Tuesday, May 30, 2023

[Herpetology • 2023] Gracixalus patkaiensis • A New Species of Green Tree Frog of the Genus Gracixalus (Anura: Rhacophoridae) from the Evergreen Forest of Northeast India

Gracixalus patkaiensis 
 Boruah, Deepak, Patel, Jithin, Yomcha & Das, 2023

Patkai Green Tree Frog  ||  DOI: 10.3897/vz.73.e98444

We describe a new species of rhacophorid frog of the genus Gracixalus from northeast India based on molecular, morphological and acoustic evidence. The new species, formally described herein as Gracixalus patkaiensis sp. nov., is morphologically distinct from other congeners by a suite of morphological characters such as snout-vent length 23.6–26.5 mm in adult males; green dorsum with irregular brown spots; dorsal skin shagreened with numerous spinules; snout shape nearly acuminate in dorsal and ventral view; a prominent dark streak along the cranial margins; white reticulations along lateral side and ventrum distinct in life. Genetically, the new taxon is found to differ from all the recognized Gracixalus species by 4–14.8% divergence in the 16S mitochondrial gene. The discovery confirms the presence of genus Gracixalus from the Indian state of Arunachal Pradesh underlines the importance of biological exploration even in well-known protected areas of India.

Keywords: Arunachal Pradesh, Indo-Burma Biodiversity Hotspot, Namdapha Tiger Reserve, rainforest

Gracixalus patkaiensis sp. nov. in life.
A Holotype (WII-ADA1353) showing dorsolateral view; B lateral view of the head (Paratype, WII-ADA1356) showing subgular vocal sac;
C–F Paratype (WII-ADA1400): C dorsolateral view, D showing dorsal spinules, E dorsal view, F closeup of head showing spinules on upper eyelids;
G ventral side of right hand (Paratype WII-ADA1352); H ventral side of the paratype (WII-ADA1400), I granular skin on belly and thigh; J showing groin of the paratype (WII-ADA1356); K showing the vent and lateral side of thigh (WII-ADA1356).

Habitat of Gracixalus patkaiensis sp. nov.
A, B yellow arrow marks indicate the representative perch of the species;
C and D two uncollected individuals of G. patkaiensis sp. nov. in natural habitat.

Gracixalus patkaiensis sp. nov.

Diagnosis: A small sized rhacophorid frog with SVL 23.6–26.5 mm (n = 6) in adult males, body slender, snout pointed, head longer than wide, nostril closer to snout tip than eye, internasal distance shorter than inter upper eyelid distance, tympanum and supratympanic fold distinct, limbs slender, digits with large disc, circum-marginal groove on disc present, nuptial pad present on first finger in males, webbing absent between fingers, vomerine ridge absent, dorsal skin on snout, head, dorsum and limbs with spinules of different size, belly granular, dorsally chartreuse green with brown spots of irregular shape and size, upper eyelids dark brown, a broad brown stripe along canthus rostralis from anterior corner of the eye to tip of the snout covering the nostril, another brown stripe from posterior edge of the upper eyelid along supratympanic fold running dorso-laterally to one third of the trunk, white patches of irregular shape and size on the lateral side of the head below mid-eye, below tympanum in the mandibular region, continues along flank to groin, below skin semi-transparent, light green with large white patch covering middle of throat, chest, axilla and anterior half of the belly, brown cross bars on fore-arm, thigh and tibia present.

Etymology: We named the species after Patkai hills range where the type locality of the new species lies within Namdapha Tiger Reserve. The specific epithet “patkaiensis” is a noun in apposition.

Suggested Common Name: Patkai green tree frog.

Distribution: Currently the species is only known from a single locality in Kamala Valley Beat, popularly known as 25 mile in the Namdapha Tiger Reserve. It may occur in similar microhabitats in the forest interior of the tiger reserve.


Bitupan Boruah, V. Deepak, Naitik G. Patel, Vijayan Jithin, Tajum Yomcha and Abhijit Das. 2023. A New Species of Green Tree Frog of the Genus Gracixalus (Anura: Rhacophoridae) from the Evergreen Forest of Northeast India. Vertebrate Zoology. 73: 557-574. DOI: 10.3897/vz.73.e98444