Mountain jade: A new high-elevation microendemic species of the genus Zhangixalus (Amphibia: Anura: Rhacophoridae) from Laos

We report on a new species, Zhangixalus melanoleucus sp. nov. , from Phou Samsoum Mountain (PSM) in Xiengkhouang Province, northeastern Laos, based on an integrative taxonomic approach, including morphological, molecular, and bioacoustic lines of evidence. Morphologically, the new species can be distinguished from its congeners by a combination of the following diagnostic characters: medium body size (SVL 34.4–36.3 mm in males, 53.7 mm in a single female); dorsum smooth and green; chest and belly lacking spots; flanks, axillae, ventral surfaces of forearms, inguinal, anterior and posterior surfaces of thighs white, covered with irregular black pattern; finger webbing formula I 2½–3 II 2–3 III 2¼–2 IV; toe webbing formula I 2–2½ II 1–2 III 1–2 IV 2–1 V; toe webbing cream with small black blotches; outer margin of forearms and feet with weak dermal ridges; supracloacal fold and pointed projection at tibiotarsal articulation absent; and iris reddish-orange. The new species is divergent from all other members of Zhangixalus based on 16S rRNA gene sequences (P=3.4%–8.8%) and is reconstructed as the sister species of Z. nigropunctatus. The advertisement call of the new species consists of clicking sounds and includes a series of notes, each 0.28 s in duration and consisting of 2–3 pulses with a dominant frequency of ca. 3.14 kHz. To date, Zhangixalus melanoleucus sp. nov. is known only from the montane evergreen forests of PSM at elevations of 2 000–2 200 m a.s.l. We preliminary suggest the new species should be considered as Data Deficient (DD) following the IUCN’s Red List categories.