Camarasaurus lentus
Camarasaurus lentus | |
---|---|
![]() | |
CM 11338, a juvenile Camarasaurus lentus, on display at the Carnegie Museum. | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | †Sauropodomorpha |
Clade: | †Sauropoda |
Clade: | †Macronaria |
Family: | †Camarasauridae |
Genus: | †Camarasaurus |
Species: | †C. lentus
|
Binomial name | |
†Camarasaurus lentus (Marsh, 1889)
| |
Synonyms | |
|
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.
Description
[edit]Like other sauropods, Camarasaurus lentus was a large, long-necked quadruped. It closely resembled other species of Camarasaurus in its anatomy, and in particular was very similar to C. supremus.[1] It was of moderate size for the genus, being similar in size to C. grandis, 20% smaller than C. supremus, and slightly larger than C. lewisi.[2] Gregory S. Paul estimated its length as 15 metres (49 ft) and mass as 15 tonnes.[3]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/6/68/Camarasaurus_lentus_USNM.jpg/232px-Camarasaurus_lentus_USNM.jpg)
The skull of C. lentus was typical for Camarasaurus; distinguishing traits between the skulls of different Camarasaurus species are not known.
The anterior dorsal vertebrae of C. lentus have low, broad neural arches, similar to C. supremus but unlike the taller, narrower anterior dorsal neural arches of C. grandis. The anterior caudal neural spines of C. lentus lack the abrupt, T-shaped expansion found in other species of the genus.
The pelvis of C. lentus is rotated relative to the sacrum so that the preacetabular blade of the ilium points slightly downward, as in C. lewisi, but seemingly unlike C. supremus.[4]
C. lentus may exhibit sexual dimorphism in the structure of its dorsal vertebrae.[5]
History of study
[edit]The holotype specimen of Camarasaurus lentus was collected from Quarry 13 at Como Bluff, Wyoming,[6] and stored at the Peabody Museum of Natural History under the catalog number YPM 1910. The specimen consisted of a partial posterior skull, mandibles, and the majority of the postcranial skeleton, the most complete Camarasaurus skeleton found during the Bone Wars. In 1889, Othniel Marsh described it as a new species, which he named Morosaurus lentus. The skeleton was later mounted in the Peabody Museum Hall in the 1930s, and remained mounted until the 2020s. Marsh used the name Morosaurus for many species now assigned to Camarasaurus. Camarasaurus had been named by his rival Edward Drinker Cope, and the two genera were recognized as synonymous in the early 20th century. C. lentus was the third of the four currently recognized valid species of Camarasaurus to be named. The holotype was later mounted for display at the Peabody Museum in 1930.[7]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/8/8f/Camarasaurus_lentus_%28sauropod_dinosaur%29_%28Morrison_Formation%2C_Upper_Jurassic%3B_Carnegie_Quarry%2C_Dinosaur_National_Monument%2C_Utah%2C_USA%29_4_%2848696432982%29.jpg/193px-Camarasaurus_lentus_%28sauropod_dinosaur%29_%28Morrison_Formation%2C_Upper_Jurassic%3B_Carnegie_Quarry%2C_Dinosaur_National_Monument%2C_Utah%2C_USA%29_4_%2848696432982%29.jpg)
In 1909, the Carnegie Museum of Natural History paleontologist Earl Douglass discovered a rich fossil site in Utah, which became protected as part of Dinosaur National Monument in 1915. Excacations at the site lead to the discovery of much additional C. lentus material. A nearly complete specimen of a juvenile C. lentus, CM 11338, was also found at the site by Douglass in 1909, and described by Charles W. Gilmore in 1925.[8] It is the most complete sauropod fossil ever discovered, and nearly every element was in articulation.[9] Later in 1918, the Carnegie Museum collected another complete and articulated skeleton of an adult (USNM V 13786) of C. lentus that was later transferred to the National Museum of Natural History in 1934. The skeleton is now mounted in the NMNH fossil hall. In 1919, the Carnegie Museum's director William Jacob Holland named a new species, Uintasaurus douglassi, on the basis of several cervical vertebrae from the quarry; this species was synonymized with C. lentus in 1958.[10][11] In 1950, another specimen consisting of an anterior dorsal vertebra from Dinosaur National Monument was named as a new species, Camarasaurus annae;[12] this too is now regarded as synonymous with C. lentus.
