Ingerana tasanae  

Alcalus tasanae, known as the Tasan Eastern frog, Tha San Frog, or Smith’s wrinkled frog, is rare and poorly known from just five locations in western and peninsular Thailand, and one recently confirmed site in the Tanintharyi region (Tenasserim) of Myanmar.  Its species name is derived from its type locality (Tasan, Thailand).  The IUCN regards it as “vulnerable” to extinction, threatened with encroachment by humans and loss/deterioration of habitat.  It does occur in protected parks and sanctuaries (Chuaynkern et al. 2004).

Recent molecular analysis has just repositioned this species in genus Alcalus (family Ceratobatrachidae) rather than genus Ingerana (Family Dicroglossidae).  This makes A. tasanae the first species of family Ceratobatrachidae reported from Myanmar and from Thailand, and significantly extends western limit of this Australasian archipelago family.  This analysis also indicates that taxa from northern and southern samples show molecular divergence that suggests additional taxonomic diversity may exist in this clade (Yan et al. 2016). 

A small frog, A. tasanae is dark brown on the dorsal surface, with its underside speckled brown on cream at the anterior, and whitish over its belly.  M.A. Smith (1921a) collected and described 46 specimen as a series, from Tasan, where he indicated the species was common (Smith 1921b).  It apparently has very delicate skin, that tore and became damaged easily upon collection.  Females are distinctly larger than males.

Alcalus tasanae lives in primary rainforest, near streams, at altitudes up to 1000 m asl.  It has also been observed on near-vertical bedrock in the spray zone of rainforest waterfalls.  All other ceratobatrachids, and members of Ingerana breed by direct development, and it is assumed that A. tasanae shares this life history strategy, although this has not been documented.  Smith (1921a) reported large and few unpigmented eggs with diameter across the vitelline membrane of 2 mm.