page_title: Diamantinasaurus
section_title: Description
hierarchical_section_title: Diamantinasaurus / Description
caption_attribution_description: English: Figure 5: Diamantinasaurus matildae, referred specimen AODF 836. (a,b) Braincase (left lateral and caudal views). (c,d) endocranium (left lateral oblique and ventral views). (e) Axis (left lateral view). (f) Cervical vertebra III (left lateral view). Abbreviations: bt, basal tuber; cca, internal carotid artery; coch, cochlea; crb, cerebral hemisphere; crbl, cerebellum; dds, dorsal dural sinus; fm, foramen magnum; hfp, hypophyseal fossa placement; ioa, internal ophthalmic artery; jug, jugular vein; lbr, endosseous labyrinth; mf, metotic foramen; midb, midbrain; mo, medulla oblongata; nc, nuchal crest; occ, occipital condyle; ofb, olfactory bulb; oft, olfactory tract; pp, paroccipital process; II, optic tract; III, oculomotor nerve; IV, trochlear nerve; V, trigeminal nerve; V1, ophthalmic branch of the trigeminal nerve; V2+3, maxillo-mandibular branch of the trigeminal nerve; VI, abducens nerve; VII, facial nerve; IX, glossopharyngeal nerve; X, vagus nerve; XI, accessory nerve; XII, hypoglossal nerve? structure of unknown or disputable identity/placement. Scale bar = 100 mm.
context_page_description: Diamantinasaurus is a genus of titanosaurian sauropod from Australia that lived during the early Late Cretaceous, about 94 million years ago. The type species of the genus is D. matildae, first described and named in 2009 by Scott Hocknull and colleagues based on fossil finds in the Winton Formation. Meaning "Diamantina lizard", the name is derived from the location of the nearby Diamantina River and the Greek word sauros, "lizard". The specific epithet is from the Australian song Waltzing Matilda, also the locality of the holotype and paratype. The known skeleton includes most of the forelimb, shoulder girdle, pelvis, hindlimb and ribs of the holotype, and one shoulder bone, a radius and some vertebrae of the paratype.
context_section_description: Diamantinasaurus was relatively small for a titanosaurian, possibly reaching 15–16 m (49–52 ft) in length and 15–20 t (17–22 short tons) in weight. Some of its relatives are known possessed armour osteoderms although is it unknown whether Diamantinasaurus had these. Like other sauropods, Diamantinasaurus would have been a large quadrupedal herbivore. Since the original description, the only major revisions include the misidentification of the "sternal plate", misplacement of manual phalanges III-1 and IV-1 as III-1 and V-1 respectively, and the identification of the missing portion of the fibula.
  The skull of Diamantinasaurus is incompletely known, with only the posterior skull roof and braincase being preserved. Similarly to Saltasaurus and Rapetosaurus and unlike Nemegtosaurus, the supratemporal fenestra was bordered by the frontal bone. Contrasting from both latter genera, Diamantinasaurus has a low supraoccipital above the cranial foramen, which is subsequently less than 1.5 times the height of the basal tuberae (which has a foramen). All of these traits are however shared with Saltasaurus. Multiple other traits are found throughout derived titanosaurs, including downward angling of the skull, prong shaped lateral braincase processes, an undisturbed pituitary fossa, and a more centrally located opening for the internal carotid artery.
  As is typical for Titanosauriformes, all cervical and dorsal vertebrae of Diamantinasaurus are opisthocoelous and camellate (many small internal chambers). The axis vertebra of the genus is short, a potential characteristic of Saltasauridae. Contrasting Saltasaurus and Rapetosaurus however, the prezygapophyses of Diamantinasaurus extend in front of the centrum. Only certain in the known middle dorsals, the postspinal lamina (ridge on posterior surface of spine) extends below the spine itself. Like more basal sauropods Europasaurus and Euhelopus, the dorsal vertebrae have a notch on the top of the posterior centrum face, giving it a heart-shaped appearance, contrasting more derived titanosaurs or Giraffatitan which possess flattened centra. Although differing in centrum shape, Opisthocoelicaudia and Diamantinasaurus are the only titanosaurs to share a ventral keel set within a sharply defined depression under the dorsals. Dorsal prezygapophyses are linked to the spine by a spinoprezygapophyseal lamina, which is absent in Opisthocoelicaudia and most dorsals of Rapetosaurus, and the postzygodiapophyseal lamina found in Diamantinasaurus is also absent in most derived titanosaurs. There is no indication of a hyposphene-hypantrum articulation, a diagnostic feature of derived titanosaurs. Shared with Opisthocoelicaudia, Alamosaurus and Lirainosaurus to the exclusion of other titanosaurs, Diamantinasaurus has a simple undivided ridge between the posterior centrum and diapophysis (posterior centrodiapophyseal lamina). A poorly preserved feature between the prezygapophysis and centrum may be the posterior centroprezygapophyseal lamina, found in some brachiosaurids, basal titanosaurs, and Opisthocoelicaudia. Diamantinasaurus possessed at least five, possibly six, sacral vertebrae.
caption: Referred neck vertebrae and skull of AODF 836
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