Thursday, July 11, 2024

[Paleontology • 2024] Comptonatus chasei • A New iguanodontian Dinosaur (Iguanodontia: Hadrosauriformes) from the Lower Cretaceous Wessex Formation of the Isle of Wight, southern England

Comptonatus chasei
Lockwood, Martill & Maidment, 2024

 artwork by John Sibbick.
A new iguanodontian dinosaur, Comptonatus chasei gen. et sp. nov., is described from the Lower Cretaceous Wessex Formation of the Isle of Wight. These strata provide an important record of a critical time in the development of iguanodontian diversity. The specimen, which is described here for the first time, was found and excavated in 2013 and represents the most complete iguanodontian skeleton discovered in the Wealden Group for a century. A new taxon is diagnosed by several autapomorphies found in the neurocranium, teeth, coracoid and other parts of the body, together with a unique suite of characters. These include a dentary with a straight ventral border, and a markedly expanded prepubic blade. These features set it apart from the sympatric Mantellisaurus atherfieldensis, Brighstoneus simmondsi and Iguanodon cf. bernissartensis, increasing the known diversity of this clade in the Barremian–early Aptian of England.  

Keywords: Barremian, Wealden Group, supraoccipitalvomer, diversity

Systematic palaeontology
Dinosauria Owen, 1842
Ornithischia Seeley, 1887

Ornithopoda Marsh, 1881
Iguanodontia Baur, 1891

Ankylopollexia Sereno, 1986
Styracosterna Sereno, 1986

Hadrosauriformes Sereno, 1997

Comptonatus gen. nov.

Etymology: Comptonatus (‘the Compton thunderer’) is a contraction of the words ‘Compton’ on the Isle of Wight and ‘tonatus’, the Latin for thundered, and reflects the place of discovery and the large size of the animal.

Location and horizon: The Wessex Formation, ‘middle’ Barremian, Lower Cretaceous. IWCMS 2014.80 was excavated during September–October 2013, from a plant debris bed on National Trust property to the west of the fault in Compton Bay, and close (c. 50 m) to where IWCMS 2013.175, a skeleton of Valdosaurus canaliculatus Galton, Citation1977 (Barrett, Citation2016) was excavated the previous year. The excavation was conducted under the supervision of Dinosaur Isle Museum (IWCMS) and site records and drawings were collected by Mr Stephen Hutt, the then curator. The site exposes a deep (c. 3 m) plant debris bed that occasionally yields articulated dinosaur remains, but frequently produces the trunks of large conifers, usually attributed to Pseudofrenelopsis parceramosa (Francis, Citation1987). Other vertebrate remains uncovered from the excavation site include ganoid fish scales (cf. Scheenstia sp.), an indeterminate crocodilian tooth and several very large, but fragmentary iguanodontian remains, including three pedal phalanges, a neural arch, and some rib sections.

 Comptonatus chasei gen. et sp. nov. (IWCMS 2014.80).
Preliminary reconstruction of the skull. Shaded areas represent material present in the holotype.
Abbreviations: d, dentary; f, frontal; m, maxilla; n, nasal; nc, neurocranium; orb, orbit; p, parietal; pa, paroccipital process; pf, prefrontal; po, postorbital; q, quadrate, s, surangular; sq, squamosal. Scale bar represents 100 mm.

 Comptonatus chasei gen. et sp. nov. (IWCMS 2014.80). Life restoration.
Original artwork by John Sibbick.

Comptonatus chasei gen. et sp. nov.

Etymology: The specific name honours the late Mr Nick Chase, winner of the Palaeontological Association’s Mary Anning Award in 2018, who made the initial discovery and through his lifetime contributed enormously to the collections at Dinosaur Isle Museum, Isle of Wight, and the Natural History Museum, London (Lockwood et al., Citation2019).

Jeremy A. F. Lockwood, David M. Martill and Susannah C. R. Maidment. 2024. 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); 2346573. DOI: