Wednesday 23 March 2016

Microhyla laterite: A new species of Narrow-mouthed Frog from the laterite terrains of western India.

Laterites are iron and aluminium rich clay soils formed by the disolution of other more soluble ions from a variety of rocks in wet tropical climates. Western India is known for its extensive laterite deposits, which are largely derived from the Deccan Traps volcanic rocks, and appear to have been forming since the End of the Cretaceous. These deposits have historically been mined for brick clay and otherwise been regarded as a wasteland environment, due to its poor quality soils, and has recieved little attention from scientists and conservationists. However it is unique environment with its own distinctive flora and fauna, with extensive grasslands and wetlands situated on mineral-poor acid soils, where trees are rare but a diverse assemblage of endemic herbs and shrubs can be found.

In a paper published in the journal PLoS One on 9 March 2016, a team of scientists led by Kadaba Seshadri of the Department of Biological Sciences at the National University of Singapore describe a new species of Narrow-mouthed Frog from laterite terrains in the Western Ghats of Karnataka State, India, which was discovered during biological surveys carried out by 'My laterite: My habitat' a citizen science project founded by Ramit Singal, second author on the paper, when he was a student at the Manipal Institute of Technology, in which surveys were carried out by local people from the laterite areas.

Narrow-mouthed Frogs, Microhyla spp., are widespread across South and Southeast Asia, with thirty eight previously described species, eight of which are found in India. They are small, generally smooth-skinned Frogs laking webed hands and feet.

The new species is named Microhyla laterite, in reference to its habitat. These frogs are small, with adult males reaching 15.3-16.6 mm in length, and the single known female measuring 18.4 mm. The forelimbs are short, and brown in colour with black markins. A prominant black line rimmed with red runs across the back between the forelimbs, the eyes are golden in colour, the vocal sacs purplish.

Dorso-lateral view of adult male Microhyla laterite. Seshadri et al. (2016).

All specimens of Microhyla laterite observed were found within an area of less than 150 km2, around ephemeral (temporary or seasonal) ponds on grassland with shrubs and small woody trees such as Strychnos nux-vomica (the Strichnine Tree), Careya arborea (the Wild Guava), Macaranga indica (the Macaranga Gum Tree) and Mangifera indica (Indian Mango). The area currently has no protected status, and is fragmented by numerous plantations. As such Seshadri et al. consider that the species should be listed as Endangered under the terms of the International Union for the Conservation of Nature’s Red List of Threatened Species.

Typical environment of Microhyla laterite. Seshadri et al. (2016).

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