O<i>nychodactylus</i> taxonomy

[william]

does anyone know how closely related this genus is to others in the hynobiidae family? surely the presence of claws and the lack of lungs would mean that it would be placed in it's own subfamily like protohynobius? just a query.

 

[john]

Claws on a caudate? Anyone got any pictures of that?

 

[henk]

Well I think Willima referes to cornified toes which streamtype salamnanders do have and which help them crawl up on the slippery stones against the stream. In some streamtype hynobidae these are already present in some adults. In a species like Pachyhynobius they are quite prominent, but there are many other examples there.

 

[william]

here are some pictures of the "claws"
http://www.rieo.net/amph/saramand/sansyouo/onych.htm

 

[TJ]

Hi William,

Japanese batrachologists (why do people shun this nice word?!) may have a different view on things, but the 1988 publication Studies on Chinese Salamanders (Ermi Zhao, Yaoming Jiang, Qixiong Hu, Yuhua Yang) offers this phylogeny of the seven genera of Hynobiidae based on morphological character analysis and comparisons:

...as opposed to these earlier ones:

So you can see from this that Onychodactylus it is considered more derivative than some other genera.

Onychodactylus is indeed the only member of Hynobiidae that lacks lungs, but Liua and Batrachuperus also have cornified coverings (on their palms, soles, fingers and toes). Still, only Onychodacuylus has what is described in the report as "sharp claw-like coverings"

This report has a very nicely detailed comparison of the hynobiid genera, aside from what's mentioned above.

 

[william]

thanks for that Tim