Tropidosuchus romeri, Arcucci, 1990, Arcucci, 1990

Marsà, Jordi Alexis Garcia, Ponce, Denis A., Agnolín, Federico Lisandro & Novas, Fernando E., 2023, Histovariability and lifestyle in Proterochampsidae Romer, 1966 (Archosauriformes) from the Chañares Formation (Late Triassic), northwestern Argentina, Comptes Rendus Palevol 22 (30), pp. 605-622 : 611

FEMUR ( PVL-4606 )

The transverse section of the bone is well preserved, although part of the cortex collapsed and infilled inside the medullary cavity.

The cortex formed by PFB is densely vascularized ( Fig. 5), even more than in the femur cortex of specimen PVL-4604 ( Marsà et al. 2020). The vascular canals are mainly longitudinally and circumferentially arranged, which give rise to a laminar vascular organization ( Fig. 5). Similar to PVL-4604 ( Marsà et al. 2020), there is a reduction in the density of primary osteons towards the subperiosteum. The cortex is not interrupted by growth marks.

The medullary cavity is surrounded by a layer of lamellar bone tissue deposited endosteally, forming the ICL, which is thicker than in PVL-4604 ( Marsà et al. 2020).

In this specimen the osteocyte lacunae are difficult to distinguish, probably due to diagenesis, and are less abundant than in Chanaresuchus bonapartei PULR-V 116 or Tropidosuchus romeri PVL-4604 ( Marsà et al. 2020). The osteocyte lacunae are subcircular in outline and present throughout the cortex, as well as in the ICL, but in very low numbers in the latter.