A tiny new tanystropheid was recently described by Fraser et al. (2013). Complete and articulated, but unfortunately too big for its slab, despite its tiny size, the holotype fossil of Fuyuansaurus lacks a tail and limbs, though undoubtedly limbs were present in vivo (phylogenetic bracketing).
It always helps when a reconstruction is made,
in this case to literally unwind the specimen.
Phylogenetic analysis nests Fuyuansaurus between the small Tanystropheus with multi-cusped teeth and the large one with simple stabbers. So does that make this another Tanystropheus species? Or do we need to separate the two Tanys generically? Depends if you’re a lumper or splitter. Fraser et al. did not publish their analysis if one was made.
That strange circular “pubis”.
Fraser et al. identified a round structure with ridge-like process terminating in a hollow bone end as a pubis, but noted that it was unlike the pubis of Tanystropheus or Macrocnemus. No kidding… Autapomorphies like this often have a different reality, as we learned earlier. I wonder if the flat round object was an egg because I found a regular strut-like pubis nearby on the inner mandible and the narrow structure that penetrates the soft ellipse could have been a chevron or a lumbar rib. So the possible tiny juvenile could actually be a possible tiny mother. And that ridge along the rim of the egg could be an embryo vertebral series. Hard to tell with available materials, but an interesting thought nevertheless that could pan out with higher resolution.
Fraser NC, Rieppel O and Chun L 2013. A long-snouted protorosaur from the Middle Triassic of southern China, Journal of Vertebrate Paleontology, 33:(5):1120-1126.