Saurophaganax

Last updated

Saurophaganax
Temporal range: Late Jurassic (Tithonian),
151  Ma
Ꞓ
O
S
D
C
P
T
J
K
Pg
N
↓
Saurophaganax.jpg
Reconstructed skeleton at the Sam Noble Oklahoma Museum of Natural History
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade:† Allosauria
Family:† Allosauridae
Genus:† Saurophaganax
Chure, 1995
Species:
†S. maximus
Binomial name
†Saurophaganax maximus
Chure, 1995
Synonyms

Saurophaganax ("lord of lizard-eaters") is a genus of large allosaurid dinosaur from the Morrison Formation of Late Jurassic (latest Kimmeridgian age, about 151 million years ago) Oklahoma, United States. [1] Some paleontologists consider it to be a junior synonym and species of Allosaurus (as A. maximus). Saurophaganax represents a very large Morrison allosaurid characterized by horizontal laminae at the bases of the dorsal neural spines above the transverse processes, and "meat-chopper" chevrons. [2] It was the largest terrestrial carnivore of North America during the Late Jurassic, reaching 10.5 metres (34 ft) in length and 2.7–3.8 metric tons (3.0–4.2 short tons) in body mass.

Contents

Discovery and naming

A drawer of Saurophaganax vertebrae, Oklahoma Museum of Natural History Saurophaganax (2).jpg
A drawer of Saurophaganax vertebrae, Oklahoma Museum of Natural History

In 1931 and 1932, John Willis Stovall 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. [3] The generic name is derived from Greek σαυρος, sauros, "lizard", φάγειν, phagein, "to eat", with the compound meaning of "lizard eater". The specific epithet maximus means "the largest" in Latin. Because the naming article did not contain a description, the name remained a nomen nudum . In 1987, Spencer George Lucas erroneously made OMNH 4666, a tibia, the lectotype, unaware that Saurophagus was a nomen nudum. [4]

Later, it was discovered that the name Saurophagus was preoccupied: in 1831, it had already been given by William Swainson to a tyrant-flycatcher, an extant eater of taxonomically true lizards. [5] In 1995, Daniel Chure named a new genus: Saurophaganax, adding Greek suffix -άναξ, anax, meaning "ruler", to the earlier name. Chure also found OMNH 4666 undiagnostic in relation to Allosaurus, so he chose OMNH 01123, a neural arch, as the holotype for Saurophaganax. [6] — and Saurophaganax is not a renaming of "Saurophagus". [7] Much of the material informally named "Saurophagus maximus", namely those diagnostic elements that could be distinguished from Allosaurus, were referred to Saurophaganax maximus by Chure. They contain disarticulated bones of at least four individuals. [7]

Saurophaganax is the official state fossil of Oklahoma, [8] 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. [9]

Relationship with Allosaurus

The identification of Saurophaganax is a matter of dispute. It has been described as its own genus, [7] or as a species of Allosaurus: Allosaurus maximus. [10] A review of basal tetanurans in 2004 and Carrano et al.'s comprehensive 2012 analysis of Tetanurae accepted Saurophaganax as a distinct genus. [11] [12] Possible Saurophaganax material from New Mexico may clear up the status of the genus. [9]

Description

Size comparison Saurophaganax Scale.svg
Size comparison

Saurophaganax was the largest carnivore found in the Morrison Formation, bigger than both its contemporaries Torvosaurus tanneri and Allosaurus fragilis , reaching 10.5 metres (34 ft) in length and 2.7–3.8 metric tons (3.0–4.2 short tons) in body mass. [13] [14] [15] [16]

Paleoecology

Life reconstruction Saurophaganax restoration 2019 by Mario Lanzas.jpg
Life reconstruction

The Morrison Formation is a sequence of shallow marine and alluvial sediments which, according to radiometric dating, ranges between 156.3 million years old (Ma) at its base, [17] to 146.8 million years old at the top, [18] which places it in the late Oxfordian, Kimmeridgian, and early Tithonian stages of the Late Jurassic period. This formation is interpreted as a semiarid environment with distinct wet and dry seasons. The Morrison Basin where dinosaurs lived, stretched from New Mexico to Alberta and Saskatchewan, and was formed when the precursors to the Front Range of the Rocky Mountains started pushing up to the west. The deposits from their east-facing drainage basins were carried by streams and rivers and deposited in swampy lowlands, lakes, river channels and floodplains. [19] This formation is similar in age to the Solnhofen Limestone Formation in Germany and the Tendaguru Formation in Tanzania. The fossils known of Saurophaganax (both the possible material from New Mexico and the Oklahoma material) are known from the Brushy Basin Member, which is the latest part of the Morrison Formation, suggesting that this genus was either always uncommon or that it first appeared rather late in the Jurassic. Because of the rarity of discovered remains, not much about its behavior is known. [20]

Mounted skeleton posed attacking a Diplodocus, New Mexico Museum of Natural History & Science. Saurophaganax VS Diplodocus.jpg
Mounted skeleton posed attacking a Diplodocus , New Mexico Museum of Natural History & Science.

The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs such as Barosaurus , Apatosaurus , Brontosaurus , Camarasaurus , Diplodocus , and Brachiosaurus . Dinosaurs that lived alongside Saurophaganax, and may have served as prey, included the herbivorous ornithischians Camptosaurus , Dryosaurus , Stegosaurus , and Nanosaurus . Predators in this paleoenvironment included the theropods Torvosaurus , Ceratosaurus , Marshosaurus , Stokesosaurus , Ornitholestes , and [21] Allosaurus , which accounted for 70 to 75% of theropod specimens and was at the top trophic level of the Morrison food web. [22] Other vertebrates that shared this paleoenvironment included ray-finned fishes, frogs such as Eobatrachus , salamanders, turtles, sphenodonts, lizards, terrestrial and aquatic crocodylomorphs like Goniopholis , and several species of pterosaur like Kepodactylus . Early mammals were present in this region, such as Fruitafossor , docodonts, multituberculates, symmetrodonts, and triconodonts. The flora of the period has been revealed by fossils of green algae, fungi, mosses, horsetails, cycads, ginkgoes, and several families of conifers. Vegetation varied from river-lining forests of tree ferns, and ferns (gallery forests), to fern savannas with occasional trees such as the Araucaria -like conifer Brachyphyllum . [23] In Oklahoma, Stovall unearthed a considerable number of Apatosaurus specimens, which may have represented possible prey for a large theropod like Saurophaganax.

Bite marks on Allosaurus and Mymoorapelta remains were found among other bones with feeding traces in the Upper Jurassic Mygatt-Moore Quarry. Unlike the others, these have left striations that, when measured to determine denticle width, produced tooth and body size extrapolations greater than any known specimen of Allosaurus or Ceratosaurus, the two large predators known for osteological remains from the quarry. The extrapolations are instead coherent either with an unusually large specimen of Allosaurus, or a separate large taxon like Torvosaurus or Saurophaganax, both of which are not known from the quarry. The result either increases the known diversity of the site based on ichnological evidence alone, or represents powerful evidence of cannibalism in Allosaurus. Based on the position and nutrient value associated with the various skeletal elements with bite marks, it is predicted that while Mymoorapelta was either predated upon or scavenged shortly after death, Allosaurus was scavenged some time after death. [24]

Related Research Articles

<i>Allosaurus</i> Extinct genus of carnosaurian theropod dinosaur

Allosaurus is an extinct genus of large carnosaurian theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic period. The name "Allosaurus" means "different lizard", alluding to its unique concave vertebrae. It is derived from the Greek words ἄλλος and σαῦρος. The first fossil remains that could definitively be ascribed to this genus were described in 1877 by famed paleontologist Othniel Charles Marsh. As one of the first well-known theropod dinosaurs, it has long attracted attention outside of paleontological circles.

<i>Camarasaurus</i> Camarasaurid sauropod dinosaur genus from Late Jurassic Period

Camarasaurus was a genus of quadrupedal, herbivorous dinosaurs and is the most common North American sauropod fossil. Its fossil remains have been found in the Morrison Formation, dating to the Late Jurassic epoch, between 155 and 145 million years ago.

<i>Ceratosaurus</i> Genus of theropod dinosaur from the Late Jurassic period

Ceratosaurus was a carnivorous theropod dinosaur that lived in the Late Jurassic period. The genus was first described in 1884 by American paleontologist Othniel Charles Marsh based on a nearly complete skeleton discovered in Garden Park, Colorado, in rocks belonging to the Morrison Formation. The type species is Ceratosaurus nasicornis.

<i>Acrocanthosaurus</i> Genus of carcharodontosaurid dinosaur from the Early Cretaceous

Acrocanthosaurus is a genus of carcharodontosaurid dinosaur that existed in what is now North America during the Aptian and early Albian stages of the Early Cretaceous, from 113 to 110 million years ago. Like most dinosaur genera, Acrocanthosaurus contains only a single species, A. atokensis. It had a continent-wide range, with fossil remains known from the U.S. states of Oklahoma, Texas, and Wyoming in the west, and Maryland in the east.

