Terrestrisuchus. Eosphorosuchus and Aenigmaspina

Terrestrisuchus gracils (Crush 1984, Spiekman et al 2023, 2024; Ladinian, Late Triassic (~210 mya), 50 cm long), was derived from a sister to SMNS 12591 at the base of the crocodylomorphs. It preceded Litargosuchus and SMNS 12352 . Distinct from SMNS 12591 the skull of Terrestrisuchus was even narrower surrounding the upper temporal fenestrae and had an even lower rostrum. The cervicals were longer, the dorsals and caudals were more gracile. The coracoid was a parallelogram in shape. Every element of the forelimbs was greatly elongated. Only the femur and tibia were elongated on the hindlimb.

Galahadosuchus jonesi (Bodham et al 2026) was a quadruped that cannot be tested yet in the LRT pending acquisition of more data.

Eosphorosuchus skeleton compared to Terrestrisuchus

Eosphorosuchus skull compared to Terrestrisuchus

Eosphorosuchus lacrimosa (Margulis-Ohnuma et al 2026, Late Triassic, New Mexico, 140cm in length estimate) was originally assigned to Hesperosuchus agilis. Here in the LRT it nests with a much smaller Briitish biped, Terrestrisuchus. The 2026 authors nested it in a polytomy with UCMP 129470, Trialestes, Pseudhesperosuchusand Carnufex, not Terrestrisuchus. The reported 'prefrontal' is unique among tetrapods in not contacting the orbit, so this may be an error. Note the robust post narial premaxilla and postorbital.

The authors reported, "A robust upper temporal arch and prominent surangular ridge indicate the presence of well-developed superficial external adductor musculature, which is divergent relative to pseudosuchians generally." By contrast these traits simply follow patterns of increased robusticity with an increase in size relative to the smaller, more gracile sister, Terrestrisuchus in the LRT. This taxon did not have an 'unusual feeding anatomy'.

Outgroup taxa to the Eosphorosuchus + Terrestrisuchus clade in the LRT include the Sphenosuchus clade at a basal node, Yonghesuchus + all more modern crocs in a sister node.

The 2026 authors used the wrong outgroup taxa for the Crocodylomorpha, Gracilisuchus and Postosuchus. The former is an ingroup member in the LRT. The latter is several nodes distant as n outgroup. Other taxa are nearer and closer relatives. The authors also consider Crocodylomorpha a pseudosuchian sub-clade. The LRT does not recover a monophyletic Pseudosuchia. Rather Crocodylomorpha + Dinosauria = Archosauria. Poposauria is the outgroup clade.

Aenigmaspina pantyffynnonensis (Patrick et al. 2019; Ladinian, Late Triassic (~210 mya), was originally considered an enigma taxon, because so little was known of it. Here the coeval from the same formation taxon, Terrestrisuchus, appears to be a good match. The paired osteoderms were fused at the midline, creating a broad Y-shape.

Allen D 2003. When Terrestrisuchus gracilis reaches puberty it becomes Saltoposuchus connectens!". Journal of Vertebrate Paleontology 23 (3): 29A.

Crush PJ 1984. A late upper Triassic sphenosuchid crocodilian from Wales. Palaeontology 27: 131-157.

Huene F von 1921. Neue Pseudosuchier und Coelurosaurier aus dem Wurttembergischen Keuper: Acta Zoologica, v. 2, p. 329-403.

Margulis-Ohnuma M, Ruebenstahl AA, Meyer DL, Bhullar B-AS 2026. A short-snouted ‘sphenosuchian’ with unusual feeding anatomy demonstrates that ecological
specialization occurred early in crocodylomorph evolution. Proc. R. Soc. B 293: 20260130.

Patrick EL, Whiteside DI and Benton MJ 2019. A new crurotarsan archosaur from the Late Triassic of South Wales. Journal of Vertebrate Paleontology e1645147 (18 pages) DOI: 10.1080/02724634.2019.1645147

Spiekman SNF et al 2023. A taxonomic revision and cranial description of Terrestrisuchus gracilis (Archosauria, Crocodylomorpha)from the Upper Triassic of Pant-y-Ffynnon Quarry (southern Wales). Papers in Palaeontology, 9(6), e1534.

Spiekman SNF, Butler RJ and Maidment, S C 2024. The postcranial anatomy and osteohistology of Terrestrisuchus gracilis (Archosauria, Crocodylomorpha) from the Late Triassic of Wales. Papers in Palaeontology, 10(4), e1577.

wiki/Terrestrisuchus
wiki/Aenigmaspina
wiki/Eosphorosuchus

Archosauria

Crocodylomorpha

Saltopus