''Diplotomodon'' (meaning "double cutting tooth") is a
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, ...
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 ...
of
theropod
Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...
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 ...
, from
New Jersey
New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...
. It was possibly a member of the
Tyrannosauroidea
Tyrannosauroidea (meaning 'tyrant lizard forms') is a superfamily (or clade) of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent b ...
, the clade that also contains ''
Tyrannosaurus
''Tyrannosaurus'' is a genus of large theropoda, theropod dinosaur. The species ''Tyrannosaurus rex'' (''rex'' meaning "king" in Latin), often called ''T. rex'' or colloquially ''T-Rex'', is one of the best represented theropods. ''Tyrannosa ...
''.
''Diplotomodon'' is only known from a single tooth,
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 ...
ANSP 9680, found near
Mullica Hill
Mullica Hill is a census-designated place (CDP) and unincorporated community in Harrison Township in Gloucester County, New Jersey. As of the 2010 United States census, the CDP's population was 3,982.Navesink or
Hornerstown Formation
The Hornerstown Formation is a Paleogene or latest Mesozoic geologic formation in New Jersey.Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607. The age of these deposits have been controversial. While most fossils are of animals typ ...
, marine deposits dating to the
Maastrichtian
The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from ...
stage of the late
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
period.
Joseph Leidy
Joseph Mellick Leidy (September 9, 1823 – April 30, 1891) was an American paleontologist, parasitologist and anatomist.
Leidy was professor of anatomy at the University of Pennsylvania, later was a professor of natural history at Swarthmore ...
originally described the tooth using the name ''Tomodon'' in 1865, considering it a carnivorous marine reptile, probably a
plesiosaur
The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia.
Plesiosaurs first appeared ...
. The generic name was derived from Greek τομός (''tomos''), "cutting", "sharp", and ὀδών (''odon''), "tooth". However, this name had already been used for the
snake
Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...
genus '' Tomodon'' Duméril 1853 and Leidy changed it in 1868 to ''Diplotomodon'', adding a Greek διπλόος (''diploos''), "double", at that time suggesting it was a fish. The
type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...
, ''Diplotomodon'' ''Tomodon''''horrificus'' (Leidy, 1865) Leidy 1868 is the only species in the genus that has been described. The
specific name Specific name may refer to:
* in Database management systems, a system-assigned name that is unique within a particular database
In taxonomy, either of these two meanings, each with its own set of rules:
* Specific name (botany), the two-part (bino ...
''horrificus'' is
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
for "dreadful".
The tooth, with a preserved length of about three inches, is very broad, flat, and symmetrical and is not recurved.Weishampel, D.B., 2006, "Another look at the dinosaurs of the East Coast of North America", ''III Jornadas Internacionales sobre Paleontología de Dinosaurios y su Entorno, Salas de los Infantes, Burgos, Spain. Colectivo Arqueológico-Paleontológico Salense Actas'', pp 129-168
In 1870
Edward Drinker Cope
Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontologist, comparative anatomist, herpetologist, and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested ...
concluded it was not a fish but a carnivorous dinosaur.
Ralph Molnar
Ralph E. Molnar is a paleontologist who had been Curator of Mammals at the Queensland Museum and more recently associated with the Museum of Northern Arizona. He is also a research associate at the Texas natural Science Centre. He co-authored descr ...
followed this up in 1990 by suggesting that it was a synonym of the
tyrannosauroid
Tyrannosauroidea (meaning 'tyrant lizard forms') is a superfamily (or clade) of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent b ...
''
Dryptosaurus
''Dryptosaurus'' ( ) is a genus of tyrannosauroid that lived approximately 67 million years ago (mya) during the latter part of the Cretaceous period, New Jersey. ''Dryptosaurus'' was a large, bipedal, ground-dwelling carnivore, that grow up to ...
''.Molnar, (1990). "Problematic Theropoda: "Carnosaurs"." Pp. 306-317 in Weishampel ''et al.'' (eds.), ''The Dinosauria''. Berkeley: University of California Press. Although from then onwards mostly seen as a dinosaur, ''Diplotomodon'' was considered a member of the Mosasauridae by Halsey Wilkinson Miller in 1955.
David Weishampel
Professor David Bruce Weishampel (born November 16, 1952) is an American palaeontologist in the Center for Functional Anatomy and Evolution at Johns Hopkins University School of Medicine. Weishampel received his Ph.D. in Geology from the Universi ...
thought it was an indeterminate member of the
Tetanurae
Tetanurae (/ˌtɛtəˈnjuːriː/ or "stiff tails") is a clade that includes most theropod dinosaurs, including megalosauroids, allosauroids, tyrannosauroids, ornithomimosaurs, compsognathids and maniraptorans (including birds). Tetanurans are ...
in 2006. Today, it is generally considered a ''
nomen dubium
In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application.
Zoology
In case of a ''nomen dubium'' it may be impossible to determine whether a s ...
''.Holtz, T.R., 2004, "Tyrannosauroidea" In: D.B. Weishampel, P. Dodson, and H. Osmolska (eds.), ''The Dinosauria''. University of California Press, Berkeley, pp 111-136
See also
*
Timeline of tyrannosaur research
This timeline of tyrannosaur research is a chronological listing of events in the history of paleontology focused on the tyrannosaurs, a group of predatory Theropoda, theropod dinosaurs that began as small, long-armed bird-like creatures with ela ...