Triassic–Jurassic Mass Extinction as Trigger for the Mesozoic Radiation of Crocodylomorphs

A new study that contrasts that of Brusatte et al. (2008), who had found a significant dropoff in pseudosuchian disparity through the end Triassic extinction.

Toljagić, O., and R. J. Butler. 2013 Triassic–Jurassic mass extinction as trigger for the Mesozoic radiation of crocodylomorphs. Biology Letters 9: 20130095. http://dx.doi.org/10.1098/rsbl.2013.0095

Abstract - Pseudosuchia, one of the two main clades of Archosauria (Reptilia: Diapsida), suffered a major decline in lineage diversity during the Triassic–Jurassic (TJ) mass extinction (approx. 201 Ma). Crocodylomorpha, including living crocodilians and their extinct relatives, is the only group of pseudosuchians that survived into the Jurassic.We reassess changes in pseudosuchian morphological diversity (disparity) across this time interval, using considerably larger sample sizes than in previous analyses. Our results show that metrics of pseudosuchian disparity did not change significantly across the TJ boundary, contrasting with previous work suggesting low pseudosuchian disparity in the Early Jurassic following the TJ mass extinction. However, a significant shift in morphospace occupation between Late Triassic and Early Jurassic taxa is recognized, suggesting that the TJ extinction of many pseudosuchian lineages was followed by a major and geologically rapid adaptive radiation of crocodylomorphs. This marks the onset of the spectacularly successful evolutionary history of crocodylomorphs in Jurassic and Cretaceous ecosystems.

Finally! Aetosaurs in National Geographic Magazine

The most recent issue of National Geographic has an article titled 'When Crocs Ruled' which mainly focuses on the long evolutionary history of the crocodile lineage and the threats extant crocodylians face today. One highlight of the article is the large two page spread of the Desmatosuchus mount from Petrified Forest National Park. It's a nice photo that almost makes me forget about the erroneous armor reconstruction (Unfortuntely, we'll need to remold and cast the whole thing to fix). I'm not as forgiving with the term "croc forerunner" in the title, because as we know aetosaurs were never crocodiles and their lineage did not give rise to the group. Still, I'm thrilled to see an aetosaur displayed prominently in National Geographic (but why not the cover?)

There is also a time line with some great reconstructions that gives props to Triassic forms such as Effigia, Postosuchus, and Proterosuchus. It also gives a good representation of crocodylomorph diversification through the later Mesozoic and Tertiary, something that often gets overshadowed by the dinosaurs, birds, and mammals.

There is also a secondary article by Paul Sereno titled "Strange Crocs of the Sahara", which again tries to demonstrate the great diversity in forms. Although I don't really care for terms such as 'RatCroc', 'DogCroc', and 'DuckCroc' they do seem to get the point across.