Claorhynchus
Encyclopedia
Claorhynchus is a dubious
genus
of ornithischia
n dinosaur
with a confusing history behind it. It has been considered to be both a hadrosaurid and a ceratopsid, sometimes the same as Triceratops
, with two different assignments as to discovery formation and location, and what bones make up its type remains
.
Edward Drinker Cope
described what he interpreted as an "agathaumid
" (horned dinosaur
)'s rostral bone
and predentary
AMNH 3978
, which he said came from the Laramie Formation
of Montana
. It was soon thought to be a hadrosaurid, though. In their influential monograph
, Richard Swann Lull and Nelda E. Wright regarded the genus as a dubious type of hadrosaurid, based on premaxilla
e and a predentary
.
This opinion stood until the work of Michael K. Brett-Surman, who stated in his dissertation that, having rediscovered and reexamined the material with Douglas A. Lawson, it was most likely part of a ceratopsid's neck frill
, probably part of the squamosal
of Triceratops
. This information reached Donald F. Glut
's series of dinosaur encyclopedia
s in a confusing form; its entry states that a squamosal and tooth
from South Dakota
were referred to the genus, and these are what Brett-Surman and Lawson identified, keeping the supposed beak remains separate. Additionally, other major reviews have left the genus as an indeterminate hadrosaurid.
Thus, there are two views: one that this genus represents a piece of Triceratops frill, and one that it is a dubious hadrosaurid. The photograph of the specimen in Glut's encyclopedia shows a mass of thick polygonal fragments. At any rate, no modern sources consider its material to permit classification farther than to family
, and so it is mostly a historical curiosity at this point.
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
genus
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 ornithischia
Ornithischia
Ornithischia or Predentata is an extinct order of beaked, herbivorous dinosaurs. The name ornithischia is derived from the Greek ornitheos meaning 'of a bird' and ischion meaning 'hip joint'...
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...
with a confusing history behind it. It has been considered to be both a hadrosaurid and a ceratopsid, sometimes the same as Triceratops
Triceratops
Triceratops is a genus of herbivorous ceratopsid dinosaur which lived during the late Maastrichtian stage of the Late Cretaceous Period, around 68 to 65 million years ago in what is now North America. It was one of the last dinosaur genera to appear before the great Cretaceous–Paleogene...
, with two different assignments as to discovery formation and location, and what bones make up its type remains
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...
.
History
Paleontologist and naturalistNatural science
The natural sciences are branches of science that seek to elucidate the rules that govern the natural world by using empirical and scientific methods...
Edward Drinker Cope
Edward Drinker Cope
Edward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of nineteen...
described what he interpreted as an "agathaumid
Agathaumas
Agathaumas is a dubious genus of a large ceratopsid dinosaur that lived in Wyoming during the Late Cretaceous . The name comes from Greek, αγαν - 'much' and θαυμα - 'wonder'...
" (horned dinosaur
Ceratopsidae
Ceratopsidae is a speciose group of marginocephalian dinosaurs including Triceratops and Styracosaurus...
)'s rostral bone
Rostral bone
The rostral bone is the edentulous dorsal component of the skeleton of the beak, unique to the ceratopsian dinosaurs. Othniel Charles Marsh recognized and named this bone, which acts as a mirror image of the predentary bone on the lower jaw....
and predentary
Predentary
The predentary is an 'extra' bone in the front of the lower jaw, which extended the dentary . It is found in the fossilised remains of ornithischian dinosaurs, which were herbivorous. The predentary coincided with the premaxilla in the upper jaw. Together they formed a beak-like apparatus used to...
AMNH 3978
American Museum of Natural History
The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...
, which he said came from the Laramie Formation
Laramie Formation
The Laramie Formation is a geologic formation of Cretaceous age, named by Clarence King in 1876 for exposures in northeastern Colorado, in the United States....
of Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
. It was soon thought to be a hadrosaurid, though. In their influential monograph
Monograph
A monograph is a work of writing upon a single subject, usually by a single author.It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article. It is by definition a single document that forms a complete text in itself...
, Richard Swann Lull and Nelda E. Wright regarded the genus as a dubious type of hadrosaurid, based on premaxilla
Premaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
e and a predentary
Predentary
The predentary is an 'extra' bone in the front of the lower jaw, which extended the dentary . It is found in the fossilised remains of ornithischian dinosaurs, which were herbivorous. The predentary coincided with the premaxilla in the upper jaw. Together they formed a beak-like apparatus used to...
.
This opinion stood until the work of Michael K. Brett-Surman, who stated in his dissertation that, having rediscovered and reexamined the material with Douglas A. Lawson, it was most likely part of a ceratopsid's neck frill
Neck frill
Neck frill is the popular term for the relatively extensive margin seen on the back of the heads of reptiles with either a bony support such as those present on the skulls of dinosaurs of the suborder Marginocephalia or a cartilaginous one as in the Frill-necked Lizard...
, probably part of the squamosal
Squamosal
The squamosal is a bone of the head of higher vertebrates. It is the principal component of the cheek region in the skull, lying below the temporal series and otic notch and bounded anteriorly by postorbital. Posteriorly, the squamosal articulates with the posterior elements of the palatal complex,...
of Triceratops
Triceratops
Triceratops is a genus of herbivorous ceratopsid dinosaur which lived during the late Maastrichtian stage of the Late Cretaceous Period, around 68 to 65 million years ago in what is now North America. It was one of the last dinosaur genera to appear before the great Cretaceous–Paleogene...
. This information reached Donald F. Glut
Donald F. Glut
Donald F. Glut is an American writer, motion picture director, screenwriter, amateur paleontologist, musician and actor....
's series of dinosaur encyclopedia
Encyclopedia
An encyclopedia is a type of reference work, a compendium holding a summary of information from either all branches of knowledge or a particular branch of knowledge....
s in a confusing form; its entry states that a squamosal and tooth
Tooth
Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...
from South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
were referred to the genus, and these are what Brett-Surman and Lawson identified, keeping the supposed beak remains separate. Additionally, other major reviews have left the genus as an indeterminate hadrosaurid.
Thus, there are two views: one that this genus represents a piece of Triceratops frill, and one that it is a dubious hadrosaurid. The photograph of the specimen in Glut's encyclopedia shows a mass of thick polygonal fragments. At any rate, no modern sources consider its material to permit classification farther than to family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
, and so it is mostly a historical curiosity at this point.