The Sri Lankan torrent toads (Bufonidae: Adenominae: Adenomus): species boundaries assessed using multiple criteria

Abstract

The bufonid genus Adenomus, an endemic of the montane and lowland rainforests of central and south-western Sri Lanka, has been considered to comprise of three species, viz. A. kelaartii, A. dasi and A. kandianus, the last of which has been recently highlighted as "the world's rarest toad". We conducted a survey across the known range of Adenomus and used multiple criteria to delineate species boundaries within the genus. These include: a molecular phylogeny based on a 16S ribosomal RNA gene fragment; an examination of the external morphology of adults and larvae, and the skeletal morphology of adults; a bioacoustic analysis; and ecological niche modelling. We show that Adenomus is monophyletic and that it comprises only two species: A. kelaartii and A. kandianus, with A. dasi being a junior synonym of the latter. For the two valid species of Adenomus, we provide detailed osteological descriptions; clarify the distribution patterns; and provide genetic data to facilitate their scientific conservation management.

Invasive Plants Distribution Modeling: A Tool for Tropical Biodiversity Conservation With Special Reference to Sri Lanka

“…Out of the 19 results that were received, none of the papers focused on SDM relevant to plants. Three publications were found relevant to the potential habitat suitability of selected animal groups, that is, the Sri Lankan leopard, an endangered and endemic subspecies Panthera pardus kotiya (Kittle, Watson, Cushman, & Macdonald, 2018;Silva et al, 2017), three bufonid species belonging to the endemic genus Adenomus (Meegaskumbura et al, 2015) and two sea cucumber species belonging to the genus Holothuria (Dissanayake & Stefansson, 2012). Furthermore, literature given in the Web of Science CAB Abstracts were searched (search date June 22, 2018) using search terms species distribution modeling and Sri Lanka.…”

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“…Often, females occupy a different habitat from that of males to prevent premature amplexus, to reduce stress and to avoid competition for food. This suggests that, larger-bodied females (Meegaskumbura et al 2015) probably wander far from the breeding streams, foraging to build up energy reserves to produce their substantial clutches of eggs and to undergo the strenuous torrent diving activity, while the smallerbodied males live in forested riparian habitats, awaiting a chance to mate.…”

“…Sequences were assembled in 4peaks v.1.7.1. Subsequently, the sequences of the new population were compared against a dataset consisting of Adenomus kanidanus and A. kelaartii obtained from Meegaskumbura et al (2015). Sequences were aligned using ClustalW as implemented in MEGA 5.0 (Tamura et al 2011).…”

“…Although the species was finally declared extinct in 2008 (Stuart et al 2008), it turned out that it had been rediscovered near Adam's Peak by Manamendra-Arachchi and Pethiyagoda (1998) and wrongly described as a new species, A. dasi, distinguished from the type specimens of A. kandianus by the pattern of dorsal tuberculation and the extent of pedal webbing. This error was finally pointed out by Meegaskumbura et al (2015) in a study that involved a morphological, morphometric, genetic, bioacoustic, osteological and ecological analyses of both metamorphs and larvae of A. kelaartii, A. kandianus and 'A. dasi'.…”

“…Discovered only recently (Meegaskumbura et al 2015), endowed with a ventral suctorial disc, the tadpoles of A. kandianus show distinct adaptations for torrent life; they are highlighted as being gastromyzophorous larvae among the very few currently known. Sucker discs and ventrally-oriented mouths enable them to feed on aufwuchs (surface films constituting of algae and other minute organisms growing on submerged substrates) while being attached to submerged substrates in torrents (Meegaskumbura et al 2015). Nothing, however, is known about stream-microhabitat partitioning of different life-history stages of these larvae, knowledge that is important for focused conservation efforts.…”