Neobatrchian’s comprise more than 95% of all living frogs (and thus the bulk of living amphibians). Until recently, the earliest fossil record of this diverse group was based on a few records from the latest Cretaceous (Maastrichtian). In a recent paper in Cretaceous Research, Ana Báez and colleagues describe several new frog taxa from the upper portion of the Lower Cretaceous (Aptian-Albian). Via a cladisitic analysis, the authors nicely demonstrate that at least two of these new taxa are nested well within Neobatrchia, thus demonstrating that these are the earliest representatives of this diverse clade.
December 2, 2009
October 8, 2009
Origin of viviparity in iguanian lizards predates recent glaciation
A recent paper by Jim Schulte and Moreno-Roark in FirstCite in Biology Letters reveals that the transition from oviparity to viviparity preceded recent glaciation events, contrary to some previous hypotheses regarding the driving factors behind the origin of viviparity. This work nicely demonstrates how phylogenetic analysis and divergence date estimation can be combined to ask basic questions about the evolution of life history traits.
September 24, 2009
The aborigine colonization of the Canary Islands
For those interested in the biogeography of our own species, especially in relation to Africa, there’s an interesting new paper out in the European Journal of Human Genetics that deals with the geographic origin of the aboriginal populations of the Canary Islands. Unsurprisingly, many of the haplotypes are similar to those from populations in Northern Africa. However, they do posit a model of frequent migration between islands which goes somewhat against previous notions of colonization via “sequential island-hopping.”
Validation of taxonomy of old museum specimens using molecular data
Nice new paper in Biology Letters about using molecular data to validate the species-level taxonomy of a hummingbird species known from a 100-year old specimen. For more click here.
While not quite the same, there has been an interesting flourishing of descriptions of new species of frogs that appear to have gone extinct many years ago. For a recent example, see here for a paper on Sri Lankan shrub frogs by Madhava Meegaskumbura. Similar papers will also soon be coming out for other genera of frogs. It’s a true shame that we are now describing species that have recently gone extinct because of habitat destruction or the spread of infectious diseases.
September 17, 2009
Sex determination, viviparity, and … MOSASAURS!
Pretty much nothing more to say than that Chris Organ always puts together papers that are interesting and fun to read!