| Angolatitan | |
|---|---|
 | |
| Reconstruction | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Clade: | †Sauropoda |
| Clade: | †Macronaria |
| Clade: | †Somphospondyli |
| Genus: | †Angolatitan Mateuset al.,2011 |
| Type species | |
| Angolatitan adamastor | |
Angolatitan (meaning "Angolan giant") is agenus oftitanosauriformsauropod dinosaur from theUpper Cretaceous. It is also the first non-avian dinosaur discovered inAngola. The genus contains a single species,Angolatitan adamastor, known from a partial right forelimb.Angolatitan was a relict form of its time; it was a Late Cretaceous basaltitanosauriform, when more derived titanosaurs were far more common.[1]
During theAngolan Civil War, palaeontological field research was not possible in Angola.[2] After the civil war ended in 2002, the PaleoAngola project planned the first Angolan palaeontological expeditions since the 1960s. The first of these expeditions started in 2005 to explore Angola's fossil rich upper Cretaceous rocks, leading to the discovery ofAngolatitan. The discovery was made byOctávio Mateus on May the 25 nearIembe in the province ofBengo, and excavations were conducted during May and August 2006.[1]
Angolatitan was described by Octávio Mateus and colleagues in 2011. The generic name means "Angolan giant". The specific name is derived fromAdamastor, a mythological sea monster that represented the dangers Portuguese sailors faced in the southern Atlantic.[1] Until 1975, Angola was a Portuguese colony.[2]
The only specimen is a partial right forelimb, includingshoulder blade,upper arm bone, the two bones of the lower arm (ulna andradius), and threemetacarpals. These fossils (Field number MGUAN-PA-003) are stored in theMuseu de Geologia of theUniversidade Agostinho Neto inLuanda.[1]
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, theolecranon was absent, and the first metacarpal was not bowed.[1]
Angolatitan was abasaltitanosauriform, more derived thanBrachiosaurus but less derived thanEuhelopus andTitanosauria, which is notable given its relatively late appearance in the sauropod fossil record.
Recent phylogenetic tests run by Gorsack and Connor (2017) recoverAngolatitan as a non-titanosauriantitanosauriform.[3]
The specimen was found in a 50 m thick subsection of theItombe Formation called the Tadi Beds. The Itombe Formation was consideredTuronian in age, but new data suggests that it dates to theConiacian.[4] These rocks were deposited under marginal marine conditions; fossils include ammonites, echinoderms, and fishes (including sharks).Tetrapods include the turtleAngolachelys mbaxi, themosasaursAngolasaurus bocagei andTylosaurus iembeensis, and severalplesiosaur fossils.[1]
The ecosystem inhabited byAngolatitan would have been desert-like. Presumably, this sauropod would have been well adapted to very dry conditions, similar to extantdesert elephants.[1]
