Ptyctolaemus gularis ( Peters, 1864 )

Balan, Amirtha, Das, Abhijit, Boruah, Bitupan, Tillack, Frank, Lalronunga, Samuel & Deepak, Veerappan, 2025, Description of two new species of Ptyctolaemus (Squamata: Agamidae) from northeast India, Vertebrate Zoology 75, pp. 487-516 : 487-516

Ptyctolaemus gularis ( Peters, 1864)

Chresonymy. Otocryptis ( Ptyctolaemus) gularis Peters, 1864: 386 .

Holotype.

ZMB 5004 , from “ Calcutta ” [in error], purchased from J. G. W. Brandt; Figure 6 .

Remarks.

The type specimen, whose origin was given as “ Calcutta ”, was acquired by the Zoologisches Museum Berlin in the middle of the 19 th century from Johann Georg Wilhelm Brandt (1794–1856), a dealer in natural history objects in Hamburg, Germany. The two additional specimens in the Museum für Naturkunde Berlin ( ZMB 31134–31135) are non-types collected from “ Margherita, in the Patkai Hills, Upper Assam ” by Ernst Hartert in the fall of 1888. The Reptile Database ( Uetz et al. 2025) lists these specimens under “ Types ” as “ additional material ” along with the holotype and refer to Ananjeva and Stuart (2001) even though Denzer et al (1997) did not list these two specimens as types. However, these two specimens are not linked to the type in any way. Given the absence of Ptyctolaemus from Kolkata (Calcutta) and the morphological similarity of the type specimen to specimens from Meghalaya, we suspect that type could have been collected from Shillong, Meghalaya.

Referred specimens.

Three adult females ( WII -ADR 3479 , WII -ADR 3480 and WII -ADR 3481 ) collected from Risa forest ( 25.55615°N 91.89389°E, elevation 1670 m a. s. l.), Shillong, East Khasi Hills district, Meghalaya, India collected on 30 June 2016 by Abhijit Das, Bitupan Boruah and V. Deepak ; one adult female ( ZSI -R-29477 ) collected from Narpuh Wildlife Sanctuary ( 25.11062°N 92.37215°E, elevation 70 m a. s. l.), East Jaintia Hills district, Meghalaya, India, collected on 30 May 2022 by Abhijit Das and Bitupan Boruah ; one adult male ( WII -ADR 3180 ) from Risa Forest ( 25.55615°N 91.89389°E, elevation 1670 m a. s. l.), Shillong, East Khasi hills District, Meghalaya, India, collected on 23 May 2022 by Abhijit Das and Bitupan Boruah ; one adult male ( WII -ADR 1436 ) from Daribokgre ( 25.49675°N 90.32742°E, elevation 1120 m a. s. l.), Nokrek, Meghalaya, India, collected on 25 May 2022 by Abhijit Das, Bitupan Boruah and Vijayan Jithin ; one adult male ( WII -ADR 108 ) from Tyrna ( 25.24052°N, 91.68183°E, elevation 750 m a. sl.), East Khasi Hills district, Meghalaya, India, collected on 17 September 2017 by Vivek Sarkar ; one adult male ( ZSI -R-29478 ) from Malki forest ( 25.55602°N, 91.88678°E, elevation 1705 m a. s. l.), Shillong, East Khasi Hills district, Meghalaya, India, collected on 5 June 2024 by Abhijit Das, Isaac Rayen and Asim Bashir ; one adult female ( WII -ADR 1054 ) from Ngengpui Wildlife Sanctuary , ( 22.49004°N, 92.75874°E, elevation 220 m a. s. l.) Lawngtlai district, Mizoram, India, collected on 7 September 2021 by Abhijit Das and Bitupan Boruah ; one adult female ( WII -ADR 1152 ) from Teirei , Dampa Tiger Reserve, Mamit district, Mizoram, India, collected on 16 September 2021 by Abhijit Das and Bitupan Boruah ; one adult male ( WII -ADR 3477 ) and one adult female ( WII -ADR 3478 ) from Darlawn ( 24.01611°N, 92.92905°E, elevation 1071 m a. s. l.), Aizawl district, Mizoram, India, collected on 24 August 2021 by Samuel Lalronunga, Isaac Zosangliana and Malsawmdawngliana ; one adult male ( WII -ADR 3482 ) and three adult females ( WII -ADR 3483 – WII -ADR 3485 ) from Reiek ( 23.69319°N, 92.60626°E, elevation 1255 m a. s. l.), Aizawl district, Mizoram, India, collected on 25 September 2018 by Samuel Lalronunga and Lalhmangaiha Khiangte ; one adult female ( WII -ADR 3018 ) from Kalai ( 27.72294°N, 96.4346°E, elevation 1110 m a. s. l.), Kamlang Tiger Reserve, Lohit district, Arunachal Pradesh, India, collected on 3 October 2022 by Abhijit Das, Bitupan Boruah and Naitik G. Patel ; one adult female ( WII -ADR 3473 ) from Kalai ( 27.72294°N, 96.4346°E, elevation 1110 m a. s. l.), Kamlang Tiger Reserve, Lohit district, Arunachal Pradesh, India, collected on 20 July 2023 by Abhijit Das, Rajiv N. V. and Jason D. Gerard ; one adult female ( WII -ADR 1450 ) from 18 Mile ( 27.49548°N, 96.3919°E, elevation 440 m a. s. l.), Namdapha Tiger Reserve, Changlang district, Arunachal Pradesh, India, collected on 20 May 2022 by Abhijit Das and Bitupan Boruah ; one adult female ( WII -ADR 1782 ) from Sally Lake ( 28.16814°N, 95.83751°E, elevation 520 m a. s. l.), Mehao Wildlife Sanctuary, Lower Dibang valley district, Arunachal Pradesh, India, collected on 12 August 2022 by Bitupan Boruah ; one adult female ( WII -ADR 3292 ) from 40 Mile ( 27.48789°N, 96.54165°E, elevation 470 m a. s. l.), Namdapha Tiger Reserve, Changlang district, Arunachal Pradesh, India, collected on 27 May 2023 by Abhijit Das, Rajiv N. V. and Sourav Dutta ; one adult female ( WII -ADR 1407 ) from Deban ( 27.49445°N 96.39022°E, elevation 460 m a. s. l.), Namdapha TR, Changlang district, Arunachal Pradesh, India, collected on 12 May 2022 by Abhijit Das and Bitupan Boruah ; one adult female ( WII -ADR 1406 ) from Motijheel Trail ( 27.49624°N 96.33304°E, elevation 405 m a. s. l.), Namdapha Tiger Reserve, Changlang district, Arunachal Pradesh, India, collected on 13 May 2022 by Abhijit Das and Bitupan Boruah .

