Priodontognathus
Encyclopedia
Priodontognathus was a genus
of ankylosauria
n dinosaur
possibly from the Oxfordian
-age Upper Jurassic Lower Calcareous Grit of Yorkshire
, England
. It is a dubious
genus based on a maxilla
, and has been erroneously mixed up with iguanodont
s and stegosaurs.
paleontologist Harry Govier Seeley, who described the genus, first mentioned the holotype
(SMC B53408), a maxilla or upper jaw bone, in 1869. 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
by his sons Charles Young and Henry Young. The provenance
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 initially assumed that it was referable to Iguanodon
, 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 prion, "saw", odous, "tooth" and gnathos, "jaw", in recognition of the form of its teeth. 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 stegosauria
n Omosaurus (now Dacentrurus
); stegosaurs are most closely related to the ankylosaurs within the Thyreophora
. At this time, he confusingly named a species Omosaurus phillipsii based on a femur
(YM 498), and seems to have tentatively assigned this species to Priodontognathus despite their having the same specific name (see at the bottom), and despite the two species being based on non-comparable material. This 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 specimens.
After this time, it was generally considered to be a stegosaurid, although at least one author, Baron Franz Nopcsa, recognized that it was not, and assigned it to "Acanthopholididae", which we would recognize as Nodosauridae
. Alfred Sherwood Romer also recognized that it was an ankylosaurian, although he synonymized it with Hylaeosaurus
.
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
. 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.
al herbivore
, built low to the ground, and possessing armor
as a protective feature against theropods and other carnivore
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.
" phillipsii or "Omosaurus" phillipsii (depending on how an author denotes dubious species), is a dubious species
of stegosauria
n from the Malton Oolite Member of the Coralline Oolite Formation, Slingsby
, North Yorkshire
. 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. The femur, which is in three pieces, is that of a juvenile
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of ankylosauria
Ankylosauria
Ankylosauria is a group of herbivorous dinosaurs of the order Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms. Ankylosaurs were bulky quadrupeds, with short, powerful limbs. They are first known to have appeared in the early Jurassic Period of...
n dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
possibly from the Oxfordian
Oxfordian stage
The Oxfordian is, in the ICS' geologic timescale, the earliest age of the Late Jurassic epoch, or the lowest stage of the Upper Jurassic series. It spans the time between 161.2 ± 4 Ma and 155.7 ± 4 Ma...
-age Upper Jurassic Lower Calcareous Grit of Yorkshire
Yorkshire
Yorkshire is a historic county of northern England and the largest in the United Kingdom. Because of its great size in comparison to other English counties, functions have been increasingly undertaken over time by its subdivisions, which have also been subject to periodic reform...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. It is a dubious
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
genus based on a maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
, and has been erroneously mixed up with iguanodont
Iguanodont
Iguanodonts were herbivorous dinosaurs that lived from the mid-Jurassic to Late Cretaceous. Some members include Camptosaurus, Callovosaurus, Iguanodon, Ouranosaurus, and the hadrosaurids or "duck-billed dinosaurs". Iguanodonts were one of the first groups of dinosaurs to be found...
s and stegosaurs.
History and Taxonomy
EnglishEnglish people
The English are a nation and ethnic group native to England, who speak English. The English identity is of early mediaeval origin, when they were known in Old English as the Anglecynn. England is now a country of the United Kingdom, and the majority of English people in England are British Citizens...
paleontologist Harry Govier Seeley, who described the genus, first mentioned the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
(SMC B53408), a maxilla or upper jaw bone, in 1869. 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
University of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...
by his sons Charles Young and Henry Young. The provenance
Provenance
Provenance, from the French provenir, "to come from", refers to the chronology of the ownership or location of an historical object. The term was originally mostly used for works of art, but is now used in similar senses in a wide range of fields, including science and computing...
of this particular bone from that collection was unknown; first believed to be found near Tilgate from a Lower Cretaceous stratum
Stratum
In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...
, it was later thought to have been discovered somewhere near the coast of Yorkshire in a Jurassic layer. Seeley initially assumed that it was referable to Iguanodon
Iguanodon
Iguanodon is a genus of ornithopod dinosaur that lived roughly halfway between the first of the swift bipedal hypsilophodontids and the ornithopods' culmination in the duck-billed dinosaurs...
, and named it Iguanodon Phillipsii. The specific name honoured geology professor John Phillips
John Phillips
-18th century and earlier:* John Phillips , Bishop of Sodor and Man in the Church of England* John Phillips , author and secretary to John Milton* John Phillips -18th century and earlier:* John Phillips (bishop of Sodor and Man) (1605–1633), Bishop of Sodor and Man in the Church of England* John...
. 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 prion, "saw", odous, "tooth" and gnathos, "jaw", in recognition of the form of its teeth. 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 stegosauria
Stegosauria
Known colloquially as stegosaurs, the Stegosauria are a group of herbivorous dinosaurs of the Jurassic and Early Cretaceous Periods, being found mostly in the Northern Hemisphere, predominantly in what is now North America and China....
n Omosaurus (now Dacentrurus
Dacentrurus
Dacentrurus , originally known as Omosaurus, was a large stegosaur of the Late Jurassic Period .-Description:...