<span class="mw-page-title-main">Morrison Formation</span> Rock formation in the western United States

The Morrison Formation is a distinctive sequence of Upper Jurassic sedimentary rock 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 gray, greenish gray, or red. Most of the fossils occur in the green siltstone beds and lower sandstones, relics of the rivers and floodplains of the Jurassic period.

<i>Torvosaurus</i> Megalosaurid theropod dinosaur genus from Late Jurassic Period

Torvosaurus is a genus of large megalosaurine theropod dinosaur that lived approximately 165 to 148 million years ago during the Callovian to Tithonian ages of the late Middle and Late Jurassic period in what is now Colorado, Portugal, Germany, and possibly England, Spain, Tanzania, and Uruguay. It contains two currently recognized species, Torvosaurus tanneri and Torvosaurus gurneyi, plus a third unnamed species from Germany.

<i>Barosaurus</i> Diplodocid sauropod dinosaur genus from Upper Jurassic Period

Barosaurus was a giant, long-tailed, long-necked, plant-eating sauropod dinosaur closely related to the more familiar Diplodocus. Remains have been found in the Morrison Formation from the Upper Jurassic Period of Utah and South Dakota. It is present in stratigraphic zones 2–5.

<i>Dryosaurus</i> Extinct genus of dinosaurs

Dryosaurus is a genus of an ornithopod dinosaur that lived in the Late Jurassic period. It was an iguanodont. Fossils have been found in the western United States and were first discovered in the late 19th century. Valdosaurus canaliculatus and Dysalotosaurus lettowvorbecki were both formerly considered to represent species of Dryosaurus.

Coelurus is a genus of coelurosaurian dinosaur from the Late Jurassic period. The name means "hollow tail", referring to its hollow tail vertebrae. Although its name is linked to one of the main divisions of theropods (Coelurosauria), it has historically been poorly understood, and sometimes confused with its better-known contemporary Ornitholestes. Like many dinosaurs studied in the early years of paleontology, it has had a confusing taxonomic history, with several species being named and later transferred to other genera or abandoned. Only one species is currently recognized as valid: the type species, C. fragilis, described by Othniel Charles Marsh in 1879. It is known from one partial skeleton found in the Morrison Formation of Wyoming, United States. It was a small bipedal carnivore with elongate legs.

<i>Stokesosaurus</i> Extinct genus of dinosaurs

Stokesosaurus is a genus of small, carnivorous early tyrannosauroid theropod dinosaurs from the late Jurassic period of Utah, United States.

<i>Szechuanosaurus</i> Extinct genus of dinosaurs

Szechuanosaurus is an extinct genus of carnivorous theropod dinosaur from the Late Jurassic. Fossils referred to the genus have been found in China, Asia in the Oxfordian-?Tithonian. Its type species is based on several undiagnostic teeth from the Kuangyuan Series. Additional possible specimens of Szechuanosaurus were also reported from the Kalaza Formation, also located in China.

<i>Koparion</i> Extinct genus of dinosaurs

Koparion is a genus of small coelurosaurian theropod dinosaur, from the late Jurassic Period, of Utah. It contains the single named species Koparion douglassi which is known only from a single isolated tooth.

<i>Nanosaurus</i> Extinct genus of dinosaurs

Nanosaurus is the name given to a genus of neornithischian dinosaur that lived about 155 to 148 million years ago, during the Late Jurassic-age. Its fossils are known from the Morrison Formation of the south-western United States. The type and only species, Nanosaurus agilis, was described and named by Othniel Charles Marsh in 1877. The taxon has a complicated taxonomic history, largely the work of Marsh and Peter M. Galton, involving the genera Laosaurus, Hallopus, Drinker, Othnielia, and Othnielosaurus, the latter three now being considered to be synonyms of Nanosaurus. It had historically been classified as a hypsilophodont or fabrosaur, types of generalized small bipedal herbivore, but more recent research has abandoned these groupings as paraphyletic and Nanosaurus is today considered a basal member of Neornithischia.

<i>Marshosaurus</i> Extinct genus of dinosaurs

Marshosaurus is a genus of medium-sized carnivorous theropod dinosaur, belonging to the Megalosauroidea, from the Late Jurassic Morrison Formation of Utah and possibly Colorado.

<i>Lourinhanosaurus</i> Extinct genus of dinosaurs

Lourinhanosaurus was a genus of carnivorous theropod dinosaur that lived during the Late Jurassic Period (Kimmeridgian/Tithonian) in Portugal. It is one of many large predators discovered at the Lourinhã Formation and probably competed with coeval Torvosaurus gurneyi, Allosaurus europaeus, and Ceratosaurus.

