Thursday, January 3, 2013

Two new Anomaloglossus frogs from Panama

Anomaloglossus astralogaster. Photo credit: Marcos Guerra
The Chagres Highlands may be a lower montane forest refuge for some rare amphibians and reptiles. In a recent paper,  Meyers et al, (2012)  documents the presence of the South American frog genus Anomaloglossus (Dendrobatoidea: Aromobatidae) based upon two new species from this area. The two species are described from a low, forested uplift in east central Panama, just northeast of Panama City. These low mountains, unnamed on maps, are designated the “Chagres Highlands” because a large part of the uplift lies in the Río Chagres drainage, an area that provides water critical to lock operation in the Panama Canal. The Chagres Highlands may be a lower montane forest refuge for some amphibians and reptiles, including the two Anomaloglossus as well as Atelopus limosus, and some rare snakes including: Atractus depressiocellus, A. imperfectus, Geophis bellus, and Rhadinaea sargenti. Several other rare species are not endemic but include the Chagres Highland area as part of their individually fragmented or mosaic distributions (Adinobates fulguritus, Anolis kunayalae, Coniophanes joanae, Geophis bracycephalus, Dipsas nicholsi). The two new frogs are  sympatric in the Chagres Highlands, but both species are rare. Anomaloglossus astralogaster, a new species, is known only from the adult 22 mm, female holotype. It has its ventral surfaces covered with whitish dots  somewhat similar to large chromatophores but possibly glandular; there is no appearance of glandular structure  but the edges of some of the pale dots can be “felt” with a fine  teasing needle and histological examination is needed. The other new taxon is Anomaloglossus isthminus, which is described from six specimens. Its dorsal surfaces are basically brown mottled with darker brown. Small pale yellowish spots located proximally above the insertions of arm and thigh are not well defined and tend to disappear after preservation (unlike normal dendrobatid flash markings). Ventral surfaces are pale blue with some dark mottling but no pale dots. The vocalization of A. isthminus resembles calls of some South American species in being a train of “peeplike” notes, but there are fundamental interspecific differences in frequency modulation, note repetition rate, and call length.

The new  Anomaloglossus are known only from the Chagres Highlands in east-central Panama, but it cannot be safely concluded that they are endemic to this area. The best known part of these highlands is the Piedras-Pacora Ridge on the continental divide,  which has been suggested as a “premontane forest refuge for some small part of the fauna that is barely surviving the climatic-vegetational changes of the Pleistocene. It is conceivable  that Anomaloglossus occurs more widely in Panama, possibly, in fragmented pockets along the broken Serranía de San Blas and northern part of the Serranía del Darién, where collecting has been very sporadic.

Myers, C. W.; Ibañez D., R.; Grant, T., Jaramillo A., César A. 2012. Discovery of the frog genus Anomaloglossus in Panama, with descriptions of two new species from the Chagres Highlands (Dendrobatoidea, Aromobatidae).American Museum of Natural History, 3763, 1-19.

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