Agilisaurus

Agilisaurus
Agilisaurus
Temporal occurrence
Middle Jurassic ( Bathonian to Callovian )
168.3 to 163.5 million years
Locations
lower Shaximiao formation , Sichuan ( People's Republic of China )
Systematics
Dinosaur (dinosauria) Pelvic dinosaur (Ornithischia) Assignment uncertain Agilisaurus
Scientific name
Agilisaurus
Peng , 1990

Skeleton of Agilisaurus (right in front) in the museum in Zigong , left in the background Gasosaurus .

Agilisaurus ( Agilis , Latin for an agile bipedal animal) is an ornithopic dinosaur whose fossil remains were found in 1984 when the foundations of the Zigong Museum were being built. They consist of a skull and an almost completely preserved skeleton. It is one of the most fully preserved skeletons of small ornithopods.

The only valid species is Agilisaurus louderbacki . The species epithet was given in honor of the American geologist George D. Louderback , who was the first scientist to search for dinosaurs in the Sichuan Basin in 1915 . Hexinlusaurus multidens was temporarily assigned to the genus as the second species ( A.multidens ).

features

Agilisaurus was about 1.2 meters long and probably weighed 40 kg. The skull was short and tall, the eyes were large.

The mouth was covered with blade-like, sawed teeth. Five teeth were on the premaxillary , 14 on each maxillary, and 20 on each dental . The premaxillary teeth were pointed and enlarged. The tips of the teeth on the maxillary and dentals were triangular or rhombic.

Agilisaurus had 9 cervical, 15 trunk, 5 sacrum and 44 caudal vertebrae. The neck and torso were short, the tail long and more than half the length of the body. The foot has the phalangeal formula 2.3.4.5.0.

Systematics

Agilisaurus was originally assigned to the Fabrosauridae , a taxon that is no longer considered valid today. Then, as the following cladogram shows, he was considered the most basal euornithopod .

Ornithischia	Thyreophora   Cerapoda     Ornithopoda    Heterodontosauridae   Euornithopoda    Agilisaurus      Other taxa      Marginocephalia

In a more recent study it stands outside the Cerapoda and therefore no longer belongs to the Ornithopoda . The new systematic position shows the following cladogram:

Ornithischia	Thyreophora   Neornithischia    Agilisaurus   Cerapoda    Ornithopoda      Marginocephalia

literature

• David B. Norman : Basal Iguanodontia. 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. 413-437.

Individual evidence

1. ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ 2010, ISBN 978-0-691-13720-9 , p. 274, online .
2. ^ Paul M. Barrett , Richard J. Butler, Fabien Knoll: Small-bodied ornithischian dinosaurs from the Middle Jurassic of Sichuan, China. In: Journal of Vertebrate Paleontology. Vol. 25, No. 4, 2005, ISSN  0272-4634 , pp. 823-834, doi : 10.1671 / 0272-4634 (2005) 025 [0823: SODFTM] 2.0.CO; 2 .
3. ↑ 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 .
4. ^ Richard J. Butler, Paul Upchurch , David B. Norman : The phylogeny of the ornithischian dinosaurs. In: Journal of Systematic Palaeontology. Vol. 6, No. 1, 2008, ISSN  1477-2019 , pp. 1-40, doi : 10.1017 / S1477201907002271 .

Web links

Commons : Agilisaurus  - collection of images, videos and audio files