Open Paleo

Asylosaurus

Galton, 2007 ah-SIGH-lo-SOR-US Disputed

From Ancient Greek asylos (ἄσυλος) meaning 'unharmed, inviolable, having right of asylum' + Greek sauros (σαῦρος) meaning 'lizard'; overall meaning 'unharmed lizard', referring to the specimens surviving World War II bombardment unlike the Thecodontosaurus holotype.

205.7–201.4 million years ago Rhaetian, Late Triassic
Late Triassic stages

Asylosaurus is a genus of basal sauropodomorph dinosaur from the Late Triassic Avon Fissure Fill of England. It is based on partial remains, discovered in the autumn of 1834, described in 1836 by Henry Riley and Samuel Stutchbury as pertaining to Thecodontosaurus, that Othniel Charles Marsh brought to Yale University between 1888 and 1890. These remains thus escaped destruction by a bombardment in 1940 during World War II, unlike the original holotype of Thecodontosaurus. Asylosaurus was described in 2007 by Peter Galton. The type species is A. yalensis, referring to Yale. The bones originally came from a Rhaetian-age cave fill at Durdham Down, Clifton, Bristol.

Under dispute

Asylosaurus yalensis is a basal sauropodomorph from the Late Triassic of England, closely comparable to Thecodontosaurus. Galton (2007) named it on three autapomorphies; Ballell and colleagues (2020) find none of them diagnostic, since the deltopectoral crest is incomplete or distorted in the comparison humeri, the manual phalangeal formula is unknown in Thecodontosaurus, and the ischia were referred without evidence, and consider it a taxon of highly questionable validity.

Diagnosis

  1. Deltopectoral crest symmetrical in lateral view with gently rounded apex at 25% of humeral length
  2. Manus with lateral reduction giving phalangeal formula 2-3-4-2-1
  3. Distal ischia separated by a Λ-shaped cleft in dorsal view at the thickest parts

Species

Asylosaurus yalensis Galton, 2007 Disputed

Type species

Named for Yale University, where the bones were brought by Othniel Charles Marsh between 1888 and 1890 and where they were preserved.

Holotype
YPM 2195 , Yale Peabody Museum of Natural History
Material
Associated partial skeleton with dorsal vertebrae, ribs, gastralia, pectoral girdle, right and proximal left humeri, articulated left forearm and manus
Horizon
Rhaetian, Late Triassic , 205.7–201.4 million years ago
Locality
Quarry Steps Quarry, Durdham Down, City of Bristol, United Kingdom

References

  1. Galton, P. M. (2007). Notes on the remains of archosaurian reptiles, mostly basal sauropodomorph dinosaurs, from the 1834 fissure fill (Rhaetian, Upper Triassic) at Clifton in Bristol, southwest England. Revue de Paléobiologie 26(2): 505-591. galton2007a
  2. Ballell, A.; Rayfield, E. J.; Benton, M. J. (2020). Osteological redescription of the Late Triassic sauropodomorph dinosaur Thecodontosaurus antiquus based on new material from Tytherington, southwestern England. Journal of Vertebrate Paleontology 40(2): e1770774. doi:10.1080/02724634.2020.1770774

    Rejects each of the three autapomorphies proposed for Asylosaurus and considers it a taxon of highly questionable validity.

    ballell2020a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026b