17.7.15

Esos pequeños driosaurios en el XIII Annual Meeting de la EAVP


La semana pasada se presentaron en el XIII Annual Meeting de la European Association of Vertebrate Paleontologist (EAVP), restos apendiculares procedentes de tres yacimientos enclavados en la orla mesozoica portuguesa de tres nuevos individuos de ornitópodos driosaurios.

Los resultados preliminares presentados en este congreso indican que estas formas de pequeños dinosaurios fitófagos corredores, con una única especie conocida en el Jurásico Superior ibérico, Eousdryosaurus nanohallucis, eran componentes con un relevante papel dentro de los ecosistemas de la parte final del Jurásico en el dominio ibérico.

Aquí va el resumen:

Dryosauridae is a monophyletic clade of small, cursorial, plant-eating ornithopod dinosaurs that lived in both Gondwana and Laurasia. This wide distribution is particularly evident during the Late Jurassic with the Laurasian Dryosaurus and Eousdryosaurus, and the Gondwanan Dysalotosaurus. The dryosaurid record from the Upper Jurassic of Portugal is based mainly on isolated material from the Lusitanian Basin in the central-west of the country. So far, merely a partial specimen from the Porto das Barcas locality represents Eousdryosaurus nanohallucis. In this context, the discovery of new localities bearing new dryosaurid specimens is worthy of note. Two new localities have provided only isolated femora, whereas a third comprises a well-preserved partial skeleton of a small dryosaurid ornithopod. The former specimens come from the upper Kimmeridgian-lower Tithonian Praia da Amoreira-Porto Novo Formation and the Tithonian Freixial Formation. The most complete specimen is a partial skeleton from the Tithonian beds of the Bombarral Formation in Peniche. It comprises mainly appendicular bones (humerus, femur, tibia) of a single individual. All the femora recorded exhibit two dryosaurid synapomorphies such as the proximally placed fourth trochanter, and the scar for the M. caudi femoralis longus restricted to the medial surface of the femoral shaft insertion and widely separated from the fourth trochanter. The new evidence of these dryosaurid ornithopods indicates that these small cursorial dinosaurs were common inhabitants and played an important role within the Iberian herbivorous communities during the Late Jurassic.