STL Science Center

STL Science Center

06 February 2018

Dino Paper

Zanno and Makovicky's 2013 Nature paper Neovenatorid theropods are apex predators in the Late Cretaceous of North America is pretty much the only paper that has been published on Siats meekerorum. There are a few other mentions of Siats specifically or descriptions of its family (Neovenatoridae) that sometimes very remotely mention Siats in passing. The majority of these mentions come from papers discussing the anatomy and phylogeny, or a combination of both subjects, of animals like Megaraptor and the early tyrannosaurids. These include Porfiri, et al. 2014, which describes a juvenile specimen of Megaraptor and what its anatomy can tell us about tyrannosaurid evolution and Coria and Currie 2016, which again describes a Megaraptorid dinosaur and discusses tyrannosaurid phylogeny. The reason that Siats is mention so often in tyrannosaurid evolution is that Siats is in an interesting position, phylogenetically.

Regardless of which of these papers you are reading, Neovenatorids are contained within the Allosauroidea. Megaraptorids are in a controversial position, with Siats resting either right outside the Megaraptora or as a stem member, depending on which papers one is reading. The cladograms presented on Wikipedia for Siats and Megaraptora, developed using different papers, disagree on this point. However, this shows the history of the phylogenetic positioning of Siats, not current disagreement on its position. These clades are often discussed within discussions about tyrannosaurid evolution because Coelurosaurs, the group to which tyrannosaurs belong, are the sister clade of Allosauroids, the group in which Siats is found. Phylogenetics can be intense to read about, but bearing in mind that the papers linked here discuss Siats and Megaraptorids because they are distant cousins of the tyrannosaurs that the phylogenetic discussions mention, may help sort out the importance of these familial bonds.

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