Bone microstructure of Lewisuchus admixtus Romer, 1972 (Archosauria, Dinosauriformes)

GARCÍA MARSÀ, JORDI; AGNOLIN, FEDERICO; NOVAS, FERNANDO E.

Historical Biology

Taylor and Francis

Año: 2017

Lewisuchus admixtus is a basal dinosauriform coming from Late Triassic outcrops of NW Argentina. Althoughthis taxon was recently anatomically restudied, histological data is still wanting. The microstructure of thelong bones (femur and two tibie) reveals a relatively fast rate of growth, comparable with that seen in otherbasal Dinosauriformes and basal dinosaurs. Cortical bone is comprised of fibro-lamellar complex in onefemur and tibia, but parallel-fibered matrix are observed in the other tibia. The secondary remodelling ofbone is poor and there is not growth marks. The vascularization is relatively dense, longitudinal, laminarand reticular. There are some features that indicate slowdown of the growth at late age of the specimens.The fast growth of L. admixtus implies a relatively high metabolic rate. This is probably related withenvironmental conditions.