Updated May 26, 2020
with new DGS tracings of the M. fuyuanensis specimen, GMPKU-P-3001.
Macrocnemus fuyuanensis (Li et al. 2007 and Jiang et al. 2011) was described as a new species of Macrocnemus, and the first from China. The skull (Figs. 1-3) was crushed, but largely articulated. Even so, the cracks looked like sutures and the sutures looked like cracks. With few other reconstructions to work from Jiang et al. (2011) got most of the skull right, but some sutures were misidentified. Their identification of a few skull elements in the rostrum was unlike those of other Macrocnemus and unlike those of other sister taxa like Huehuecuetzpalli, Tanystropheus, Cosesaurus and Jesairosaurus. Let’s correct them.
Not So Different After All
The resulting reconstruction of the Chinese Macrocnemus is not so different from the European specimens. That should come as no surprise. The post-crania were also quite similar. Even so, there were distinct morphologies that suggest speciation, as originally described. The many cracks in the skull bones and an apparent lack of experience in reconstructing Macrocnemus skull bones produced certain mistakes in the Jiang et al. (2011) report that were corrected here.
Macrocnemus: a Tritosaur lepidosaur, not a protorosaur
Just as a reminder, Macrocnemus nests with that new third clade of lizards, the Tritosauria. Despite convergent appearances, Macrocnemus was not related to Protorosaurus and Prolacerta.
Li C, Zhao L-J and Wang L-T 2007. A new species of Macrocnemus (Reptilia: Protorosauria) from the Middle Triassic of southwestern China and its palaeogeographical implication. Science in China D, Earth Sciences 50(11)1601-1605.
Jiang D-Y, Rieppel O, Fraser NC, Motani R, Hao W-C, Tintori A, Sun Y-L and Sun Z-Y 2011. New information on the protorosaurian reptile Macrocnemus fuyuanensis Li et al., 2007, from the Middle/Upper Triassic of Yunnan, China. Journal of Vertebrate Paleontology 31: 2011-1237, DOI:10.1080/02724634.2011.610853