Comptonatus

Not to be confused with Camptonotus or Camptosaurus.

Comptonatus Temporal range: Early Cretaceous, Barremian–Aptian PreꞒ Ꞓ O S D C P T J K Pg N
Speculative life reconstruction
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Dinosauria
Clade:	† Ornithischia
Clade:	† Ornithopoda
Genus:	† Comptonatus Lockwood, Martill & Maidment, 2024
Species:	†C. chasei
Binomial name
†Comptonatus chasei Lockwood, Martill & Maidment, 2024

Comptonatus (meaning "the Compton thunderer") is a genus of ornithopod dinosaur from the early Cretaceous period. Its remains are known from the Wessex Formation in England. The type and only species is C. chasei.

Discovery and naming

The holotype specimen, IWCMS 2014.80, was excavated in September–October 2013, close to where a Valdosaurus specimen was recovered the previous year. It is the most complete ornithopod dinosaur found on the Isle of Wight since Mantellisaurus in 1914. ^{[1] [2]}

Comptonatus was described as a new genus and species of iguanodontian dinosaur in 2024. The generic name, Comptonatus, combines the name of the location Compton with the Latin tonatus, meaning "thundered", and has the intended meaning of "the Compton thunderer", in reference to its discovery location and large size. The specific name, chasei, honours the late Nick Chase, who won the Palaeontological Association's Mary Anning Award in 2018 and discovered the specimen. ^{[1] [3]}

Classification

Comptonatus was entered into a phylogenetic analysis using the dataset of the description of the contemporary Brighstoneus . It was found to be in a clade with Iguanodon , Barilium , and Mantellisaurus , all from southern England, which has been termed the Iguanodontidae. ^[4] The cladogram from the analysis is shown below: ^[1]

Styracosterna	Uteodon Dakotadon Hippodraco Iguanacolossus Proa Lanzhousaurus Hypselospinus Bayannurosaurus Ouranosaurus Hadrosauriformes Iguanodontidae Iguanodon Barilium Comptonatus Mantellisaurus Hadrosauroidea Brighstoneus Bolong Jinzhousaurus Altirhinus Equijubus Batyrosaurus Penelopognathus Sirindhorna Hadrosauromorpha

Using a novel phylogenetic matrix for their description of the Portuguese hadrosauroid Cariocecus bocagei , Bertozzo et al. (2025) recovered this taxon as the sister taxon to a clade formed by Comptonatus and Brighstoneus. These taxa were placed within the Hadrosauroidea, diverging after the Iguanodontidae. ^[5] A study by Huang and colleagues (2026) using an updated version of this matrix recovered a comparable clade. ^[6] The results of the former study are displayed in the cladogram below:

Hadrosauriformes

Iguanodontidae Iguanodon bernissartensis Mantellisaurus atherfieldensis Hadrosauroidea Ouranosaurus nigeriensis Morelladon beltrani Cariocecus bocagei Brighstoneus simmondsi Comptonatus chasei Bolong yixianensis Altirhinus kurzanovi Jinzhousaurus yangi Equijubus normani Xuwulong yueluni Jintasaurus meniscus Batyrosaurus rozhdestvenskyi Probactrosaurus gobiensis Hadrosauromorpha ⊞ ⇒ Gongpoquansaurus mazongshanensis Eolambia caroljonesa Protohadros byrdi Jeyawati rugoculus Plesiohadros Gilmoreosaurus mongoliensis Bactrosaurus johnsoni Levnesovia transoxiana Eotrachodon orientalis Telmatosaurus transsylvanicus Tanius sinensis Tethyshadros insularis Tethyshadros insularis Huehuecanauhtlus tiquichensis Hadrosauridae ⊟

Paleoenvironment

Comptonatus is one of several iguanodontians known from the Isle of Wight, distinct from Iguanodon , Brighstoneus , and Mantellisaurus . The deposition of the Wessex Formation likely spans several million years, and so it is unlikely to have been contemporaneous with all of these other taxa. The Wessex Formation had a warm and semi-arid Mediterranean climate, formed on alluvial meander plains. Forests on higher ground north of the floodplain consisted of Pinophyta, Ginkgophyta, Pteridophyta, Cycadophyta. Forest fires and floods were common occurrences, resulting in the formation of plant debris beds. ^[4]

References

1. Lockwood, Jeremy A. F.; Martill, David M.; Maidment, Susannah C. R. (2024-12-31). "Comptonatus chasei, a new iguanodontian dinosaur from the Lower Cretaceous Wessex Formation of the Isle of Wight, southern England". Journal of Systematic Palaeontology . 22 (1). Bibcode:2024JSPal..2246573L. doi: 10.1080/14772019.2024.2346573 . ISSN   1477-2019.
2. "The most-complete UK dinosaur in a century has been found on the Isle of Wight". www.nhm.ac.uk. Retrieved 2024-07-10.
3. Hall, Rachel; Sample, Ian (2024-07-10). "Dinosaur unearthed on Isle of Wight identified as new plant-eating species". The Guardian. ISSN   0261-3077 . Retrieved 2024-07-10.
4. Lockwood, Jeremy A. F.; Martill, David M.; Maidment, Susannah C. R. (2021-11-10). "A new hadrosauriform dinosaur from the Wessex Formation, Wealden Group (Early Cretaceous), of the Isle of Wight, southern England". Journal of Systematic Palaeontology. 19 (12): 847–888. Bibcode:2021JSPal..19..847L. doi: 10.1080/14772019.2021.1978005 . ISSN   1477-2019. S2CID   244067410.
5. Bertozzo, Filippo; Camilo, Bruno; Araújo, Ricardo; Manucci, Fabio; Kullberg, José Carlos; Cerio, Donald G.; Carvalho, Victor Feijó de; Marrecas, Pedro; Figueiredo, Silvério D.; Godefroit, Pascal (2025-09-15). "Cariocecus bocagei, a new basal hadrosauroid from the Lower Cretaceous of Portugal". Journal of Systematic Palaeontology. 23 (1) 2536347. doi:10.1080/14772019.2025.2536347. ISSN   1477-2019.
6. Huang, J.; Wu, W.; Mao, L.; Bertozzo, F.; Dhouailly, D.; Robin, N.; Pittman, M.; Kaye, T. G.; Manucci, F.; He, X.; Wang, X.; Godefroit, P. (2026). "Cellular-level preservation of cutaneous spikes in an Early Cretaceous iguanodontian dinosaur". Nature Ecology & Evolution: 1–8. doi:10.1038/s41559-025-02960-9.