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Ristevski J, Weisbecker V, Scanlon JD, Price GJ, Salisbury SW. Cranial anatomy of the mekosuchine crocodylian Trilophosuchus rackhami Willis, 1993. Anat Rec (Hoboken) 2023; 306:239-297. [PMID: 36054424 PMCID: PMC10086963 DOI: 10.1002/ar.25050] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/09/2022] [Accepted: 07/11/2022] [Indexed: 01/25/2023]
Abstract
One of the best-preserved crocodylian fossil specimens from the Cenozoic of Australia is the holotype of the mekosuchine Trilophosuchus rackhami, from the middle Miocene (13.56 ± 0.67 Ma) Ringtail Site at Riversleigh, northwestern Queensland. Although lacking most of the snout, the holotype skull of T. rackhami (QMF16856) has an exceptionally well-preserved cranium. Micro-CT scanning of the holotype has allowed for all the preserved cranial bones to be digitally disarticulated, facilitating an unprecedented insight into the cranial anatomy of not just T. rackhami, but any mekosuchine. Trilophosuchus rackhami was a small-bodied crocodylian and one of the most morphologically distinct mekosuchines, characterized by a unique combination of cranial characteristics several of which are exclusive to the species. Fossil material that is definitively referrable to the species T. rackhami is currently known solely from the middle Miocene Ringtail Site. However, an isolated parietal from Hiatus Site at Riversleigh demonstrates that Trilophosuchus also occurred during the late Oligocene (~25 Ma), extending the range of the genus by more than 10 million years. The new description of T. rackhami also allowed for a reevaluation of its phylogenetic relationships. Our results reaffirm the placement of T. rackhami as a member of Mekosuchinae within the subclade Mekosuchini. In all analyses, Mekosuchinae was consistently found to be monophyletic and part of the larger crocodylian clade Longirostres. However, the assignment of Mekosuchinae as a subset of Crocodylidae is brought into question, suggesting that the status of Mekosuchinae as a subfamily should be reconsidered.
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Affiliation(s)
- Jorgo Ristevski
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Vera Weisbecker
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia.,College of Science and Engineering, Flinders University, Bedford Park, South Australia, Australia
| | - John D Scanlon
- Phoenix Environmental Sciences, Osborne Park, Western Australia, Australia
| | - Gilbert J Price
- School of Earth and Environmental Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Steven W Salisbury
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
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Jannel A, Salisbury SW, Panagiotopoulou O. Softening the steps to gigantism in sauropod dinosaurs through the evolution of a pedal pad. Sci Adv 2022; 8:eabm8280. [PMID: 35947665 PMCID: PMC9365286 DOI: 10.1126/sciadv.abm8280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
How sauropod dinosaurs were able to withstand the forces associated with their immense size represents one of the most challenging biomechanical scenarios in the evolution of terrestrial tetrapods, but also one lacking robust biomechanical testing. Here, we use finite element analyses to quantify the biomechanical effects of foot skeletal postures with and without the presence of a soft tissue pad in sauropodomorphs. We find that none of the models can maintain bone stresses that fall within optimal bone safety factors in the absence of a soft tissue pad. Our findings suggest that a soft tissue pad in sauropods would have reduced bone stresses by combining the mechanical advantages of a functionally plantigrade foot with the plesiomorphic skeletally digitigrade saurischian condition. The acquisition of a developed soft tissue pad by the Late Triassic-Early Jurassic may represent one of the key adaptations for the evolution of gigantism that has become emblematic of these dinosaurs.
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Affiliation(s)
- Andréas Jannel
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Steven W. Salisbury
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia
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Abstract
Based on the known fossil record, the majority of crocodylians from the Cenozoic Era of Australia are referred to the extinct clade Mekosuchinae. The only extant crocodylians in Australia are two species of Crocodylus. Hence, the viewpoint that Crocodylus and mekosuchines have been the only crocodylians inhabiting Australia during the Cenozoic has remained largely undisputed. Herein we describe Australia's first tomistomine crocodylian, Gunggamarandu maunala gen. et sp. nov., thus challenging the notion of mekosuchine dominance during most of the Cenozoic. The holotype specimen of Gunggamarandu maunala derives from the Pliocene or Pleistocene of south-eastern Queensland, marking the southern-most global record for Tomistominae. Gunggamarandu maunala is known from a large, incomplete cranium that possesses a unique combination of features that distinguishes it from other crocodylians. Phylogenetic analyses place Gunggamarandu in a basal position within Tomistominae, specifically as a sister taxon to Dollosuchoides from the Eocene of Europe. These results hint at a potential ghost lineage between European and Australian tomistomines going back more than 50 million years. The cranial proportions of the Gunggamarandu maunala holotype specimen indicate it is the largest crocodyliform yet discovered from Australia.
