Protoceratopsidae
| Protoceratopsidae | ||||||||||||
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Skeletal reconstruction of Protoceratops |
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| Temporal occurrence | ||||||||||||
| Upper Cretaceous ( Santonium to Campanium ) | ||||||||||||
| 86.3 to 72 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Protoceratopsidae | ||||||||||||
| Granger & Gregory , 1923 |
The Protoceratopsidae (also Protoceratopidae ) are a taxon (a systematic group) of the dinosaurs from the group of Ceratopsia . According to today's perspective, they include Protoceratops and Bagaceratops as well as some little-known, controversial genera.
features
The Protoceratopsidae were relatively small dinosaurs, Protoceratops reached up to 2 meters in length, Bagaceratops only about half. (The controversial Udanoceratops, however, reached up to 4 meters.) As with all Ceratopsia, the snout was formed from the rostral bone and the predentale . Features of this group include a small horn on the nasal bone and changes in the lower jaw - such as a pointed front end of the predentale. As with all Ceratopsia, the teeth were geared towards a plant-based diet, but in contrast to the tooth batteries of the Ceratopsidae they were simply built.
External system and history of development
All Protoceratopsidae finds come from East Asia ( Mongolia and China ) and are dated to an age of 85 to 70 million years in the Upper Cretaceous ( Santonium or Campanium ). They are incorporated into the Neoceratopsia within the Ceratopsia . A possible cladogram looks like this.
| Neoceratopsia |
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Other studies, however, see the Leptoceratopsidae as the basal representatives of the Coronosauria and the Protoceratopsidae as more closely related to the Ceratopsoidea.
Internal system
The Protoceratopsidae were coined in 1923 by Walter W. Granger and William King Gregory , initially as a monotypic family for Protoceratops . Later the group served as a reservoir for all Ceratopsia, which were more developed than the Psittacosauridae , but more basal than the Ceratopsidae . This group has turned out to be paraphyletic , so today, among other things, the predominantly North American Leptoceratopsidae are regarded as a separate family.
A possible generic list looks like this:
- Bagaceratops
- Bainoceratops
- Breviceratops
- Graciliceratops
- Lamaceratops
- Magnirostris
- Platyceratops
- Protoceratops
- Udanoceratops
Protoceratops and Bagaceratops are closely related and, according to various analyzes, form a monophyletic group. Graciliceratops was ascribed to the Protoceratopsidae when it was first described in 2000, as was Magnirostris in 2003. Also in 2003, Alifanov described two new dinosaurs, Lamaceratops and Platyceratops , which he classified together with Bagaceratops and Breviceratops in a new family, Bagaceratopsidae.
There have been uncertainties about the validity of Breviceratops for some time, it could only be a young of Bagaceratops . Makovicky and Norell also questioned the validity of Lamaceratops , Magnirostris and Platyceratops in 2006 , in their opinion they could also be synonyms of Bagaceratops .
The affiliation of Udanoceratops is controversial. In the construction of the lower jaw it shows similarities with the Leptoceratopsidae and is sometimes assigned to this group. Bainoceratops is likely to be closely related to Udanoceratops and how it should be classified.
In summary, a close relationship and monophyly of the two better known genera Protoceratops and Bagaceratops is largely beyond doubt, while the other, poorly preserved, finds are controversial.
literature
- You Hailu, Peter Dodson : Basal Ceratopsia. In: David B. Weishampel , Peter Dodson, Halszka Osmólska (eds.): The Dinosauria . 2nd edition. University of California Press, Berkeley CA et al. 2004, ISBN 0-520-24209-2 , pp. 478-493, digitized version (PDF; 807.25 kB) .
- David E. Fastovsky , David B. Weishampel: The Evolution and Extinction of the Dinosaurs. 2nd edition. Cambridge University Press, Cambridge et al. 2005, ISBN 0-521-81172-4 .
Web links
Individual evidence
- ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , pp. 250-257, online .
- ↑ after You & Dodson (2004).
- ^ You & Dodson (2004).
- ^ A b Paul C. Sereno : The fossil record, systematics and evolution of pachycephalosaurs and ceratopsians from Asia. In: Michael J. Benton , Mikhail A. Shishkin, David M. Unwin, Evgenii N. Kurochkin (eds.): The Age of Dinosaurs in Russia and Mongolia. Cambridge University Press, Cambridge et al. 2000, ISBN 0-521-55476-4 , pp. 480-516.
- ↑ You Hailu, Dong Zhiming : A New Protoceratopsid (Dinosauria: Neoceratopsia) from the Late Cretaceous of Inner Mongolia, China. In: Acta Geologica Sinica. English edition. Vol. 77, No. 3, 2003, ISSN 1000-9515 , pp. 299-303, doi : 10.1111 / j.1755-6724.2003.tb00745.x .
- ↑ Владимир Р. Алифанов: Два новых динозавра инфраотряда Neoceratopsia (Ornithischia) из отложений верхнего мела мела НинымэгэМтинской кэмэгэмтинской. In: Палеонтологический Журнал. No. 5, 2003, ISSN 0031-031X , pp. 77-88, abstract ( memento of the original from March 6, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. .
- ↑ Peter J. Makovicky , Mark A. Norell : Yamaceratops dorngobiensis, a new primitive ceratopsian (Dinosauria: Ornithischia) from the Cretaceous of Mongolia (= American Museum Novitates. No. 3530, ISSN 0003-0082 ). American Museum of Natural History, New York NY 2006, digital version (PDF; 7.3 MB) .
