Elasmaria is a clade of Ornithopoda known from Cretaceous deposits in the former Gondwana (South America, Antarctica, Australia, and possibly Africa) that contains many bipedal ornithopods that were previously considered
/ref>[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.]
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.
