Thursday, February 23, 2012

[Herpetology • 2011] Ansonia penangensis | Penang Slender Toad • Re-discovery and Re-description of Ansonia penangensis Stoliczka, 1870 (Anura: Bufonidae) from Penang Island, Malaysia

Penang Slender Toad | Ansonia penangensis 
from Penang Hill, Penang, West Malaysia

Ansonia penangensis Stocliczka 1870 is re-discovered from its type locality in Penang Hill from Penang Island, Malaysia after more than a century. The species was previously known only from the type series; two adults and a larval series collected in 1898, and had not been recorded since. An expanded description of this species is provided, based on four recently acquired specimens and corroborate the morphological differences between Ansonia penangensis, A. malayana and A. jeetsukumarani, with which A. penangensis has been confused. 
Key words: Bufonidae, Ansonia penangensis, Penang Island, Malaysia, re-discovery

Penang Slender Toad | Ansonia penangensis
photo: Evan Quah S.H.

Natural history: All individuals were collected between 1900-2100 h, following periods of afternoon precipitation. All specimens were found on the ground amongst leaf litter near a trail in evergreen forest with a thin canopy and gaps in the canopy, approximately 300 m from a river (Figure 1e; N 05.44º, E 100.28º, 263 m elevation). Tadpoles were found, clinging onto the rocks in fast flowing portions of the river (Figure 1c). These observations are similar to the remarks made by Boulenger (1912) and Flower (1899) who noted the tadpoles of A. penangensis can be found in swift-flowing hill-streams. A partially metamorphosed froglet was also observed (Figure 1d). The tadpole and the partially metamorphosed froglet were not collected, but these findings indicate breeding by A. penangensis in this river.

Similar to other species of Ansonia that show very limited and specific ranges (Grismer 2006a,b; Wood et al. 2008, Matsui et al. 2009), A. penangensis is endemic only to Penang Island. Earlier reports by Berry, 1975 of this species occurring sympatrically with A. malayana is erroneous. Berry, 1975 never listed any vouchered specimens that were deposited at any museums or institutions. Exhaustive searches have not yielded any evidence of the presence of A. malayana on Penang Island.

FIGURE 1. (a) Ansonia penangensis (USMHC 0001) from Penang Hill, Penang, West Malaysia (b) Ventral view of A. penangensis (USMHC 0001) 
(c) Tadpole of A. penangensis clinging onto rock in stream of fast flowing stream 
(d) Partially metamorphosed froglet of A. penangensis (All photos: Evan Quah S.H.). 

FIGURE 1. (e) Natural habitat of Ansonia penangensis (photo: Evan Quah S.H.).

Re-discovery and Re-description of Ansonia penangensis Stoliczka, 1870 (Anura: Bufonidae) from Penang Island, Malaysia: