Saurophaganax
Encyclopedia
Saurophaganax is a genus
of allosaurid
dinosaur
from the Morrison Formation
of Late Jurassic
Oklahoma
(latest Kimmeridgian
age, about 151 million years ago). Some paleontologists consider it to be a species of Allosaurus
(A. maximus). Saurophaganax represents a very large (13 metres (42.7 ft) long) Morrison allosaurid characterized by horizontal laminae at the bases of the dorsal neural spines above the transverse processes, and "meat-chopper" chevrons
.
uncovered remains of a large theropod near Kenton
in Cimarron County, Oklahoma
in layers of the late Kimmeridgian
. In 1941 these were named Saurophagus maximus by Stovall in an article by journalist Grace Ernestine Ray. The generic name is derived from Greek sauros, "lizard" and phagein, "to eat", with the compound meaning of "eater of saurians". The specific epithet means "the largest" in Latin
. As the naming article did not contain a description., the name remained a nomen nudum
. In 1950 Stovall described the finds. However, in 1987 Spencer George Lucas e.a. concluded a lectotype
had to be designated among the many bones: OMNH 4666, a tibia
.
Later it was discovered that the name Saurophagus was preoccupied: it had already in 1831 been given by William Swainson
to a tyrant-flycatcher, a real eater of lizards. In 1995 Daniel Chure named a new genus: Saurophaganax, adding Greek anax, "ruler", to the earlier name. Chure also established that the lectotype tibia was not diagnostic in relation to Allosaurus. He designated another element as the type specimen: OMNH 01123, a neural arch. This was not intended as a neotype of the old genus but as the holotype
of a genus different from "Saurophagus". The type species
Saurophaganax maximus, based on diagnostic material, is thus not to be considered conspecific with Saurophagus maximus based on a undiagnostic bone — which species Chure later stated to be a nomen dubium
— and Saurophaganax is not a renaming of "Saurophagus". Much of the material previously referred to Saurophagus maximus, namely those diagnostic elements that could be distinguished from Allosaurus, were by Chure referred to Saurophaganax maximus. They contain disarticulated bones of at least four individuals.
Saurophaganax is the official state fossil
of Oklahoma
, and a large skeleton of Saurophaganax can be seen in the Jurassic hall in the Sam Noble Oklahoma Museum of Natural History
. Although the best known Saurophaganax material was found in the panhandle of Oklahoma, possible Saurophaganax material, NMMNH P-26083, a partial skeleton including a femur, several tail vertebrae, and a hip bone, has been found in northern New Mexico
.
specimens, a possible prey for a large theropod.
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 allosaurid
Allosaurid
Allosauridae was a family of medium to large sized carnivorous theropod dinosaurs. Members included Saurophaganax, Allosaurus, and the poorly known Epanterias, which could well be a specimen of Allosaurus...
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...
from the Morrison Formation
Morrison Formation
The Morrison Formation is a distinctive sequence of Late Jurassic sedimentary rock that is found in the western United States, which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone and limestone and is light grey, greenish...
of Late Jurassic
Late Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago , which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age...
Oklahoma
Oklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...
(latest Kimmeridgian
Kimmeridgian
In the geologic timescale, the Kimmeridgian is an age or stage in the Late or Upper Jurassic epoch or series. It spans the time between 155.7 ± 4 Ma and 150.8 ± 4 Ma . The Kimmeridgian follows the Oxfordian and precedes the Tithonian....
age, about 151 million years ago). Some paleontologists consider it to be a species of Allosaurus
Allosaurus
Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros...
(A. maximus). Saurophaganax represents a very large (13 metres (42.7 ft) long) Morrison allosaurid characterized by horizontal laminae at the bases of the dorsal neural spines above the transverse processes, and "meat-chopper" chevrons
Chevron (anatomy)
A chevron is one of a series of bones on the ventral side of the tail in many reptiles, dinosaurs , and some mammals such as kangaroos and manatees....
.
Discovery and naming
In 1931 and 1932 John Willis StovallJ. Willis Stovall
John Willis Stovall was a paleontologist at the University of Oklahoma. Along with his student Wann Langston, Jr., he named the theropod dinosaur Acrocanthosaurus in 1950. Most of his research centered on the Cimarron Valley region of extreme northwestern Oklahoma.-Selected publication:*Stovall,...
uncovered remains of a large theropod near Kenton
Kenton
-Notable people:* Actress Michele Austin, best known as PC Yvonne Hemmingway in ITV's The Bill, attended Claremont High School in Kenton* Cricketer Denis Compton lived in Kenton* TV exercise instructor Mr Motivator lived in Kenton...
in Cimarron County, Oklahoma
Oklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...
in layers of the late Kimmeridgian
Kimmeridgian
In the geologic timescale, the Kimmeridgian is an age or stage in the Late or Upper Jurassic epoch or series. It spans the time between 155.7 ± 4 Ma and 150.8 ± 4 Ma . The Kimmeridgian follows the Oxfordian and precedes the Tithonian....
