Let this week be known as the week of UW paleobiology in the literature! It should be noted that these papers were either single author publications or the grad was the primary author.
David DeMar described a new genus and species of salamander from the end of the Mesozoic in the Journal of Vertebrate Paleontology.
Dave: Paranecturus garbanii is a new genus and species of fossil salamander from the latest Cretaceous of Montana and is closely related to the modern day mudpuppy of the family Proteidae. P. garbanii is the oldest and only species of proteid salamander known to live prior to the Cretaceous-Paleogene boundary (~66 million years ago) thus implying that proteid salamanders survived the end Cretaceous mass extinction event.
Here is Dave’s paper.
Jonathan Calede’s paper in the Journal of Mammalian Evolution looks at ontogenetic changes in a burrowing beaver and is based on his term paper for Greg Wilson’s mammal evolution class.
Jonathan: This project was actually initiated as my term project for BIOL 443. It is the first description of palaeocastorine beavers (an extinct subfamily of burrowing beavers) from the Fort Logan Formation of Montana (~28 million years old, Meagher County). I found that there were at least three species of these beavers including one previously only known from the John Day Formation of Oregon: Palaeocastor peninsulatus. This species is represented by three skulls and associated partial skeletons forming an ontogenetic series from a juvenile to a mature adult. The analysis of these specimens shows that morphological changes throughout ontogeny are associated with increased burrowing ability in adults. It appears that the the changes in burrowing behavior between juveniles and adults mirrors changes observed throughout the evolution of palaeocastorines.
Daril Vilhena (back again!), Elisha Harris, and Max Maliska authored a collaborative paper dealing with extinction selectivity among bivalves at the end Cretaceous mass extinction event in Scientific Reports.
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| The world’s continents as they were at the end of the Mesozoic Era 66,000,000 years ago. Map by Ron Blakey. |
Daril: The Cretaceous-Paleogene (K/Pg) extinction event has remarkably equal extinction rates across the globe for marine bivalves, which are arguably the best preserved clade for that time interval. This is surprising considering that proposed mechanisms for extinction vary considerably geographically (volcanism, asteroid, dust cloud versus heat pulse, etc). However, we grouped bivalves by their biogeography, and found that regions at lower latitudes had higher extinction than expected given the geographic ranges of the bivalves. This suggests that i) the mechanism for extinction declined in intensity towards the poles, ii) tropical lineages were more vulnerable to extinction, or iii) both.
Last, but not least, Adam Huttenlocker returns for his unprecedented, third consecutive appearance on SciPos. That’s right ladies and gentlemen, three pubs in as many weeks. This week Adam’s paper describes two new genera of burrowing amphibians from nearly 300 million years ago (sort of a weird combo of Dave and Jonathan’s papers?). One of the new genera has been dubbed Huskerpeton in honor of its Nebraska ‘corn-husker’ provenance and (unofficially) the University of Washington huskies. Adam: Recumbirostran microsaurs were small amphibians with elongate bodies and pointed shovel-like snouts, and are best known from late Early Permian redbeds in the southwestern US in which they often co-occur with lungfish in estivation assemblages. They superficially resemble modern caecilians, and have at times been suggested to share a close relationship with caecilians and salamanders. The paper describes two new genera of morphologically conservative recumbirostrans from the earliest Permian of Kansas and Nebraska. The new taxa share a close relationship to some lesser understood forms from Germany, sharing a similar degree of morphological conservatism. We suggest that the diverse forms of burrowing recumbirostrans that radiated during the Early Permian were already biogeographically widespread by the Carboniferous-Permian transition (~300 million years ago), but are poorly sampled in the fossil record due to the relative conservatism and small body sizes of early forms.
~Brandon