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Affiliation(s)
- Jorgo Ristevski
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia.
| | - Gilbert J Price
- School of Earth and Environmental Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Vera Weisbecker
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
| | - Steven W Salisbury
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia
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Ristevski J, Yates AM, Price GJ, Molnar RE, Weisbecker V, Salisbury SW. Australia's prehistoric 'swamp king': revision of the Plio-Pleistocene crocodylian genus Pallimnarchus de Vis, 1886. PeerJ 2020; 8:e10466. [PMID: 33391869 PMCID: PMC7759136 DOI: 10.7717/peerj.10466] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/10/2020] [Indexed: 12/16/2022] Open
Abstract
The crocodylian fossil record from the Cenozoic of Australasia is notable for its rich taxonomic diversity, and is primarily represented by members of the clade Mekosuchinae. Reports of crocodylian fossils from Australia date back to the late nineteenth century. In 1886, Charles Walter de Vis proposed the name Pallimnarchus pollens for crocodylian fossils from southeast Queensland-the first binomen given to an extinct crocodylian taxon from Australia. Pallimnarchus has come to be regarded as a large, broad-snouted crocodylian from Australia's Plio-Pleistocene, and numerous specimens, few of which are sufficiently complete, have been assigned to it by several authors throughout the twentieth century. In the late 1990s, the genus was expanded to include a second species, Pallimnarchus gracilis. Unfortunately, the original syntype series described as Pallimnarchus pollens is very fragmentary and derives from more than one taxon, while a large part of the subsequently selected lectotype specimen is missing. Because descriptions and illustrations of the complete lectotype do not reveal any autapomorphic features, we propose that Pallimnarchus pollens should be regarded as a nomen dubium. Following this decision, the fossil material previously referred to Pallimnarchus is of uncertain taxonomic placement. A partial skull, formerly assigned to Pallimnarchus pollens and known as 'Geoff Vincent's specimen', possesses many features of diagnostic value and is therefore used as basis to erect a new genus and species-Paludirex vincenti gen. et sp. nov. A comprehensive description is given for the osteology of 'Geoff Vincent's specimen' as well as aspects of its palaeoneurology, the latter being a first for an extinct Australian crocodyliform. The newly named genus is characterized by a unique combination of premaxillary features such as a distinctive arching of the anterior alveolar processes of the premaxillae, a peculiar arrangement of the first two premaxillary alveoli and a large size disparity between the 3rd and 4th premaxillary alveoli. These features presently allow formal recognition of two species within the genus, Paludirex vincenti and Paludirex gracilis comb. nov., with the former having comparatively more robust rostral proportions than the latter. The Paludirex vincenti holotype comes from the Pliocene Chinchilla Sand of the Darling Downs, south-eastern Queensland, whereas the material assigned to Paludirex gracilis is from the Pleistocene of Terrace Site Local Fauna, Riversleigh, northwest Queensland. Phylogenetic analyses recover Paludirex vincenti as a mekosuchine, although further cladistic assessments are needed to better understand the relationships within the clade.
