SVP 2018: A super-matrix for an invalid ‘Thyreophora’

Raven, Maidment and Barrett 2018 report,
“The individual lineages, Ankylosauria and Stegosauria, have been studied thoroughly, but there has never before been a comprehensive whole-group cladistic analysis of Thyreophora.”

According to Wikipedia:
“Thyreophorans are characterized by the presence of body armor lined up in longitudinal rows along the body. Threophora (Nopsca 1915) has been defined (Sereno 1998) as the group consisting of all species more closely related to Ankylosaurus than to Triceratops. Thyreophoroidea was first named by Nopcsa in 1928 and defined by Sereno in 1986, as “ScelidosaurusAnkylosaurus, their most recent common ancestor and all of its descendants”. Eurypoda was first named by Sereno in 1986 and defined by him in 1998, as “Stegosaurus, Ankylosaurus, their most recent common ancestor and all of their descendants”.

Raven, Maidment and Barrett 2018 report,
“Here, the first species-level phylogenetic super matrix of the whole-group Thyreophora is presented, incorporating all previous known cladistic analyses of ankylosaurs, stegosaurs and basal thyreophorans and including all valid species within Thyreophora, for a total of 89 taxa and 338 characters.

Unfortunately
in the large reptile tree (LRT, 1308 taxa, Fig. 1) the last common ancestor of Ankylosauria and Stegosauria also includes among its descendants: heterodontosaurids, lesothosaurs, duckbills and horned dinosaurs.

So ‘Goodbye, Eurypoda and Thyreophora’
(unless these clades someday become more inclusive by consensus). The super-matrix of Raven, Maidment and Barrett 2018 probably does not include the LRT or the taxonomic tree it finds within the clade Ornithischia. So use their study to learn about the stegosaurs and the ankylosaurs, but not the last common ancestor of stegosaurs and ankylosaurs. That would be a sister to late-surviving Late Cretaceous Haya and/or Late Triassic Pisanosaurus.

Figure 4. Subset of the LRT focusing on the Phytodinosauria. Three sauropods are added here.

Figure 1. Subset of the LRT focusing on the Phytodinosauria. Scelidosaurus through Minmi are basal ankylosaurs. Lesothosaurus through Stegosaurus are basal stegosaurs.

References
Raven TJ, Maidment SC and Barrett PM 2018. The first phylogenetic super-matrix of the armored dinosaurs (Ornithischia, Thyreophora). SVP abstracts.

wiki/Thyreophora

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