Additional specimens of C. lentus were discovered by the Wyoming Dinosaur Center in 1992, and are among the most complete adult specimens of the species.[13]
Fossils
[edit]Fossils of Camarasaurus lentus are found in the Morrison Formation. Though most specimens of Camarasaurus cannot be identified to species, C. lentus is the most abundant among specimens that can; 11.1% of Camarasaurus specimens have been assigned to C. lentus.[14] It is among the most well-known sauropod species, with exceptionally complete remains, including the aforementioned CM 11338. Two of the fourteen known sauropod specimens to preserve complete necks belong to C. lentus, and the holotype of C. lentus has a nearly complete neck as well.[15]
Most Camarasaurus specimens from Dinosaur National Monument have been referred to C. lentus.[1] The "Wall of Bones" at the Quarry Visitor Center includes specimens of C. lentus still preserved in the rock. A mostly complete but undescribed specimen of C. lentus from Dinosaur National Monument is displayed at the Smithsonian.
Classification
[edit]The phylogenetic position of Camarasaurus within Eusauropoda, simplified from Mannion et al. 2019[16] |
As a species of Camarasaurus, C. lentus belongs to Camarasauridae, a family of basal macronarian sauropods. It is one of four species of Camarasaurus widely regarded as valid, alongside C. supremus, C. grandis, and C. lewisi.
Camarasaurus lentus has two junior subjective synonyms, Uintasaurus douglassi and Camarasaurus annae.[17] Uintasaurus douglassi is the type species of Uintasaurus.
Due to the close similarity between C. lentus and C. supremus, it has been at times debated whether C. lentus is distinct from the latter.[18] Takehito Ikejiri has noted that, as the holotype of C. lentus is a juvenile, the features used to distinguish between different species in adults of the genus cannot be identified, and the specimen came from a part of the Morrison Formation where C. grandis is more typically found. As such, the holotype of C. lentus may actually be a specimen of C. grandis, rather than belonging to the species conventionally known as C. lentus.[17]
Paleobiology
[edit]Ontogeny
[edit]Camarasaurus lentus is known from several growth stages, so its ontogeny is relatively well-understood. As C. lentus grew, its neck lengthened.[19] The extent of neural spine bifurcation may have increased with age; in the younger CM 11338, the first cervical vertebra to have a partially bifurcated neural spine is the seventh, whereas in the older YPM 1910, bifurcation begins with the fifth.[20] The limb bones show nearly isometric growth, but become slightly slenderer with age.[21]
Paleoecology
[edit]Camarasaurus lentus lived during the late Kimmeridgian and early Tithonian ages of the Jurassic in what is now the western United States. The Dinosaur Quarry of Dinosaur National Monument, one of the sites where C. lentus has been found, dates to between 150.91 and 150.04 million years ago.[22] The range of C. lentus includes what is now Utah, Colorado, Wyoming, and possibly South Dakota.[17][23] Camarasaurus lentus fossils have been found in systems tract B4 of the Morrison Formation,[24] strata from which have been dated to times ranging from 151.88 Ma to 149.1 Ma.[25] At this time, a large lake, Lake T'oo'dichi', covered an area around what is now the Four Corners area of the western United States.[25]
C. lentus is one of the sauropod species present at the Cleveland-Lloyd Dinosaur Quarry,[26][27] a controversial site known for its dense accumulation of dinosaur bones and disproportionate abundance of the predatory theropod Allosaurus. One interpretation of the site is that it represents a drought assemblage.[28]
At the Cleveland-Lloyd Dinosaur Quarry, C. lentus has been found to coexist an unidentified apatosaurine, an unidentified diplodocine,[29] Stegosaurus, Camptosaurus, Allosaurus, Ceratosaurus, Stokesosaurus, Marshosaurus, and Torvosaurus.[27] At Carnegie Quarry, it has been found to coexist with Apatosaurus louisae, Diplodocus hallorum, Barosaurus, Stegosaurus, Dryosaurus elderae, Camptosaurus aphanoecetes, Allosaurus, Ceratosaurus, Torvosaurus, and Marshosaurus.[30] Possible Haplocanthosaurus bones have been reported from Carnegie Quarry as well.[31] The WDC specimens of C. lentus, the geologically youngest known of the species,[32] were found at the same site as the apatosaurine skeleton NSMT-PV 20375,[33] which may represent an as-yet unnamed genus and species of sauropod.[34]
C. lentus may be descended from the earlier species C. grandis, and the later species C. supremus may be a descendant of C. lentus.[3] C. supremus first appears in the fossil record shortly before C. lentus disappears.[35]
References
[edit]- ^ a b Foster 2020, p. 275.
- ^ Ikejiri 2005, p. 375.
- ^ a b Paul 2016, p. 220.
- ^ McIntosh et al. 1996, p. 93.
- ^ Ikejiri, Tidwell & Trexler 2005, pp. 162–163.
- ^ Foster 2020, p. 94.
- ^ Lull 1930.
- ^ Gilmore 1925.
