Two New Day Geckos Discovered

Shakila Ifham

March 18, 2023


 A scientific team comprising both local and international researchers earlier this week released the findings of two new day geckos of the genus Cnemaspis from the Ethagala (a dry zone forest) in Ampara District, and the Galgiriya (an intermediate forest) in the Kurunegala District.

Lead Scientist Suranjan Karunarathnaof the Nature Explorations and Education Team told The Earthlanka that Jayaweera’s day gecko (Cnemaspis jayaweerai) is found in Ethagala, and the Nanayakkara’s day gecko (Cnemaspis nanayakkarai) is found in Galgiriya.

“We reported these two new species only from these two isolated mountain forests. Therefore, according to the International Conservation Union -IUCN Red List criteria, they are identified as critically endangered due to their low population density and narrow distribution,” the Scientist added.

Both new species were named after two reputed people in Young Zoologists Association (YZA). Shanthasiri Jayaweera, Senior Instructor of the Fish Study Group, YZA and Ananda Lal Nanayakkara, Senior Instructor of the Reptile Study Group, YZA.

The team comprises of Suranjan Karunarathnaof the Nature Explorations and Education Team, Kanishka D.B. Ukuwelaof the Department of Biological Sciences, Faculty of Applied Sciences, Rajarata University, Anslem De Silvaof the Amphibia and Reptile Research Organization of Sri Lanka, Aaron M. Bauerof the Department of Biology and Centre for Biodiversity and Ecosystem Stewardship, Villanova University, Majintha Madawalaof the Victorian Herpetological Society,Nikolay A. Poyarkovof the Department of Vertebrate Zoology, Lomonosov Moscow State University, Madhava Botejueof the Biodiversity Conservation Society, Dinesh Gabadageof the Biodiversity Conservation Society, L. Lee Grismerof the Department of Herpetology, San Diego Natural History Museumand Vladislav A. GorinJoint Russian-Vietnamese Tropical Research and Technological Center.

Sri Lanka is a local hotspot for Cnemaspisday geckos with 40 currently known species with 100% endemism. In this paper, the team evaluated the phylogenetic relationships of Cnemaspisspecies belonging to the alwisigroup of the podihunacladeand describe two additional new species of Cnemaspisfrom Sri Lanka; one from Galgiriya mountain, Kurunegala District, and another from Ethagala mountain, Ampara District.

These new species were recorded from granite caves within forested areas in isolated mountains in the dry bioclimatic zone (point-endemics). Both new species are microhabitat specialists with narrow niches limited to humid, cool, canopy-shaded granite caves and old buildings associated with granite caves, where they are camouflaged by their cryptic morphology and body colouration.

Furthermore, both species prefer narrow (~ 6–12 mm), long (~ 120–450 mm) and deep (~ 80–260 mm) crevices as refugia. The regions in which these habitats are located receive relatively low annual rainfall (1,000–1,500 mm).

These new species are medium in size (28.5–36.8 mm SVL) and can be differentiated from all other Sri Lankan Cnemaspisby the presence of clearly enlarged, subhexagonal subcaudal scales and the absence of precloacal pores in males. Both species described here are categorised herein as Critically Endangered (CR) under the IUCN Red List criteria. The major threats for these new species are habitat loss due to expansion of commercial-scale agriculture, illicit forest encroachments, and forest fires. Therefore, we recommend that relevant authorities take immediate conservation action to ensure the protection of these forest areas with their buffer zones in the near future.

Sri Lanka, along with the Western Ghats of India, is ranked as one of the world’s smallest biodiversity hotspots (Meegaskumbura et al. 2002). Of the 242 species of reptiles described, ~66% are endemic to the country, and thus Sri Lanka is also considered a reptile diversity hotspot (Roll et al. 2017, Karunarathna et al. 2020).

Within this rich reptile assemblage, the diversity of geckos (Family Gekkonidae) is remarkable; 63 species (from eight genera) have been described so far, accounting for ~26% of the overall reptilian species-richness (de Silva et al. 2019; Amarasinghe and Karunarathna 2020; Amarasinghe et al. 2021b). Of these, 53 species (~84%) are endemic and 48 species (~76%) are threatened and vulnerable to extinction due to ongoing climate change effects, irresponsible development, loss of good quality habitats, and forest fragmentation (Amarasinghe and Karunarathna 2020; Dayananda et al. 2021).