Microauris, 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 : 440-441

Microauris gen. nov.

( Fig. 8b )

Type species. Calotes aurantolabium ( Krishnan, 2008)

Etymology. The genus epithet is derived by adding the word ‘Micro’ as a prefix to the Latin word ‘auris’ meaning ear, referring to the extremely small tympanum of this genus.

Diagnosis. Microauris gen.nov. differs from all other members of draconinae lizards from the Indian subcontinent in having the smallest tympanum. Microauris gen.nov. differs from Mantheyus phuwuanensis by the absence of femoral pores ( Manthey & Nabhitabhata, 1991; Ananjeva & Stuart 2001); from the members of the genus Bronchocela by the absence of a fold of skin from angle of jaw to shoulder ( Hallermann & Böhme 2000). Microauris gen. nov. can be easily diagnosed from the genera Otocryptis , Sarada and Sitana by the presence of a well-developed fifth toe ( Smith, 1935; Deepak et al, 2016); from Cophotis, Ceratophora , Lyriocephalus , Ptyctolaemus , Phoxophrys , Japalura otai , J. planidorsata , J. sagittifera and Otocryptis by the presence of external tympanum ( Boulenger, 1885; Smith, 1935; Inger, 1 960; Pethiyagoda & Manamendra-Arachchi 1998; Schulte II et al. 2004; Bahir & Silva 2005; Manamendra-Arachchi et al. 2006; Samarawickrama et al. 2006). Microauris gen. nov. can be diagnosed from other members of genus Japalura by the absence of heterogenous dorsal scales and short and thick nuchal scales; from Salea by the absence of enlarged plate like scales between the eye and tympanum (Smith, 1 935). Microauris gen. nov. can be diagnosed from the members of Psammophilus and Monilesaurus by the absence of a well developed antehumeral fold. Microauris gen. nov. can be diagnosed from Complictus nigrigularis, Hypsicalotes kinabaulensis, Malayadracon robinsonii, Oriocalotes , Pseudocophotis and Pseudocalotes by the absence of enlarged row of suborbital scales ( Smith, 1935; Taylor 1963; Ota & Hikida, 1991; Manthey & Denzer 1992; Inger & Steubing 1994; Ota & Hikida, 1996; Hallermann & Böhme 2000; Manthey & Denzer, 2000; Hallermann & McGuire 2001; Leong 2001; Manamendra-Arachchi et al. 2006; Samarawickrama et al. 2006; Ananjeva et al. 2007; Hallermann & Böhme 2007; Das & Lakim 2008; Hallermann et al. 2010; Mahony 2010; Harvey et al. 2014; Denzer et al. 2015; Grismer LL et al. 2016; Harvey et al. 2017).

Microauris gen.nov. can be distinguished from the members of the genus Calotes ( C. bachae , C. bhutanensis , C. calotes , C. ceylonensis , C. chincollium , C. desilvai , C. emma , C. grandisquamis , C. hutunwini , C. irawadi , C. jerdoni , C. liocephalus , C. liolepis , C. versicolor , C. manamendrai , C. maria , C. medgoensis , C. minor , C. mystaceus , C. nemoricola , C. nigrilabris , C. nigriplicatus and C. pethiyagodai ) and Lophocalotes ( Günther, 1872) in having the smallest tympanum ( Hardwicke & Gray, 1827; Duméril and Bibron, 1837; Gray, 1845; Jerdon, 1854; Günther, 1864; Günther, 1870, Günther, 1872, Günther, 1875; Boulenger, 1885; Biswas, 1975; Zhao & Li, 1984; Hallerman, 2000; Vindum et al. 2003; Hallerman et al. 2004; Bahir & Maduwage, 2005; Zug et al. 2006; Manthey, 2008; Krishnan, 2008; Hartmann et al. 2013; Amarasinghe et al. 2014a, b; Deepak et al. 2015).

Suggested English. Small-eared dragon

Holotype. BNHS 1436 , an adult female collected from Kalakkad Mundanthurai Tiger Reserve, Tamil Nadu, India; by N. M. Ishwar in 1997.

Referred specimens. CESL 104 , an adult female collected from a branch in the canopy of a shola forest tree near Chemunji peak, Peppara Wildlife Sanctuary, Kerala, India ; by SPP, SPV, MVP, VTR and ADR in 18th August 2010.

