Dimorphodon

Dimorphodon (pronounced /daɪˈmɔrfədɒn/) was a genus of medium-sized pterosaur from the early Jurassic Period. It was named by paleontologistRichard Owen in 1859. Dimorphodon means "two-form tooth", derived from Greek δι/di meaning 'two', μορφη/morphe meaning 'shape' and οδων/odonmeaning 'tooth', referring to the fact that it had two distinct types of teeth in its jaws - which is comparatively rare among reptiles.

The first fossil remains now attributed to Dimorphodon were found in England by fossil collector Mary Anning, at Lyme Regis in Dorset, UK in December 1828.^[1] This region of Britain is now a World Heritage Site, dubbed the Jurassic Coast; in it layers of the Blue Lias are exposed, dating from the Hettangian-Sinemurian. The specimen was acquired by William Buckland and reported in a meeting of the Geological Society on 5 February 1829.^[2] In 1835, after a thorough study by William Clift and William John Broderip, this report, strongly expanded, was published in the Transactions of the Geological Society, describing and naming the fossil as a new species. As was the case with most early pterosaur finds, Buckland classified the remains in the genus Pterodactylus, coining the new species Pterodactylus macronyx.^[3] The specific name is derived from Greek makros, "large" and onyx, "claw", in reference to the large claws of the hand. The specimen, presently NHMUK PV R 1034, consisted of a partial and disarticulated skeleton on a slab, lacking the skull. Buckland in 1835 also assigned a piece of jaw from the collection of Elizabeth Philpot to P.macronyx. Later, the many putative species assigned toPterodactylus had become so anatomically diverse that they began to be broken into separate genera.

In 1858, Richard Owen reported the find of two new specimens, NHMUK PV R 41212 and NHMUK PV R 1035, again partial skeletons but this time including the skulls. Having found the skull to be very different from that of Pterodactylus, Owen assigned Pterodactylus macronyx its own genus, which he named Dimorphodon.^[4] His first report contained no description and the name remained a nomen nudum. In 1859 however, a subsequent publication by Owen provided a description.^[5] After several studies highlighting aspects of Dimorphodon 's anatomy, Owen in 1874 made NHMUK PV R 1035 theholotype.^[6]

Meanwhile, though Dimorphodon is not a very common fossil, other fragmentary specimens were found. Some of these were acquired by Othniel Charles Marsh between 1873 and 1881 from the London fossil dealer Bryce McMurdo Wright. One of these had been recovered from early Jurassic strata at the south bank of the Severn river, at theAust Cliff.^[7]