Redescription of the holotype.

ZMB 5004 (Fig. 6 ), an adult male with SVL 65.7 mm and TAL 153 mm; tail length more than twice of snout-vent length ( TAL / SVL = 2.33). Head distinct from neck, head longer than wide ( HW / HL = 0.59), slightly concave on top; rostral scale crescent, snout rounded; pupil rounded, scales on loreal region slightly keeled, surrounded by heterogeneous scales; nasal separated from rostral by one scale; canthus rostralis sharp, strongly keeled with 14 enlarged scales on each side; the keels gradually reduces towards snout; nostrils rounded, positioned slightly towards lateral side, in contact with first supralabials; snout scales irregular in shape and size, series of seven enlarged, keeled scales on the snout form an inverted “ Y ” - shaped pattern, with the first three anterior scales aligned along the midline and pointed posteriorly; head height 11.04 mm; scales on head, snout and interorbital region heterogenous in size and shape; tympanum hidden and covered with smooth scales; neck region with overlapping small scales interspersed with enlarged scales and are large towards the trunk; in the temporal region three enlarged, keeled, and elevated scales positioned posterior; scales around orbital region small and irregular in shape; parietal eye not distinct; scales on anterior region of gular pouch smaller than the middle region, heterogeneous in size feebly keeled and mucronate, the scales in middle region are larger than those of anterior and posterior region; three distinct raised gular folds on either side of midline; folds curved towards midline posteriorly, scales on the inner folds are granular; nine supralabials on both sides; ten infralabials on left and nine on right; nuchal crest poorly developed with 25 conical scales (Tables S 4, S 5).

Mental scale triangular, broader than long, and slightly narrower than the rostral; bordered posteriorly by one infralabial on each side and two enlarged postmentals in contact with the first infralabials; postmentals medially separated by a single small gular scale; four chin shields present on each side, positioned parallel to the infralabials; the anterior portion of the first chin shield contacts the first infralabial, while the remaining part of the first and second chin shields separated from infralabial by one intervening scale row, while subsequent two chin shields separated from the infralabials by two intervening scale row; scales in the anterior region of gular feebly keeled.

