Diamantinasaurus
Encyclopedia
Diamantinasaurus is a genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of derived
Derived
In phylogenetics, a derived trait is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered. This may also refer to structures that are not present in an organism, but were present in its ancestors, i.e. traits that have undergone secondary...

 titanosaur
Titanosaur
Titanosaurs were a diverse group of sauropod dinosaurs, which included Saltasaurus and Isisaurus. It includes some of the heaviest creatures ever to walk the earth, such as Argentinosaurus and Paralititan — which some believe have weighed up to 100 tonnes...

ian dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

 from late Albian
Albian
The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 112.0 ± 1.0 Ma to 99.6 ± 0.9 Ma...

 (Early Cretaceous
Early Cretaceous
The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...

)-age rocks of Australia. It is known from partial postcrania
Postcrania
Postcrania[p] in zoology and vertebrate paleontology refers to all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g...

l remains.

Description and history

Diamantinasaurus is based on
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

 AODL 603, a partial skeleton including a right shoulder blade
Scapula
In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....

, a sternal
Sternum
The sternum or breastbone is a long flat bony plate shaped like a capital "T" located anteriorly to the heart in the center of the thorax...

 plate, much of the forelimbs, much of the hindlimbs except the feet, partial hips
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...

, and ribs. Diamantinasaurus was unusual for a derived titanosaurian in retaining a thumb claw. The limb bones were stout. Diamantinasaurus was described in 2009
2009 in paleontology
-Anomalocaridids:-Arachnids:-Insects:-Cephalopods:Three new species of extinct Octopoda discovered in 2009. The species - Keuppia hyperbolaris, Keuppia levante, and Styletoctopus annae - lived about 95 million years ago, and bear a strong resemblance to modern octopuses, suggesting that the...

 by Scott Hocknull
Scott Hocknull
Scott Hocknull is a vertebrate palaeontologist and Senior Curator in Geology at the Queensland Museum in Brisbane. He was the 2002 recipient of the Young Australian of the Year Award....

 and colleagues. The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

 is D. matildae, in reference to the folk song "Waltzing Matilda", which was written by Banjo Paterson
Banjo Paterson
Andrew Barton "Banjo" Paterson, OBE was an Australian bush poet, journalist and author. He wrote many ballads and poems about Australian life, focusing particularly on the rural and outback areas, including the district around Binalong, New South Wales where he spent much of his childhood...

 in nearby Winton
Winton, Queensland
-Qantas:Winton was one of the founding towns of the Australian airline Qantas. The first board meeting was held at the Winton Club on 10 February 1921.-Waltzing Matilda:...

. A phylogenetic analysis
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...

 found Diamantinasaurus to be a lithostrotian titanosaurian sauropod, in the same clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 as sauropods such as Opisthocoelicaudia
Opisthocoelicaudia
Opisthocoelicaudia was 12-metre-long sauropod dinosaur of the Late Cretaceous Period discovered in Mongolia in 1965 by Polish and Mongolian scientists in what is now the Gobi Desert...

and Saltasaurus
Saltasaurus
Saltasaurus is a genus of titanosaurid sauropod dinosaur of the Late Cretaceous Period. Relatively small among sauropods, though still massive by the standards of modern creatures, Saltasaurus was characterized by a diplodocid-like head...

. The discovery has been nicknamed "Matilda" after "Waltzing Matilda", and is described as a stocky herbivore about 52 feet (15.8 m) in length.

Many titanosaurids are known to have had small armor
Armour (zoology)
Armour in animals is external or superficial protection against attack by predators, formed as part of the body , usually through the hardening of body tissues, outgrowths or secretions. It has therefore mostly developed in 'prey' species...

 plates, however, it is not known whether Diamantinasaurus had them.

