Wednesday, June 10, 2020

[Herpetology • 2020] Platypelis laetus • Frogs of the Genus Platypelis from the Sorata Massif in northern Madagascar: Description of A New Species and Reports of Range Extensions

Platypelis laetus 
Rakotoarison, Scherz, Köhler, Ratsoavina, Hawlitschek, Megson, Vences & Glaw, 2020

DOI: 10.3897/zse.96.47088 

We describe a new species of arboreal microhylid frog, genus Platypelis, from northeastern Madagascar and report the expansion of distribution ranges of two other species. Platypelis laetus sp. nov. is small to medium-sized (24.3–25.6 mm snout-vent length) compared to other Platypelis, exhibits a greenish colored throat and was found in bamboo forest of the Sorata Massif. Its advertisement call consists of a single short tonal note repeated at regular intervals in long call series. Based on DNA sequences of a fragment of the mitochondrial 16S rRNA gene, the new species was placed in a clade with Platypelis olgae from the Tsaratanana Massif, and with two other, unconfirmed candidate species from the Sorata Massif and from Andravory, herein named Platypelis sp. Ca12 and Ca13. Molecular divergences among these lineages were substantial, amounting to 7.6‒8.1% uncorrected 16S p-distance to the closest nominal species, P. olgae, from which the new species is also distinguished by a lack of allele sharing in the nuclear RAG-1 gene. We also provide new records of Platypelis alticola and P. tsaratananaensis from the Sorata Massif, supported by molecular analysis. This confirms a wider distribution of these two species that previously were considered to be endemic to the Tsaratanana Massif. However, their populations in Sorata were characterized by a certain degree of genetic differentiation from Tsaratanana populations suggesting they require more detailed taxonomic assessment.

Key Words: Amphibia, Anura, Cophylinae, distribution, Microhylidae, molecular genetics, Platypelis laetus sp. nov., Platypelis alticola, Platypelis tsaratananaensis, Sorata, systematics

Figure 3. Photographs in life of Platypelis laetus sp. nov. from the Sorata massif:
a–c ZSM 5652/2012 (FGZC 3761), holotype; d, e ZSM 5651/2012 (FGZC 3588), paratype; f, g ZSM 5653/2012 (FGZC 3762), paratype; h Eggs and embryos found in the same bamboo hole with the specimens ZSM 5652/2012 and ZSM 5653/2012.

Platypelis laetus sp. nov.

Diagnosis: Assigned to the genus Platypelis in the microhylid subfamily Cophylinae based on enlarged terminal discs on fingers and toes, absence of nuptial pads, and molecular phylogenetic relationships. The species can be identified among other cophylines by the combination of the following character states: (1) medium-sized species (adult male SVL 24.3–25.6 mm); (2) manus with second finger slightly shorter than fourth and pes with third toe much shorter to very slightly shorter than fifth; (3) males with prepollical tubercle but lacking a finger-like prepollex as typical for Anodonthyla; (4) throat greenish in life; (5) chest and anterior belly translucent gray, with distinct white spotting that is absent on the posterior belly; (5) absence of red color on limbs and ventral side.

Distribution: The species is known only from the Sorata Massif, northern Madagascar, at elevations of 1339‒1541 m above sea level (Fig. 2).

Natural history: Platypelis laetus sp. nov. occurs in rainforest on the Sorata Massif, but most of the specimens were collected in the bamboo forest of the massif. The holotype was calling from a bamboo hole at about 5 m above the ground. The bamboo node was occupied by another specimen, was water-filled, and contained 35 whitish eggs and embryos, probably of this species, in at least two different developmental stages (Fig. 3h). Another male was found on a palm tree at around 4 m above the ground. Calling occurred around dusk.

Etymology: The specific epithet is a masculine Latin adjective meaning “happy”. The new species is so named in reflection of the joy and happiness of the first author to get to work on the cophyline microhylid frogs of Madagascar.


 Andolalao Rakotoarison, Mark D. Scherz, Jörn Köhler, Fanomezana M. Ratsoavina, Oliver Hawlitschek, Steven Megson, Miguel Vences and Frank Glaw. 2020. Frogs of the Genus Platypelis from the Sorata Massif in northern Madagascar: Description of A New Species and Reports of Range Extensions.  Zoosystematics and Evolution. 96(1): 263-274. DOI: 10.3897/zse.96.47088