Bone histology of Azendohsaurus laaroussii: Implications for the evolution of thermometabolism in Archosauromorpha

This paper is aimed at constraining the phylogenetic frame of the acquisition of endothermy by Archosauromorpha. We analyzed the bone histology of Azendohsaurus laaroussii . Stylopodial and zeugopodial bones show three tissue types: (1) avascular lamellar zonal bone formed at low growth rates; (2) a scaffold of parallel-fibered bone containing either small primary osteons or simple vascular canals; and (3) fibrolamellar bone formed at high...