Atlascopcosaurus
| Atlascopcosaurus | ||||||||||
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Atlascopcosaurus live reconstruction |
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| Temporal occurrence | ||||||||||
| Lower Cretaceous (Upper Aptian to Lower Albian ) | ||||||||||
| 123 to 110.2 million years | ||||||||||
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Atlascopcosaurus | ||||||||||
| Rich & Vickers-Rich , 1989 | ||||||||||
| Art | ||||||||||
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Atlascopcosaurus is a dubious (dubious) genus of the bird basin dinosaur (Ornithischia) from the group of Ornithopoda . It is only known from the fragment of an upper jaw , which comes from the so-called "Dinosaur Cove" in the Australian state of Victoria and is dated to the Lower Cretaceous (Upper Aptium to Lower Albium ). Atlascopcosaurus wasscientifically described for the first timein 1989 by Thomas Rich and Patricia Vickers-Rich ; only species is Atlascopcosaurus loadsi . Since the genus cannot be distinguished from related genera on the basis of unique anatomical features, it is now used as the noun dubium (genus with dubious validity).
Material and characteristics
In the single Fund ( holotype , copy number NMV P166409) is a fragment of the left upper jaw (maxilla) with an erupted and three unerupted molars. Initially, the genus was assigned other finds - another left upper jaw and fragments of the lower jaw - but the assignment of these finds to Atlascopcosaurus was recently rejected.
In their first description, Thomas Rich and Patricia Vickers-Rich (1989) demarcated the genus from other genera known at the time based on characteristics of the teeth: For example, these researchers stated that the tooth crowns of the upper jaw drop forward so that their highest point is close the back of the teeth. Today it is known, however, that these characteristics are also present in various other genera and were therefore not unique to Atlascopcosaurus .
Systematics
Atlascopcosaurus was initially described as a member of the Hypsilophodontidae , a group of small, two-legged herbivores within the Ornithopoda . Today the Hypsilophodontidae are considered to be paraphyletic , so they do not represent a natural group. Atlascopcosaurus is classified today as an original representative of the Ornithopoda with unclear relationships. Federico Agnolin (2010) notes that the jaw fragment found shows similarities with the genera Gasparinisaura and Anabisetia - a possible closer relationship with these genera can only be verified on the basis of further fossils.
Find history and naming
The fossil was found together with 85 other bone fragments at a depth of over 400 meters in the so-called "Dinosaur Bay" in Victoria, Australia. The excavations were made possible by the Swedish Atlas Copco group, which provided the necessary mining equipment. The fossils come from sediments from former river beds; lithostratigraphically they belong to the Otway group .
While the generic name is named after the Atlas Copco group, the second part of the species name honors William Loads, the main manager of Atlas Copco at the time of the excavation.
Individual evidence
- ↑ a b c Thomas H. Rich , Patricia Vickers-Rich : Polar dinosaurs and biotas of the Early Cretaceous of southeastern Australia. In: National Geographic Research. Vol. 5, No. 1, 1989, ISSN 8755-724X , pp. 15-53, here pp. 18, 31-33.
- ↑ a b c d Federico L. Agnolin, Martín D. Ezcurra, Diego F. Pais, Steven W. Salisbury: A reappraisal of the Cretaceous non-avian dinosaur faunas from Australia and New Zealand: evidence for their Gondwanan affinities. In: Journal of Systematic Palaeontology. Vol. 8, No. 2, 2010, ISSN 1477-2019 , pp. 257-300, here pp. 268-269, doi : 10.1080 / 14772011003594870 .
- ↑ Donald F. Glut : Dinosaurs. The Encyclopedia. McFarland, Jefferson NC et al. 1997, ISBN 0-89950-917-7 , pp. 177-178.