Tuesday, 9 March 2010

Green-eyed tree frogs

This is a green-eyed tree frog Litoria serrata from Queensland's Wet Tropics. A couple of days ago, it was still known as L. genimaculata, but a paper published in the 8 March 2010 edition of the online systematics journal Zootaxa has restricted that name to the New Guinea population.

It is not a new species. Litoria serrata was originally described in 1916 from specimens collected in Atherton, Carrington and Malanda on the Atherton Tablelands. It resembles both L. genimaculata and L. eucnemis and has been synonymised with both. This new paper has extracted it from synonymy and re-established it as a separate species.

Nothing is ever that simple, of course. Molecular studies show that there are odd things going on within the populations. That's apart from a new species (Litoria myola) with a very, very limited range (Kuranda), which had previously been mixed up in that froggy mess.

Litoria serrata has two distinct populations — north and south. (From a quick look at the paper, I suspect there are actually three populations. But I don't have the data, so that's nothing more than a wild guess.) They are currently being studied and may yet turn out to be different species. The good news is that, if they do turn out to be different, the species that hangs around here will retain the name L. serrata.

Litoria serrata is the 'house frog' in the rainforest. It has a particular fondness for bathrooms, but may turn up anywhere in the building. This one was viewing its domain from patio.

Hoskin, C.J. (2007). Description, biology and conservation of a new species of Australian tree frog (Amphibia: Anura: Hylidae: Litoria) and an assessment of the remaining populations of Litoria genimaculata Horst, 1883: systematic and conservation implications of an unusual speciation event. Biological Journal of the Linnean Society 91: 549–563

Richards, S.J., Hoskin, C.J., Cunningham, M.J., McDonald, K. & Donnellan, S.C. (2010). Taxonomic re-assessment of the Australian and New Guinean green-eyed treefrogs Litoria eucnemis, L. genimaculata and L. serrata (Anura: Hylidae). Zootaxa 2391: 33–46.


desertnutmeg said...

"odd things going on in the populations" good odd things or bad odd things, good/bad in respect to--i'll get to it in a mo.
"apart from a new species".
Okay, not a scientist. Gotta put that out on the table right up front.
I'm thinking i once read something about frogs being the first affected in the demise of a biosystem and thus our earth. Is that familiar to you-help me out here.

So, that being somewhat said, do you think the odd things and a new species is a good sign? No, i'm not niave enough to think we aren't killing our planet, but it seems somewhat promising that frogs are doing well. At least where you are.

What do you think?

Snail said...

Sorry, I should have been clearer!

The odd thing is a good (interesting) odd thing. :Litoria serrata has a continuous distribution across the Wet Tropics, but it appears to be divided into two (or more) genetically distinct populations, which are currently in contact. This pattern is probably the result of old (Ice Age?) fragmentation of the rainforest.

Several species of animals show evidence of having the gene flow interrupted at some point in the past. The principal hypothesis refers to the break up of the rainforest into separate blocks during cooler, drier periods. Populations in each of those blocks (effectively rainforest islands in dryland seas) developed their own genetic identities, which were maintained when the rainforest blocks expanded and joined up again in the warmer, wetter periods between ice ages. What we're probably seeing with L. serrata is the result of this.

Frogs are definitely wet-skinned canaries in the ecological coal mine. A lot of our frog species have succumbed to chytrid fungus disease. (I think it was first identified here.) And as for pollutants, changes in land use, etc, it's not looking good.

Mel said...

That's a cool frog. Thanks for the details about it, it's always nice to learn something new :)

Snail said...

You're welcome, Mel. This one was posing so nicely I couldn't resist taking a photo!