Projoanusaurus
| Projoanusaurus | |
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| Mounted P. palmensis skeleton cast, Vollardie Paleontological Museum | |
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| Genus: | Projoanusaurus |
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| †Projoanusaurus palmensis Weitzmann, 1979
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Projoanusaurus is an extinct genus of basal joanusauroid theropod dinosaur from the mid-Jurassic period of Sarpolevantia with proportionally large limbs to its slender body. Generally considered the very first of the joanusauroids,[2] Projoanusaurus is known from a single species, Projoanusaurus palmensis, literally "before Joanusaurus named for Palmen" after Yonderian actor Hector Palmen.[3]
Being a basal joanusauroid, Projoanusaurus would have lived in the mid-Jurassic of Sarpolevantia alongside the numerous sauropodomorphs, ornithischians and other theropods of the period. As a basal joanusauroid, Projoanusaurus would have had a triangular-shaped pubic boot, a common trait among all joanuauroids, as well as sarponychids, three fingers on either hand, a femur larger than its tibia and chevron bases on their tails that had anterior and posterior bone growth. Most notably however, Projoanusaurus would have sported two large crests running parallel along the nasal bones on top of its skull, more than likely a socio-sexual signalling structure.[4] Projoanusaurus would have measured around 3-4 meters (10-13 ft) in length at adult and weighed about 400–550 kilograms (880–1,210 lb).[5]
First discovered in 1977 in Cape Aedan, Urcea, Projoanusaurus is now known from more than two dozen specimens of which about half are considered "good".[6] The comparative lack of specimens as opposed to later joanusauroids is thought to be a result of the comparatively poor fossil-bearing rocks of the mid-Jurassic of Levantia.[7]
Phylogeny
Widespread paleontological consensus places Projoanusaurus as the earliest, most basal joanusauroid in taxonomic phylogenies for the clade.[8] This is based largely on the traits it shares with later joanusauroids and also with its seemingly more basal stage of evolution compared with the closely related Magnalophosaurus which is oterwhise very close to Projoanusaurus in age. Projoanusaurus' taxonomic tree thus looks as such:
| Joanusauroidae |
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See also
Notes
- ↑ Weitzmann, Stephan: A most basal Joanusauroid of mid-Jurrasic Urcea, University of Collinebourg, 1979.
- ↑ Kalthorn, Erwin: Cladistic analysis of the joanusauroids and their immediate ancestry, University of Gabion, 2012.
- ↑ Weitzmann, Stephan: A most basal Joanusauroid of mid-Jurrasic Urcea, University of Collinebourg, 1979.
- ↑ Horner, David: Social and sexual signalling in theropods, University of Collinebourg, 1999. Pg. 22-24.
- ↑ de Blaise, Anton: Mass estimates in derived joanusaurids, University of Collinebourg, 2007.
- ↑ Himmelreich, Ewald: Joanusauroid taxonomy of the late 20th century, University of Sainte-Catherine, 1999.
- ↑ Konsaháken, Vurdhan: Paleogeology of Great Kiravia, University of Belarus, pg. 99-105. 2012.
- ↑ Kalthorn, Erwin: Cladistic analysis of the joanusauroids and their immediate ancestry, University of Gabion, 2012.