Elasmaria

Classification

Calvo et al. (2007) coined Elasmaria to accommodate Macrogryphosaurus and Talenkauen, which they recovered as basal iguanodonts distinct from other iguanodontians in having mineralized plates on the ribs. In 2016, a paper describing the genus Morrosaurus found Elasmaria to be far larger than its initial contents of two taxa, instead containing a variety of ornithopods from the Southern Hemisphere. In 2021, under the Phylocode, Madzia et al. (2021) formally defined Elasmaria as "the smallest clade containing Macrogryphosaurus gondwanicus and Talenkauen santacrucensis, provided that it does not include Hypsilophodon foxii, Iguanodon bernissartensis, or Thescelosaurus neglectus. Fonseca et al. (2024) redefined Elasmaria as "the largest clade containing Macrogryphosaurus gondwanicus and Talenkauen santacrucensis but not Dryosaurus altus, Hypsilophodon foxii, Iguanodon bernissartensis, and Thescelosaurus neglectus" so that it included more related taxa. The cladogram below follows their preferred reference phylogeny, taken from the results of their own study.

References

References

1. Boyd CA. (2015) The systematic relationships and biogeographic history of ornithischian dinosaurs. PeerJ 3:e1523 https://doi.org/10.7717/peerj.1523
2. Madzia, Daniel; Boyd, Clint A.; Mazuch, Martin (2017). "A basal ornithopod dinosaur from the Cenomanian of the Czech Republic". Journal of Systematic Palaeontology: 1–13. doi:10.1080/14772019.2017.1371258.
3. (2007). "Discovery of a new ornithopod dinosaur from the Portezuelo formation (Upper Cretaceous), Neuquen, Patagonia, Argentina.". Arquivos do Museu Nacional, Rio de Janeiro.
4. (2016). "A new ornithopod (Dinosauria, Ornithischia) from the Upper Cretaceous of Antarctica and its palaeobiogeographical implications". Cretaceous Research.
5. (2021-12-09). "The phylogenetic nomenclature of ornithischian dinosaurs". PeerJ.
6. (2024-06-21). "A comprehensive phylogenetic analysis on early ornithischian evolution". Journal of Systematic Palaeontology.