Habitus slender, slightly compressed, dorsal scales keeled, imbricate, posteriorly pointed; mid-dorsal scale row strongly keeled, enlarged scales appearing discontinuously; lateral scales heterogeneous in size, mostly smaller than the dorsal, slightly keeled, imbricate, and interspersed with enlarged, strongly keeled scales; 99 vertebral scales ( VTSR), 93 rows of scales around the midbody; ventral scales 135, larger than the lateral scales and approximately equal to the enlarged dorsal scales, strongly keeled, imbricate, and pointed backward.

Limbs slender, moderate sized, scales on dorsal surface strongly keeled, imbricate scales, lower arm slightly longer than the upper arm ( UAL / LAL = 1.11); thigh length approximately equal to crus length (femur / crus = 1.22); scales on dorsal surface of the forelimbs strongly keeled, uniform and imbricate; scales on dorsal side of the hindlimb slightly enlarged, keeled and imbricate; scales on ventral side of the hindlimb smaller than the dorsal, slightly keeled and imbricate; relative length of digits: IV > III > II > V > I; relative length of toes: IV > III > V > II > I; 33 / 34 bicarinate subdigital lamellae under fourth toe.

Tail rounded in cross section, slightly compressed laterally, thick at the base, covered with homogeneous scales on the dorsal and ventral surface arranged regularly, strongly keeled and imbricate.

Colouration in preservative.

Dorsal surface of head brown; lateral side of head light-brown; lips pale-brown coloured; paravertebral region with feeble irregular shaped greyish patches; feeble greyish indistinct patch on lateral region; limbs brown with dark brown or greyish patches; radial stripes around the eye indistinct except for two below the eye; inner folds of gular black; ventral side of body light-brown with light-greyish spots; forelimb and hindlimbs slightly darker than the rest of the ventral region with brown light-grey; digits with indistinct bands; tail brown with indistinct greyish cross bands.

Morphological description based on newly collected materials ( 6 males, 18 females).

Morphometric and meristic characters are provided in Tables 3 and 4 . Moderate-sized lizard, SVL 62.7–79.2 mm (male) and 46.7–76.3 mm (female); TAL 131.3–181.2 mm (male) and 101.3–166.2 mm (female); tail length more than twice the of snout-vent length ( TAL / SVL = 2.0–2.4). Head distinct from neck, head longer than wide ( HW / HL = 0.43–0.59), slightly concave on top; rostral scale crescent, snout rounded; pupil rounded, scales on loreal region slightly keeled, surrounded by heterogeneous scales; nasal separated from rostral by one scale; canthus rostralis sharp, strongly keeled with 12–15 enlarged scales on each side; the keels gradually reduces towards snout; nostrils rounded, positioned slightly towards lateral side, in contact with first supralabials; snout scales irregular in shape and size, series of 5–7 enlarged, keeled scales on the snout form an inverted “ Y ” - shaped pattern, with the first three anterior scales aligned along the midline and pointed posteriorly; head height 7. 4–11. 7 mm; scales on head, snout and interorbital region heterogenous; tympanum hidden and covered with smooth scales; neck region with overlapping small scales interspersed with enlarged scales and are large towards the trunk; three enlarged, keeled, and elevated scales positioned posterior and horizontal to orbit; scales around orbital region small and irregular in shape; parietal eye not distinct; gular in males distinct; scales on gular region smaller than the surrounding scales slightly heterogeneous in size feebly keeled and mucronate, the scales in middle region are larger than those of anterior and posterior region; three distinct raised gular folds on either side of midline; folds curved towards midline posteriorly (Fig. 7 ), scales on the inner folds are granular; 6–10 supralabials on left and 6–10 on right side; 7–10 infralabials on left and 6–10 on right side; nuchal crest poorly developed with 14–29 conical scales.

Mental scale triangular, broader than long, and slightly narrower than the rostral; bordered posteriorly by one infralabial on each side and two enlarged postmentals in contact with the first infralabials; postmentals followed by 1–3 small gular scale; four chin shields present on each side, positioned parallel to the infralabials; the anterior portion of the first chin shield contacts the first infralabial, while the remaining part of the first and second chin shields separated from infralabial by one intervening scale row, while subsequent two chin shields separated from the infralabials by two intervening scale row; scales in the anterior region of gular feebly keeled.

