''Angolatitan'' (meaning "Angolan giant") is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
titanosauriform sauropod
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their bo ...
dinosaur from the
Upper Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...
. It is also the first non-avian dinosaur discovered in
Angola
, national_anthem = " Angola Avante"()
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, capital = Luanda
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, religion_year = 2020
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. 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 basal
titanosauriform, when more derived titanosaurs were far more common.
[
]
Discovery and naming
After the Angolan 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 of ''Angolatitan''. The discovery was made by Octávio Mateus
Octávio Mateus (born 1975) is a Portuguese dinosaur paleontologist and biologist Professor of Paleontology at the Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa. He graduated in Universidade de Évora and received his PhD at U ...
on May the 25 near Iembe in the province of Bengo, and excavations were conducted during May and August 2006.[
''Angolatitan'' was described by Octávio Mateus and colleagues in 2011. The generic name means "Angolan giant". The specific name is derived from ]Adamastor
Adamastor is a mythological character created by the Portuguese poet Luís de Camões in his epic poem ''Os Lusíadas'' (first printed in 1572), as a personification of the Cape of Good Hope, symbolizing the dangers of the sea and the formidable ...
, a mythological sea monster that represented the dangers Portuguese sailors faced in the southern Atlantic.[ Until 1975, Angola was a Portuguese colony.
]
Description
The only specimen is a partial right forelimb, including shoulder blade
The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on either ...
, upper arm bone, the two bones of the lower arm (ulna
The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...
and radius
In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ...
), and three metacarpals. These fossils (Field number MGUAN-PA-003) are stored in the ''Museu de Geologia'' of the ''Universidade Agostinho Neto'' in Luanda
Luanda () is the capital and largest city in Angola. It is Angola's primary port, and its major industrial, cultural and urban centre. Located on Angola's northern Atlantic coast, Luanda is Angola's administrative centre, its chief seaport ...
.[
The upper arm bone measures , the ulna 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.][
]
Classification
''Angolatitan'' was a basal
Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''.
Science
* Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure
* Basal (medicine), a minimal level that is nec ...
titanosauriform, more derived than ''Brachiosaurus
''Brachiosaurus'' () is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about 154to 150million years ago. It was first described by American paleontologist Elmer S. Riggs in 1903 from fossils found in th ...
'' but less derived than '' Euhelopus'' and Titanosauria, which is notable given its relatively late appearance in the sauropod fossil record.
Recent phylogenetic tests run by Gorsack and Connor (2017) recover ''Angolatitan'' as a non-titanosaur
Titanosaurs (or titanosaurians; members of the group Titanosauria) were a diverse group of sauropod dinosaurs, including genera from all seven continents. The titanosaurs were the last surviving group of long-necked sauropods, with taxa still th ...
ian titanosauriform.
Palaeoecology
The specimen was found in a 50 m thick subsection of the Itombe Formation
The Itombe Formation is a geological formation of the Kwanza Basin in Angola dated to the Coniacian stage of the Late Cretaceous. The environment of deposition is shallow marine. Reptile fossils have been recovered from the Tadi beds locality wi ...
called the Tadi Beds. The Itombe Formation was considered Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by t ...
in age, but new data suggests that it dates to the Coniacian
The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series and spans the time between 89.8 ± 1 Ma and 86.3 ± 0.7 Ma (million years ago). The Coniacian is preceded by t ...
.Tetrapod
Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct theraps ...
s include the turtle ''Angolachelys mbaxi
''Angolachelys'' is an extinct genus of African eucryptodiran turtle which existed in Angola during the Turonian stage of the Late Cretaceous. The type species is ''Angolachelys mbaxi''. The type MGUAN-PA includes skull, jaw, and postcranial frag ...
'', the mosasaur
Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Greek ' meaning 'lizard') comprise a group of extinct, large marine reptiles from the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on th ...
s ''Angolasaurus bocagei
''Angolasaurus'' ("Angola lizard") is an extinct genus of mosasaur. Definite remains from this genus have been recovered from the Turonian and Coniacian of Angola, and possibly the Coniacian of the United States, the Turonian of Brazil, and the M ...
'' and '' Tylosaurus iembeensis,'' and several plesiosaur
The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia.
Plesiosaurs first appeared ...
fossils.[
The ecosystem inhabited by ''Angolatitan'' would have been desert-like. Presumably, this sauropod would have been well adapted to very dry conditions, similar to extant ]desert elephant
Desert elephants or desert-adapted elephants are not a distinct species of elephant but are African bush elephants (''Loxodonta africana'') that have made their homes in the Namib and Sahara deserts in Africa. At one time they were classified as ...
s.[
]
References