Research Progress

Amphibians and Reptiles

Comparative Osteology of the Genus Pachytriton (Caudata:Salamandridae) from Southeastern China

Update time: 08/31/2012   Author:

With the growing application of DNA-sequence and other genetic data since the 1990s, osteological work has largely given way to molecular approaches in the study of amphibian biodiversity. Many influential works from the mid-20th century (e. g., Francis, 1934; Tihen, 1958; Hansen and Tanner, 1958; Wake, 1963; Özeti andake, 1969) are still cited today, but few such works are produced anew by contemporary biologists. However, as an independent source of data, osteological characters can provide invaluable insights into evolutionary relationships of living taxa that are as important as those derived from nucleotide substitutions. Homology and homoplasy are directly associated with biological functions.

Osteological evidence provides invaluable insights into patterns of amphibian biodiversity. In small montane streams of southeastern China, an endemic genus of salamanders (Pachytriton) displays remarkable aquatic specializations, many of which are reflected in skeletal morphology, but these specializations remain to be studied inan integrated perspective.

Attempts to fully resolve the taxonomy within the genus also can benefit from knowledge of internal morphology. We present a detailed description of the adult skeleton of P. brevipes, P. inexpectatus and P.
archospotus by analyzing both cleared-and-stained and radiographed specimens in a comparative framework. Compared to terrestrial and amphibious salamanders, the most distinctive osteological features of Pachytriton include a modified hyobranchial apparatus, a reduced frontosquamosal arch, and deep neural and haemal arches of the caudal vertebrae.


The hyobranchial apparatus of P. archospotus is distinctly different from that of congeners and likely secondarily derived. Patterns of interspecific variation suggest that northeastern P. inexpectatus is more closely related to P. brevipes than it is to southwestern P. inexpectatus, thereby reinforcing results from earlier molecular phylogenetic analyses. We advocate assigning northeastern P. inexpectatus to P. brevipes.

Researchers from Harvard University and Chengdu Institute of Biology, Chinese Academy of Sciences cooperated to study this job.



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