Lonchodectes
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Lonchodectes (meaning "lance biter") was a genus of ?azhdarchoid pterosaur from several formations dating from the ?Valanginian to the Turonian (Lower Cretaceous-Upper Cretaceous) of England, mostly in the area around Kent. The species belonging to it had been assigned to Ornithocheirus until David Unwin's work of the 1990s and 2000s, and the genus is not universally accepted as distinct.[1] Several potential species are known; most are based on scrappy remains, and have gone through several other generic assignments. The genus is part of the complex taxonomy issues surrounding Early Cretaceous pterosaurs from Brazil and England, such as Amblydectes, Anhanguera, Criorhynchus, Coloborhynchus, Ornithocheirus, and Tropeognathus.
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[edit] History and species
Numerous species have been referred to this genus over time, and only those more widely connected with the genus are included here.
The type species, L. compressirostris, is based on BMNH 39410, a partial upper jaw from the Turonian-age Upper Cretaceous Upper Chalk near Kent. Richard Owen named in 1851 as a species of Pterodactylus;[2] it was transferred to Ornithocheirus in 1870 by Harry Govier Seeley,[3] before becoming the type species of Lonchodectes in Hooley's 1914 review of Ornithocheirus.[4]
Hooley added two other species at this time, both of which had also been originally referred to Pterodactylus, then to Ornithocheirus: L. giganteus, a Cenomanian-age jaw fragment;[5] and L. daviesii, another jaw fragment, from an Albian-age formation.[6]
The genus acquired several more former Pterodactylus and Ornithocheirus species in the 1990s-2000s. L. sagittirostris, based on BMNH R1823, a lower jaw fragment from the ?Valanginian-Hauterivian-age Lower Cretaceous Hastings Beds of East Sussex,[6] and L. platystomus[3] had been acquired by 2000.[7] Two additional species of jaw fragments, both from the Albian-age Cambridge Greensand,[3] were added in 2006: L. machaerorhynchus and L. microdon, joining L. compressirostris, L. giganteus, L. platystomus, and L. sagittirostris in his listing of valid species (thus, additional dubious species may also be referred here).[8]
[edit] Classification
The genus is poorly known and not universally accepted, as noted above. In Peter Wellnhofer's 1991 The Illustrated Encyclopedia of Pterosaurs the other major recent synopsis of pterosaurs, written before Unwin's work, the species are included with Ornithocheirus, and are in fact the main fossils illustrated to represent the genus.[9] Unwin has them in their own family, Lonchodectidae, which is grouped with the azhdarchoids, including the tapejarids and azhdarchids.[8]
[edit] Paleobiology
Unwin considers Lonchodectes to have been a generalist, like a seagull, with its conservative jaws and teeth (like those of the much older Pterodactylus) and small to medium size; he estimates its maximum wingspan at about 2 m (6.6 ft). Lonchodectes had long jaws with many short teeth, and the jaws were compressed vertically, like "a pair of sugar tongs with teeth".[10] At least some of these species had crests on their lower jaws.[11]
[edit] References
- ^ Kellner, A.W.A. (2003). Pterosaur phylogeny and comments on the evolutionary history of the group: In: Buffetaut, E., and Mazin, J.-M. (Eds.). Evolution and Palaeobiology of Pterosaurs. Geological Society Special Publication 217:105-137. 1-86239-143-2.
- ^ Owen, R. (1851). Monograph on the fossil Reptilia of the Cretaceous Formations. The Palaeontographical Society 5(11):1-118.
- ^ a b c Seeley, H.G. (1870). The Ornithosauria: an Elementary Study of the Bones of Pterodactyles. Cambridge, 130 pp.
- ^ Hooley, R.W. (1914). On the Ornithosaurian genus Ornithocheirus with a review of the specimens from the Cambridge Greensand in the Sedgwick Museum, Cambridge. Annals and Magazine of Natural History, series 8, 78:529-557.
- ^ Bowerbank, J.S. (1846). On a New Species of Pterodactyl. Found in the Upper Chalk of Kent (P. giganteus). Quarterly Journal of the Geological Society 2:7–9.
- ^ a b Owen, R. (1874). A Monograph on the Fossil Reptilia of the Mesozoic Formations. 1. Pterosauria. The Palaeontographical Society Monograph 27:1–14.
- ^ Unwin, D.M., Lü, J., and Bakhurina, N.N. (2000). On the systematic and stratigraphic significance of pterosaurs from the Lower Cretaceous Yixian Formation (Jehol Group) of Liaoning, China. Mitteilungen Museum für Naturkunde der Humboldt-Universität zu Berlin, Geowissenschaftliche Reihe 3:181–206.
- ^ a b Unwin, D.M. (2006). The Pterosaurs: From Deep Time. Pi Press:New York, p. 273. ISBN 0-13-146308-X.
- ^ Wellnhofer, P. (1996). The Illustrated Encyclopedia of Pterosaurs. Barnes and Noble Books:New York, 110-113. ISBN 0-7607-0154-7. (later reprint)
- ^ Unwin, D.M. (2006). The Pterosaurs: From Deep Time. Pi Press:New York, p. 251. ISBN 0-13-146308-X.
- ^ Unwin, D.M. (2006). The Pterosaurs: From Deep Time. Pi Press:New York, p. 106. ISBN 0-13-146308-X.
[edit] External links
- Upper Cretaceous species of Lonchodectes (scroll down), The Pterosaur Database. Accessed 2007-02-10
- Upper Cretaceous species of Lonchodectes (scroll down), The Pterosaur Database. Accessed 2007-02-10
- Re: Pterosaur Help, a posting from George Olshevsky on the Dinosaur Mailing List, which, although incomplete, should give some idea as to the complexity of the taxonony here. Additional, even more dubious species are included. Accessed 2007-02-10
