''Priodontognathus'' (meaning " saw

tooth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tea ...

jaw") was a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of ankylosaurian

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

possibly from the Oxfordian-age Upper Jurassic Lower Calcareous Grit of

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England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

. It is a dubious genus based on a maxilla, and has been erroneously mixed up with iguanodonts and stegosaurs.

History and taxonomy

English paleontologist Harry Govier Seeley, who described the genus, first mentioned the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

(SMC B53408), a maxilla or upper jaw bone, in 1869.Seeley, H.G. (1869). ''Index to the fossil remains of ''Aves, Ornithosauria'', and ''Reptilia'' from the Secondary Strata.'' Cambridge University Press:Cambridge, 143 p. Seeley was at the time compiling a catalogue of the fossils of the Woodwardian Museum. Part of these formed the Forbes Collection that after the death of James Forbes-Young had in 1862 been donated to the

University of Cambridge The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209, the University of Cambridge is the List of oldest universities in continuous operation, wo ...

by his sons Charles Young and Henry Young. The

provenance Provenance () is the chronology of the ownership, custody or location of a historical object. The term was originally mostly used in relation to works of art, but is now used in similar senses in a wide range of fields, including archaeology, p ...

of this particular bone from that collection was unknown; first believed to be found near Tilgate from a Lower Cretaceous stratum, it was later thought to have been discovered somewhere near the coast of Yorkshire in a Jurassic layer.Seeley, H.G. (1893). On ''Omosaurus phillipsii''. ''Annual Report, Yorkshire Philosophical Society, 1892''. 52-57. Seeley initially assumed that it was referable to ''

Iguanodon ''Iguanodon'' ( ; meaning 'iguana-tooth'), named in 1825, is a genus of iguanodontian dinosaur. While many species found worldwide have been classified in the genus ''Iguanodon'', dating from the Late Jurassic to Early Cretaceous, Taxonomy (bi ...

'', and named it ''Iguanodon Phillipsii''. The specific name honoured geology professor John Phillips. The five inch long fragment lacked the teeth, only seventeen empty tooth sockets being visible. By 1875, after subsequent preparation had uncovered the replacement teeth within the jaw bone, Seeley had recognized that it was different, and so gave it the generic name ''Priodontognathus''. The name is derived from Greek ', "saw", ', "tooth" and ', "jaw", in recognition of the form of its teeth.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'' 31:439-443. Because the replacement teeth had not yet erupted, their serrations had not been worn down and many sharp denticula could be seen, shaped as the points of a saw. Because armored dinosaurs were very poorly known at the time, he had little to compare it to, and in light of this it is not too surprising that he later, in 1893, had it mixed up with the stegosaurian ''Omosaurus'' (now '' Dacentrurus''); stegosaurs are most closely related to the ankylosaurs within the Thyreophora. At this time, he named a species ''Omosaurus phillipsii'' based on a

femur The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femo ...

(YM 498), but also provisionally equated this species to ''Priodontognathus phillipsii'', despite the two species being based on non-comparable material. This was extremely confusing as both shared the same specific name
see at the bottom
. It led to a later misunderstanding by some authors, assuming ''Omosaurus phillipsii'' was nothing but ''Priodontognathus phillipsii'' reassigned to ''Omosaurus''. However, this is precluded by the mere fact that both species have been based on different

