Protungulatum ('first ungulate') is an extinct genus of eutherian mammals within extinct family Protungulatidae,[2] and is possibly one of the earliest known placental mammals in the fossil record, that lived in North America from the Late Cretaceous to early Paleocene.[6][3][7]
| Protungulatum Temporal range: late Maastrichtian to Puercan
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|---|---|
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| lower jaw of Protungulatum donnae | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Grandorder: | Ferungulata |
| Clade: | Pan-Euungulata |
| Family: | †Protungulatidae Chatterjee, Scotese & Bajpai, 2017[2] |
| Genus: | †Protungulatum Sloan & Van Valen, 1965[1] |
| Type species | |
| †Protungulatum donnae Sloan & Van Valen, 1965
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| Species | |
Fossils of this genus were first found in the Bug Creek Anthills in northeastern Montana. The Bug Creek Anthills were initially believed to be Late Cretaceous (latest Maastrichtian) because of the presence of the remains of non-avian dinosaurs and common Cretaceous mammals,[8] but these were later shown to have been reworked[a] from Late Cretaceous strata, and consequently the Bug Creek Anthills are currently believed to be Early Paleocene (Puercan) in age.[9] Remains from the Ravenscrag Formation of Saskatchewan, Canada have been assigned to Protungulatum donnae. These remains may also be Cretaceous in age, but the age of the Ravenscrag Formation is not entirely certain. In 2011, remains of a new species in this genus, Protungulatum coombsi from the Hell Creek Formation suggested that Protungulatum was present in both the Cretaceous and the Paleocene.[3] However, some later studies questioned this Late Cretaceous age for the genus, considering Protungulatum to be exclusively Paleocene in age.[10]
Studies differ on the placement of Protungulatum. This genus was initially assigned to the family Arctocyonidae,[11] in order Condylarthra,[12][13] (a group of archaic "ungulates", that is now known to be polyphyletic). Some found that it is not a true placental mammal and it is eutherian found to be close to Placentalia.[14][3][15][16] However, a number of studies consider it to be a placental mammal and stem relative to true ungulates in clade Pan-Euungulata,[17][18][19][20][7][21][22][10] based on anatomy of inner ear.[7]
Phylogeny
editThe phylogenetic relationships of genus Protungulatum are shown in the following cladogram.[17][20]
| Scrotifera |
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Notes
edit- ^ A derived or reworked fossil is a fossil found in rock made significantly later than when the fossilized animal or plant died: it happens when a hard fossil is freed from a soft rock formation by erosion and redeposited in a currently forming sedimentary deposit.
References
edit- ^ R. E. Sloan and L. Van Valen (1965.) "Cretaceous mammals from Montana." Science 148(3667):220-227
- ^ a b Sankar Chatterjee, Christopher R. Scotese, Sunil Bajpai (2017) "Indian Plate and Its Epic Voyage from Gondwana to Asia: Its Tectonic, Paleoclimatic and Paleobiogeographic Evolution", Geological Society of America, Volume 529
- ^ a b c d Archibald, J. David; Zhang, Yue; Harper, Tony; Cifelli, Richard L. (May 6, 2011). "Protungulatum, confirmed Cretaceous occurrence of an otherwise Paleocene eutherian (placental?) mammal" (PDF). Journal of Mammalian Evolution. 18 (3): 153–161. doi:10.1007/s10914-011-9162-1. S2CID 16724836. Archived from the original (PDF) on March 3, 2016. Retrieved April 28, 2013.
- ^ L. M. Van Valen (1978.) "The beginning of the Age of Mammals." Evolutionary Theory 4:45-80
- ^ J. D. Archibald (1982.) "A study of Mammalia and geology across the Cretaceous-Tertiary boundary in Garfield County, Montana." University of California Publications in Geological Sciences 122:1-286
- ^ Z. Kielan-Jaworowska, R. L. Cifelli and Z. X. Luo (2004.) "Mammals from the age of dinosaurs: Origins, evolution, and structure." Columbia University Press, New York 1-630
- ^ a b c Maeva Orliac (2016.) "The inner ear of Protungulatum (Pan-Euungulata, Mammalia)" Journal of Mammalian Evolution 23(4)
- ^ Z. Kielan-Jaworowska, T. M. Bown and J. A. Lillegraven (1979.) "Eutheria." In J. A. Lillegraven, Z. Kielan-Jaworowska, W. A. Clemens (eds.), "Mesozoic mammals: the first two-thirds of mammalian history" 221-258
- ^ D. L. Lofgren (1995.) "The Bug Creek problem and the Cretaceous-Tertiary transition at McGuire Creek, Montana." University of California Publications in Geological Sciences 140:1-185
- ^ a b Velazco, Paúl M.; Buczek, Alexandra J.; Hoffman, Eva; Hoffman, Devin K.; O’Leary, Maureen A.; Novacek, Michael J. (June 2022). "Combined data analysis of fossil and living mammals: a Paleogene sister taxon of Placentalia and the antiquity of Marsupialia". Cladistics. 38 (3): 359–373. doi:10.1111/cla.12499. ISSN 0748-3007.