. In 1941 these were named Saurophagus maximus by Stovall in an article by journalist Grace Ernestine Ray. The generic name is derived from Greek sauros, "lizard" and phagein, "to eat", with the compound meaning of "eater of saurians". The specific epithet means "the largest" in Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
. As the naming article did not contain a description., the name remained a nomen nudum
Nomen nudum
The phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...
. In 1950 Stovall described the finds. However, in 1987 Spencer George Lucas e.a. concluded a lectotype
Lectotype
In botanical nomenclature and zoological nomenclature, a lectotype is a kind of name-bearing type. When a species was originally described on the basis of a name-bearing type consisting of multiple specimens, one of those may be designated as the lectotype...
had to be designated among the many bones: OMNH 4666, a tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
.
Later it was discovered that the name Saurophagus was preoccupied: it had already in 1831 been given by William Swainson
William Swainson
William John Swainson FLS, FRS , was an English ornithologist, malacologist, conchologist, entomologist and artist.-Life:...
to a tyrant-flycatcher, a real eater of lizards. In 1995 Daniel Chure named a new genus: Saurophaganax, adding Greek anax, "ruler", to the earlier name. Chure also established that the lectotype tibia was not diagnostic in relation to Allosaurus. He designated another element as the type specimen: OMNH 01123, a neural arch. This was not intended as a neotype of the old genus but as 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...
of a genus different from "Saurophagus". The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
Saurophaganax maximus, based on diagnostic material, is thus not to be considered conspecific with Saurophagus maximus based on a undiagnostic bone — which species Chure later stated to be a nomen dubium
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
— and Saurophaganax is not a renaming of "Saurophagus". Much of the material previously referred to Saurophagus maximus, namely those diagnostic elements that could be distinguished from Allosaurus, were by Chure referred to Saurophaganax maximus. They contain disarticulated bones of at least four individuals.
Saurophaganax is the official state fossil
State fossil
Most American states have made a state fossil designation, in many cases during the 1980s. It is common to designate one species in which fossilization has occurred, rather than a single specimen, or a category of fossils not limited to a single species....
of Oklahoma
Oklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...
, and a large skeleton of Saurophaganax can be seen in the Jurassic hall in the Sam Noble Oklahoma Museum of Natural History
Sam Noble Oklahoma Museum of Natural History
The Sam Noble Oklahoma Museum of Natural History is a natural history museum in Norman, Oklahoma, operated by the University of Oklahoma. It is currently housed in a building on Chautauqua Avenue that opened on May 1, 2000. The museum's exhibits include a Native American gallery and collections of...
. Although the best known Saurophaganax material was found in the panhandle of Oklahoma, possible Saurophaganax material, NMMNH P-26083, a partial skeleton including a femur, several tail vertebrae, and a hip bone, has been found in northern New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
.
Relationship with Allosaurus
The identification of Saurophaganax is a matter of dispute. It has been described as its own genus, or as a species of Allosaurus: Allosaurus maximus. The most recent review of basal tetanurans accepted Saurophaganax as a distinct genus. New possible Saurophaganax material from New Mexico may clear up the status of the genus.Ecology
Saurophaganax was one of the largest carnivores of Late Jurassic North America. Ray even gave an estimate of the body length of fifteen metres and Chure of fourteen, though later estimations have been lower. The fossils known of Saurophaganax (both the possible New Mexican material and the Oklahoma material) are known from the latest part of the Morrison formation, suggesting that they were either always uncommon or appeared rather late in the fossil record. Saurophaganax was large for an allosaurid, and bigger than both its contemporaries Torvosaurus tanneri and Allosaurus fragilis. Being much rarer than its contemporaries, making up one percent or less of the Morrison theropod fauna, not much about its behavior is known. Stovall in Oklahoma also unearthed a considerable number of ApatosaurusApatosaurus
Apatosaurus , also known by the popular but scientifically deprecated synonym Brontosaurus, is a genus of sauropod dinosaur that lived from about 154 to 150 million years ago, during the Jurassic Period . It was one of the largest land animals that ever existed, with an average length of and a...
specimens, a possible prey for a large theropod.
External links
- Saurophaganax in The Dinosaur Encyclopaedia at Dino Russ's Lair