Arundel Formation

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Template:Short description Script error: No such module "Infobox".Template:Template otherScript error: No such module "check for unknown parameters".

The Arundel Formation, also known as the Arundel Clay, is a clay-rich sedimentary rock formation, within the Potomac Group, found in Maryland[1] of the United States of America. It dates to the Early Cretaceous, and is of late Aptian or (more likely) early Albian age.[2] This rock unit had been economically important as a source of iron ore, but is now more notable for its dinosaur fossils.[3] It is named for Anne Arundel County, Maryland.[4]

It consists of clay lenses within depressions in the upper part of the Patuxent Formation that may represent oxbow swamp facies.[3] The Arundel Formation contains a high number of terrestrial fauna, indicating that it was deposited in a freshwater fluvial environment, likely representing slow-moving river channels and oxbows. The Arundel Formation is the only major source for Early Cretaceous terrestrial vertebrates in eastern North America, and provides the best record of the dinosaurs that inhabited the region at the time.[2]

Vertebrate paleofauna

Dinosaurs present include the large theropod Acrocanthosaurus,[5][6][7] the giant sauropod Astrodon, the possible ornithischian Magulodon,[5] the poorly known theropods "Allosaurus" medius, "Creosaurus" potens, and "Coelurus" gracilis, the ornithomimosaurian "Dryosaurus" grandis,[8] as well as another indeterminate ornithomimosaurian (though it most likely is Nedcolbertia),[9] the nodosaurid Priconodon,[10] a possible basal ceratopsian,[11] and potentially the ornithopod Tenontosaurus.[3] Other vertebrates are not as well known from the formation, but include a freshwater shark, a lungfish,[12] at least three genera of turtles, and several crocodilians.[3]

The dinosaurian fauna of the Arundel Formation is very similar to that found in the concurrent, more comprehensive geological formations from further west (i.e. the Antlers, Cloverly, and Cedar Mountain Formations). This supports the idea of a largely homogenous dinosaur fauna stretching across North America during the Early Cretaceous, until the formation of the Western Interior Seaway divided the continent and led to major faunal changes on both halves.[13] In contrast, among other vertebrate taxa, there are major differences between the Arundel and these western formations; in the Arundel, crocodylomorph and shark remains are far more common than those of bony fishes, whereas the opposite is true for the western formations. This may owe to differing environmental conditions on the Atlantic coast compared to the North American interior.[2]

Cartilaginous fish

Cartilaginous fish reported from the Arundel Formation
Genus Species Location Stratigraphic position Material Notes Images
Egertonodus E. basanus Teeth, spine A hybodont shark. File:Hybodus fraasi (fossil).jpg
Planohybodus P. ensis Teeth A hybodont shark, formerly placed in Hybodus. File:FOS763.jpg

Ray-finned fish

Ray-finned fish reported from the Arundel Formation
Genus Species Location Stratigraphic position Material Notes Images
cf. Lepidotes Teeth, jaw A semionotid. File:Lepidotes notopterus.jpg
cf. Vidalamiinae Teeth An amiid.

Lobe-finned fish

Lobe-finned fish reported from the Arundel Formation
Genus Species Location Stratigraphic position Material Notes Images
Ceratodus C. kranzi Tooth plate A ceratodontid lungfish.[14] File:Ceratodus.jpg

Reptiles

Dinosaurs

Template:Paleobiota-key-compact

Dinosaurs reported from the Arundel Formation
Genus Species Location Stratigraphic position Material Notes Images
Acrocanthosaurus[5][7] A. cf. atokensis[7] "Teeth",[5] "incomplete skeleton"[7] A large carcharodontosaurid theropod. Presence long suspected but uncertain, but confirmed in 2024 following the discovery of more complete remains.[7]
File:Acrocanthosaurus restoration.jpg
Acrocanthosaurus

Allosaurus[15]

"A." medius[15]

"Tooth."[16]

An indeterminate theropod tooth.

File:Astrodon johnstoni.jpg
Astrodon
File:Deinonychus ewilloughby.png
Deinonychus
File:Tenontosaurus BW.jpg
Tenontosaurus

Astrodon[17]

A. johnstoni[17]

"Tooth."[19]

"Capitalsaurus"[20]

"C." potens

"Vertebra."[16]

A neotheropod possibly synonymous with Acrocanthosaurus.[21]

Coelurus[15]

"C." gracilis

"Manual ungual and teeth."[16]

A dromaeosaurid synonymous with Deinonychus.[21]

Creosaurus[15]

"C." potens[15]

Reclassified as "Capitalsaurus" potens

cf. Deinonychus[15]

Indeterminate[15]

A dromaeosaurid

Dryosaurus

"D." grandis

"Limb elements."[22]

An indeterminate member of Ornithomimosauria.

Magulodon[23]

M. muirkirkensis[23]

"Tooth"[23]

Likely an ornithischian, this genus is a nomen nudum that has not been formally published.

Neoceratopsia indet.[11] Indeterminate[11] "Teeth"[11] An indeterminate member of Neoceratopsia. Initially believed to have belonged to an indeterminate member of Dryosauridae or the genus Tenontosaurus.

Ornithomimus

"O." affinis

Junior synonym of "Dryosaurus" grandis

Pleurocoelus[15]

P. altus[15]

"Tibia [and] fibula."[24]

A sauropod synonymous with Astrodon.

