Theloderma asperum (Boulenger, 1886)

BAIN, RAOUL H. & TRUONG, NGUYEN QUANG, 2004, Herpetofaunal Diversity of Ha Giang Province in Northeastern Vietnam, with Descriptions of Two New Species, American Museum Novitates 3453, pp. 1-43 : 32

Theloderma asperum (Boulenger, 1886)

Calling males referable to Theloderma asperum were recorded from 1000 m on Mt. Muong Cha and from 1400 to1700 m on Mt. Tay Con Linh II. Calls were made from high in the canopy and could be heard from several kilometers away, either alone or in choruses. Each call consists of a repeating twonote ‘‘peep­peep’’ (at ~180 beats/minute), with a 2­second intermittent silence. Choruses could be heard either within a small forest area (~ 100 m 2) or several kilometers across valleys. Individuals would begin to call independently, and then proximal individuals would call together in synchrony and eventually fall into syncopation with distant groups. In this way, a cluster of frogs dispersed throughout the canopy on one side of a valley would call during the 2­second rest of the group on the other side of the valley, and vice versa. This continued for up to 30 minutes uninterrupted. The calls were heard more often at 1400 m (on Tay Con Linh II) than at higher elevations, and calling was undeterred during a full moon. Although not measured, several discrete pitches of calls were heard across valleys. No vouchers were collected, but calls were recognized by one of us (R.H.B.) as identical to those of Theloderma asperum from Tam Dao, Vinh Phu Province (referred specimens currently housed in the ROM).

Rhacophoridae spp.

Two species of Rhacophoridae were heard calling from trees. One species was heard calling from a small hardwood (DBH 5 cm) several hundred meters from any type of water at 1700 m elevation. Although the call was persistent, it stopped as soon as the moon rose. At 1900 m, another species was heard calling in foliage close to the ground. Two males were calling in syncopation with a single ‘‘peep’’. No specimens of either species was recovered.