Open Paleo

Priodontognathus

Seeley, 1875 PRY-oh-don-TOG-nah-thus Disputed

From Greek 'prion' meaning 'saw', 'odous/odontos' meaning 'tooth', and 'gnathos' meaning 'jaw', meaning 'saw tooth jaw.'

161.5–154.8 million years ago Oxfordian, Late Jurassic
Late Jurassic stages

Priodontognathus is a genus of ankylosaurian dinosaur known from a single maxilla, possibly from the Late Jurassic (Oxfordian-aged) Calcareous Grit of Yorkshire, England. Whether it is a valid genus is disputed. It was first identified as an iguanodont and later linked to stegosaurs.

Under dispute

Priodontognathus is based on a single maxilla with a long history of misidentification. Vickaryous and colleagues (2004) list it as a nomen dubium, while Naish and Martill (2008) call that status probably unjust, pointing to its unusual teeth. It is retained at Ankylosauria incertae sedis.

Diagnosis

  1. Jugal process: posteriorly-directed, claw-like process on maxilla prolonged outward and backward with concave inner surface
  2. Tooth sockets: 18 semiovate sockets of moderate crowding, smaller than Iguanodon, more like Scelidosaurus
  3. Dental foramina: unusually large perforations along lower external alveolar border, one per tooth, larger than in Teratosaurus or Megalosaurus
  4. Teeth crowns: more compressed mediolaterally than Echinodon, with 5-7 denticles per serrated side, lacking basal thickening, terminating in sharp point
  5. Nasal process: ascending process on middle of upper margin ~1.5 inches high, thin and posteriorly-extended, dividing orbit from naris
  6. Infraorbital canal: remarkable longitudinal groove on dorsal surface originating near anterior end, bifurcating into larger inner and smaller outer portions

Species

Priodontognathus phillipsii Seeley, 1875 Disputed

Type species

Named for John Phillips, a geology professor, honored when Harry Govier Seeley originally described the specimen as Iguanodon phillipsii.

Holotype
SMC B53408 , Sedgwick Museum, University of Cambridge
Material
Maxillary bone (jaw) ~4.5 inches long; partially compressed, lacking palatal portion
Horizon
Calcareous Grit Formation, Oxfordian, Late Jurassic , 161.5–154.8 million years ago
Locality
North Yorkshire, United Kingdom The unit is a matrix identification, not a collection record. The specimen reached Cambridge in 1861 from a private collection with no field data, and Seeley could trace no history for it in 1875 or 1893. Judd and Etheridge proposed the Calcareous Grit from the matrix and a Pecten in the block, while offering the Coral Rag as an alternative and the shore at Hastings as an alternative to the Yorkshire coast. Naish and Martill (2008) leave that choice open.

References

  1. Seeley, H. G. (1875). On the Maxillary Bone of a new Dinosaur (Priodontognathus Phillipsii), contained in the Woodwardian Museum of the University of Cambridge. Quarterly Journal of the Geological Society of London 31(1-4): 439-443. Geological Society of London. doi:10.1144/gsl.jgs.1875.031.01-04.30 seeley1875a
  2. Vickaryous, M. K.; Maryańska, T.; Weishampel, D. B. (2004). Ankylosauria. The Dinosauria, Second Edition (Weishampel, D. B.; Dodson, P.; Osmólska, H., eds.) 363-392. University of California Press, Berkeley.

    Lists Priodontognathus phillipsii among the ankylosaur nomina dubia.

    vickaryous2004a
  3. Naish, D.; Martill, D. M. (2008). Dinosaurs of Great Britain and the role of the Geological Society of London in their discovery: Ornithischia. Journal of the Geological Society 165(3): 613-623. Geological Society of London. doi:10.1144/0016-76492007-154

    Leaves the horizon open between the Upper Jurassic of Yorkshire and the Lower Cretaceous of Sussex, the same alternative Etheridge raised in 1875.

    naish2008a