- ^ Chure & McIntosh 1990, p. 35.
- ^ Holland 1919.
- ^ White 1958.
- ^ Ellinger 1950.
- ^ Ikejiri, Tidwell & Trexler 2005, pp. 155–156.
- ^ Woodruff & Foster 2017, p. 48.
- ^ Taylor 2022.
- ^ Mannion et al. 2019.
- ^ a b c Ikejiri 2005.
- ^ Madsen, McIntosh & Berman 1995, p. 36.
- ^ Ikejiri, Tidwell & Trexler 2005, p. 173.
- ^ Wedel & Taylor 2013, p. 12.
- ^ Ikejiri, Tidwell & Trexler 2005, p. 176.
- ^ Maidment, Balikova & Muxworthy 2017.
- ^ Woodruff & Foster 2017, p. 53.
- ^ Tschopp et al. 2019.
- ^ a b Maidment & Muxworthy 2019.
- ^ Ikejiri 2005, p. 369.
- ^ a b Gates 2005, p. 365.
- ^ Gates 2005, p. 371.
- ^ Foster & Peterson 2016.
- ^ Turner & Peterson 1999, p. 112.
- ^ Foster & Wedel 2014, p. 207.
- ^ Ikejiri 2005, p. 373.
- ^ Ikejiri, Tidwell & Trexler 2005, p. 156.
- ^ Tschopp, Mateus & Benson 2015, p. 200.
- ^ Ikejiri 2005, p. 374.
Works cited
[edit]- Chure, Daniel J.; McIntosh, John S. (1990). "Stranger in a strange land: a brief history of the paleontological operations at Dinosaur National Monument". Earth Sciences History. 9 (1): 34–40. Bibcode:1990ESHis...9...34C. doi:10.17704/eshi.9.1.x8l67355k7745582. ISSN 0736-623X. JSTOR 24138198.
- Ellinger, Tage U. H. (1950). "Camarosaurus annae—a new American sauropod dinosaur". The American Naturalist. 84 (816): 225–228. doi:10.1086/281626. S2CID 84738614.
- Foster, John Russell (2020). Jurassic West: the dinosaurs of the Morrison Formation and their world. Life of the past (2nd ed.). Bloomington, Indiana: Indiana University Press. ISBN 978-0-253-05158-5.
- Foster, John R.; Peterson, Joseph E. (2016). "First report of Apatosaurus (Diplodocidae: Apatosaurinae) from the Cleveland-Lloyd Quarry in the Upper Jurassic Morrison Formation of Utah: Abundance, distribution, paleoecology, and taphonomy of an endemic North American sauropod clade". Palaeoworld. 25 (3): 431–443. doi:10.1016/j.palwor.2015.11.006. ISSN 1871-174X.
- Foster, John R.; Wedel, Mathew J. (2014). "Haplocanthosaurus (Saurischia: Sauropoda) from the lower Morrison Formation (Upper Jurassic) near Snowmass, Colorado". Volumina Jurassica. 12 (2): 197–210.
- Gates, T. A. (August 1, 2005). "The Late Jurassic Cleveland-Lloyd Dinosaur Quarry as a Drought-Induced Assemblage". PALAIOS. 20 (4): 363–375. Bibcode:2005Palai..20..363G. doi:10.2110/palo.2003.p03-22. ISSN 0883-1351. S2CID 130274431.
- Gilmore, Charles W. (1925). "A nearly complete articulated skeleton of Camarasaurus, a saurischian dinosaur from the Dinosaur National Monument, Utah". Memoirs of the Carnegie Museum. 10 (3): 347–384. doi:10.5962/p.217807. S2CID 128077427.
- Holland, W. J. (1919). "Annual report upon the condition of the Carnegie Museum". Annual reports of the officers, committees, and departments for the fiscal year ending March 31, 1919. Pittsburgh. pp. 139–182.
{{cite book}}
: CS1 maint: location missing publisher (link) - Ikejiri, Takehito (2005). "Distribution and biochronology of Camarasaurus (Dinosauria, Sauropoda) from the Jurassic Morrison Formation of the Rocky Mountain Region". New Mexico Geological Society Field Conference Guidebook, Geology of the Chama Basin. Vol. 56. pp. 367–379.
- Ikejiri, Takehito; Tidwell, Virginia; Trexler, David L. (2005). "New adult specimens of Camarasaurus lentus highlight ontogenetic variation within the species". Thunder-Lizards: the Sauropodomorph Dinosaurs. Indiana University Press. p. 26. ISBN 0-253-34542-1.
- Lull, Richard S. (1930). "Skeleton of Camarasaurus lentus recently mounted at Yale". American Journal of Science. 14 (109): 1–5. Bibcode:1930AmJS...19....1L. doi:10.2475/ajs.s5-19.109.1.
