Comparative Osteology of Montane Climbing Salamanders (Plethodontidae: Bolitoglossa Subgenus Magnadigita) from Nuclear Central America
The skeletal features of six species of salamanders in the genus Bolitoglossa (subgenus: Magnadigita) were described and compared. Many osteological features of the Magnadigita subgenus were found to be highly conserved, such as the presence of bifurcated first caudal vertebrae and distal expansions on the terminal phalanges. Key traits were identified that were distinct among the species in this study, including the prefrontals and frontoparietal fenestrae; we suggest these traits may be useful in future taxonomic studies of Bolitoglossa. We also discuss the evolution of paedomorphosis and webbed feet in relation to Magnadigita. Bolitoglossa diaphora has highly webbed feet but lacks the osteological features typically associated with this paedomorphic trait, such as fused or accentuated elements, but rather has the osteological features typical of other Magnadigita. Se describió y comparó, características esqueléticas de seis especies de salamandras del género Bolitoglossa en el subgénero Magnadigita. Varias características osteológicas del subgénero Magnadigita se consideran altamente conservadas, como la presencia de la primera vértebra caudal bifurcada y las expansiones distales en las falánges terminales. Se identificó rasgos clave, distintivos entre las especies de estudio, incluyendo las fenestras frontoparietales y prefrontales. Sugerimos que estos rasgos pueden ser útiles en estudios taxonómicos de Bolitoglossa. Además discutimos la evolución de la pedomorfosis y patas palmeadas en relación a Magnadigita. Bolitoglossa diaphora posee patas altamente palmeadas pero carece de características osteológicas generalmente asociadas con este rasgo pedomórfico, como son los elementos fusionados o acentuados. En vez, posee características osteológicas típicas de otras Magnadigita.

Dorsal views of the skulls of (A) B. suchitanensis, (B) B. tenebrosa, (C) B. meliana, (D) B. longissima, (E) B. diaphora, and (F) B. heiroreias. Scale bar = 3 mm.

Lateral views of the skulls of (A) B. tenebrosa, (B) B. meliana, (C) B. suchitanensis, (D) B. longissima, and (E) B. diaphora. Scale bar = 3 mm.

Ventral views of the skulls of (A) B. tenebrosa, (B) B. meliana, (C) B. suchitanensis, (D) B. longissima, and (E) B. diaphora. Scale bar = 3 mm.

First caudal vertebrae of (A) B. heiroreias with the branched morphology, (B) B. longissima with the fused morphology, and B. diaphora (C) CM 2990 and (D) CM 2898 with an atypical morphology with highly reduced bifurcations. A–C are dorsal views and D is a ventral view. Scale bar = 1 mm.

The (A) forelimb bones, (B) hind limb bones, (C) pectoral girdle, (D) pelvic girdle of B. suchitanensis, and ventral views of the (E) pectoral girdle and (F) pelvic girdle of B. diaphora. Scale bar = 1 mm.

Forefeet and hind feet of (A, B) B. diaphora, (C, D) B. heiroreias, and (E, F) B. longissima. Scale bar = 1 mm.
Contributor Notes
Associate Editor: W. L. Smith.