P. nanus[15]

Priconodon[15]

P. crassus[15]

"Teeth, tibia."[25]

A large nodosaurid.
cf. Richardoestesia[2] Indeterminate[2] "Teeth" A small theropod.

cf. Tenontosaurus[26]

Indeterminate[26]

Pterosaurs

Unassigned pteradactyloid tracks.[27] Template:Paleobiota-key-compact

Pterosaurs of the Arundel Formation
Genus Species Location Stratigraphic position Abundance Notes Images

Pteraichnus[27]

[27]

Turtles

Turtles reported from the Arundel Formation
Genus Species Location Stratigraphic position Material Notes Images
Arundelemys A. dardeni "A single, incomplete skull lacking the lower jaws and cheek region" A baenid.
Glyptops G. caelatus "Carapace fragments probably pertaining to a single individual" A pleurosternid. File:Glyptops depressus Hay, 1908.jpg
Naomichelys N. sp. "Shell fragments" A helochelydrid. File:FMNH Naomichelys.jpg

Crocodylomorphs

Crocodylomorphs reported from the Arundel Formation
Genus Species Location Stratigraphic position Material Notes Images
cf. Bernissartiidae indet. Indeterminate Tooth A likely bernissartiid.
cf. Goniopholididae indet. Indeterminate Scutes, teeth A likely goniopholidid, the most common crocodylomorph from the formation.
cf. Pholidosauridae indet. Indeterminate Teeth A likely pholidosaurid.

Mammals

Mammals reported from the Arundel Formation
Genus Species Location Stratigraphic position Material Notes Images
Argillomys A. marylandensis Molar tooth A multituberculate.
Arundelconodon A. hottoni Dentary with teeth A triconodontid.

Other fossils

William Bullock Clark (1897) described lignitized trunks of trees often found in upright positions with their roots still intact.[28]

G. J. Brenner (1963) described spores and pollen within the formation.[29]

See also

Script error: No such module "Portal".

Footnotes

<templatestyles src="Reflist/styles.css" />

  1. ↑ a b Script error: No such module "citation/CS1".
  2. ↑ a b c d e f g h i j k l m n o p q r s Script error: No such module "citation/CS1".
  3. ↑ a b c d Script error: No such module "citation/CS1".
  4. ↑ Script error: No such module "citation/CS1".
  5. ↑ a b c d Script error: No such module "citation/CS1".
  6. ↑ Script error: No such module "citation/CS1".
  7. ↑ a b c d e Script error: No such module "Citation/CS1".
  8. ↑ Script error: No such module "Citation/CS1".
  9. ↑ Script error: No such module "Citation/CS1".
  10. ↑ Script error: No such module "citation/CS1".
  11. ↑ a b c d Script error: No such module "citation/CS1".
  12. ↑ Frederickson, J. A., Lipka, T. R., & Cifelli, R. L. (2016). A new species of the lungfish Ceratodus (Dipnoi) from the Early Cretaceous of the eastern USA. Journal of Vertebrate Paleontology, e1136316.
  13. ↑ Script error: No such module "Citation/CS1".
  14. ↑ Script error: No such module "Citation/CS1".
  15. ↑ a b c d e f g h i j k l m n o p q r s t u v "3.25 Maryland, United States; 1. Arundel Clay," in Weishampel, et al. (2004). Page 556.
  16. ↑ a b c "Table 4.1," in Weishampel, et al. (2004). Page 78.
  17. ↑ a b "3.25 Maryland, United States; 1. Arundel Clay" and "3.34 Washington D. C., United States; 1. Arundel Clay," in Weishampel, et al. (2004). Page 556.
  18. ↑ "3.34 Washington D. C., United States; 1. Arundel Clay," in Weishampel, et al. (2004). Page 556.
  19. ↑ "Table 13.1," in Weishampel, et al. (2004). Page 270.
  20. ↑ Kranz, D. 1998. Mostly Dinosaurs: A Review of the Vertebrates of the Potomac Group (Aptian Arundel Formation), USA, in Lucas, Kirkland and Estep, eds., 1998: 235-238.
  21. ↑ a b Script error: No such module "Citation/CS1".
  22. ↑ "Table 6.1," in Weishampel, et al. (2004). Page 139.
  23. ↑ a b c d Kranz, P. (1996). Notes on the sedimentary iron ores of Maryland and their dinosaurian faunas. Maryland Geological Survey Special Publications 3:87–115.
  24. ↑ "Table 13.1," in Weishampel, et al. (2004). Page 266.
  25. ↑ "Table 17.1," in Weishampel, et al. (2004). Page 368.
  26. ↑ a b Listed as "?Tenontosaurus sp." in "3.25 Maryland, United States; 1. Arundel Clay," in Weishampel, et al. (2004). Page 556.
  27. ↑ a b c Lockley, M.; Harris, J.D.; and Mitchell, L. 2008. "A global overview of pterosaur ichnology: tracksite distribution in space and time." Zitteliana. B28. p. 187-198. Template:Catalog lookup linkScript error: No such module "check isxn".Script error: No such module "check isxn".Script error: No such module "check isxn".Script error: No such module "check isxn".Script error: No such module "check isxn".Script error: No such module "check isxn".Script error: No such module "check isxn".Script error: No such module "check isxn".Script error: No such module "check isxn"..
  28. ↑ Cite error: Script error: No such module "Namespace detect".Script error: No such module "Namespace detect".
  29. ↑ Brenner, Gilbert J., 1963, The spores and pollen of the Potomac Group of Maryland: Maryland Geological Survey Bulletin, no. 27, 215 p. [1]

Script error: No such module "Check for unknown parameters".

References

  • Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. Template:ISBN.

External links

Template:Sister project

Script error: No such module "Coordinates".

Retrieved from "http://debianws.lexgopc.com/wiki143/index.php?title=Arundel_Formation&oldid=5587828"