); stegosaurs are most closely related to the ankylosaurs within the Thyreophora
Thyreophora
The Thyreophora were a subgroup of the ornithischian dinosaurs...
. At this time, he confusingly named a species Omosaurus phillipsii based on a femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
(YM 498), and seems to have tentatively assigned this species to Priodontognathus despite their having the same specific name (see at the bottom), and despite the two species being based on non-comparable material. This 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 specimens.
After this time, it was generally considered to be a stegosaurid, although at least one author, Baron Franz Nopcsa, recognized that it was not, and assigned it to "Acanthopholididae", which we would recognize as Nodosauridae
Nodosauridae
Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous Period of what are now North America, Asia, Antarctica and Europe.-Characteristics:...
. Alfred Sherwood Romer also recognized that it was an ankylosaurian, although he synonymized it with Hylaeosaurus
Hylaeosaurus
Hylaeosaurus is the most obscure of the three animals used by Sir Richard Owen to first define the new group Dinosauria, in 1842. The original specimen, recovered by Gideon Mantell from the Tilgate Forest in the south of England in 1832, now resides in the Natural History Museum of London, where...
.
Peter Galton
Peter Galton
Peter M. Galton is a British vertebrate paleontologist working in America, who has to date written or co-written about a hundred papers in scientific journals or chapters in paleontology textbooks, especially on ornithischian and prosauropod dinosaurs.With Robert Bakker in a joint article...
reassessed the genus in 1980 and established that it was a distinct genus, which he compared to Priconodon
Priconodon
Priconodon is an extinct genus of dinosaur , known from its large teeth. Its remains have been found in the Aptian-Albian age Lower Cretaceous Arundel Formation of Muirkirk, Prince George's County, Maryland.-History:...
and Sauropelta
Sauropelta
Sauropelta is a genus of nodosaurid dinosaur that existed in the Early Cretaceous Period of North America. One species has been named although others may have existed. Anatomically, Sauropelta is one of the most well-understood nodosaurids, with fossilized remains recovered in the U.S. states of...
and assigned to Nodosauridae
Nodosauridae
Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous Period of what are now North America, Asia, Antarctica and Europe.-Characteristics:...
. 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.
Paleobiology
As an ankylosaurian, Priodontognathus would have been a slow quadrupedQuadruped
Quadrupedalism is a form of land animal locomotion using four limbs or legs. An animal or machine that usually moves in a quadrupedal manner is known as a quadruped, meaning "four feet"...
al herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
, built low to the ground, and possessing armor
Armour (zoology)
Armour in animals is external or superficial protection against attack by predators, formed as part of the body , usually through the hardening of body tissues, outgrowths or secretions. It has therefore mostly developed in 'prey' species...
as a protective feature against theropods and other carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
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.
"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 species name. Omosaurus phillipsii, now known as "DacentrurusDacentrurus
Dacentrurus , originally known as Omosaurus, was a large stegosaur of the Late Jurassic Period .-Description:...
" phillipsii or "Omosaurus" phillipsii (depending on how an author denotes dubious species), is a dubious species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of stegosauria
Stegosauria
Known colloquially as stegosaurs, the Stegosauria are a group of herbivorous dinosaurs of the Jurassic and Early Cretaceous Periods, being found mostly in the Northern Hemisphere, predominantly in what is now North America and China....
n from the Malton Oolite Member of the Coralline Oolite Formation, Slingsby
Slingsby, North Yorkshire
Slingsby is a village and civil parish in the Ryedale district of North Yorkshire, England. It is about 6 miles west of Malton. According to the 2001 census had a population of 634....
, North Yorkshire
North Yorkshire
North Yorkshire is a non-metropolitan or shire county located in the Yorkshire and the Humber region of England, and a ceremonial county primarily in that region but partly in North East England. Created in 1974 by the Local Government Act 1972 it covers an area of , making it the largest...
. Galton (1983) found it to have no diagnostic features, and that its major significance was of being the only record then known of Oxfordian
Oxfordian stage
The Oxfordian is, in the ICS' geologic timescale, the earliest age of the Late Jurassic epoch, or the lowest stage of the Upper Jurassic series. It spans the time between 161.2 ± 4 Ma and 155.7 ± 4 Ma...
stegosaurians. The femur, which is in three pieces, is that of a juvenile
Juvenile (organism)
A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles sometimes look very different from the adult form, particularly in terms of their colour...
.
Miscellany
The double "i" at the end of the species name for both Priodontognathus and "Omosaurus" phillipsii is an old formulation and is today not done. The extra "i" has not been formally removed, 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 being used for the beginning of all specific epithets even if they were derived from personal names, resulting in this case in a phillipsi.External links
- A Dinosaur Mailing List post mentioning the confusing taxonomy (scroll to the bottom)