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Abstract

Istiodactylus latidens is a pterodactyloid pterosaur from the Wessex Formation of the Isle of Wight. Previously known as Ornithodesmus latidens, it was assigned to the new genus Istiodactylus (Howse et al. 2001) as the former was occupied by a dinosaurian synsacrum (NHMUK PV R.187) owing to an error by H. G. Seeley (1887, 1901). Significant descriptions of I. latidens, then Ornithodesmus latidens, were given by Hooley (1913). Hooley's monograph was comprehensive for the time, but the information is now outdated and incomplete. This project addresses this issue and supplements it with a deeper look into taxonomy, and validity of other istiodactylid taxa.
Specimens of I. latidens are preserved in 3-D; including the greater portion of the skull. The quality of preservation, coupled with the scarcity of information surrounding the genus served as an ideal platform to perform a detailed contemporary osteological description
The highly apomorphic morphology of the I. latidens skull served as the primary driver for the conclusions of this study. Detailed observation identified characteristics that further define Istiodactylus latidens, and the genus of Istiodactylus as a whole. These characters include; skull approx. 3.5 times longer than it is wide; mandibular length approx. 70% of total skull length; convex posterior margin of the nasoantorbital fenestrae: sub-orbital vacuity inclined at approx.38-39⁰.
Using established newly identified diagnostic features, and the results of previous studies (Hooley, 1913; Howse et al. 2001; Witton, 2012) it has been possible to not only provide a more complete view of the istiodactylids, but also affirm the validity of more questionable taxa within Istiodactylidae. The analysis concludes that Istiodactylus latidens, and Istiodactylus sinensis represent derived istiodactylids, whilst Longchengpterus zhaoi and Nurhachius ignaciobritoi, if not synonymous, form the plesiomorphic istiodactylids. All other previously purported istiodactylids, are not considered valid istiodactylids.

Course: Master of Philosophy - MPhil

Date Deposited: 2022-05-11

URI/permalink: https://library.port.ac.uk/dissert/dis13896.html