<span class="mw-page-title-main">Dry Mesa Quarry</span>

The Dry Mesa Dinosaur Quarry is situated in southwestern Colorado, United States, near the town of Delta. Its geology forms a part of the Morrison Formation and has famously yielded a great diversity of animal remains from the Jurassic Period, among them Ceratosaurus, Supersaurus, and Torvosaurus. The quarry is found within the Uncompahgre National Forest.

<span class="mw-page-title-main">Lourinhã Formation</span> Late Jurassic geological formation in Portugal

The Lourinhã Formation is a fossil rich geological formation in western Portugal, named for the municipality of Lourinhã. The formation is mostly Late Jurassic in age (Kimmeridgian/Tithonian), with the top of the formation extending into the earliest Cretaceous (Berriasian). It is notable for containing a fauna especially similar to that of the Morrison Formation in the United States and a lesser extent to the Tendaguru Formation in Tanzania. There are also similarities to the nearby Villar del Arzobispo Formation and Alcobaça Formation. The stratigraphy of the formation and the basin in general is complex and controversial, with the constituent member beds belonging to the formation varying between different authors.

<i>Camarasaurus lentus</i> Species of sauropod

Camarasaurus lentus is an extinct species of sauropod dinosaur that lived during the Jurassic period in what is now the western United States. It is one of the four valid species of the well-known genus Camarasaurus. C. lentus fossils have been found in Wyoming, Colorado, and Utah. It is the species of Camarasaurus found in Dinosaur National Monument and the middle layers of the Morrison Formation. Camarasaurus lentus is among the best-known sauropod species, with many specimens known. A juvenile specimen of C. lentus, CM 11338, is the most complete sauropod fossil ever discovered.

<i>Uteodon</i> Genus of reptiles (fossil)

Uteodon is a genus of herbivorous iguanodontian dinosaur. It is a basal iguanodontian which lived during the late Jurassic period in what is now Uintah County, Utah. It is known from the middle of the Brushy Basin Member, Morrison Formation. The genus was named by Andrew T. McDonald in 2011 and the type species is U. aphanoecetes.

