BackgroundAustralia's dinosaurian fossil record is exceptionally poor compared to that of other similar-sized continents. Most taxa are known from fragmentary isolated remains with uncertain taxonomic and phylogenetic placement. A better understanding of the Australian dinosaurian record is crucial to understanding the global palaeobiogeography of dinosaurian groups, including groups previously considered to have had Gondwanan origins, such as the titanosaurs and carcharodontosaurids.Methodology/Principal FindingsWe describe three new dinosaurs from the late Early Cretaceous (latest Albian) Winton Formation of eastern Australia, including; Wintonotitan wattsi gen. et sp. nov., a basal titanosauriform; Diamantinasaurus matildae gen. et sp. nov., a derived lithostrotian titanosaur; and Australovenator wintonensis gen. et sp. nov., an allosauroid. We compare an isolated astragalus from the Early Cretaceous of southern Australia; formerly identified as Allosaurus sp., and conclude that it most-likely represents Australovenator sp.Conclusion/SignificanceThe occurrence of Australovenator from the Aptian to latest Albian confirms the presence in Australia of allosauroids basal to the Carcharodontosauridae. These new taxa, along with the fragmentary remains of other taxa, indicate a diverse Early Cretaceous sauropod and theropod fauna in Australia, including plesiomorphic forms (e.g. Wintonotitan and Australovenator) and more derived forms (e.g. Diamantinasaurus).

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The titanosaurian sauropod dinosaur Diamantinasaurus matildae is represented by two individuals from the Cenomanian–lower Turonian ‘upper’ Winton Formation of central Queensland, north-eastern Australia. The type specimen has been described in detail, whereas the referred specimen, which includes several elements not present in the type series (partial skull, atlas, axis and postaxial cervical vertebrae), has only been described briefly. Herein, we provide a comprehensive description of this referred specimen, including a thorough assessment of the external and internal anatomy of the braincase, and identify several new autapomorphies of D. matildae. Via an expanded data matrix consisting of 125 taxa scored for 552 characters, we recover a close, well-supported relationship between Diamantinasaurus and its contemporary, Savannasaurus elliottorum. Unlike previous iterations of this data matrix, under a parsimony framework we consistently recover Diamantinasaurus and Savannasaurus as early-diverging members of Titanosauria using both equal weighting and extended implied weighting, with the overall topology largely consistent between analyses. We erect a new clade, named Diamantinasauria herein, that also includes the contemporaneous Sarmientosaurus musacchioi from southern Argentina, which shares several cranial features with the referred Diamantinasaurus specimen. Thus, Diamantinasauria is represented in the mid-Cretaceous of both South America and Australia, supporting the hypothesis that some titanosaurians, in addition to megaraptoran theropods and possibly some ornithopods, were able to disperse between these two continents via Antarctica. Conversely, there is no evidence for rebbachisaurids in Australia, which might indicate that they were unable to expand into high latitudes before their extinction in the Cenomanian–Turonian. Likewise, there is no evidence for titanosaurs with procoelous caudal vertebrae in the mid-Cretaceous Australian record, despite scarce but compelling evidence for their presence in both Antarctica and New Zealand during the Campanian–Maastrichtian. These later titanosaurs presumably dispersed into these landmasses from South America before the Campanian (~85 Mya), when seafloor spreading between Zealandia and Australia commenced. Although Australian mid-Cretaceous dinosaur faunas appear to be cosmopolitan at higher taxonomic levels, closer affinities with South America at finer scales are becoming better supported for sauropods, theropods and ornithopods.

We report new skeletal elements pertaining to the same individual which represents the holotype of Australovenator wintonensis, from the ‘Matilda Site’ in the Winton Formation (Upper Cretaceous) of western Queensland. The discovery of these new elements means that the hind limb of Australovenator is now the most completely understood hind limb among Neovenatoridae. The new hind limb elements include: the left fibula; left metatarsal IV; left pedal phalanges I-2, II-1, III-4, IV-2, IV-3; and right pedal phalanges, II-2 and III-1. The detailed descriptions are supported with three dimensional figures. These coupled with the completeness of the hind limb will increase the utility of Australovenator in comparisons with less complete neovenatorid genera. These specimens and the previously described hind limb elements of Australovenator are compared with other theropods classified as neovenatorids (including Neovenator, Chilantaisaurus, Fukuiraptor, Orkoraptor and Megaraptor). Hind limb length proportion comparisons indicate that the smaller neovenatorids Australovenator and Fukuiraptor possess more elongate and gracile hind limb elements than the larger Neovenator and Chilantaisaurus. Greater stride lengths to body size exist in both Fukuiraptor and Australovenator with the femur discovered to be proportionally shorter the rest of the hind limb length. Additionally Australovenator is identified as possessing the most elongate metatarsus. The metatarsus morphology varies with body size. The larger neoventorids possess a metatarsus with greater width but shorter length compared to smaller forms.