Habitus slender, slightly compressed, dorsal scales keeled, imbricate, posteriorly pointed; mid-dorsal scale row strongly keeled, enlarged scales appearing discontinuously; lateral scales heterogeneous in size, mostly smaller than the dorsal, slightly keeled, imbricate, and interspersed with enlarged, strongly keeled scales; 79–114 dorsal scales ( VTSR), 71–101 rows of scales around the midbody; ventral scales 114–142, larger than the lateral scales and approximately equal to the enlarged dorsal scales, strongly keeled, imbricate, and pointed backward.

Limbs slender, moderate sized, scales on dorsal surface strongly keeled, imbricate scales, lower arm slightly longer than the upper arm ( UAL / LAL = 0.84–1.01); femur length approximately equal to crus length (femur / crus = 0.95–1.08); scales on dorsal surface of the forelimbs strongly keeled, uniform and imbricate; scales on dorsal side of the hindlimb slightly enlarged, keeled and imbricate; scales on ventral side of the hindlimb smaller than the dorsal, slightly keeled and imbricate; relative length of digits: IV > III > II > V > I; relative length of toes: IV > III > V > II > I; 29–40 / 27 – 36 bicarinate subdigital lamellae under fourth toe.

Tail rounded in cross section, slightly compressed laterally, thick at the base, covered with homogeneous scales on the dorsal and ventral surface arranged regularly, strongly keeled and imbricate.

Coloration in preservative.

Dorsal head golden brown; greyish-white blotch on the parietal region; lateral head light brown; nostril light-greyish; enlarged keeled scales on the posterior mandibular region light coloured; lips pale greyish coloured; body golden brown coloured; paravertebral region with scattered greyish patches; greyish indistinct patch on lateral region; limbs light brown with greyish patch; radial stripes around the eye indistinct; mental white to light golden brown; inner folds of gular dark coloured, midline of gular light golden brown coloured; ventral side of forelimb and body light yellow with light greyish patch, ventral side of hindlimb light grey coloured; digits with indistinct bands; tail golden brown with indistinct greyish cross bands; scales on gular region smaller than the surrounding scales slightly heterogenous in size and mucronate, the scales in middle region are larger than those of anterior and posterior region; three distinct raised gular folds on either side of midline; folds curved towards midline posteriorly, scales on the inner folds are granular (Fig. 6 ).

Expanded diagnosis based on newly collected materials.

A medium-sized agamid lizard, SVL 46.67–79.24 mm (n = 22), TAL 101.32–181.23 mm (n = 22). Nuchal crest is poorly developed, consisting of 14–29 nuchal scales. Supratympanic spines absent. Body laterally compressed, scales at the trunk heterogeneous in size, larger than ventrals, dorsally and posteriorly oriented, 79–114 dorsal scales ( VTSR), 71–101 rows of scales at midbody, 114–142 ventrals. Mental smaller than chin shields, first pair of chin shields elongated and in midline contact, the gular scales at the midline are smaller than the adjacent scales away from the midline.

Colouration in life.

Colouration in life variable (Figs 8 – 10 ). Head primarily brown to dark brown intermixed with pale-brown scales, or intermixed with pale-green or yellowish green scales in some individuals; three pale-brown or pale-greenish brown bands on dorsal surface of head, first one concaved on snout followed by one diffused in front of the orbital region, third one broad, nearly bow shaped on interorbital region connecting the supraciliary scales; occipital region paler; supralabials and infralabials uniform brown or with dark-brown patches or anteriorly dark-brown and gradually paler towards angle of jaw forming a pale stripe, in some individuals this stripe colour pale-greenish; alternative dark-brown and pale-brown streaks radiating from eyes; these streaks may be diffused, or dark stripes may represent only by dark edges; one similar streak radiating from eye to angle of jaw; lateral side of neck pale-brown or pale-greenish or pale-yellowish green with dark-brown oblique streaks on neck and dark-brown reticulation on trunk; paravertebral region with irregular shaped enlarged dark-brown patches separated by pale-brown / pale-green narrow lines or rusty brown patches separated by greyish brown narrow patches; pale-yellow / greenish stripe may be present running parallel along the paravertebral region starting at neck and posteriorly diffused on trunk; dorsal surface of the limbs brown or dark-brown or greyish brown with irregular pale-brown lines; dorsally tail with alternative broad dark-brown and comparatively narrow pale-brown patches; lateral sides of tail base pale-brown or rusty brown; on ventral side, lower jaw pale brown with or without dark-brown lines; ground colour of gular region pale-brown or pale-bluish green or pale-yellowish green; three to four broad dark-blue stripes with lighter edge and separated by narrow light lines; edge of the dark-blue stripes irregular; belly pale-brown.

