Family- Nyctibatrachidae

The family nyctibatrachidae is restricted to south India and Sri Lanka. This family is further divided in to three subfamilies: Astrobatrichnae, Nyctibatrachinae and Lankanectinae (Vijayakumar et al. 2019). Subfamilies Astrobatrichnae and Nyctibatrachinae are found only in South India while Lankanectinae is endemic to Sri Lanka. There are no morphological features that are common to both subfamilies except thier wrinkled skin. Previously Lankanectinae and Nyctibatrachinae were placed as subfamilies under the family Ranidae. But molecular analysis showed that these two subfamiles are distinctly related to Ranids (Frost et al., 2006; Bossuyt et al., 2006). The subfamily Lankanectinae diverged from the subfamily Nyctibatchinae in the Cretaceous period (145-66 MYA) (Van Bocxlaer et al., 2012). Subfamily Lankanectinae consists of a single genus: Lankanectes and two species.

Genus- Lankanectes Dubois and Ohler, 2001

The members of this genus of frogs are characterized by having a heavily wrinkled body and two teeth like processes on the lower jaw. These are the only frogs in Sri Lanka that have teeth like processes on the lower jaw and this feature has earned them the name “Sri Lanka Fanged frogs”. Adult frogs also possess a lateral line system making them well adapted to the aquatic life. These frogs have fully webbed hind limbs but they lack digital disks. The adult frogs can reach up to a snout to went length of 70mm. Both species are completely aquatic occurring in both still and slow flowing waters in the wet and intermediate zones of Sri Lanka.

Species of Lankanectes in Sri Lanka

Lankanectes corrugatus (Peters, 1863)^E
Lankanectes pera Senevirathne, Samarawickrama, Wijayathilaka, Manamendra-Arachchi, Bowatte, Samarawickrama, & Meegaskumbura, 2018^E

Lankanectes pera can be distinguished from Lankanectes corrugatus mainly by its tuberculated throat (vs smooth throat in Lankanectes corrugatus) and the absence of dark patches on venter, throat, fore and hind-limbs (Senevirathne et al., 2018). Lankanectes corrugatus is widely distributed in the lowlands up to 1800 m in elevation in the central highlands except in the higher elevations (>1000m) in the Knuckles mountain range (Dutta & Manamendra-Aarachchi, 1996). Lankanectes pera inhabits only clear streams that flow through canopy covered montane forests in the highest elevations (>1000m) of the Knuckles Mountain range (Senevirathne et al., 2018). Tadpoles of Lankanectes corrugatus are seen in fast flowing streams as well as small ponds with muddy substrates (Ukuwela & Bandara, 2009).

Abreviations in superscript

E- Endemic species, Ex- Extinct species, Cr- Critically Endangered species, En- Endangered species

References

Bossuyt, F., R. M. Brown, D. M. Hillis, D. C. Cannatella, and M. C. Milinkovitch (2006) Phylogeny and biogeography of a cosmopolitan frog radiation: Late Cretaceous diversification resulted in continent-scale endemism in the family Ranidae. Systematic Biology, 55: 579–594.

Dubois, A., A. Ohler, & S. D. Biju (2001) A new genus and species of Ranidae (Amphibia, Anura) from south-western India. Alytes, 19: 53–79.

Dutta, S. K., and K. Manamendra-Arachchi (1996) The Amphibian Fauna of Sri Lanka. Colombo: Wildlife Heritage Trust of Sri Lanka. Colombo.

Frost, D. R., T. Grant, J. Faivovich, R. H. Bain, A. Haas, C. F. B. Haddad, R. O. de Sá, A. Channing, M. Wilkinson, S. C. Donnellan, C. J. Raxworthy, J. A. Campbell, B. L. Blotto, P. E. Moler, R. C. Drewes, R. A. Nussbaum, J. D. Lynch, D. M. Green, and W. C. Wheeler (2006) The amphibian tree of life. Bulletin of the American Museum of Natural History, 297: 1–370

Senevirathne, G., Samarawickrama, V.A.M.P.K., Wijayathilaka, N., Manamendra-Arachchi, K., Bowatte, G., Samarawickrama, D.R.N.S. & Meegaskumbura, M. (2018) A new frog species from rapidly dwindling cloud forest streams of Sri Lanka - Lankanectes pera (Anura, Nyctibatrachidae). Zootaxa, 4461 (4): 519. doi:10.11646/zootaxa.4461.4.4

Van Bocxlaer, I., S. D. Biju, B. Willaert, V. B. Giri, Y. S. Shouche, and F. Bossuyt (2012) Mountain-associated clade endemism in an ancient frog family (Nyctibatrachidae) on the Indian subcontinent. Molecular Phylogenetics and Evolution, 62: 839–847.

Vijayakumar, S.P., Pyron, R.A., Dinesh, K.P., Torsekar, V.R., Srikanthan, A.N., Swamy, P., Stanley, E.L., Blackburn, D.C., Shanker, K. (2019). A new ancient lineage of frog (Anura: Nyctibatrachidae: Astrobatrachinae subfam. nov.) endemic to the Western Ghats of Peninsular India. PeerJ 7:e6457 (https://doi.org/10.7717/peerj.6457)

Ukuwela, K. D. B., and I. N. Bandara (2009) The first description of the tadpole of Lankanectes corrugatus (Peters, 1864) (Anura: Nyctibatrachidae) from Sri Lanka. Russian Journal of Herpetology, 16: 213–216.