Thursday, March 1, 2018

[Herpetology • 2018] Psychrophrynella glauca • A New Species of Terrestrial-breeding Frogs (Anura, Strabomantidae) from the Montane Forests of the Amazonian Andes of Puno, Peru


Psychrophrynella glauca
 Catenazzi​ & Ttito, 2018


Abstract

We describe a new species of small strabomantid frog (genus Psychrophrynella) from a humid montane forest in the Peruvian Department of Puno. Specimens were collected at 2,225 m a.s.l. in the leaf litter of primary montane forest near Thiuni, along the Macusani–San Gabán road, in the province of Carabaya. The new species is assigned to Psychrophrynella on the basis of morphological similarity, including presence of a tubercle on the inner edge of the tarsus, and call composed of multiple notes. We also include genetic distances for 16S rRNA partial sequences between the new species and other strabomantid frogs. The species with lowest genetic distances are Psychrophrynella chirihampatu and Psychrophrynella usurpatorPsychrophrynella glauca sp. n. is readily distinguished from the three other species of Psychrophrynella (Psychrophrynella bagrecito, P. chirihampatu, and P. usurpator) by its small size, and by having belly and ventral surfaces of legs reddish-brown or red, and chest and throat brown to dark brown with a profusion of bluish-gray flecks. The new species is only known from its type locality. With the discovery of P. glauca, the geographic distribution of Psychrophrynella is extended to the Department of Puno, where it was no longer represented after the description of the genus Microkayla. Furthermore, the Cordillera de Carabaya is the only mountain range known to be home to four of the seven genera of Holoadeninae (Bryophryne, Microkayla, Noblella, and Psychrophrynella), suggesting an intriguing evolutionary history for this group in southern Peru.

Keywords: Cloud forest, Frog, Bioacoustics, Carabaya, Ollachea, Leaf litter amphibian, 16S rRNA, Taxonomy, Holoadeninae, Terrarana


Figure 2: Photographs of live and preserved specimen of the holotype of Psychrophrynella glauca  sp. n. Live (A, C, E) and preserved (B, D, F) specimen of the holotype, female CORBIDI 18729 (SVL 18.2 mm) in dorsolateral (A, B), dorsal (C, D), and ventral (E, F) views. Photographs by A. Catenazzi.



Psychrophrynella glauca sp. n.

Diagnosis: The new species differs from the three known species of Psychrophrynella by its unique combination of red coloration on ventral surfaces of legs and belly, and profusion of bluish-gray flecks on ventral surfaces of head, body, and legs. Morphologically, it is most similar to P. bagrecito in having a short fold-like tubercle on the inner edge of tarsus, a prominent ovoid outer metatarsal tubercle, discoidal fold present, an elliptical pupil, small size reaching ∼19 mm, and dark brown flanks in at least some specimens. It can be distinguished from P. bagrecito (characters in parenthesis in P. bagrecito) by having smooth skin on venter (areolate), dorsal coloration with broad markings (longitudinal stripes), snout short and bluntly rounded (snout moderately long, rounded in dorsal view and in profile), and ventral coloration in preservative brown with light gray flecks (white to cream with brown mottling). The new species can be distinguished from P. chirihampatu by having reddish-brown to dark brown coloration and bluish-gray flecks on ventral parts (ventral coloration yellow with reddish-brown or gray flecks), Finger I slightly shorter or the same length as Finger II (Finger I shorter than Finger II), inner metatarsal tubercle the same length of outer metatarsal tubercle (inner metatarsal tubercle at least three times the size of outer metatarsal tubercle), more bluntly rounded head (slender and longer head), smaller size reaching 19.8 mm in females (27.7 mm), and advertisement call having 26 notes and a fundamental frequency of 3,027 Hz (up to 68 notes, 2,712 Hz). The new species differs from P. usurpator by its reddish-brown ventral coloration (dull brown, gray or black with cream flecks), smaller SVL reaching 19.8 mm in females (SVL up to 30.5 mm), and by the fold-like tubercle on the inner edge of tarsus being short (long and prominent tubercle).

Etymology: The specific name glauca is the feminine form of the Latin adjective glaucus, from the ancient Greek noun glaûkos, meaning “bluish-gray,” in reference to the bluish-gray flecks on the ventral parts of body and limbs.

Distribution, natural history, and threats: The four specimens were found in the leaf litter along a descending ridge separating two creeks in the humid montane forest along the road from Thiuni to Ollachea. Sympatric species detected during our quick survey included Gastrotheca testudinea, Pristimantis platydactylus, and an unnamed Pristimantis sp. Much of the original forest vegetation has been replaced by cultivated fields and pasture along the road, but this remnant forest extended from nearly the side of the road to the upper ridge of the mountain. Further advance of agriculture, or clearing of the forest might threaten this species if its distribution is restricted to the Ollachea Valley. In absence of more detailed data regarding its extent of occurrence, and according to the IUCN Red List criteria and categories (IUCN, 2013), we suggest this species to be in the “Data Deficient” category of the Red List.

Figure 4: Dorsolateral and ventral views of four paratypes of Psychrophrynella glauca  sp. n.  showing variation in dorsal and ventral coloration. Female MUBI 16322 (A, B). Male CORBIDI 18730 (C, D). Juvenile MUBI 16323 (E, F). Photographs by A. Catenazzi. 

Conclusion: 
We describe a new species of terrestrial-breeding frog of the family Strabomantidae, and provide evidence for its allocation within the genus Psychrophrynella. The new species P. glauca is only known from its type locality, similarly to most other small Holoadeninae known to occur at high elevations in the Andes of southern Peru and Bolivia. With our description we contribute to a better knowledge of the diversity of this group, and reveal the presence of four genera of Holoadeninae in the Cordillera de Carabaya of southern Peru, suggesting that phylogeographic studies of the Holoadeninae species of this mountain range may shed insights into radiation in this group.


Alessandro Catenazzi​ and Alex Ttito. 2018. Psychrophrynella glauca sp. n., A New Species of Terrestrial-breeding Frogs (Amphibia, Anura, Strabomantidae) from the Montane Forests of the Amazonian Andes of Puno, Peru. PeerJ. 6:e4444.  DOI: 10.7717/peerj.4444

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