Dakotadon
Named after Dakota (the Lakota Formation of South Dakota, USA where the fossils were found) + Greek odon ('tooth'), meaning 'Dakota tooth'.
Dakotadon is a genus of iguanodont dinosaur from the Early Cretaceous (Valanginian to Barremian) Lakota Formation of South Dakota, USA, known from a partial skull. It was first described in 1989 as Iguanodon lakotaensis, by David B. Weishampel and Philip R. Bjork. Its assignment has been controversial. Some researchers suggested that "I." lakotaensis was more basal than I. bernissartensis, and related to Theiophytalia, but David Norman has suggested that it was a synonym of I. bernissartensis. Gregory S. Paul, working on a revision of iguanodont species, gave "I." lakotaensis its own genus, Dakotadon, in 2008. Paul measured its length at 6 meters (20 ft) and body mass at 1 metric ton (1.1 short tons).
Under dispute
Dakotadon lakotaensis (originally Iguanodon lakotaensis) is treated as a valid basal styracosternan by some (Madzia and colleagues, 2021), but its skull closely resembles Iguanodon bernissartensis and its validity has been questioned (Norman, 2015).
Diagnosis
- Ventral margin of premaxilla not below maxilla; maxillary process of premaxilla deep
- Dorsal midline trough in nasals
- Dorsal apex of maxilla near middle of element
- Antorbital fossa and fenestra large
- Lacrimal long, does not contact maxilla posterior to antorbital fossa
- Approximately 19 tooth positions in maxilla
Species
Dakotadon lakotaensis (Weishampel & Bjork, 1989)
Type species
First named as Iguanodon lakotaensis
Named for the Lakota people who inhabited the land and gave their name to the Lakota Formation where the holotype was found.
- Holotype
- SDSM 8656 , Museum of Geology, South Dakota School of Mines and Technology
- Material
- Incomplete distinctive skull associated with a couple of vertebrae.
- Horizon
- lower Fuson Member, Lakota Formation, Valanginian–Barremian, Early Cretaceous , 137.1–121.4 million years ago
- Locality
- SDSM V 2015-1, South Dakota, United States
Synonyms
-
Iguanodon lakotaensis reassigned
Original combination established by Weishampel and Bjork (1989); reassigned to the new genus Dakotadon by Paul (2008).
References
- Paul, G. S. (2008). A revised taxonomy of the iguanodont dinosaur genera and species. Cretaceous Research 29(2): 192-216. Elsevier BV. doi:10.1016/j.cretres.2007.04.009 paul2008a
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Boyd, C. A.; Pagnac, D. C. (2015). Insight on the anatomy, systematic relationships, and age of the Early Cretaceous ankylopollexian dinosaur Dakotadon lakotaensis. PeerJ 3: e1263. PeerJ. doi:10.7717/peerj.1263
Relocated the type locality in the field, recording it as museum locality SDSM V 2015-1 in Lawrence County and its horizon as unit L2, the lower Fuson Member equivalent.
boyd2015b -
Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.
Source of the hip height estimate, and the appearance features.
jones2026a -
Madzia, D.; Arbour, V. M.; Boyd, C. A.; Farke, A. A.; Cruzado-Caballero, P.; Evans, D. C. (2021). The phylogenetic nomenclature of ornithischian dinosaurs. PeerJ 9: e12362. doi:10.7717/peerj.12362
Treated Dakotadon as a valid basal styracosternan in ornithischian phylogenetic nomenclature analysis.
madzia2021a -
Norman, D. B. (2015). On the history, osteology, and systematic position of the Wealden (Hastings group) dinosaur Hypselospinus fittoni (Iguanodontia: Styracosterna). Zoological Journal of the Linnean Society 173: 92-189. doi:10.1111/zoj.12193
Rejected Paul's (2008) separation of Dakotadon as unjustified, treating the skull as closely resembling Iguanodon bernissartensis (cf. Iguanodon lakotaensis).
norman2015a - Weishampel, D. B.; Bjork, P. R. (1989). The first indisputable remains of Iguanodon (Ornithischia: Ornithopoda) from North America: Iguanodon lakotaensis, sp. nov. Journal of Vertebrate Paleontology 9(1): 56-66. doi:10.1080/02724634.1989.10011738 weishampel1989a