What is Elasmaria?

Talenkauen santacrucensis, Macrogryphosaurus gondwanicus, their most recent common ancestor and all descendants. Elasmaria is a clade of basal iguanodontians that lived in Gondwana (current Antarctica, South America, Africa, Madagascar, Australia, the Arabian Peninsula and South Asia) during the Late Cretaceous. Its members (Elasmarians) were characterized by bowed humeri, tightly bunched foot bones and expanded tail chevrons suggesting they were geared up for speed and balance, and thus occupied an ecological niche different from that of other herbivorous dinosaurs from the same time and place.

Initially, Elasmaria included two critters (Talenkauen santacrucencis and Macrogryphosaurus gondwanicus) that were 4-5 meters in length. But, in 2015, Novas added Morrosaurus, Gasparinisaura, Trinisaura, Notohypsilophodon and Anabisetia which are either much smaller than the founding members or their size is unknown and, funnily enough, they lack the thin plates for which the group was named. They all seem to be able runners, though.

Click here to search Dinochecker for instances of Elasmaria. Elasmaria, in Greek, means "thin plate" and refers to the strange thin plates found within the thorax of its members. Once thought to be armour, most paleontologists now suspect these plates are discs of mineralised intercostal (between the ribs) cartilage.