Natural history and distribution.

Ptyctolaemus gularis is a widely distributed agamid lizard inhabiting forested landscape of northeast India (Fig. 8 ). In Meghalaya, where it has been recorded from Khasi, Garo and Jaintia Hills from low lying areas ( 50 m) of Jaintia hills to ~ 1600 m in Shillong plateau (Fig. 11 A, B ). On 30 June 2016, we surveyed for agamid lizards in the areas adjoining Malki forest in Shillong between 10: 00–13: 00 hrs. We found six individuals of P. gularis , all were females and five were gravid females. The smallest female individual measured was 61.1 mm ( SVL) and the largest was 79.9 mm ( SVL). We caught and gently pressed the belly to find out the number of eggs in these individuals. The number of eggs in these individuals varied between 2, 5 and 7. During June 2016, in Malki forest we observed a gravid female making a pit on loose soil using its snout probably for laying eggs. In the Barail hills of southern Assam, it is found as low as 30 m to 900 m elevation. Subadult individuals were often recorded along the forest edges during May. One large male was detected on the trunk of a tree growing on a forested hill slope. During September two females were recorded along riparian vegetation showing dark crypsis. In Dampa Tiger Reserve, one Individual was seen in a bamboo dominated patch during 15 September 2021. This species is widely distributed in the mountains of northeast India across south of Brahmaputra valley and to the eastern part of the valley. The westernmost distribution limit of the species we recorded was the Garo hills and are distributed in the Mehao Wildlife Sanctuary, Arunachal Pradesh in the east (Fig. 1 ), and in the Ngengpui Wildlife Sanctuary, Mizoram in the south.

Figures

Figure 1. Sampling localities of the current study and type localities of the Ptyctolaemus species. See Table 1 for sampling locality (1–31) details. Type localities are indicated by stars and other localities are indicated with a circle. Green circles: Ptyctolaemus gularis; purple star and circle: Ptyctolaemus siangensis sp. nov.; blue star and circle: Ptyctolaemus namdaphaensis sp. nov.; yellow star: Ptyctolaemus collicristatus; pink star: Ptyctolaemus chindwinensis.

Figure 6. Holotype of Ptyctolaemus gularis (ZMB 5004). A Lateral view; B dorsal view; C ventral view; D lateral view of head; E dorsal view of head; F ventral view of head. Scale bar = 10 mm.

Figure 7. Gular fold arrangement in males of the three species of Ptyctolaemus found in India. Ptyctolaemus gularis A WII - ADR 3477, B WII - ADR 3180, C WII - ADR 3482, D WII - ADR 1436; P. siangensis sp. nov., E WII - ADR 1210, F ZSI - R- 29479, G WII - ADR 1176, H WII - ADR 2542 and P. namdaphaensis sp. nov., I WII - ADR 3283, J WII - ADR 3178, K. WII - ADR 3061, L ZSI - R- 29481. Scale bar = 10 mm.

Figure 8. Variation in the live gular colour pattern in P. gularis. A Uncollected female from Namdapha Tiger Reserve, Arunachal Pradesh; B a female (WII - ADR 3292) from Namdapha, Tiger Reserve, Arunachal Pradesh; C a female (WII - ADR 3473) from Kamlang Tiger Reserve, Arunachal Pradesh; D a female (WII - ADR 1152) from Dampa Tiger Reserve, Mizoram; E a male (WII - ADR 1436) from Daribokgre, Garo Hills, Meghalaya; F a male (WII - ADR 3180) from Shillong, Khasi Hills, Meghalaya.

Figure 10. Ptyctolaemus gularis in life. A WII - ADR 3180 from Shillong, Meghalaya; B WII - ADR 3473 from Kamlang Tiger Reserve, Arunachal Pradesh; C WII - ADR 1436 from Daribokgre, Meghalaya; D WII - ADR 1406 from Namdapha Tiger Reserve, Arunachal Pradesh; E WII - ADR 1152 from Dampa Tiger Reserve, Mizoram; F ZSI - R- 29477 from Narpuh Wildlife Sanctuary, Meghalaya.

Figure 11. Habitat of Ptyctolaemus species in northeast India. A, B Habitat of P. gularis in Shillong, Khasi Hills, Meghalaya; C habitat of P. siangensis sp. nov. at Potin, Arunachal Pradesh; D habitat of P. namdaphaensis sp. nov. at Kamala valley, Namdapha Tiger Reserve, Arunachal Pradesh.