Temporal range: Early Cretaceous, Early Valanginian
In 1889 Richard Lydekker named an Iguanodon "hollingtoniensis" based on remains found at Hollington near Hastings in East Sussex. It was named as a new genus Huxleysaurus by Gregory S. Paul in 2012. The generic name honours Thomas Henry Huxley, both for being "Darwin's Bulldog" and for coining the term "agnostic". The species had been considered by David Bruce Norman (2010) to be a synonym of Hypselospinus fittoni, but Paul rejected this as there was no overlapping material known from the two taxa showing shared derived traits (synapomorphies).
Huxley had based the species on a syntype series found in the Wadhurst Clay of the Lower Wealden Formation dating from the early Valanginian. These included the specimens BMNH R1148 (a femur), BMNH R1629 (limb elements), and BMNH R1632 (vertebrae and a foot claw). Paul did not choose a lectotype but added specimens BMNH R811, BMNH R811b and BMNH R604, referred by Lydekker, to the "holotype". These additional fossils include vertebrae and an ilium.
Paul gave a short diagnosis of the species. The thighbone is robust and moderately curved. The fourth trochanter is pendent. In 2013 Norman claimed that the robustness and curvature of the thighbone are not diagnostic and that the fourth trochanter is in fact not pendent, concluding that Huxleysaurus was a junior synonym of Hypselospinus.
- Lydekker, R., 1889, "Notes on new and other dinosaurian remains", Geological Magazine, 6: 352-356
- Gregory S. Paul (2012). "Notes on the rising diversity of iguanodont taxa, and iguanodonts named after Darwin, Huxley and evolutionary science". Actas de V Jornadas Internacionales sobre Paleontologia de Dinosaurios y su Entorno, Salas de los Infantes, Burgos (PDF). Colectivo de Arqueologico-Paleontologico de Salas de los Infantes (Burgos). pp. 121–131.
- David B. Norman, 2013, "On the taxonomy and diversity of Wealden iguanodontian dinosaurs (Ornithischia: Ornithopoda)", Revue de Paléobiologie, 32(2): 385–404