Wachtlerosaurus: a thalattosaur, not an archosaur

Perner 2018
introduces Wachtlerosaurus ladinicus (Fig. 1, 2), a tiny disarticulated reptile from the Middle Triassic Dolomites of northern Italy. Perner considers the specimen an archosaur. In the large reptile tree (LRT, 1264 taxa) the specimen nests with thalattosaurs and Thalattosaurus in particular. The purported antorbital fenestra is the naris.

Figure 1. From Perner 2018, the original reconstruction of Wachtlerosaurus. Scale bar added.

Figure 1. From Perner 2018, the original reconstruction of Wachtlerosaurus. Scale bar added. Note the elongate ribs considered parts of the pelvis here. Pes of Euparkeria added by Perner. Manus appears to be from a coelophysoid theropod and flipped left to right.

The Dolomites are about 250 million years old
and are formed from coral reefs in the Tethys Sea, a perfect niche for a marine reptile like a thalattosaur.

Figure 1. Wachtlerosaurus in situ and reconstructed in lateral view.

Figure 2. Wachtlerosaurus in situ and reconstructed in lateral view.

A reconstruction of the skull helps
(Fig. 1) put the pieces of the broken skull back together again.

A few other new interpretations on the paper.

  1. Perner 2018 identifies two long, parallel dorsal ribs surrounding a jumble of ?vertebrae as parts of an oversized pelvis (Fig. 1).
  2. Perner employs the humerus in place of a scapula (Fig. 1).
  3. Probably this scattered bone specimen is incomplete, not nearly complete, as described.
Figure 3. Subset of the LRT nesting Wachtlerosaurus with Thalattosaurus.

Figure 3. Subset of the LRT nesting Wachtlerosaurus with Thalattosaurus.

References
Perner T 2018. A new interesting archosaur from the Ladinian (Middle Triassic) of the Dolomites (Northern Italy) Preliminary report. Pp 1–8 in Some new and exciting Triassic Archosauria from the Dolomites (Northern Italy). Perner T and Wachtler M eds. Dolomythos-Museum, Oregon Institute of Geological Research.

1 thought on “Wachtlerosaurus: a thalattosaur, not an archosaur

  1. Hahaha. You’re completely right about the Euparkeria pes and flipped coelophysid manus. That’s hilarious, and his reconstruction is laughable. You know, I think you may be right about the skull being a thalattosaur, there’s a good resemblence there. But the postcrania clearly isn’t, with the gracile limb elements with well developed crests and condyles. You can see from his radiograph (pg. 5) that the cervical vertebrae point away from the postcrania off the edge of the slab and they are far larger than the scattered vertebrae. I bet that’s a thalattosaur skull and neck (the snout’s more like Heschleria than Thalattosaurus though) with a smaller terrestrial reptile postcranium associated. Exactly what kind of reptile I don’t know and don’t have time to compare, but you or someone else should go through Middle Triassic taxa and see which humeri and femora match.

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