Dicynodontoides, Broom, 1940

Botha-Brink, Jennifer & Angielczyk, Kenneth D., 2010, Do extraordinarily high growth rates in Permo-Triassic dicynodonts (Therapsida, Anomodontia) explain their success before and after the end-Permian extinction?, Zoological Journal of the Linnean Society 160 (2), pp. 341-365 : 351

DICYNODONTOIDES (PREVIOUSLY KINGORIA )

A tibia and femur from specimen NMQR479 were analysed. Both elements revealed a relatively thick cortex of 45% for the tibia and 32% for the fibula ( Table 2). The bone tissue consists of moderately vascularized fibrolamellar bone interrupted by faint, narrow annuli ( Fig. 3B ). Although the vascular canals are fairly numerous, they are small, narrow, and consist mostly of longitudinally orientated simple canals and primary osteons with short anastomoses in radial rows. There is a slight decrease in vascularization towards the periphery of the femur. Distinct Sharpey’s fibres were also observed in a small peripheral region of the tibia.

Figures

Figure 3. Permo-Triassic dicynodont bone histology. A, subadult Cistecephalus ulna NMQR1465b; B, early subadult Dicynodontoides tibia NMQR479a; C, adult Rhachiocephalus ulna SAM-PK-3714a; D, subadult Tropidostoma tibia SAM-PK-K9960c; E, adult Oudenodon femur SAM-PK-K4807a; F, adult Aulacephalodon femur NMQR3016. Arrows indicate enlarged midcortical channels in Rhachiocephalus and Aulacephalodon. Scale bars: A, D, E = 500 mm; B, C, F = 413 mm.