- ^ R. Tabuce, J. Clavel and M. T. Antunes (2011.) "A structural intermediate between triisodontids and mesonychians (Mammalia, Acreodi) from the earliest Eocene of Portugal." Naturwissenschaften 98:145-155
- ^ Malcolm C. McKenna, Susan K. Bell: Classification of Mammals: Above the Species Level in Columbia University Press, New York (1997), 631 Seiten. Protungulatum
- ^ J. D. Archibald (1998.) "Archaic ungulates ("Condylarthra")." In C. M. Janis, K. M. Scott, and L. L. Jacobs (eds.), "Evolution of Tertiary Mammals of North America" 1:292-331
- ^ Wible, J. R.; Rougier, G. W.; Novacek, M. J.; Asher, R. J. (2007). "Cretaceous eutherians and Laurasian origin for placental mammals near the K/T boundary". Nature. 447 (7147): 1003–1006. Bibcode:2007Natur.447.1003W. doi:10.1038/nature05854. PMID 17581585. S2CID 4334424.
- ^ Halliday, Thomas J. D. (2015). "Resolving the relationships of Paleocene placental mammals" (PDF). Biological Reviews. 92 (1): 521–550. doi:10.1111/brv.12242. PMC 6849585. PMID 28075073.
- ^ Halliday, Thomas John Dixon; Upchurch, Paul; Goswami, Anjali (2016-06-29). "Eutherians experienced elevated evolutionary rates in the immediate aftermath of the Cretaceous–Palaeogene mass extinction". Proceedings of the Royal Society B: Biological Sciences. 283 (1833): 20153026. doi:10.1098/rspb.2015.3026. PMC 4936024. PMID 27358361.
- ^ a b O'Leary, Maureen A.; Bloch, Jonathan I.; Flynn, John J.; Gaudin, Timothy J.; Giallombardo, Andres; Giannini, Norberto P.; Goldberg, Suzann L.; Kraatz, Brian P.; Luo, Zhe-Xi; Meng, Jin; Novacek, Michael J.; Perini, Fernando A.; Randall, Zachary S.; Rougier, Guillermo; Sargis, Eric J.; Silcox, Mary T.; Simmons, Nancy B.; Spaulding, Micelle; Velazco, Paul M.; Weksler, Marcelo; Wible, John R.; Cirranello, Andrea L. (8 February 2013). "The Placental Mammal Ancestor and the Post–K-Pg Radiation of Placentals". Science. 339 (6120): 662–667. Bibcode:2013Sci...339..662O. doi:10.1126/science.1229237. hdl:11336/7302. PMID 23393258. S2CID 206544776.
- ^ Wilford, John Noble (7 February 2013). "Rat-Size Ancestor Said to Link Man and Beast". New York Times. Retrieved 9 February 2013.
- ^ Averianov, A. O. & Lopatin, A. V. (2014.) "High-level systematics of placental mammals: Current status of the problem." Biology Bulletin, 41(9), 801–816.
- ^ a b Burger, Benjamin J. (2015). The Systematic Position of the Saber-Toothed and Horned Giants of the Eocene: The Uintatheres (Order Dinocerata) (PDF). Society of Vertebrate Paleontology 75th Annual Meeting. Dallas. Conference abstract (p. 99) Archived 2019-12-24 at the Wayback Machine. Explanation and conclusions: Episode 17: Systematic position of the Uintatheres (Order Dinocerata) on YouTube.
- ^ Upham, N. S.; Esselstyn, J. A.; Jetz, W. (2021). "Molecules and fossils tell distinct yet complementary stories of mammal diversification". Current Biology. 31 (19): 4195–4206.e3. doi:10.1016/j.cub.2021.07.012. PMC 9090300. PMID 34329589.
- ^ Carlisle, E.; Janis, C. M.; Pisani, D.; Donoghue, P. C. J.; Silvestro, D. (2023). "A timescale for placental mammal diversification based on Bayesian modeling of the fossil record". Current Biology. 33 (15): 3073–3082.e3. doi:10.1016/j.cub.2023.06.016.