''Angolatitan'' (meaning "Angolan giant") is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

titanosauriform Macronaria is a clade of sauropod dinosaurs. Macronarians are named after the large diameter of the nasal opening of their skull, known as the external naris, which exceeded the size of the orbit, the skull opening where the eye is located (hence ...

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 b ...

dinosaur from the

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent 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 ''cret ...

. It is also the first non-avian dinosaur discovered in

Angola Angola, officially the Republic of Angola, is a country on the west-Central Africa, central coast of Southern Africa. It is the second-largest Portuguese-speaking world, Portuguese-speaking (Lusophone) country in both total area and List of c ...

. 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

, when more derived titanosaurs were far more common.

Discovery and naming

After the

Angolan Civil War The Angolan Civil War () was a civil war in Angola, beginning in 1975 and continuing, with interludes, until 2002. The war began immediately after Angola became independent from Portugal in November 1975. It was a power struggle between two for ...

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 Portugal, Portuguese dinosaur paleontologist and biologist Professor of Paleontology at the Faculdade de Ciências e Tecnologia da NOVA University Lisbon, Universidade Nova de Lisboa. He graduated in University of � ...

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, 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 (: 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 side ...

, upper arm bone, the two bones of the lower arm (

ulna The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...

and

radius In classical geometry, a radius (: radii or radiuses) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The radius of a regular polygon is th ...

), and three

metacarpals In human anatomy, the metacarpal bones or metacarpus, also known as the "palm bones", are the appendicular skeleton, appendicular bones that form the intermediate part of the hand between the phalanges (fingers) and the carpal bones (wrist, wris ...

. These fossils (Field number MGUAN-PA-003) are stored in the ''Museu de Geologia'' of the

Universidade Agostinho Neto The Agostinho Neto University () is the largest public university of Angola, based in Luanda and in the nearby city of Talatona, in Angola. In the academic year 2005–06, 68 licensing courses were ministered by the university: 18 in Bachelo ...

Luanda Luanda ( ) is the Capital city, capital and List of cities and towns in Angola, largest city of Angola. It is Angola's primary port, and its major industrial, cultural and urban centre. Located on Angola's northern Atlantic coast, Luanda is Ang ...

. 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 The olecranon (, ), is a large, thick, curved bony process on the proximal, posterior end of the ulna. It forms the protruding part of the elbow and is opposite to the cubital fossa or elbow pit (trochlear notch). The olecranon serves as a lever ...

was absent, and the first metacarpal was not bowed.

Classification

''Angolatitan'' was a basal

, more derived than ''

Brachiosaurus ''Brachiosaurus'' () is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about . It was first Species description, described by American paleontologist Elmer S. Riggs in 1903 in paleontology, 1903 from fossi ...

'' but less derived than ''

Euhelopus ''Euhelopus'' is a genus of sauropod dinosaur that lived between 145 and 133 million years ago during the Berriasian and Valanginian ages of the Early Cretaceous in what is now Shandong Province in China. It was a large quadrupedal herbivore. Lik ...

'' and

Titanosauria Titanosaurs (or titanosaurians; members of the group Titanosauria) were a diverse group of Sauropoda, sauropod dinosaurs, including genera from all seven continents. The titanosaurs were the last surviving group of long-necked sauropods, with tax ...

, 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 thr ...

ian

Palaeoecology

The specimen was found in a 50 m thick subsection of the

Itombe Formation The Itombe Formation is a geological formation of the Angola Basin#Kwanza Basin, 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 ...

called the Tadi Beds. The Itombe Formation was considered

Turonian The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...

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 ...

. These rocks were deposited under marginal marine conditions; fossils include ammonites, echinoderms, and fishes (including sharks).

Tetrapod A tetrapod (; from Ancient Greek :wiktionary:τετρα-#Ancient Greek, τετρα- ''(tetra-)'' 'four' and :wiktionary:πούς#Ancient Greek, πούς ''(poús)'' 'foot') is any four-Limb (anatomy), limbed vertebrate animal of the clade Tetr ...

s include the turtle '' Angolachelys mbaxi'', the

mosasaur Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Ancient Greek, Greek ' meaning 'lizard') are an extinct group of large aquatic reptiles within the family Mosasauridae that lived during the Late Cretaceous. Their first fossil remains wer ...

s '' Angolasaurus bocagei'' and '' Tylosaurus iembeensis,'' and several

plesiosaur The Plesiosauria or plesiosaurs are an Order (biology), order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period (geology), Period, possibly in the Rhaetian st ...

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. Previously they were classified as ...

References

{{Taxonbar, from=Q1287938 Macronaria Dinosaur genera Coniacian dinosaurs Dinosaurs of Africa Fossil taxa described in 2011