The biggest captorhinind – Moradisaurus

Known from a multi-tooth row jaw fragment, a few bits and pieces and a complete hind limb, Moradisaurus grandis (O’Keefe et al. 2005, Late Permian) is the largest known captorhinid. And it’s a little different, as well (Fig. 1).

F. Robin O'Keefe , Christian A. Sidor , Hans C. E. Larsson , Abdoulaye Maga & Oumarou Ide (2005) The vertebrate fauna of the Upper Permian of Niger—III, morphology and ontogeny of the hindlimb of Moradisaurus grandis (Reptilia, Captorhinidae), Journal of Vertebrate Paleontology, 25:2, 309-319, DOI: 10.1671/0272-4634(2005)025[0309:TVFOTU]2.0.CO;2

Figure 1. Moradisaurus reconstructed from pieces illustrated in O’Keefe et al 2005). Digits p2.1 and p3.1 are colorized and transposed in the alternate reconstruction. Note the simpler PILs. And this pattern follows Captorhinus and Labidosaurus.

Moradisaurus has several distinct traits
I’m most curious about that distal fibula connection with that fused astragalus/intermedium with no connection at all to the calcaneum, which appears to have developed a tuber of sorts. Generally the distal fibula is broader than the proximal fibula, but not here. Also, note the fusion of the calcaneum with distal tarsal 5. The toes are shorter, befitting its greater size and mass, approaching the size of contemporary pareiasaurs and diadectids.

Otherwise, I’ve switched p2.1 with p3.1 for better PILs and to fall in line with the phylogenetic sisters to Moradisaurus, Labidosaurus and Captorhinus. O’Keefe et al. noted the reconstruction of the metatarsals was done with confidence, less so with the scattered digits. I think they only made one mistake, based on the PILs.

Phylogenetic nesting confirms a derived captorhinid node.

References
O’Keefe FR, Sidor Ca , Larsson HCE, Maga A and Ide O 2005. The vertebrate fauna of the Upper Permian of Niger—III, morphology and ontogeny of the hindlimb of Moradisaurus grandis (Reptilia, Captorhinidae), Journal of Vertebrate Paleontology, 25:2, 309-319.

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