Paleobiology

AODL 603 was found about 60 kilometres (37.3 mi) northwest of Winton, near Elderslie Station. It was recovered from the lower part of the Winton Formation
Winton Formation
The Winton Formation is a Cretaceous formation in central-western Queensland, Australia. The sauropod dinosaur Austrosaurus is found in the early Cretaceous Winton formation....

, dated to the latest Albian. AODL 603 was found in a clay layer between sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

 layers, interpreted as an oxbow lake
Oxbow lake
An oxbow lake is a U-shaped body of water formed when a wide meander from the main stem of a river is cut off to create a lake. This landform is called an oxbow lake for the distinctive curved shape, named after part of a yoke for oxen. In Australia, an oxbow lake is called a billabong, derived...

 deposit. Also found at the site were the type specimen
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

 of the theropod Australovenator
Australovenator
Australovenator is a genus of allosauroid theropod dinosaur from late Albian -age rocks of Australia...

, bivalves
Bivalvia
Bivalvia is a taxonomic class of marine and freshwater molluscs. This class includes clams, oysters, mussels, scallops, and many other families of molluscs that have two hinged shells...

, fish, turtles, crocodilia
Crocodilia
Crocodilia is an order of large reptiles that appeared about 84 million years ago in the late Cretaceous Period . They are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria...

ns, and plant fossils. The Winton Formation had a faunal assemblage including bivalves, gastropods
Gastropoda
The Gastropoda or gastropods, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca. The class Gastropoda includes snails and slugs of all kinds and all sizes from microscopic to quite large...

, insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s, the lungfish
Lungfish
Lungfish are freshwater fish belonging to the Subclass Dipnoi. Lungfish are best known for retaining characteristics primitive within the Osteichthyes, including the ability to breathe air, and structures primitive within Sarcopterygii, including the presence of lobed fins with a well-developed...

 Metaceratodus
Metaceratodus
Metaceratodus is an extinct genus of prehistoric sarcopterygian or lobe-finned fish. From the Early Cretaceous of Queensland, Australia.-See also:* Sarcopterygii* List of sarcopterygians* List of prehistoric bony fish...

, turtles, the crocodilia
Crocodilia
Crocodilia is an order of large reptiles that appeared about 84 million years ago in the late Cretaceous Period . They are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria...

n Isisfordia
Isisfordia
Isisfordia is an extinct genus of crocodyliform closely related to crocodilians that lived during the Middle Cretaceous . Its fossils were discovered in the Winton Formation in Isisford, Queensland, Australia in the mid 1990s...

, pterosaur
Pterosaur
Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...

s, and several types of dinosaurs, such as the theropod Australovenator, the sauropod Wintonotitan
Wintonotitan
Wintonotitan is a genus of titanosauriform dinosaur from late Albian -age rocks of Australia. It is known from partial postcranial remains.-Description and history:...

, and unnamed ankylosauria
Ankylosauria
Ankylosauria is a group of herbivorous dinosaurs of the order Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms. Ankylosaurs were bulky quadrupeds, with short, powerful limbs. They are first known to have appeared in the early Jurassic Period of...

ns and hypsilophodont
Hypsilophodont
Hypsilophodonts were small ornithopod dinosaurs, regarded as fast, herbivorous bipeds on the order of 1–2 meters long . They are known from Asia, Australia, Europe, New Zealand, North America, and South America, from rocks of Middle Jurassic to late Cretaceous age...

s. Diamantinasaurus bones can be distinguished from Wintonotitan bones because Diamantinasaurus bones are more robust. Plants known from the formation include fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...

s, ginkgo
Ginkgo
Ginkgo , also spelled gingko and known as the Maidenhair Tree, is a unique species of tree with no close living relatives...

es, gymnosperm
Gymnosperm
The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...

s, and angiosperms. Like other sauropods, Diamantinasaurus would have been a large quadruped
Quadruped
Quadrupedalism is a form of land animal locomotion using four limbs or legs. An animal or machine that usually moves in a quadrupedal manner is known as a quadruped, meaning "four feet"...

al herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...

.
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