti ( Günther, 1864) comb. nov.

Calotes rouxii— (not of Dum. & Bibr., 1837), Jerdon, 1853. J. Asiat. Soc. Beng. (2) xxii, 1853: 471

Calotes ellioti — Günther, 1864. Rept. Brit. Ind. 1864: 142.

Bronchocela indica —Theobald, 1876. Cat. Rept. Brit. Ind. 1876: 105.

Calotes elliotti — Smith, 1935. Fauna of British India, ii, 1935: 207.

Original description. Günther, A. 1864. The Reptiles of British India. London (Taylor & Francis), xxvii, 452 pp.

Taxonomic comments. Monilesaurus ellioti was described, based on Jerdon’s observation of C. rouxii like animals from “Malabar” in his list of Reptiles of Southern India, 1853 and a collection of drawings of this species in the possession of W. Elliot. Historically, southern Karnataka and northern Kerala have been referred to as Malabar. Boulenger (1885) gave a short description of this species based on the collections made by Col. R.H. Beddome from Anamalai hills, Sivagiri Ghat, Tirunelveli and Malabar. As there are no type specimens associated with this species, we hereby designate a neotype for this species. The selection of the neotype is roughly congruent with the original type locality of this species “Malabar” as mentioned by Jerdon (1853). Murthy (1978) described a subspecies Calotes ellioti amarambalamensis the type locality of which is Amarambalam, Nilambur. The holotype of this species is now at ZSI Madras (ZSI Madras 159) (Das et al. 1998). We were unable to trace the specimen in ZSI collections despite repeated attempts. For now, the specimen may be considered as lost. Hence, we compare another specimen collected from the same locality (BNHS 1033), a female individual whose characters match well with other M. ellioti and the description provided by Murthy. Also, the locality is within the distribution range of M. ellioti and contiguous with the type locality. Therefore, we consider Calotes ellioti amarambalamensis as a junior synonym of M. ellioti ( Günther, 1864) . ZSI Madras 159 is wrongly mentioned as a type specimen of Calotes ellioti ( Uetz & Hošek, 2016) .

Neotype. CESL 0 45, adult male collected from Chembra reserve forest, Kerala by SPP, MVP and SPV on 10th June 2010.

Other material examined. ZSI 4325 gravid female & ZSI 4328 male collected from Southern India ; CESL 0 42 adult male collected from Manikunjamalai, Wayanad reserve forest, Kerala ; CESL 0 45 adult male collected from Chembra reserve forest, Kerala ; CESL 0 47 adult female collected from Vaithiri, Wayanad reserve forest, Kerala ; CESL 0 57, CESL 0 59 and CESL 0 61 adult females and CESL 0 58 and CESL 0 60 adult males collected from Vallerimala, Wayanad reserve forest, Kerala ; CESL 0 77, adult female collected from Arlam Wildlife Sanctuary , Kerala ; CESL 0 33 adult male collected from Bonacord, Peppara Wildlife Sanctuary , Kerala ; CESL 162 , adult male collected from Sholyar, Vazhachal reserve forest, Kerala ; CESL 204 , adult female collected from Pamba, Periyar tiger reserve, Kerala and CESL 369 adult male collected from Peppara, Cardemom hills, Kerala and BNHS 1033 , adult female collected from Nilambur reserve forest, Kerala. Details of collection locality, specimen voucher and GenBank accession number in Appendix 1.

Diagnosis and comparison. A small sized Monilesaurus (SVL up to 73.8 mm) characterized by the posteroventral orientation of lateral scales; antehumeral fold well developed, extending across the throat; 52–58 midbody scale rows; nuchal crest composed of 3–4 long, well developed spines; two separated supratympanic spines; a long, distinct isolated postorbital spine; dorsal and lateral scales keeled, ventral scales strongly keeled; paired postmentals, first pair separated by a single scale; 24–28 subdigital lamellae under fourth finger, 26–34 subdigital lamellae under fourth toe; 9–10 supralabials and 8–9 infralabials; olive brown above with angular darker cross bars on dorsum, a white spot below the eye.

Morphologically M. ellioti is superficially similar to M. montanus gen. et sp. nov., M. rouxii comb. nov.; and M. acanthocephalus gen. et sp. nov., but can be distinguished by a combination of the following characters: 52–58 midbody scale rows (vs. 46–52 in M. montanus gen. et sp. nov., 62–64 in M. acanthocephalus gen. et sp. nov., and 52–56 in M. rouxii ) presence of a long, distinct isolated spine in the posterior corner of orbit (vs. absent in M. rouxii ; very small, indistinct tubercle like in M. montanus gen. et sp. nov., and much longer in M. acanthocephalus gen. et sp. nov.); 3–4 long nuchal spines (vs. 3–6 small nuchal spines in M. montanus gen. et sp. nov., 6 much longer nuchal spines in M. acanthocephalus gen. et sp. nov., 7–8 smaller nuchal spines in C. rouxii ); longer, prominent isolated spine on the back of head and above tympanum (vs. much smaller in M. montanus gen. et sp. nov., and M. rouxii ) and presence of a white spot below the eye (vs. absent in M. rouxii ; in the form of a band in M. montanus gen. et sp. nov.) and smaller body size: adult SVL 59.4–73.8 mm, n=9 (vs. C. montanus gen. et sp. nov., adult SVL 61–83.4 mm, n=8; and M. acanthocephalus gen. et sp. nov. adult SVL 68.9–72.6 mm, n=3).

