Monday, February 23, 2009

The always difficult Leptodactylus

The neotropical frog family Leptodactylidae is a massive one, and the most prominent among its members is the genus Eleutherodactylus, the largest vertebrate genus with over 700 species (of course, the recent flurry of systematic changes in amphibians has begun carving up these groups, so neither statement may hold true anymore). These are small nondescript brown frogs whose identification makes Empidonax seem incredibly simplistic.

Another member of this group is Leptodactylus, a genus of larger species who are convergent on our northern frogs in the genus Rana (actually, that name may have changed too!) in habits and shape - long-legged jumping species of wet areas and edges. In my research before herping in Venezuela I narrowed down a list of about eight possible Leptodactylus and relatives that I could potentially see. Even with this pared down list, details on identification were sketchy, and I still had a rough time sorting out these frogs. When I compiled enough photos of all of Leptodactylus I saw on Hato Masaguaral, I could break it down into two groups. With some help from fieldherpforum, I confirmed the ID on these two species:

Leptodactylus wagneri (probably a species complex, so look for that name to change too)

Leptodactylus macrosternum

I would say these identifications are more tentative than the others I post, so don't run off and claim these as a taxonomic authority on the subject!

For video of the wagneri calling, see my frog video post.

Are these the only two species I saw on the ranch? Probably not, but they are so difficult to catch many got away.

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