Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 6, 34467

New Australian Sauropods Shed Light on Cretaceous Dinosaur Palaeobiogeography

Affiliations

New Australian Sauropods Shed Light on Cretaceous Dinosaur Palaeobiogeography

Stephen F Poropat et al. Sci Rep.

Abstract

Australian dinosaurs have played a rare but controversial role in the debate surrounding the effect of Gondwanan break-up on Cretaceous dinosaur distribution. Major spatiotemporal gaps in the Gondwanan Cretaceous fossil record, coupled with taxon incompleteness, have hindered research on this effect, especially in Australia. Here we report on two new sauropod specimens from the early Late Cretaceous of Queensland, Australia, that have important implications for Cretaceous dinosaur palaeobiogeography. Savannasaurus elliottorum gen. et sp. nov. comprises one of the most complete Cretaceous sauropod skeletons ever found in Australia, whereas a new specimen of Diamantinasaurus matildae includes the first ever cranial remains of an Australian sauropod. The results of a new phylogenetic analysis, in which both Savannasaurus and Diamantinasaurus are recovered within Titanosauria, were used as the basis for a quantitative palaeobiogeographical analysis of macronarian sauropods. Titanosaurs achieved a worldwide distribution by at least 125 million years ago, suggesting that mid-Cretaceous Australian sauropods represent remnants of clades which were widespread during the Early Cretaceous. These lineages would have entered Australasia via dispersal from South America, presumably across Antarctica. High latitude sauropod dispersal might have been facilitated by Albian-Turonian warming that lifted a palaeoclimatic dispersal barrier between Antarctica and South America.

Figures

Figure 1
Figure 1. Map of Queensland, northeast Australia, showing the distribution of Cretaceous outcrop.
From Poropat et al..
Figure 2
Figure 2. Winton Formation outcrop surrounding the town of Winton, with key localities marked.
The holotype of Savannasaurus elliottorum (AODF 660) and the new specimen of Diamantinasaurus matildae (AODF 836) were both found on Belmont sheep station, whereas the type specimen of Diamantinasaurus matildae (AODF 603) was found on Elderslie sheep station. This map was drafted by the senior author (S.F.P.) in Adobe Illustrator CS5, and incorporates geological information from Vine and Vine & Casey [© Commonwealth of Australia (Geoscience Australia) 2016. This product is released under the Creative Commons Attribution 4.0 International Licence. http://creativecommons.org/licenses/by/4.0/legalcode].
Figure 3
Figure 3. Savannasaurus elliottorum gen. et sp. nov., holotype specimen AODF 660.
Type site map showing the approximate association of the bones. Scale bar = 1 m.
Figure 4
Figure 4. Savannasaurus elliottorum gen. et sp. nov., holotype specimen AODF 660.
(a–e) Dorsal vertebrae (left lateral view). (f) Sacrum (ventral view). (g,h) Caudal vertebrae (left lateral view). (i) Left coracoid (lateral view). (j) Right sternal plate (ventral view). (k) Left radius (posterior view). (l) Right metacarpal III (anterior view). (m) Left astragalus (anterior view). (n) Coossified right and left pubes (anterior view). A number of ribs were preserved but have been omitted for clarity. Scale bar = 500 mm.
Figure 5
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.
Figure 6
Figure 6. Scapulae of Diamantinasaurus matildae.
(a) Diamantinasaurus matildae holotype right scapula AODF 603 (right lateral view). (b) Diamantinasaurus matildae referred right scapula AODF 836 (right lateral view). Abbreviations: fs, flattened surface; vtp, ventral triangular process. Scale bar = 200 mm for (a) and 140 mm for (b).
Figure 7
Figure 7. Time-calibrated phylogenetic tree, with basal nodes collapsed for simplicity.
(see Supplementary Fig. S2 for full version). The box next to each taxon demarcates its temporal range (including stratigraphic uncertainty), whereas the colour of the box reflects the continent(s) from which the taxon derives (light blue = North America; light green = Europe; red = Asia; dark blue = South America; yellow = Africa; purple = India; dark green = Australia).
Figure 8
Figure 8. Palaeogeographic map of the mid-Cretaceous world.
Showing the possible high latitude dispersal routes that might have been utilised by titanosaurs and other sauropods during the late Albian–Turonian. The base map is the 105 Ma time slice from the Global Paleogeography and Tectonics in Deep Time series by Ron Blakey [© Colorado Plateau Geosystems Inc.].

Similar articles

See all similar articles

Cited by 12 PubMed Central articles

See all "Cited by" articles

References

    1. Upchurch P. Gondwana break-up: legacies of a lost world? Trends in Ecology & Evolution 23, 229–236 (2008). - PubMed
    1. Seton M. et al. . Global continental and ocean basin reconstructions since 200 Ma. Earth-Science Reviews 113, 212–270 (2012).
    1. Benson R. B. J. et al. . Cretaceous tetrapod fossil record sampling and faunal turnover: implications for biogeography and the rise of modern clades. Palaeogeography, Palaeoclimatology, Palaeoecology 372, 88–107 (2013).
    1. Novas F. E. The Age of Dinosaurs in South America (Indiana University Press, 2009).
    1. Jacobs L. L., Winkler D. A. & Gomani E. M. Cretaceous dinosaurs of Africa: examples from Cameroon and Malawi. Memoirs of the Queensland Museum 39, 595–610 (1996).

Publication types

Feedback