Convolosaurus
Convolosaurus | |
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Composite skeleton in Perot Museum of Nature and Science | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | †Ornithischia |
Clade: | †Neornithischia |
Clade: | †Ornithopoda |
Genus: | †Convolosaurus Andrzejewski, Winkler & Jacobs, 2019 |
Type species | |
†Convolosaurus marri Andrzejewski, Winkler & Jacobs, 2019
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Convolosaurus (
Discovery and naming
In May 1985, James "Rusty" Branch at the
In 2019, the type species Convolosaurus marri was named and described by Kate A. Andrzejewski, Dale A. Winkler and Louis Leo Jacobs. The generic name is derived from the Latin convolare, "to flock", a reference to the dense concentration of fossils. The specific name honours Dr. Ray H. Marr who has propagated the Society of Vertebrate Paleontology at the SMU.[1]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/7/78/Convolosaurus_display.jpg/220px-Convolosaurus_display.jpg)
The holotype, SMU 72834, was found in a layer of the Twin Mountains Formation dating from the Aptian. It consists of a partial skeleton with skull. It preserved the cranium with the lower jaws, the vertebral column up to the twenty-third tail vertebra, the shoulder girdle, the left arm, the right humerus, the pelvis, both thighbones, both shinbones and the left calfbone. It represents a subadult individual.[1] A large amount of fossils have been referred to the species. In 2019 these amounted to 488 specimens, representing at least twenty-nine individuals, ranging from small juveniles to subadults. Almost the entire skeleton is now known.[1]
Description
![](http://upload.wikimedia.org/wikipedia/commons/thumb/b/be/Convolosaurus_skull.jpg/220px-Convolosaurus_skull.jpg)
The holotype individual had an estimated length of between two-and-a-half and three metres. It was not yet fully grown; the adult size was considered to be unknown. Thighbones found vary between 51 and 315 millimetres in length.[1]
The describing authors established a number of distinguishing traits. One of these is an autapomorphy, a unique derived character. The premaxilla bears four teeth, which have a vertical trough on the outside.[1]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Convolosaurus_forelimb.jpg/220px-Convolosaurus_forelimb.jpg)
Phylogeny
While initially considered a member of the Hypsilophodontidae, Convolosaurus was in 2019 placed in the Ornithopoda in a basal position, between Hypsilophodon and Thescelosaurus in the evolutionary tree. Previous analyses had found Thescelosaurus to be more basal than Hypsilophodon but this was now reversed as Convolosaurus possessed two supraorbitals that it shared with Thescelosaurus, indicating that Hypsilophodon had lost this trait independently.[1]
The cladogram below results from analysis by Andrzejewski et al., 2019.[1]
Ornithischia |
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References
- ^ PMID 30860999.
- ^ Winkler, D.A; Murry, P.A; Jacobs, L.L.; Downs, W.R.; Branch, J.R.; Trudel, P. (1988). "The Proctor Lake dinosaur locality, Lower Cretaceous of Texas". Hunteria. 2 (5): 1–8.
- ISBN 0-8137-2238-1.