Bioacoustics of Platypelis ravus

Natural History Numerous specimens of the new species were heard in the evening in dense primary forest directly next to Camp Simpona campsite, calling from leaves in bushes and on trees at perch heights of 1-2 m above the ground. Advertisement calls Calls of the holotype (ZSM 349/2005) were recorded at Camp Simpona, Marojejy National Park, on 15 February 2005 (19:20 h) at 21.1°C air temperature. They have been published by Vences et al. (2006 ; CD3, Track 64). The call is a single melodious note that is repeated at regular intervals. Note duration ranges from 384-443 ms (418 ± 16; n = 11), duration of intervals between notes varies between 2504- 3200 ms (2797 ± 243; n = 10). Note repetition rate is approximately 18-19 notes/minute. The dominant frequency ranges between 3990-4028 Hz (4010 ± 13; n = 11).

Diagnosis The new species is assigned to the genus Platypelis based on enlarged terminal finger discs, absence of prepollex, and molecular phylogenetic relationships ( Wollenberg et al. 2008 ). It differs from other arboreal cophyline microhylids of the genus Anodonthyla by the absence of a prepollex in males, and from Plethodontohyla with enlarged finger and toe discs [ P. guentheri Glaw & Vences, 2007 , P. inguinalis Boulenger, 1882 , P. mihanika Vences, Raxworthy, Nussbaum & Glaw, 2003 , P. notosticta (Günther, 1877) ] by much smaller size (SVL 17-19 mm vs. 26-100 mm ). Within the Platypelis / Cophyla clade, the species is distinguished from Cophyla berara Vences, Andreone & Glaw, 2005 , C. phyllodactyla Boettger, 1880 , Platypelis alticola (Guibé, 1974) , P. cowanii Boulenger, 1882 , P. grandis (Boulenger, 1889) , P. mavomavo Andreone, Fenolio & Walvoord, 2003 , P. milloti Guibé, 1950 , P. pollicaris Boulenger, 1888 , P. tsaratananaensis Guibé, 1974 , and P. tuberifera (Methuen, 1920) by distinctly smaller size (SVL of adult males 17-19 mm vs. 23-88 mm ), and from P. tetra Andreone, Fenolio & Walvoord, 2003 by presence of a regular pattern of moderately-sized tubercles on the back (vs. four symmetrically arranged and distinctly enlarged white tubercles), a third toe of the same length than the fifth (vs. toe three longer than toe five), by presence of yellow ventral colouration (vs. absence), and by a much higher note repetition rate of the advertisement calls. It differs from Cophyla occultans (Glaw & Vences, 1992) by smaller size (SVL 17-19 mm vs. 18-21 mm ), and equal length of toe 3 and 5 (vs. toe 3 <5). It is distinguished from Platypelis barbouri Noble, 1940 (and most likely from its junior synonym Paracophyla tuberculata Millot & Guibé, 1951 , described from the well sampled type locality Andasibe) by absence of red colour on the ventral side of the hindlimbs and belly, and a largely smooth dorsal surface (vs. strongly tuberculate). Summarizing, the new species is most similar to P. barbouri (the only other Platypelis without vomerine teeth and in addition with a rather similar advertisement call, but with reddish instead of yellow ventral surface, and more strongly expressed and irregularly arranged tubercles on dorsal surface), and to P. mavomavo (with yellow ventral surface but distinctly larger SVL). It differs, however, from these and all other nominal species of Platypelis and Cophyla (except P. cowanii for which no genetic data is available) by a high genetic divergence (see Wollenberg et al. 2008 ; Vieites et al. 2009 and unpublished data for P. alticola , P. tsaratananaensis , P. tetra and Cophyla occultans ). Phylogenetically, it appears to be sister to P. milloti (see below) which however is larger, has a much more contrasting dorsal pattern, red colour ventrally, and a much faster note repetition rate in advertisement calls (106/min vs. 18-19/ min).