References

  1. ↑ Turner, C.E. and Peterson, F., (1999). "Biostratigraphy of dinosaurs in the Upper Jurassic Morrison Formation of the Western Interior, U.S.A." Pp. 77–114 in Gillette, D.D. (ed.), Vertebrate Paleontology in Utah. Utah Geological Survey Miscellaneous Publication 99-1.
  2. ↑ Glut, Donald F. (1997). "Saurophagus". Dinosaurs: The Encyclopedia. Jefferson, North Carolina: McFarland & Co. pp. 793–794. ISBN   978-0-89950-917-4.
  3. ↑ Ray, G.E., 1941, "Big for his day", Natural History48: 36–39
  4. ↑ Lucas, S.G., Mateer, N.J., Hunt, A.P., and O'Neill, F.M., 1987, "Dinosaurs, the age of the Fruitland and Kirtland Formations, and the Cretaceous-Tertiary boundary in the San Juan Basin, New Mexico", p. 35-50. In: Fassett, J.E. and Rigby, J.K., Jr. (eds.), The Cretaceous-Tertiary boundary in the San Juan and Raton Basins, New Mexico and Colorado. GSA Special Paper 209
  5. ↑ W. Swainson and J. Richardson, 1831, Fauna boreali-americana, or, The zoology of the northern parts of British America: containing descriptions of the objects of natural history collected on the late northern land expeditions under command of Captain Sir John Franklin, R.N. Part 2, Birds, London, J. Murray
  6. ↑ Chure, D., 2000, A new species of Allosaurus from the Morrison Formation of Dinosaur National Monument (Utah-Colorado) and a revision of the theropod family Allosauridae. Ph.D. dissertation, Columbia University, pp. 1–964
  7. 1 2 3 Chure, Daniel J. (1995). "A reassessment of the gigantic theropod Saurophagus maximus from the Morrison Formation (Upper Jurassic) of Oklahoma, USA". In A. Sun; Y. Wang (eds.). Sixth Symposium on Mesozoic Terrestrial Ecosystems and Biota, Short Papers. Beijing: China Ocean Press. pp. 103–106.
  8. ↑ "OK State Symbols". OkInsider.com. Oklahoma Publishing Today. 2006. Archived from the original on August 7, 2007. Retrieved December 27, 2007.
  9. 1 2 Foster, John (2007). Jurassic West: the Dinosaurs of the Morrison Formation and Their World. Bloomington, Indiana:Indiana University Press. p. 117.
  10. ↑ Smith, David K. (1998). "A morphometric analysis of Allosaurus". Journal of Vertebrate Paleontology. 18 (1): 126–142. Bibcode:1998JVPal..18..126S. doi:10.1080/02724634.1998.10011039.
  11. ↑ Holtz, Thomas R. Jr.; Molnar, Ralph E.; Currie, Philip J. (2004). Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 71–110. ISBN   978-0-520-24209-8.
  12. ↑ Carrano, Matthew T.; Benson, Roger B. J.; Sampson, Scott D. (June 1, 2012). "The phylogeny of Tetanurae (Dinosauria: Theropoda)". Journal of Systematic Palaeontology. 10 (2): 211–300. Bibcode:2012JSPal..10..211C. doi:10.1080/14772019.2011.630927. ISSN   1477-2019. S2CID   85354215.
  13. ↑ Farlow, J. O.; Coroian, D.; Currie, P.J.; Foster, J.R.; Mallon, J.C.; Therrien, F. (2022). ""Dragons" on the landscape: Modeling the abundance of large carnivorous dinosaurs of the Upper Jurassic Morrison Formation (USA) and the Upper Cretaceous Dinosaur Park Formation (Canada)". The Anatomical Record. 306 (7): 1669–1696. doi: 10.1002/ar.25024 . PMID   35815600.
  14. ↑ Paul, G. S. (2010). The Princeton Field Guide to Dinosaurs. Princeton University Press. pp.  96. ISBN   978-0-691-13720-9.
  15. ↑ Persons, S. W.; Currie, P. J.; Erickson, G. M. (2020). "An Older and Exceptionally Large Adult Specimen of Tyrannosaurus rex". The Anatomical Record. 303 (4): 656–672. doi: 10.1002/ar.24118 . ISSN   1932-8486. PMID   30897281.
  16. ↑ Campione, Nicolás E.; Evans, David C. (2020). "The accuracy and precision of body mass estimation in non-avian dinosaurs". Biological Reviews. 95 (6): 1759–1797. doi: 10.1111/brv.12638 . ISSN   1469-185X. PMID   32869488. S2CID   221404013.
  17. ↑ Trujillo, K.C.; Chamberlain, K.R.; Strickland, A. (2006). "Oxfordian U/Pb ages from SHRIMP analysis for the Upper Jurassic Morrison Formation of southeastern Wyoming with implications for biostratigraphic correlations". Geological Society of America Abstracts with Programs. 38 (6): 7.
  18. ↑ Bilbey, S.A. (1998). "Cleveland-Lloyd Dinosaur Quarry – age, stratigraphy and depositional environments". In Carpenter, K.; Chure, D.; Kirkland, J.I. (eds.). The Morrison Formation: An Interdisciplinary Study. Modern Geology 22. Taylor and Francis Group. pp. 87–120. ISSN   0026-7775.
  19. ↑ Russell, Dale A. (1989). An Odyssey in Time: Dinosaurs of North America. Minocqua, Wisconsin: NorthWord Press. pp. 64–70. ISBN   978-1-55971-038-1.
  20. ↑ Foster, J. (2020). Jurassic West, Second Edition: The Dinosaurs of the Morrison Formation and Their World (Life of the Past). Indiana University Press. ISBN   9780253051578.
  21. ↑ Foster, J. (2007). "Appendix." Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indiana University Press. pp. 327–329.
  22. ↑ Foster, John R. (2003). Paleoecological Analysis of the Vertebrate Fauna of the Morrison Formation (Upper Jurassic), Rocky Mountain Region, U.S.A. New Mexico Museum of Natural History and Science Bulletin, 23. Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. p. 29.
  23. ↑ Carpenter, Kenneth (2006). "Biggest of the big: a critical re-evaluation of the mega-sauropod Amphicoelias fragillimus". In Foster, John R.; Lucas, Spencer G. (eds.). Paleontology and Geology of the Upper Jurassic Morrison Formation. New Mexico Museum of Natural History and Science Bulletin, 36. Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. pp. 131–138.
  24. ↑ Drumheller, Stephanie K.; McHugh, Julia B.; Kane, Miriam; Riedel, Anja; D’Amore, Domenic C. (May 27, 2020). "High frequencies of theropod bite marks provide evidence for feeding, scavenging, and possible cannibalism in a stressed Late Jurassic ecosystem". PLOS ONE. 15 (5): e0233115. Bibcode:2020PLoSO..1533115D. doi: 10.1371/journal.pone.0233115 . ISSN   1932-6203. PMC   7252595 . PMID   32459808.

Sources

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.