Description. Based on CESL 0 45. A medium sized adult male (SVL- 63.7 mm), Morphometric and meristic data are summarised in Appendix 2 & 3. General habitus moderately compressed. Head moderately large (HL/SVL ratio 0.29), elongate (HW/HL ratio 0.63), maximum height less than maximum width; snout pointed; rostral broader than high; nostrils in single nasal shield, which is separated from rostral by a single scale; mental shield narrower than rostral; two postmentals, first pair in contact with each other; genials keeled; gular scales strongly keeled, slightly smaller than genials; scales on top of snout smooth except median row, which is keeled; scales on top of head heterogenous in size and shape, keeled; supraorbital scales keeled; canthus-rostralis and supraciliary edge sharp; a spine at the posterior corner of the orbit; two separated long spines on posterior end of head, the anterior slightly longer, midway between nuchal crest and tympanum, posterior above tympanum; orbit diameter 70% of distance between anterior border of orbit and snout tip; tympanum exposed, its greatest diameter 54% horizontal diameter of orbit; enlarged keeled scale between tympanum and orbit; posterior region of jaws swollen; supralabials 10/10; infralabials 9/9.

Nuchal crest well developed, composed of four primary, long conical spines, the first being the smallest and the third longest; the remaining vertebral scales slightly enlarged relative to adjacent rows and possess a more pronounced median keel forming a serrated ridge like the dorsal crest which continues till the tail base; 54 longitudinal scale rows around midbody; scales on dorsum keeled, oriented postero-dorsally, while lateral ones oriented postero-ventrally; lateral scales smaller than dorsal, keeled; ventrals strongly keeled, irregular, slightly smaller than dorsals but of similar size as laterals, genials and gular scales; a strong, oblique antehumeral fold, nearly extending across the throat.

Limbs slender and covered with strongly keeled scales, larger than laterals, forming parallel longitudinal rows; scales under thighs weakly keeled; length of hindlimb ca. 87% SVL; relative length of fingers 4>3>2>5>1; relative lengths of toes 4>3>5>2>1; fourth toe longer than fifth finger; 23 subdigital lamellae under fourth finger; 27 subdigital lamellae under fourth toe; subdigital lamellae with sharp keels, bicarinate; tail slender, swollen at the base; scales on dorsal and ventral surface of tail with sharp keels, larger than laterals; tail length 172 mm.

Colouration. In life: dorsum and head blackish-brown with irregular lighter patches on the back; a light brown band from above the shoulder till the dorsal crest forming a ‘v’ shape; head laterally dark blackish with a white spot below the posterior end of eye; stripe from above nostril to anterior margin of orbit extending till the tympanum from the posterior margin of orbit in the form of a black band; tympanum pale grey, lip scales white; a blackish triangular patch behind the tympanum continuing to the antehumeral fold; ventral uniformly lighter, pale grey; gular pouch with a reddish stripe extending beyond the throat; tail with alternating dark and light blotches forming irregular bands towards the end. Representative image showing live colouration ( Fig. 6b ). In preservative: colouration pattern mostly similar to that in life, except overall paler; bands on the head dull greyish brown.

Variation and secondary sexual characteristics. The other specimens examined agree with the CESL 0 45 in general morphology and scalation except for some differences that are summarised in Appendix 2 & 3. All the examined female specimens (CESL 0 47, CESL 0 58 and CESL 061) have much smaller nuchal spines compared to the males, reduced postero-orbital spine; lack a dorsal crest and gular sac; overall colouration olive-brown, lighter head and vertebral region, a dark band along the side of the head to the neck and presence of a black antehumeral fold.

Genetic distance. M. ellioti comb. nov. shows 1–2% intraspecific genetic divergence in the 16S gene; 4–7% interspecific genetic divergence from M. rouxii comb. nov.; 5–7% interspecific genetic divergence from M. acanthocephalus gen. et sp. nov and 4–8% interspecific genetic divergence from M. montanus gen. et sp. nov. (Appendix 5).

Distribution. Monilesaurus ellioti comb. nov. is endemic to the Western Ghats and is distributed across the low and medium elevation forests (up to 1000 m asl) of southern parts of central Western Ghats (Coorg plateau and south) and the southern Western Ghats. This is one of the most common evergreen forest dwelling agamid lizards in this region. During this study, M. ellioti comb.nov. was recorded in various sites in the central and southern Western Ghats (See Fig. 3 & Appendix 1 for details).

Ecology and natural history. Monilesaurus ellioti is a diurnal lizard, semi-arboreal to arboreal in habit, and so far, has been recorded mostly in semi-evergreen and evergreen forests. Individuals were mostly seen perching on shrubs, branches and actively moving on tree trunks. In some instances, it has also been observed in coffee plantations surrounded by evergreen forests. In some sites like Parambikulam, Vazhachal reserve forest and Brahmagiri hills, it was observed to occur syntopically in the same habitat as M. rouxii comb. nov., but more abundant within dense forests, while M. rouxii comb. nov. is generally restricted to forest edges. In some instances, gravid females were recorded during pre-and mid monsoon (June–August), which hints that monsoon might be a breeding season for this species.

Figures

FIGURE 3. Map showing distribution of members of Monilesaurus gen. nov. across the Western Ghats, India. Coloured symbols indicate selected sampling localities.

FIGURE 6. Lateral photograph showing live coloration of A. adult male Monilesaurus rouxii comb. nov. and B. adult male Monilesaurus ellioti comb. nov.