Sunday, December 26, 2021

[Herpetology • 2021] Osteocephalus melanops • A New Species of Osteocephalus Steindachner, 1862 (Anura, Hylidae) from Brazilian Amazonia

Osteocephalus melanops
Melo-Sampaio, Ferrão & Moraes, 2021

Treefrogs of the genus Osteocephalus have been the focus of several taxonomic and phylogenetic studies, especially in the last two decades. These recent studies have shown that the diversity of this charismatic Amazonian genus is still largely underestimated. Through the evidence of morphological and molecular data, we describe a new species of the Osteocephalus alboguttatus species group from the Purus-Madeira Interfluve, southwestern Brazilian Amazonia. The new species differs from other Osteocephalus by having a small body size (snout–vent length 32.1–44.1 mm), skin texture non-sexually dimorphic, dorsum smooth with a few scattered small tubercles, vocal sac single and subgular, frontoparietal ridges not externally visible, and a dark tan brown iris with lighter vermiculation. The rapid increase in the number of new frog species described from the Purus-Madeira Interfluve highlight the importance of sampling poorly explored and remote areas in Amazonia, as well as the value of supporting taxonomic research to accelerate species documentation in face of the biodiversity crisis.

KEY WORDS: Amazonas; Arapixi Extractive Reserve; bamboo-dominated forests; Osteocephalus alboguttatus species group; Purus-Madeira Interfluve; taxonomy

Color in life of Osteocephalus melanops.
(A, B) Dorsal view and close-up of the iris of the male holotype MNRJ 93639;
(C) lateral view of the female paratopotype MNRJ 93640;
(D) lateral view of the female paratype UFAC-RB 5553.
Photographs: Paulo R. Melo-Sampaio.

Osteocephalus melanops, sp. nov.

Diagnosis. A small-sized species of Osteocephalus characterized by: 1) SVL of adults 32.1–44.1 mm; 2) skin texture of dorsum non–sexually dimorphic, smooth with a few scattered small tubercles; 3) skin texture of flanks shagreened; 4) canthus rostralis rounded; 5) frontoparietal ridges not externally visible; 6) supratympanic fold thin, from the posterior edge of the eye, sloping in an arch toward the arm insertion, not reaching tympanum posteroventrally; 7) webbing on inner edge of third finger slightly extending beyond penultimate subarticular tubercle; 8) distal subarticular tubercle on finger IV bifid; 9) dorsum light tan with irregular blotches; 10) throat, chest, and abdomen uniformly cream to white; 11) large cream subocular spot; 12) flanks creamy white, with variable amount of dark vermiculation; 13) vocal sac single, subgular; 14) tibiofibular bones green in preservative; 15) in life, iris dark tan brown, with variable amount of lighter vermiculation.

Etymology. The specific epithet melanops is derived from Greek ‘‘melanos-’’ meaning black and ‘‘ops-’’ meaning eye. The name is a reference to intense dark coloration of the species’ irises.

Dorsal view of species from Osteocephalus alboguttatus species group.
(A, B) Osteocephalus alboguttatus, unvouchered specimen and QCAZ 15972, respectively.
(C, D) Osteocephalus heyeri, SINCHI 0727 and CZPB 1625, respectively.
(E–I) Osteocephalus subtilis, unvouchered specimen (D), SINCHI 00485 (E), MTR 28225 (F), MTR 28100 (G), and CORBIDI 6176 (H), respectively;
Osteocephalus cf. subtilis, an unvouchered specimen (I).

 Photographs: Morley Read— (A); Santiago Ron— (B); Germán Chávez (C, E); Alexandre Almeida (D); Pedro Peloso (F, G); Pablo Venegas (H); Jhon Jairo Lopez Rojas (I).

Paulo Roberto Melo-Sampaio, Miquéias Ferrão and Leandro João Carneiro de Lima Moraes. 2021. A New Species of Osteocephalus Steindachner, 1862 (Anura, Hylidae), from Brazilian Amazonia. Breviora. 572(1); 1-21. DOI: 10.3099/0006-9698-572.1.1