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

s. After this time, ''Priodontognathus'' was generally considered to be a stegosaurid,von Huene, F. (1909). Skizze zu einer Systematik und Stammesgeschichte der Dinosaurier. ''Centralblatt für Mineralogie, Geologie und Paläontologie'' 1909:12-22. erman/ref>von Zittel, K.A.. (1911). Grundzüge der Paläontologie (Paläozoologie). II. Abteilung. Vertebrata. Druck und Verlag von R. Oldenbourg:München, 1-598. erman/ref> although at least one author, Baron Franz Nopcsa, recognized that it was not, and assigned it to "Acanthopholididae", which we would recognize as Nodosauridae.Nopcsa, F. (1902). Notizen über cretacische Dinosaurier. ''Sitzungsberichte der Mathematisch-Naturwissenschaftlichen Classe der Kaiserlichen Akademie der Wissenschaften'' 111(1):93-114. erman/ref> Alfred Sherwood Romer also recognized that it was an ankylosaurian, although he synonymized it with '' Hylaeosaurus''.Romer, A.S. (1956). Osteology of the Reptiles. ''University of Chicago Press'':Chicago, 1-772. Peter Galton reassessed the genus in 1980 and established that it was a distinct genus, which he compared to '' Priconodon'' and '' Sauropelta'' and assigned to Nodosauridae.Galton, P.M. 1980. ''Priodontognathus phillipsii'' (Seeley), an ankylosaurian dinosaur from the Upper Jurassic (or possibly Lower Cretaceous) of England. ''Neues Jahrbuch für Geologie und Paläontologie - Monatshefte'' 1980(8):477-489. While his assessment of it as a type of ankylosaurian has been accepted, his belief that it was valid was not, and it has been usually considered a dubious genus of uncertain ankylosaurian affinities since then.Coombs, Jr., W.P., and Maryańska, T. (1990). Ankylosauria. In: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.). ''The Dinosauria (first edition)''. University of California Press:Berkeley, 456-483. Ford, T.L. (2000). A review of ankylosaur osteoderms from New Mexico and a preliminary review of ankylosaur armor. In: Lucas, S.G., and Heckert, A.B. (eds.). ''Dinosaurs of New Mexico.'' New Mexico Museum of Natural History and Science Bulletin 17:157-176.Carpenter, K. (2001). Phylogenetic analysis of the Ankylosauria. In: Carpenter, K. (ed.). ''The Armored Dinosaurs''. Indiana University Press:Bloomington, 455-483. Vickaryous, M.K., Maryańska, T., and Weishampel, D.B. (2004). Ankylosauria. In: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.). ''The Dinosauria (second edition)''. University of California Press:Berkeley, 363-392.

"Omosaurus" ''phillipsii''

As mentioned, Seeley named a femur ''Omosaurus phillipsii'' in 1893, which has become confused with this animal, due to being discussed in the same article (and considered to possibly be the same genus), and due to them having the same specific name. ''Omosaurus phillipsii'', now known as " Dacentrurus" ''phillipsii'' or "Omosaurus" ''phillipsii'' (depending on how an author denotes dubious species), is a dubious

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of stegosaurian from the Malton Oolite Member of the Corallian Oolite Formation,

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. Galton (1983) found it to have no diagnostic features, and that its major significance was of being the only record then known of Oxfordian stegosaurians.A juvenile stegosaurian dinosaur, ''Omosaurus phillipsii'' Seeley from the Oxfordian (Upper Jurassic) of England. ''Géobios'' 16:95-101. The femur, which is in three pieces, is that of a juvenile.

Paleobiology

As an ankylosaurian, ''Priodontognathus'' would have been a slow quadrupedal

herbivore A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

, built low to the ground, and possessing armor as a protective feature against theropods and other

carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they ar ...

s. It was a rather small animal, a few metres long; if the Oxfordian date is correct this might be seen as a feature shared with all early nodosaurids.

Miscellany

The double "i" at the end of the specific name for both ''Priodontognathus'' and "Omosaurus" ''phillipsii'' is an old formulation and is today not done. The extra "i" has not been formally removed and is the only valid spelling under the

International Code of Zoological Nomenclature The International Code of Zoological Nomenclature (ICZN) is a widely accepted Convention (norm), convention in zoology that rules the formal scientific name, scientific naming of organisms treated as animals. It is also informally known as the I ...

, but authors sometimes leave it off. For that matter, as mentioned above regarding the name of "Omosaurus" ''phillipsi'', ''Priodontognathus'' will sometimes be referred to as "Iguanodon" ''phillipsii''. Seeley's original use of a capital to write ''Phillipsii'' is now no longer conventional,

lower case Letter case is the distinction between the letters that are in larger uppercase or capitals (more formally ''majuscule'') and smaller lowercase (more formally '' minuscule'') in the written representation of certain languages. The writing system ...

being used for the beginning of all specific epithets even if they were derived from personal names, resulting in this case in a ''phillipsi''.

References

External links