YPM VP057103: neither Dromicosuchus nor Poposaurus

Identified online
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, 1342 taxa) as a member of the basal Crocodylomorpha, between incomplete Junggarsuchus and bipedal Pseudhesperosuchus.

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 curved posteriorly, as in another quadruped, Trialestes (Fig. 5). 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.

Another long-legged, quadrupedal, basal crocodylomorph
is Trialestes (Fig. 5) which shares several traits arrived at by convergence. Note the femur remains longer than the humerus and the pubis curves posteriorly

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.

The YPM specimen shares many traits
and nests with Pseudhesperosuchus (Fig. 7), another basal crocodylomorph, and not far from the origin of dinosaurs.

References:
http://collections.peabody.yale.edu/search/Record/YPM-VP-057103