Sunday, July 10, 2011

[Herpetology • 2010] Leptolalax aereus | 'Copper-backed' Leaf Litter Toad • Megophryid frog from Savannakhet Province, Laos

Leptolalax aereus
Rowley, Stuart, Richards, Phimmachak & Sivongxay, 2010

We describe a new species of megophryid frog in the genus Leptolalax from southern Laos. Leptolalax aereus sp. nov. is distinguished from its congeners by a combination of size (25.1–28.9 mm in 28 adult males, 27.1–38.6 mm in 12 adult females), absence of distinct black or dark brown dorsolateral markings on head, near immaculate white chest and belly, head length greater than head width, no webbing or lateral fringing on fingers, rudimentary webbing between toes I–IV and no webbing between toes IV–V, toes with weak lateral fringing, and a call consisting of an average of 3–4 notes containing 1–2 pulses, and with a dominant frequency of 6187.5–7875 Hz. The new species is associated with rocky streams in semi-evergreen and evergreen forest between 284–511 m elevation.

Key words: Acoustics, Anura, Leptolalax aereus sp. nov., Laos, Southeast Asia, Indochina

FIGURE 2. Leptolalax aereus sp. nov. in life. (A) Dorsolateral view in the field of male holotype SAMA R64236, (B) ventral view of male paratype NCSM 76064.

Etymology: Specific epithet from aereus L., meaning made of copper or bronze; in reference to copper hue evident in life on the dorsal surface of most specimens.

Holotype: SAMA R64236, by original designation.
Type locality: Mid-stream rock pile in 6 m wide, swift rocky stream in semi-evergreen forest in the Sepon Mining Tenement, Vilabouli District, Savannakhet Province, Laos (16.96317° N, 106.0466° E, 326 m).

FIGURE 1. Collection sites of Leptolalax aereus sp. nov.

Ecology: Leptolalax aereus was abundant at rocky streams in closed evergreen or semi-evergreen forest. All known locations are between 284–511 m elevation, and animals were collected at night between 20:25–23:15 h. Males were observed calling from crevices between boulders, on rocks, and on stream banks. Females were found on rocks mid-stream, and up to 1 m from the streams. Leptolalax aereus was heard calling in both June and November, suggesting that breeding may occur throughout the year.

Rowley, J.J.L., B.L. Stuart, S.J. Richards, S. Phimmachak & N. Sivongxay 2010: A new species of Leptolalax (Anura: Megophryidae) from Laos. Zootaxa, 2681: 35–46. Fulltext from