Characters used in this study
External morphology. We studied 231 specimens of Fan-throated lizard from across India, including 56 museum specimens and 175 from our own collection. One hundred and six out of the 231 specimens are males and 78 are female, with 39 subadults and 8 hatchlings. Twenty six of those specimens were damaged or badly preserved. Morphometric characters were measured from 158 specimens out of the 231 individuals. Most morphometric characters were measured following Zug et al. (2006), as described below. Most measurements (to the nearest 0.01 mm) were taken with digital calipers (MitutoyuTM). Measurements from photographs were extracted using software ImageJ (Rasband, 2004). The following measurements were taken: snout-vent length (SVL, from tip of snout to anterior border of cloaca), head length (HL, from snout tip to posterior border of tympanum), head width (HW, distance from left to right outer edge of the head at its widest point), head height (HH, Dorsoventral distance from top of head to underside of jaw at transverse plane intersecting angle of jaws), snout-eye length (SE, from snout tip to anterior border of orbit), eye to tympanum (ET, from posterior border of orbit to anterior border of tympanum), jaw length (JL, from rostrum to corner of jaw), interorbital width (IO, transverse distance between anterodorsal corners of left and right orbits), naris to eye (NE, distance from the anterior edge of orbit to posterior edge of naris), snout width/internasal distance (IN, transverse distance between left and right nares), tympanum diameter (TD, greatest diameter of tympanum), orbit diameter (OD, distance between anterior and posterior margins of orbit), lower arm length (LAL, distance from elbow to distal end of wrist, or just underside of forefoot), upper arm length (UAL, distance from anterior insertion of forelimb to elbow), finger lengths (F1, F2, F3, F4, F5) (e.g. F4 = Distance from juncture of 3rd and 4th digits to distalmost extent of 4th finger, femur length (FEL, length of femur from groin to knee), crus length (CL, length of crus (tibia) from knee to heel), hind foot length (HFL, distance from proximal end (heel) of hindfoot to distal most point of fourth toe), hind limb length (HLL, from groin to tip of fourth toe), toe lengths (T1, T2, T3, T4, T5) (e.g. T4 = Distance from juncture of 3rd and 4th digits to distal end of 4th digit on hindfoot), trunk length (TrL, from forelimb insertion to hind limb insertion), trunk height (TrH, depth midway between the fore- and hind limb insertions), trunk width (TrW, width midway between the fore- and hind limb insertions), tail length (TL, from posterior border of cloacal opening to tip of tail), tail height (TH) and tail width (TW) at tail base. Dewlap length (DWL, distance between posterior end of dewlap and tip of lower jaw). One morphometric character described by Amarasinghe et al. (2015) axilla-throat-fan length is renamed as extent of dewlap in trunk (DWLT, measured from the axilla till the end of the dewlap).
Meristic characters were counted for multiple individuals per species. The following characters were scored: mid-body scale rows (MBS, number of scale rows around the trunk at midbody), ventral scales (VEN, number of scales from below mental to anterior border of cloaca), fourth toe lamellae (LAM4, number of 4th toe lamellae, from 1st lamella at the digit’s cleft to the most distal lamella), dewlap scales (ESD, number of enlarged scale rows on the dewlap), supralabials (SL, posterior end defined by the last enlarged scale that touches infralabials at rear corner of mouth), infralabials (IL, posterior end defined by the posterior-most enlarged scales that contact the supralabials at the rear corner of the mouth).
Hemipenis morphology. For most specimens collected during the breeding season, we everted and prepared the hemipenes during specimen preparation. 4% formaldehyde was injected under the tail base in order to evert the hemipenes. Hemipenis morphology was documented using standard hemipenial nomenclature (Dowling and Savage, 1960). Hemipenis drawings were done under a camera lucida attached to the microscope (Leica M165C).
Osteology. One male and one female each of Sitana ponticeriana, Sitana spinaecephalus sp. nov., Sarada darwini sp. nov. and Sarada deccanensis comb. nov. were cleared and stained following protocols from Hanken and Wassersug (1981). Osteological descriptions were made from both sexes of a species. Skulls were prepared by maceration. Descriptions of skeletal characters followed Romer (1956), Oelrich (1956), Jollie (1960) and Moody (1980).