- Madsen, James H.; McIntosh, John S.; Berman, David S. (October 10, 1995). "Skull and atlas-axis complex of the Upper Jurassic sauropod Camarasaurus Cope (Reptilia: Saurischia)". Bulletin of Carnegie Museum of Natural History. 31: 1–115. doi:10.5962/p.240778. ISSN 0145-9058. S2CID 198252192.
- Maidment, S.C.R.; Balikova, D.; Muxworthy, A.R. (2017). "Magnetostratigraphy of the Upper Jurassic Morrison Formation at Dinosaur National Monument, Utah, and Prospects for Using Magnetostratigraphy as a Correlative Tool in the Morrison Formation". Terrestrial Depositional Systems. Elsevier. pp. 279–302. ISBN 978-0-12-803243-5.
- Maidment, Susannah C.R.; Muxworthy, Adrian (October 29, 2019). "A chronostratigraphic framework for the Upper Jurassic Morrison Formation, western U.S.A." Journal of Sedimentary Research. 89 (10): 1017–1038. Bibcode:2019JSedR..89.1017M. doi:10.2110/jsr.2019.54. hdl:10141/622707. ISSN 1527-1404. S2CID 210343715.
- Mannion, Philip D.; Upchurch, Paul; Schwarz, Daniela; Wings, Oliver (February 27, 2019). "Taxonomic affinities of the putative titanosaurs from the Late Jurassic Tendaguru Formation of Tanzania: phylogenetic and biogeographic implications for eusauropod dinosaur evolution". Zoological Journal of the Linnean Society. 185 (3): 784–909. doi:10.1093/zoolinnean/zly068. eISSN 1096-3642. hdl:10044/1/64080. ISSN 0024-4082.
- Marsh, O. C. (1889). "Notice of new American Dinosauria". American Journal of Science. 37 (220): 331–336. Bibcode:1889AmJS...37..331M. doi:10.2475/ajs.s3-37.220.331. S2CID 131729220.
- McIntosh, John S; Miller, Wade E; Stadtman, Kenneth L; Gillette, David D (1996). "The osteology of Camarasaurus lewisi (Jensen, 1988)". Brigham Young University Geology Studies. 41: 73–115. ISSN 0068-1016.
- Paul, Gregory S. (2016). The Princeton Field Guide to Dinosaurs (2nd ed.). Princeton and Oxford: Princeton University Press. ISBN 978-0-691-16766-4.
- Taylor, Michael P. (January 24, 2022). "Almost all known sauropod necks are incomplete and distorted". PeerJ. 10: e12810. doi:10.7717/peerj.12810. ISSN 2167-8359. PMC 8793732. PMID 35127288.
- Tschopp, Emanuel; Mateus, Octávio; Benson, Roger B.J. (April 7, 2015). "A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda)". PeerJ. 3: e857. doi:10.7717/peerj.857. ISSN 2167-8359. PMC 4393826. PMID 25870766.
- Tschopp, Emanuel; Whitlock, John A.; Woodruff, D. Cary; Foster, John R.; Lei, Roberto; Giovanardi, Simone (October 30, 2019). "The Morrison Formation Sauropod Consensus: A freely accessible online spreadsheet of collected sauropod specimens, their housing institutions, contents, references, localities, and other potentially useful information". Peer Community in Paleontology. 1: 100003. doi:10.24072/pci.paleo.100003. ISSN 2606-4820. S2CID 214143170.
- Turner, Christine E.; Peterson, Fred (1999). "Biostratigraphy of dinosaurs in the Upper Jurassic Morrison Formation of the Western Interior, U.S.A.". Vertebrate Paleontology in Utah. Utah Geological Survey. pp. 77–114.
- Wedel, Mathew J.; Taylor, Michael P. (2013). "Neural spine bifurcation in sauropod dinosaurs of the Morrison Formation: ontogenetic and phylogenetic implications". PalArch's Journal of Vertebrate Palaeontology. 10 (1): 1–34. ISSN 1567-2158.
- White, Theodore E. (1958). "The braincase of Camarasaurus lentus (Marsh)". Journal of Paleontology. 32 (3): 477–494. JSTOR 1300674.
- Woodruff, D. Cary; Foster, John R. (May 31, 2017). "The first specimen of Camarasaurus (Dinosauria: Sauropoda) from Montana: The northernmost occurrence of the genus". PLOS ONE. 12 (5): e0177423. Bibcode:2017PLoSO..1277423W. doi:10.1371/journal.pone.0177423. ISSN 1932-6203. PMC 5451207. PMID 28562606.