Camarasauridae is a family ofsauropoddinosaurs.[1] Among sauropods, camarasaurids are small to medium-sized, with relatively short necks. They are visually identifiable by a short skull with large nares, and broad, spatulate teeth filling a thick jaw.[2][3] Based on cervical vertebrae and cervical rib biomechanics, camarasaurids most likely moved their necks in a vertical, rather than horizontal, sweeping motion, in contrast to most diplodocids.[2]
Camarasauridae is typically regarded as belonging toMacronaria, one of the two major branches ofNeosauropoda. Within Macronaria, it occupies abasal position, outside ofTitanosauriformes. However, some studies have found Camarasauridae to lie outside Neosauropoda.[5]
Camarasaurus is the only taxon uncontroversially regarded as a valid genus of camarasaurid. It contains four species:C. grandis,C. lentus,C. lewisi, andC. supremus.C. lewisi may represent a distinct genus,Cathetosaurus.[6]Lourinhasaurus, the type species of which was formerly assigned toCamarasaurus, is regarded as a camarasaurid by most studies,[7][5] though it has also been considered to be a basal eusauropod.[8]
Oplosaurus, from theEarly Cretaceous of theUnited Kingdom, has been suggested to be a camarasaurid,[9] but as it is only known from a tooth, its position within Eusauropoda is difficult to determine.[10]Tehuelchesaurus, from the Late Jurassic ofArgentina, has been considered a camarasaurid in some studies,[7][11] but a wide range of other phylogenetic positions have been proposed, including a close relationship toOmeisaurus,[8] a position inTuriasauria,[5] or as a non-camarasaurid basal macronarian.
Bellusaurus, which is only known from juvenile remains, may be a camarasaurid,[12] though it has also been considered a basal macronarian, turiasaur, or mamenchisaurid.[5][11]
In 1970, Rodney Steel took an expansive concept of Camarasauridae, encompassing all sauropods then known except diplodocoids and titanosaurs.[13] In 1990, John S. McIntosh regarded Camarasauridae as made up of two subfamilies: Camarasaurinae, containingCamarasaurus,Aragosaurus,Euhelopus, andTienshanosaurus, and Opisthocoelicaudiinae, containingOpisthocoelicaudia andChondrosteosaurus.[14]Dashanpusaurus, from the Middle Jurassic of China, was originally described as a camarasaurid,[15] but was subsequently found to be a basal macronarian by phylogenetic analysis.[16]
Several skeletal features have been used to characterize the camarasaurids. In the skull, these include an external narial diameter approximately 40% of the long-axis length of the skull, an arched internarial bar, a short muzzle anterior to the nares, and maxillary shelf.[17] In the rest of the axial skeleton, these include flat ventral faces on the cervical vertebrae, a triangular flare to the neural spines of the middle and posterior dorsal vertebrae, and a concave posterior surface to the anterior thoracic ribs, as well as an external haemal canal across the anterior vertebrae of the tail.[17][18] A reduction to two carpals, long metacarpals relative to the radius, and a twisted ischial shaft serve to identify the appendicular skeleton.[2][18]
Broadly speaking, camarasaurids occupied a distribution limited to theLaurasian continent during theUpper Jurassic.[17] Most currently accepted camarasaurid specimens have been discovered in theMorrison Formation of North America, however some specimens from the AfricanTendaguru Formation have been speculated to belong to the genusCamarasaurus, and the closely relatedLourinhasaurus was found in Portugal.[19][20][21]
Dental microwear indicates that camarasaurids had a narrow ecological niche breadth, as variability in microwear patterns between different camarasaurids is very low, and that they likely frequently migrated in search of new food sources. In North America, camarasaurids filled a similar niche toturiasaurs, while in Europe, where turiasaurs were present, camarasaurids and turiasaurs occupied clearly distinct niches due toniche partitioning.[22]
^1. Taylor, M. P., & Naish, D. (2005).The phylogenetic taxonomy of Diplodocoidea (Dinosauria: Sauropoda). Museum of Paleontology, University of California, Berkeley.
^abc1. Weishampel, D. B., Dodson, P., & Osmólska, H. (Eds.). (1990).The dinosauria. Univ of California Press.
^abUpchurch, Paul; Barrett, Paul M.; Dodson, Peter (2004). "Sauropoda". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.).The Dinosauria (2 ed.). Berkeley: University of California Press. pp. 259–322.ISBN0-520-24209-2.
^Canudo, José Ignacio; Ruiz-Omeñaca, José Ignacio; Barco, José Luis (2002). "¿Saurópodos asiáticos en el Barremiense inferior (Cretácico Inferior) de España?".Ameghiniana.39 (4):443–452.
^Upchurch, Paul; Mannion, Philip D.; Barrett, Paul M. (2011). "Sauropod dinosaurs".Field Guide to English Wealden Fossils. London. pp. 476–525.{{cite book}}: CS1 maint: location missing publisher (link)
^Steel, Rodney (1970).Saurischia. Handbuch der Paläoherpetologie. Stuttgart: Gustav Fischer Verlag.
^McIntosh, J. S. (1990). "Sauropoda". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.).The Dinosauria (1 ed.). Berkeley: University of California Press. pp. 345–401.
^Peng, G.; Y. Ye; Y. Gao; C. Shu; S. Jiang (2005).Jurassic Dinosaur Faunas in Zigong. Chengdu: Sichuan Publishing Group People's Press.ISBN7-220-07051-9.
^Ren, Xin-Xin; Jiang, Shan; Wang, Xu-Ri; Peng, Guang-Zhao; Ye, Yong; Jia, Lei; You, Hai-Lu (2022-11-14). "Re-examination ofDashanpusaurus dongi (Sauropoda: Macronaria) supports an early Middle Jurassic global distribution of neosauropod dinosaurs".Palaeogeography, Palaeoclimatology, Palaeoecology.610 111318.doi:10.1016/j.palaeo.2022.111318.ISSN0031-0182.
^abWilson, J. A., & Sereno, P. C. (1998). Early evolution and higher-level phylogeny of sauropod dinosaurs.Journal of Vertebrate Paleontology,18(S2), 1-79.
^FosteR, J. R., & Wedel, M. J. (2014). Haplocanthosaurus (Saurischia: Sauropoda) from the lower Morrison Formation (Upper Jurassic) near Snowmass, Colorado. Volumina Jurassica, 12(2), 197-210.
^Foster, J. R., & Lucas, S. G. (Eds.). (2006).Paleontology and Geology of the Upper Jurassic Morrison Formation: Bulletin 36(Vol. 36). New Mexico Museum of Natural History and Science.
^Raath, J. S. (1987). Sauropod dinosaurs from the Central Zambezi Valley, Zimbabwe, and the age of the Kadzi Formation.South African Journal of Geology,90(2), 107-119.
