Revised March 31, 2020
with the realization that the postfrontal and postorbital of the YPM specimen were fused, the quadrate was dislodged from its anterior lean and the restoring of several other traits that now nest this taxon with wider-skulled Orthosuchus (Fig. 2), both of which had binocular vision due to somewhat forward-facing orbits.
by Brian Switek in 2016 on Twitter Fossil Friday as Poposaurus (Fig. 6), and published by the Yale Peabody Museum as cf. Dromicosuchus (Fig. 4) by Sterling Nesbitt 2018, specimen YPM VP 057 103 (Figs. 1–3) nests in the large reptile tree (LRT, then 1342 taxa, now 1660+ taxa) as a member of the Crocodylomorpha, close to Dromicosuchus, but closer to Orthosuchus.
Notable traits in the YPM specimen:
The premaxilla was elevated and pointed anteriorly forming a shark-like nose. The rostrum was elongate. The cervicals are longer than in sister taxa. The pubis may have curved posteriorly, as in another quadruped, Trialestes (Fig. 5), which led to earlier confusion. Distinct from sister taxa (and most tetrapods), the humerus was much longer than the femur in the YPM specimen. This basal crocodylomorph with long limbs and a short torso appears to have been able to gallop rapidly, something a few extant crocs are able to do.
The skull of the YPM specimen
does indeed remind one of Dromicosuchus (Fig. 4), but the skull of the YPM specimen all by itself can nest it with basal crocs in the LRT, 20 steps apart from Dromicosuchus.
Poposaurus (Fig. 6) has distinctly different proportions. Likely the identification of this specimen changed behind the scenes between 2016 and 2018. Someone should mention this to Brian Switek so he can make an edit to his Twitter account.