SVP 2018: Large biped in the Permian

Shelton, Wings, Martens, Sumida and Berman 2018 report,
from the same quarry that produced bipedal Eudibamus, comes a MUCH larger taxon most closely comparable to Eudibamus (Fig. 1) with long bones 10 to 24 cm in length. They report, “Given this evidence, we hypothesize that either there was an additional bipedal species that existed sypatrically with E. cursori, or these bone casts represent a later ontogenetic stage of Eudibamus with the type specimen being a juvenile.”

FIgure 1. Eudibamus scaled to femoral (=long bone) lengths of 10 and 24 cm. This makes the giant eudibamid either half a meter or a meter in snout-vent length.

FIgure 1. Eudibamus scaled to femoral (= long bone) lengths of 10 and 24 cm. This makes the giant eudibamid either half a meter or a meter in snout-vent length.

None of the present sisters
to Eudibamus (Fig. 2) in the LRT approach the size of the new bone cast specimen.

Figure 1. Basal diasids and proto-diapsids. Largely ignored these putative synapsids actually split from other synapsids while retaining the temporal fenestra trait that serves as the basis for the addition of upper temporal fenestra in diapsids. Included here are Protorothyris, Archaeovenator, Mycterosaurus, Heleosaurus, Mesenosaurus, Broomia, Milleropsis, Eudibamus, Petrolacosaurus, Spinoaequalis, and Tangasaurus.

Figure 2. Basal diasids and proto-diapsids. Largely ignored these putative synapsids actually split from other synapsids while retaining the temporal fenestra trait that serves as the basis for the addition of upper temporal fenestra in diapsids. Included here are Protorothyris, Archaeovenator, Mycterosaurus, Heleosaurus, Mesenosaurus, Broomia, Milleropsis, Eudibamus, Petrolacosaurus, Spinoaequalis, and Tangasaurus.

The authors continue to hold to their original hypothesis
that Eudibamus is a bolosaurid (Fig. 3). In the large reptile tree (LRT, 1313 taxa) bolosaurids nest with diadectids and procolophonids. Eudibamus nests with basalmost diapsids (Fig. 3).

Figure 2. Eudibamus skull revised here with new data compared to bolosaurids, on the left, and basal diapsids, on the right. Post crania for bolosaurids is very fragmentary. Bolosaurids are related to pareiasaurs and turtles, all derived from millerettids. Can you see why Eudibamus was confused with bolosaurids?

Figure 2. Eudibamus skull revised here with new data compared to bolosaurids, on the left, and basal diapsids, on the right. Post crania for bolosaurids is very fragmentary. Bolosaurids are related to pareiasaurs and turtles, all derived from millerettids. Can you see why Eudibamus was confused with bolosaurids?

It will be interesting to see
what this new Early Permian taxon looks like when it becomes available. Right now it is an outlier.

References
Shelton CD, Wings O, Martens T, Sumida SS and Berman DS 2018. Evidence of a large bipedal tetrapod from the Early Permian Tambach Formation preserved as natural bone casts discovered at the Bromacher quarry (Thuringia, Germany). SVP abstracts.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.