by Dilrukshi Handunnetti
COLOMBO –From the misty Knuckles Hills that form a part of Sri Lanka’s Central Highlands, a new snake species has been added to the island’s already rich catalog of unique reptiles.
De Silva’s rough-sided snake (Aspidura desilvai) is described in a new paper published in Zootaxa, making it the ninth species in the genus Aspidura, endemic to Sri Lanka.
The new species bears a strong resemblance to A. trachyprocta and A. ravanai, a species described in 2017, but is easily distinguishable by its color pattern, scales in the ischiadic region, and morphometric characteristics, the paper says.
The new species has so far been recorded only in the Knuckles Massif in the central district of Matale, known for its rich biodiversity and part of a UNESCO-declared World Heritage Site.
The researchers carried out a detailed comparison between the new species and A. ravanai and A. trachyprotoca, and all other known Aspidura species, before identifying it as a distinct species.
“They are only found in this single habitat, and are readily distinguished from their coastal scale count and the color pattern,” L.J. Mendis Wickramasinghe, lead author of the new paper and founder of the Herpetological Foundation of Sri Lanka, told Mongabay. The snake bears the color of latosolic soil or soil found in tropical rainforests.
A. rachyprocta is distributed throughout the central highlands except the Knuckles Massif, while A. ravanai is only found in the higher altitudes of Adam’s Peak of the Central Hills. The new species, in contrast, is observed from an elevation of about 925 meters (3,030 feet) in the Knuckles Massif and its habitat doesn’t overlap with those of the other two species.
The species was collected during field surveys carried out in the region to document the diversity of the area’s herpetofauna, or reptile life.
A. desilvai has been commonly observed in its habitat in and above the lower montane forests of Knuckles. Commonly spotted beneath leaf litter and loose soil, it has also been seen under rocks, boulders and decaying logs, and tends to surface during the day. Its reddish-brown color is similar to the shade of the soil in the area.
A unique habitat
Sri Lanka’s Central Highlands massif complex consists of three major massifs of significant biodiversity — Central Hills, Rakwana Hills and Knuckles Hills — which are separated by two major river basins.
The Knuckles Massif forms a part of the Central Highlands and Knuckles World Heritage Site (WHS) and is biogeographically separated by the Mahaweli River basin from the rest of the Central Highlands massifs.
Its forest cover consists of a diverse range of forest types, including montane, sub-montane, pygmy, semi-evergreen, riverine, rock outcrop, savanna, patana grassland, and scrubland.
The Knuckles range varies in altitude from 760 to 1,900 meters (2,500 to 6,200 feet) and the forest serves as an important catchment area to the island’s longest river, the Mahaweli. The altitudinal variations and geographical location have resulted in a wide diversity of flora and fauna in the region.
Importantly, this biogeographical separation of the Knuckles region from a major river basin has resulted in species isolation from the rest of the region.
Despite the uniqueness of the mountain range that makes it a biodiversity hotspot, several issues are impacting Sri Lanka’s Central Highlands and threatening species survival.
According to the paper, increased tourism activity in the area, especially uncontrolled ecotourism trends in the Knuckles region, pose a serious problem.
“The (new) species is threatened by habitat destruction from the expansion of existing roads and an increase in the number of visitors travelling in vehicles. During the study period alone, the researchers observed as many as seven road kills of A. desilvai, in the Reverseturn area alone,” the paper says.
A. desilvai is also threatened by acute habitat loss caused by forest fragmentation, illegal cardamom plantations, uncontrolled gem mining, forest fires caused by human activity, and the introduction and spread of invasive alien species.
The new species is named in honor of Pilippu Hewa Don Hemasiri de Silva, a former director of the National Museums of Sri Lanka and author of several books, including an acclaimed publication on Sri Lanka’s herpetofauna.
WICKRAMASINGHE, L. J. MENDIS et al. A new species of Aspidura Wagler, 1830 (Squamata: Colubridae: Natricinae) from Knuckles, World Heritage Site, Sri Lanka. Zootaxa, [S.l.], v. 4559, n. 2, p. 265–280, feb. 2019. ISSN 1175-5334.
Banner image: Aspidura desilvai sp.nov. a newly discovered “rough-sided” snake in Sri Lanka’s Knuckles Massifis. Image by Wickramasinghe L. J. Mendis.