Wednesday, June 3, 2015

[Herpetology • 2011] Chaltenobatrachus grandisonae (Lynch, 1975) • A New Genus of Neobatrachian Frog from southern Patagonian Forests, Argentina and Chile

Genus: Chaltenobatrachus Basso, Úbeda, Bunge, and Martinazzo, 2011
Chaltenobatrachus grandisonae (Lynch, 1975)

In 1975 Lynch named a new species of frog based on two specimens from Puerto Eden, Wellington Island, southern Chile, tentatively allocated to the genus Telmatobius. Telmatobius grandisonae Lynch was later included by the same author in his genus Atelognathus. Based on a reappraisal of the type material and the description of the internal and external morphology, karyotype, tadpole morphology and molecular evidence from recently discovered specimens collected at Lago del Desierto, southern Argentina, we describe the monotypic genus Chaltenobatrachus, with Telmatobius grandisonae (Lynch) serving as the type species. Chaltenobatrachus differs from Atelognathus mainly in having a uniform bright green dorsal coloration, with brown to reddish warts; orange iris with gold spots; fingers with interdigital membrane; frontoparietals well developed; small nasals;well ossified sphenethmoid; anteriorly expanded homosternum; skin of tadpole transparent; oral disc with protruding anterior and lateral papillae; diploid number 2n = 32 chromosomes. The genetic distances between Chaltenobatrachus and Atelognathus meet or exceed most other intergeneric comparisons.

Key words: Chaltenobatrachus gen. nov., Chaltenobatrachus grandisonae comb. nov., Batrachylinae, systematics

FIGURE 4. (a) Chaltenobatrachus grandisonae larva, stage 26, 37 mm total length, not collected. (b) Chaltenobatrachus grandisonae larva, CNP A–397, stage 38. Scale = 10 mm; lateral view (upper); dorsal view (middle); ventral view (lower). (c) Oral disc of Chaltenobatrachus grandisonae larva, CNP A–398, stage 39. Scale = 1 mm.
FIGURE 7. (a) Temporary pond in an open area of the austral beech, Nothofagus pumilio, forest near Lago del Desierto, Chubut, Argentina. Reproductive and developmental habitat of Chaltenobatrachus grandisonae. (b) General view of a rainforest of the austral beech, Nothofagus pumilio.


Chaltenobatrachus gen. nov.
Type species. Telmatobius grandisonae Lynch, 1975
Content. The genus is monotypic

Definition and diagnosis. Size small to medium, up to 46 mm SVL. Dorsal coloration uniform bright green, with brown to reddish warts. Dorsal skin thin and mucoid, finely granulated. Iris orange. Vomerine teeth in two patches between and at posterior level of the choana. Tympanum and columella absent. Fingers with evident interdigital membrane. Plantar skin turgid with low metatarsal tubercles. Supernumerary palmar and plantar tubercles absent. Length of toes in increasing order: 1–2–5–3–4. Frontoparietals moderately extensive, exposing a thin frontoparietal fontanelle. Nasals relatively small, separated medially. Independent quadratojugal absent. Alary processes of premaxillae extensive, directed dorsally. Maxillary teeth extending up to the middle of the orbit. Palatines relatively long, reaching the maxilla, bearing well developed anterior processes. Sphenethmoid well ossified, extending anteriorly beyond the anterior edge of nasals. Cotylar facets of atlas narrowly separated. Transverse processes of posterior presacral vertebrae slightly shortened. Omosternum cartilaginous, elongate, with anterior end expanded. Inner metacarpal with a distinct distal flange at the medial margin of the bone. Terminal phalanges knobbed, not T–shaped. Tadpole with ventral and lateral skin transparent. Anterior and lateral papillae of oral disc protruding from the contour of the snout in dorsal view. Chromosome number 2n = 32.

Etymology. The genus name derives from Chaltén, the name given by Tehuelche natives to the main mountain located south of Lago del Desierto, also known as Mount Fitz Roy, of 3406 m elevation.

synonyms:  Chaltenobatrachus grandisonae (Lynch 1975) comb. nov.
Telmatobius grandisonae Lynch (1975)
Atelognathus grandisonae Lynch (1982)

Basso, N.G., C.A. Úbeda, M.M. Bunge and L.B. Martinazzo. 2011. A New Genus of Neobatrachian Frog from southern Patagonian Forests, Argentina and Chile. Zootaxa. 3002: 31–44.

Helen Díaz-Páez, Nicza Alveal, Ingrid Cisternas-Medina and Juan Carlos Ortiz. 2015. New Distribution Records of Chaltenobatrachus grandisonae (Anura: Batrachylidae) in Patagonia, Chile. Check List. 11(4): 1668. DOI:  10.15560/11.4.1668

Javiera Cisternas, Claudio Correa, Nelson Velásquez and Mario Penna. 2013. Reproductive features of Chaltenobatrachus grandisonae (Anura: Batrachylidae) within a protected area in Patagonia, Chile. [Características reproductivas de Chaltenobatrachus grandisonae (Anura: Batrachylidae) en un área protegida en Patagonia, Chile.] Revista Chilena de Historia Natural. 86: 365-368