Angolatitan
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Angolatitan Temporal range: Late Turonian, 90 Ma |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Superorder: | Dinosauria |
| Order: | Saurischia |
| Suborder: | †Sauropodomorpha |
| Infraorder: | †Sauropoda |
| (unranked): | †Titanosauriformes |
| (unranked): | †Somphospondyli |
| Genus: |
†Angolatitan Mateus et al., 2011 |
| Species | |
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Angolatitan ("Angolan giant") is a genus of sauropod dinosaur from the Upper Cretaceous and the first dinosaur discovered in Angola. Based on a forelimb, it was described in 2011 by Octávio Mateus and colleagues. The only species is Angolatitan adamastor. Angolatitan was a relict form of its time, being a basal titanosauriform sauropod in a world dominated by the more derived titanosaurs.
The only specimen is a partial right forelimb, including shoulder blade, upper arm bone, the two bones of the lower arm (ulna and radius), and three metacarpals. These fossils (Field number MGUAN-PA-003) are stored in the Museu de Geologia of the Universidade Agostinho Neto in Luanda.
The upper arm bone measures 110 centimetres (43 in), the ulna 69 centimetres (27 in) in length. In general, the forelimb was less robust than in most of the more derived titanosaurs. The metacarpals were slender and equal in length; those of titanosaurs were more robust with varying lengths. Unlike titanosaurs, the olecranon was absent, and the first metacarpal was not bowed.
Angolatitan was a basal titanosauriform, more derived than Brachiosaurus but less derived than Euhelopus and Titanosauria, which is notable given its relatively late appearance in the sauropod fossil record. It is classified as a Somphospondyli based on features of the upper arm bone.
The specimen was found in a 50 m thick subsection of the Itombe Formation, called the Tadi Beds, which could be dated late Turonian in age (approximately 90 million years old) based on the characteristic fish community. These rocks were deposited under marginary marine conditions; fossils include ammonites, echinoderms, and fishes (including sharks). Tetrapods include the turtle Angolachelys mbaxi, the Mosasaurs Angolasaurus bocagei and Tylosaurus iembeensis as well as several plesiosaur fossils.
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