Benggwigwishingasuchus: a bipedal ornithosuchid in the LRT

Smith et al 2024
“describe[d] a new pseudosuchian archosaur, Benggwigwishingasuchus eremicarminis
gen. et sp. nov.,(Figs 1, 2) from the Anisian (Middle Triassic) Fossil Hill Member of the Favret Formation (Nevada, USA), a pelagic setting in the eastern Panthalassan Ocean characterized by the presence of abundant ammonoids and large-bodied ichthyosaurs.”

“Benggwigwishingasuchus is recovered as part of an expanded Poposauroidea, including several taxa (e.g. Mandasuchus, Mambawakalae) from the Middle Triassic Manda Beds of Tanzania among its basally branching members.”

Figure 1. Benggwigwishingasuchus in situ. Frame 2 is the provided DGS color diagram. Frame 3 is the diagram matched to the fossil. ” data-image-caption=”

Figure 1. Benggwigwishingasuchus in situ. Frame 2 is the provided DGS color diagram. Frame 3 is the diagram matched to the fossil.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-insitu588.gif?w=285″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-insitu588.gif?w=584″ class=”size-full wp-image-94008″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-insitu588.gif” alt=”Figure 1. Benggwigwishingasuchus in situ. Frame 2 is the provided DGS color diagram. Frame 3 is the diagram matched to the fossil. ” width=”584″ height=”614″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-insitu588.gif?w=584&h=614 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-insitu588.gif?w=143&h=150 143w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-insitu588.gif?w=285&h=300 285w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-insitu588.gif 588w” sizes=”(max-width: 584px) 100vw, 584px” />

Figure 1. Benggwigwishingasuchus in situ. Frame 2 is the provided DGS color diagram. Frame 3 is the diagram matched to the fossil.

By contrast,
when added to the large reptile tree (LRT, 2340 taxa) bipedal Benggwigwishingasuchus nests with a larger Ornithosuchus (Fig 2). The LRT does not recover a monophyletic ‘Pseudosuchia‘. Rather only crocodylomorphs + dinosaurs = Archosauria. Poposauria (including omitted Turfanosuchus and Silesaurus) is the proximal outgroup to Archosauria in the LRT, which minimizes taxon exclusion and tends to avoid largely incomplete taxa.

Figure 2. Reconstruction of Benggwigwishingasuchus by moving the diagram elements. Compare to Ornithosuchus to a similar girdle-girdle length and to scale with a full-size Ornithosuchus and its pes. ” data-image-caption=”

Figure 2. Reconstruction of Benggwigwishingasuchus by moving the diagram elements. Compare to Ornithosuchus to a similar girdle-girdle length and to scale with a full-size Ornithosuchus and its pes.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-recon588.jpg?w=295″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-recon588.jpg?w=584″ class=”size-full wp-image-94010″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-recon588.jpg” alt=”Figure 2. Reconstruction of Benggwigwishingasuchus by moving the diagram elements. Compare to Ornithosuchus to a similar girdle-girdle length and to scale with a full-size Ornithosuchus and its pes.” width=”584″ height=”593″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-recon588.jpg?w=584&h=593 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-recon588.jpg?w=148&h=150 148w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-recon588.jpg?w=295&h=300 295w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/08/benggwigwishingasuchus-recon588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />

Figure 2. Reconstruction of Benggwigwishingasuchus by moving the diagram elements. Compare to Ornithosuchus to a similar girdle-girdle length and to scale with a full-size Ornithosuchus and its pes.

According to Wikipedia – Paracrocodylomorpha:
“The most recent definition of Paracrocodylomorpha, as defined by Sterling Nesbitt in 2011, is “the least inclusive clade containing Poposaurus and Crocodylus niloticus (the Nile crocodile).

In the LRT that definition = Poposauria + Archosauria (which includes Dinosauria + Crocodylomorpha only).

The Ornithosuchidae phylogenetically precedes all of these clades by several nodes.

According to Wikipedia – Benggwigwishingasuchus
“has been noted for having both a large number of neck vertebrae and a low number of dorsal vertebrae, both ranging from about 10 to 11 individual bones.”

Actually there is a typical number of cervicals (7) and the reconstruction (Fig 2) shows how the pectoral girdle has to move to that point based on the large basket of gastralia and robust cervical ribs. No reconstruction was provided by the authors.
However, they did DGS color the bones. Very helpful.

“Unlike derived poposauroids like Poposaurus, Benggwigwishingasuchus still retains its osteoderm armour, which is arranged in a simple paramedial double-row as in many pseudosuchians.”

Benggwigwishingasuchus armor is like that of Ornithosuchus (Fig 2).

“The phylogenetic analysis published in the type description of Benggwigwishingasuchus recovered it as a member of the Poposauroidea, a group of highly diverse paracrocodylomorphs that form the sister clade to Loricata.”

According to Wikipedia – Loricata:

“Loricata is a clade of archosaur reptiles that includes crocodilians and some of their Triassic relatives, such as Postosuchus and Prestosuchus.”

The LRT does not recover a clade ‘Loricata‘ because it does not include dinosaurs, the sister clade to Crocodylomorpha, together = Archosauria. Add taxa to test this.

The name Loricata gained a new phylogenetic definition in 2011. In his study of early archosaur phylogeny, paleontologist Sterling J. Nesbitt defined it as the most inclusive clade containing Crocodylus niloticus (the Nile crocodile), but not Poposaurus gracilis, Ornithosuchus longidens, or Aetosaurus ferox, all of which were extinct species of Triassic archosaurs closer to crocodilians than to dinosaurs.”

We looked at Nesbitt 2011 earlier in a 9-part series that ended here. In summary: taxon exclusion and scoring errors weakened and distorted the Nesbitt analysis. When rescored the cladogram more closely matched the LRT.

Nevertheless Newbitt 2011 has been trusted and borrowed ever since.

References
Smith ND, Klein N, Sander PM, Schmitz L 2024. A new pseudosuchian from the Favret Formation of Nevada reveals that archosauriforms occupied coastal regions globally during the Middle Triassic. Biology Letters 20: 20240136. https://doi.org/10.1098/rsbl.2024.0136

wiki/Paracrocodylomorpha
wiki/Benggwigwishingasuchus
wiki/Poposauoidea
wiki/Poposauridae