The hypertrophied manual claws and modified manus of megaraptoran theropods represent an unusual morphological adaptation among carnivorous dinosaurs. The skeleton of Australovenator wintonensis from the Cenomanian of Australia is among the most complete of any megaraptorid. It presents the opportunity to examine the range of motion of its forearm and the function of its highly modified manus. This provides the basis for behavioural inferences, and comparison with other Gondwanan theropod groups. Digital models created from computed tomography scans of the holotype reveal a humerus range of motion that is much greater than Allosaurus, Acrocanthosaurus, Tyrannosaurus but similar to that of the dromaeosaurid Bambiraptor. During flexion, the radius was forced distally by the radial condyle of the humerus. This movement is here suggested as a mechanism that forced a medial movement of the wrist. The antebrachium possessed a range of motion that was close to dromaeosaurids; however, the unguals were capable of hyper-extension, in particular manual phalanx I-2, which is a primitive range of motion characteristic seen in allosaurids and Dilophosaurus. During flexion, digits I and II slightly converge and diverge when extended which is accentuated by hyperextension of the digits in particular the unguals. We envision that prey was dispatched by its hands and feet with manual phalanx I-2 playing a dominant role. The range of motion analysis neither confirms nor refutes current phylogenetic hypotheses with regards to the placement of Megaraptoridae; however, we note Australovenator possessed, not only a similar forearm range of motion to some maniraptorans and basal coelurosaurs, but also similarities with Tetanurans (Allosauroids and Dilophosaurus).

The titanosaurian sauropod dinosaur Savannasaurus elliottorum is 20 represented by a partial postcranial skeleton from the lower Upper Cretaceous (Cenomanian-21 lowermost Turonian) Winton Formation of Queensland, northeast Australia. Here, we present 22 a detailed description of this specimen, as well as an emended diagnosis of Savannasaurus 23 elliottorum. Savannasaurus displays numerous character states that are generally regarded as 24 plesiomorphic for Titanosauria, as well as several traits that are often regarded as apomorphic 25 of that clade or a less inclusive subset thereof. Several features of Savannasaurus support a 26 close relationship with the coeval Diamantinasaurus matildae, and this clade appears to 27 occupy an early-branching position within Titanosauria. Relative to body size, the thoracic 28 and abdominal breadth of Savannasaurus is greater than that seen in giant titanosaurs such as 29 the contemporaneous South American lognkosaurians; however, this relative breadth is not 30 quite as extreme as that of the small-bodied latest Cretaceous saltasaurines, or 31 Opisthocoelicaudia skarzynskii. The possible advantages engendered by the barrel-shaped 32 thorax, robust limbs, wide-gauge gait, and lack of hyposphene-hypantrum articulations are 33 explored, and it is hypothesised that these traits were positively selected by the wet, 34 temperate floodplain environment in which Savannasaurus lived. Greater stability and 35 flexibility might have reduced the risk of bogging, and/or facilitated more expedient self-36 extraction from muddy waterholes. Similar environmental pressures acting upon other 37 titanosaurian taxa or clades elsewhere might have led to the repeated independent 38 development, or accentuation, of the bauplan regarded as 'typical' for the clade Titanosauria. 39 This would explain the many observed convergences between Savannasaurus and 40 Diamantinasaurus, and Saltasauridae. 41 42 INTRODUCTION Society of Vertebrate Paleontology Journal of Vertebrate Paleontology: For Review Only 43 Cretaceous sedimentary sequences in Australia have mostly provided only limited 44 evidence of sauropod dinosaurs. The Western Australian Cretaceous record is restricted to 45 footprints from the Valanginian-Barremian Broome Sandstone (Thulborn et al., 1994; 46 Thulborn, 2012;Salisbury et al., 2017), whereas the Victorian Cretaceous sauropod record is 47 non-existent: both the upper Strzelecki Group (upper Barremian-lower Aptian) and the 48 Eumeralla Formation (upper Aptian-lower Albian) entirely lack sauropods, despite 49 preserving abundant remains of ornithopods, ankylosaurs, and theropods (Poropat et al., 50 2018). The upper Albian Toolebuc Formation of Queensland has produced several 51 fragmentary sauropod specimens (Molnar and Salisbury, 2005), whereas the upper Albian 52 Allaru Mudstone has yielded only one: the holotype of the somphospondylan titanosauriform 53 Austrosaurus mckillopi (Longman, 1933; Poropat et al., 2017). The Cenomanian Griman 54 Creek Formation in New South Wales has produce...