Taxonomic comments. Microauris aurantolabium comb. nov. was described as Calotes aurantolabium in 2008 based on a single specimen ( Krishnan 2008). Prior to this, the specimen was wrongly identified and reported as the rediscovery of Calotes andamanensis . ( Ishwar and Das, 1998). During our fieldwork in the Agasthyamalai hills of Kerala in August 2010, we found a single female specimen sleeping on a branch of a tree in a shola forest. There have been no other reports of this species thereafter and thus all the known specimens are females. There is a clear gap in the knowledge of the morphology of this rare lizard considering that male lizards are known to be better representatives for morphological characterization because of the presence of secondary sexual characters. In spite of this, the two specimens share some common characters, which are unique to this lizard. Based on the presence of unique morphological characters along with the phylogenetic position of this species in the subfamily Draconinae , we designate this species as a new monotypic genus.

Diagnosis. A medium sized light green agamid lizard with a distinct orange streak from above the lip scales till behind the jaw; a moderately broad head with a pointed snout; very small tympanum relative to the orbit diameter (TymD/OrbD = 0.14–0.19); acutely keeled scales over the body and throat; scales on head small, sub-triangular (vs. uniform shield like in members of genus Calotes ); 3rd and 4th toe almost equal in length; dorsal and lateral body scales oriented backwards and downwards; nuchal crest indistinct, poorly developed; supratympanic and postorbital spines absent and a long and slender tail.

Description of the Holotype. BNHS 1436; a medium sized agamid, adult female (SVL- 68.5 mm) Morphometric and meristic data are summarised in Appendix 2 & 3. General habitus moderately compressed. Head moderate (HL/SVL ratio 0.28), broad (HW/HL ratio 0.56), 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 almost as wide as the rostral; two postmentals; first pair touching each other at the base; genials partially keeled; gular sac small, composed of partially keeled scales, slightly smaller than genials; scales on the snout smooth, unkeeled; scales on top of head heterogenous, keeled, small, subtriangular; supraorbital scales keeled; orbit diameter 95% of distance between anterior border of orbit and snout tip; tympanum very small, exposed, its greatest diameter 11% of horizontal diameter of orbit; slightly keeled scales between tympanum and orbit; posterior region of jaws partially swollen; supralabials 10/10; infralabials 11/11.

Nuchal crest poorly developed, composed of 13 small conical spines; the remaining vertebral scales slightly enlarged relative to adjacent rows and possess a more pronounced median keel; 54 longitudinal scale rows around midbody; scales on dorsum keeled; lateral scales smaller than dorsal, keeled, oriented postero-ventrally; ventrals slightly larger then dorsals, genials and gular scales strongly keeled.

Limbs slender and covered with strongly keeled scales, larger than laterals; scales under thighs keeled; length of hindlimb ca. 64% SVL; relative lengths of toes 4=3>5>2>1; fourth toe and third toe subequal; 20 subdigital lamellae under fourth finger; 21 subdigital lamellae under fourth toe; tail slender, long; scales on dorsal and ventral surface of tail with sharp keels, mucronate, slightly larger than laterals; tail length 117 mm.

Colouration. In life (CESL 104): dorsum and head uniform, light green overall with a distinct reddish orange streak from above the third lip scale covering 2–3 scale rows below the tympanum, ending just at the shoulder. A distinct pale whitish grey band, edged with black speckles from the base of tail till underside of knee. Mid-dorsal scales edged anteriorly with black, which is visible when the body is inflated; gular scales lighter, yellowish green; ventrally brighter, uniform green with a few rows of pale whitish scales towards the lateral side. This lizard was observed to quickly change its body color to dark blackish-brown on disturbance but the orange streak and band on thigh remained unchanged.

In preservative: dorsum and head uniform, overall pale blue with brownish patches above the eyes and neck continuing on the mid-dorsal line, broader towards the tail; tail pale brown; orange lip streak paler turning whitish towards the neck; laterally pale blue with anteriorly black edged scales; ventrally pale whitish grey overall; limbs edged with brown blotches, broader towards the tips.

Distribution. Currently, this lizard is known only from two sites in the high elevation tropical evergreen forests of Agasthyamalai hills. The second locality near Chemunji peak in Peppara wildlife sanctuary is approximately 50 kms northeast of the type locality near Kakachi in KMTR (See Appendix 1 for details). Both these sites are separated by almost contiguous shola grassland mosaic on undulating hills.

Ecology and natural history. Nothing much is known about the ecology and natural history of this species. Ishwar and Das (1998) reported sightings of 3 individuals, all gravid females in the month of August. Two of these lizards laid 4 elliptical eggs each. This suggests that monsoon might be a breeding season for this lizard. Ishwar and Das (1998) also mentioned that this is a canopy dwelling species. The fact that it was only found again 12 years after its discovery and that too from a fairly well explored habitat suggests that this might be a rare lizard or it may occur high in the canopy of rain forests and thus escape detection.

Figures

FIGURE 8. Lateral photograph showing live coloration of A. adult male Psammophilus dorsalis and B. adult female Microauris aurantolabium comb. nov.