Figure 8: Osteology of hand and foot of Osornophryne simpsoni sp. n. in ventral view; adult male, QCAZ 45899.

Mentions: The phalangeal formulae for the hand and foot are standard—i.e., 2-2-3-3 and 2-2-3-4-3, respectively; however, the distal phalange of Finger I, Toe I, and Toe III are greatly reduced and formed mostly by cartilage (Fig. 8). Relative length of fingers, in increasing order, is: I-II-IV-III, and of the foot is: I-II-III-V-IV. The carpus is composed of a radiale, ulnare, Element Y, Carpal 2, and a large postaxial assumed to represent a fusion of Carpals 3–5. Element Y is about 3 times the size of Carpal 2, and the prepollex is an elongated cartilage. The terminal phalanges are acuminate, except Finger III that is slightly T-shaped. The tarsus is composed of two tarsal elements, presumably Tarsal 1 and Tarsal 2 + 3. The prehallux is presented by a proximal mineralized cartilage element associated with a small bony element.

Páez-Moscoso DJ, Guayasamin JM, Yánez-Muñoz M - Zookeys (2011)

Bottom Line: Combining a molecular phylogeny and morphological data, we discovered a new species of Osornophryne from the Amazonian slope of the Ecuadorian Andes.Morphologically, the new taxon is distinguished from all others species in Osornophryne by having the Toes IV and V longer than Toes I-III, a short and rounded snout with a small rostral papilla, and conical pustules on flanks.A taxonomic key is provided for all known species of Osornophryne.

Affiliation: Museo de Zoología, Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Av. 12 de Octubre y Roca, Aptdo. 17012184, Quito, Ecuador.

Abstract: Combining a molecular phylogeny and morphological data, we discovered a new species of Osornophryne from the Amazonian slope of the Ecuadorian Andes. Morphologically, the new taxon is distinguished from all others species in Osornophryne by having the Toes IV and V longer than Toes I-III, a short and rounded snout with a small rostral papilla, and conical pustules on flanks. The new species previously was confused with Osornophryne guacamayo. A taxonomic key is provided for all known species of Osornophryne.