Austrosaurus mckillopi Longman, 1933 was the first Cretaceous sauropod reported from Australia, and the first Cretaceous dinosaur reported from Queensland (northeast Australia). This sauropod taxon was established on the basis of several fragmentary presacral vertebrae (QM F2316) derived from the uppermost Lower Cretaceous (upper Albian) Allaru Mudstone, at a locality situated 77 km west-northwest of Richmond, Queensland. Prior to its rediscovery in 2014, the type site was considered lost after failed attempts to relocate it in the 1970s. Excavations at the site in 2014 and 2015 led to the recovery of several partial dorsal ribs and fragments of presacral vertebrae, all of which clearly pertained to a single sauropod dinosaur. The discovery of new material belonging toof the type individual of Austrosaurus mckillopi, in tandem with a reassessment of the type seriesmaterial collected in the 1930s, has facilitated the rearticulation of the specimen. The resultant vertebral series comprises six presacral vertebrae—the posteriormost cervical and five anteriormost dorsals—in association with five left dorsal ribs and one right one. The fragmentary nature of the type specimen has historically hindered assessments of the phylogenetic affinities of Austrosaurus, as has the fact that these evaluations were often based on a subset of the type material. The reappraisal of the type series of Austrosaurus presented herein, on the basis of both external morphology and internal morphology visualised through CT data, validates it as a diagnostic titanosauriform taxon (, tentatively placed in Somphospondyli),, and characterised by the possession of an accessory lateral pneumatic foramen on dorsal vertebra I (a feature which appears to be autapomorphic) and by the presence of a robust ventral midline ridge on the centra of dorsal vertebrae I and II. The interpretation of the anteriormost preserved vertebra in Austrosaurus as a posterior cervical has also prompted the re-evaluation of an isolated, partial, posterior cervical vertebra (QM F6142, the “Hughenden sauropod”) derived from the upper Albian Toolebuc Formation (which underlies the Allaru Mudstone). Although this vertebra preserves an apparent unique character of its own (a spinopostzygapophyseal lamina fossa), it is not able to be referred unequivocally to Austrosaurus and is retained as Titanosauriformes indet. Austrosaurus mckillopi is one of the oldest known sauropods from the Australian Cretaceous based on skeletal remains, and potentially provides phylogenetic and/or palaeobiogeographic context for later taxa such as Wintonotitan wattsi, Diamantinasaurus matildae and Savannasaurus elliottorum

The Australian pterosaur record is poor by world standards, comprising fewer than 20 fragmentary specimens. Herein, we describe the new genus and species Ferrodraco lentoni gen. et sp. nov., based on the most complete pterosaur specimen ever found in Australia, and the first reported from the Winton Formation (Cenomanian–lower Turonian). The presence of premaxillary and mandibular crests, and spike-shaped teeth with subcircular bases, enable Ferrodraco to be referred to Anhangueria. Ferrodraco can be distinguished from all other anhanguerian pterosaurs based on two dental characters: the first premaxillary and mandibular tooth pairs are small; and the fourth–seventh tooth pairs are smaller than the third and eighth ones. Ferrodraco was included in a phylogenetic analysis of Pterosauria and resolved as the sister taxon to Mythunga camara (upper Albian Toolebuc Formation, Australia), with that clade occupying the most derived position within Ornithocheiridae. Ornithocheirus simus (Albian Cambridge Greensand, England), Coloborhynchus clavirostris (Valanginian Hastings Sands, England), and Tropeognathus mesembrinus (upper Aptian–lower Albian Romualdo Formation, Brazil) were resolved as successive sister taxa, which suggests that ornithocheirids were cosmopolitan during the Albian–Cenomanian. Furthermore, the stratigraphic age of Ferrodraco lentoni (Cenomanian–lower Turonian) implies that anhanguerians might have survived later in Australia than elsewhere.