Beddomixalus bijui (Zachariah, Dinesh, Radhakrishnan, Kunhikrishnan, Palot & Vishnudas 2011)

Beddomixalus bijui is a slender, elongated medium-sized frog. It has vomerine teeth and no lingual papilla. Its supratympanic fold and tympanum are distinct. The canthus rostralis is rounded, while the loreal region is obtusely concave. The small exotrophic, nektonic tadpole is oval and depressed. Their eyes are moderate size, positioned dorsolaterally and directed more laterally than anteriorly. The eyes are not visible in ventral view. In lateral view, the body is slightly depressed, and snout slightly rounded. The musculus interhyoideus and intestine are visible through the ventral parts of the body. The naris is equidistant from both the snout and eye. Spiracle is sinistral and ventrolaterally positioned at midbody. Myotomes of the tail musculature are of moderate development. Tail fin is moderately sized and rounded at the end. The upper fin is smaller than lower fin. The oral disc, which is antero-ventrally positioned, and is of a triangular shape in the relaxed state, but of oval shape in the expanded state, and slightly emarginated laterally. Marginal papillae frame the oral disc ventrally and laterally, but they are absent on the upper labium. Small submarginal papillae cover the entire inner rim of oral disc. The upper jaw sheath is narrow and stretched into a wide U-shaped arch, while the lower jaw sheath is V-shaped. The labial tooth row formula (LTRF) is 5(2-5)/3 (Abraham et al 2013). Beddomixalus bijui is very similar to the newly described Mercurana myristicapalustris, but can be distinguished in that B. bijui has vomerine teeth but no lingual papilla, has a sharply pointed symphysial knob, has a pale distinct stripe on the dorsolateral margin, a rounded canthus rostralis, half/moderately webbed toes, moderate finger discs, and rounded subarticular tubercle on finger IV (Abraham et al 2013). In life, adult Beddomixalus bijui has a yellowish-buff or reddish-brown dorsum with two distinct yellowish-cream colored parallel longitudinal stripes, extending from the supratympanic fold to the vent along the dorsolateral margin. Tadpoles are consistently dark pigmented from the snout to the tip of the tail, including fins. The ventral and ventrolateral body sides are pale pink and less pigmented. Eyes are reddish (Abraham et al 2013).Species Authority: Abraham R. K., Pyron R. A., Ansil B. R., Zachariah A., Zachariah A. (2013) Two novel genera and one new species of treefrog (Anura: Rhacophoridae) highlight cryptic diversity in the Western Ghats of India. Zootaxa 3640(2): 177-199. doi:10.11646/zootaxa.3640.2.3Beddomixalus bijui is a recent addition to the family Rhacophoridae and represents an ancient, independent clade, which is the sister clade to the clade containing the Sri Lankan and Indian-Chinese-Indochinese radiations of bushfrogs (Pseudophilautus + Raorchestes; Abraham et al 2013). The genus name is coined from combining the cognomen of Colonel Richard Henry Beddome, in recognition of his pioneering and extensive fieldwork, which contributed to a fundamental understanding of amphibian diversity of the Western Ghats during the colonial period, and Ixalus (Dumeril & Bibron, 1839), often used as a suffix for names of rhacophorid genera (Abraham et al 2013). The species name was dedicated to S. D. Biju of the University of Delhi in India (Abraham et al 2013). The genus Beddomixalus currently contains one species (Abraham et al 2013).

Beddomixalus bijui is known only from the western slopes of the High Ranges and the Valparai plateau in the Southern Western Ghats in the states of Kerala and Tamil Nadu in India. The species occurs mostly in mid- to high-elevation montane forests, between elevations of 1100 and 1600m ASL (Abraham et al 2013).

Beddomixalus bijui is primarily arboreal and inhabits trees in and around seasonal highland swamps or marshes. Observations on breeding and development were conducted from April to July 2012. During the early part of the breeding season (late April to early June), hundreds of males aggregated around optimal breeding locations in moist swamp beds that were not yet filled with water. Males begin migrating towards breeding sites (swamp beds) during the onset of pre-monsoon showers in late April from surrounding forest, where they congregate. These highland swamps are few in number and form part of the headwaters of regional streams and the substrate is mostly moist clay in April, when the pre-monsoon showers begin. Most males perch on shrubs and bushes (at up to 2m height) along the periphery of the dry swamp and in unison make a pulsating breeding chorus. But, individual males that occupy territories on shrubs within the swamp bed make a different call that could not be recorded, akin to that of the Polypedates spp. from Southern India. The air was dominated by a strong odor, which was reminiscent of the ‘burnt rubber’ smell characteristic of aggregating males of Hylarana malabarica (Daniel 1976). Close examination of individual males suggested this odor to be produced by glands on their dorsolateral margin. Such an ambient odor and loud pulsating call could be reason for prompting males to form mass aggregations and attracting females, but further observations are needed to validate this. Males descend from their calling perches as the night progresses and occupy positions closer to grass patches in the muddy swamp bed (Abraham et al 2013). Beddomixalus biju lays non-pigmented eggs and early development occurs exposed on moist swamp beds, without any form of protection, neither in the form of foam nests or parental care. Free-living aquatic tadpoles are adapted to lentic conditions and complete metamorphosis is swampy pools (Abraham et al 2013).

Information on trends in abundance is currently unknown. However, much of the habitat within the historical range of the species has been converted to monocultures such as tea and cardamom plantations. This would have had reduced the abundance of the species in parts of its original range. Additionally, since the reproduction of the species is intricately linked with the early pre-monsoon showers, the recent abrupt nature of rains would clearly impact survival of eggs and early stage tadpoles, in turn affecting population recruitment. Urgent studies are needed to study the threats caused by habitat destruction, pollution and climate change (Abraham et al 2013).