''Priconodon'' (meaning "saw cone tooth") is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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

(perhaps

nodosaurid Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous period in what is now North America, South America, Europe, and Asia. Description Nodosaurids, like their close relatives the ankylosaurids, we ...

), known from its large

teeth 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, tear ...

. Its remains have been found in the

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...

Albian The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 M ...

age

Lower Cretaceous Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eight ...

Arundel Formation The Arundel Formation, also known as the Arundel Clay, is a clay-rich sedimentary rock formation, within the Potomac Group, found in Maryland of the United States of America. It is of Aptian age (Lower Cretaceous). This rock unit had been econ ...

Muirkirk Muirkirk ( gd, Eaglais an t-Slèibh) is a small village in East Ayrshire, southwest Scotland. It is located on the north bank of the River Ayr, between Cumnock and Glenbuck on the A70. Conservation The Muirkirk & North Lowther Uplands Special ...

Prince George's County ) , demonym = Prince Georgian , ZIP codes = 20607–20774 , area codes = 240, 301 , founded date = April 23 , founded year = 1696 , named for = Prince George of Denmark , leader_title = Executive , leader_name = Angela D. Alsobrook ...

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...

, USA and the

Potomac Group The Potomac Group is a geologic group in Delaware, Maryland, New Jersey, and Virginia. It preserves fossils dating back to the Cretaceous period. An indeterminate tyrannosauroid and '' Priconodon crassus'', a nodosaurid, are known from indetermi ...

, also located in

History

O. C. Marsh Othniel Charles Marsh (October 29, 1831 – March 18, 1899) was an American professor of Paleontology in Yale College and President of the National Academy of Sciences. He was one of the preeminent scientists in the field of paleontology. Among h ...

named the genus for USNM 2135, a large worn tooth from what was then called the

Potomac Formation The Potomac Group is a geologic group in Delaware, Maryland, New Jersey, and Virginia. It preserves fossils dating back to the Cretaceous period. An indeterminate tyrannosauroid and '' Priconodon crassus'', a nodosaurid, are known from indetermi ...

. As

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, similar to turtles. Ankylosaurs were bulky quadrupeds, with short, powerful limbs. ...

ns were by and large unknown at the time, he compared it to '' Diracodon'' (=''

Stegosaurus ''Stegosaurus'' (; ) is a genus of herbivorous, four-legged, armored dinosaur from the Late Jurassic, characterized by the distinctive kite-shaped upright plates along their backs and spikes on their tails. Fossils of the genus have been foun ...

'') teeth.Marsh, O.C. (1888). Notice of a new genus of Sauropoda and other new dinosaurs from the Potomac Formation. ''American Journal of Science'' 135:89-94. It was not identified as an ankylosaurian until Walter Coombs assigned it to

Nodosauridae Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous period in what is now North America, South America, Europe, and Asia. Description Nodosaurids, like their close relatives the ankylosaurids, wer ...

in 1978.Coombs, Jr., W.P. (1978). The families of the ornithischian dinosaur order Ankylosauria. ''Palaeontology'' 21(1):143-170. In 1998

Kenneth Carpenter Kenneth Carpenter (born September 21, 1949, in Tokyo, Japan) is a paleontologist. He is the former director of the USU Eastern Prehistoric Museum and author or co-author of books on dinosaurs and Mesozoic life. His main research interests ...

and James Kirkland, in a review of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

n Lower Cretaceous ankylosaurs, considered it tentatively valid as an unusually large nodosaurid, larger than all those described before.Carpenter, K., and Kirkland, J.I. (1998). Review of Lower and middle Cretaceous ankylosaurs from North America. In: Lucas, S.G., Kirkland, J.I., and Estep, J.W. (eds.). ''Lower and Middle Cretaceous Terrestrial Ecosystems.'' New Mexico Museum of Natural History and Science Bulletin 14:249-270. Carpenter (2001) retained it as a valid nodosaurid, but did not employ it in his

phylogenetic analysis In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

.Carpenter, K. (2001). Phylogenetic analysis of the Ankylosauria. In: Carpenter, K. (ed.). ''The Armored Dinosaurs.'' Indiana University Press:Bloomington 455-483. Vickaryous ''et al.'' (2004), in a review of armored dinosaurs, considered it to be

dubious Doubt is a mental state in which the mind remains suspended between two or more contradictory propositions, unable to be certain of any of them. Doubt on an emotional level is indecision between belief and disbelief. It may involve uncertainty ...

without comment.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. West and Tibert, however, followed this with a preliminary account of a

morphometric Morphometrics (from Greek μορϕή ''morphe'', "shape, form", and -μετρία ''metria'', "measurement") or morphometry refers to the quantitative analysis of ''form'', a concept that encompasses size and shape. Morphometric analyses are co ...

study that found it to be a unique genus.

Material

Carpenter and Kirkland (1998) listed 12 additional teeth from the same area as the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

tooth, and tentatively added a robust

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...

(USNM 9154) to the genus. They found the lack of

armor Armour (British English) or armor (American English; see spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, especially direct contact weapons or projectiles during combat, or fr ...

found in the Arundel to be peculiar, but noted that fossils are rare in that formation anyway.

Paleobiology

As a nodosaurid, ''Priconodon'' would have been a slow, armored,

quadruped Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor' ...

herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

. It would have been a large nodosaurid, but since only teeth are definitely known for the genus, size estimation has not been done.

References

{{Taxonbar, from=Q1756414 Ankylosaurs Early Cretaceous dinosaurs of North America Taxa named by Othniel Charles Marsh Fossil taxa described in 1888 Paleontology in Maryland Ornithischian genera

History

Material

Paleobiology

See also

References