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Affiliation(s)
- Jorgo Ristevski
- School of Biological Sciences, The Univeristy of Queensland, Brisbane, QLD, Australia
| | - Adam M. Yates
- Museum of Central Australia, Museum and Art Gallery of the Northern Territory, Alice Springs, NT, Australia
| | - Gilbert J. Price
- School of Earth and Environmental Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Ralph E. Molnar
- University of California Museum of Paleontology, Berkeley, CA, USA
| | - Vera Weisbecker
- School of Biological Sciences, The Univeristy of Queensland, Brisbane, QLD, Australia
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Steven W. Salisbury
- School of Biological Sciences, The Univeristy of Queensland, Brisbane, QLD, Australia
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Hart LJ, Bell PR, Smith ET, Salisbury SW. Isisfordia molnari sp. nov ., a new basal eusuchian from the mid-Cretaceous of Lightning Ridge, Australia. PeerJ 2019; 7:e7166. [PMID: 31275756 PMCID: PMC6590469 DOI: 10.7717/peerj.7166] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 05/22/2019] [Indexed: 11/29/2022] Open
Abstract
The Australian Mesozoic crocodyliform record is sparse in comparison to other Gondwanan localities. A single formally-named taxon is known from this interval; Isisfordia duncani (Winton Formation, Albian–Turonian, Queensland). We present a previously undescribed crocodyliform braincase from the Griman Creek Formation (Cenomanian), New South Wales, which we assign to Isisfordia molnari sp. nov. Assignment to the genus is based on the possession of a newly-defined autapomorphy of Isisfordia: a broadly exposed prootic within the supratemporal foramen. A second autapomorphy of I. duncani (maximum diameter of the caudal aperture of the cranioquadrate siphonium approximately one-third the mediolateral width of the foramen magnum, with the lateral wall of the caudal aperture formed exclusively by the quadrate) may also be present in I. molnari; however, definitive recognition of this feature is marred by incomplete preservation. The new taxon is differentiated from I. duncani based on the absence of a median ridge on the parietal, and the lack of characteristic ridges on the parietal that form the medial margin of the supratemporal foramina. Reanalysis of a second specimen (the former holotype of the nomen dubium,‘Crocodylus (Bottosaurus) selaslophensis’) allows for its referral to the genus Isisfordia. Crucial to this reappraisal is the reinterpretation of the specimen as a partial maxilla, not the dentary as previously thought. This maxillary fragment possesses specific characteristics shared only with I. duncani; namely an alveolar groove. However, several key features differentiate the maxillary fragment from I. duncani, specifically the presence of continuous alveolar septa, the thickening of the medial alveolar rim, and the alveolar and crown base morphology. These findings constitute the first evidence of Isisfordia outside of the type locality and indicate its widespread occurrence on the freshwater floodplains along the eastern margin of the epeiric Eromanga Sea during the Albian–Cenomanian.
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Affiliation(s)
- Lachlan J Hart
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia
| | - Phil R Bell
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia
| | | | - Steven W Salisbury
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
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Jannel A, Nair JP, Panagiotopoulou O, Romilio A, Salisbury SW. “Keep your feet on the ground”: Simulated range of motion and hind foot posture of the Middle Jurassic sauropod
Rhoetosaurus brownei
and its implications for sauropod biology. J Morphol 2019; 280:849-878. [DOI: 10.1002/jmor.20989] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 03/06/2019] [Accepted: 03/21/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Andréas Jannel
- School of Biological SciencesThe University of Queensland Brisbane Queensland Australia
| | - Jay P. Nair
- School of Biological SciencesThe University of Queensland Brisbane Queensland Australia
| | - Olga Panagiotopoulou
- Department of Anatomy and Developmental BiologyMonash Biomedicine Discovery Institute, Monash University Clayton Victoria Australia
| | - Anthony Romilio
- School of Biological SciencesThe University of Queensland Brisbane Queensland Australia
| | - Steven W. Salisbury
- School of Biological SciencesThe University of Queensland Brisbane Queensland Australia
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Fletcher TL, Moss PT, Salisbury SW. The palaeoenvironment of the Upper Cretaceous (Cenomanian-Turonian) portion of the Winton Formation, Queensland, Australia. PeerJ 2018; 6:e5513. [PMID: 30210941 PMCID: PMC6130253 DOI: 10.7717/peerj.5513] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 08/02/2018] [Indexed: 11/20/2022] Open
Abstract
The Winton Formation is increasingly recognised as an important source of information about the Cretaceous of Australia, and, more broadly, the palaeobiogeographic history of eastern Gondwana. With more precise dating and stratigraphic controls starting to provide temporal context to the geological and palaeontological understanding of this formation, it is timely to reassess the palaeoenvironment in which it was deposited. This new understanding helps to further differentiate the upper, most-studied portion of the formation (Cenomanian-Turonian) from the lower portions (Albian-Cenomanian), allowing a coherent picture of the ecosystem to emerge. Temperatures during the deposition of the Upper Cretaceous portion of the Winton Formation were warm, with high, seasonal rainfall, but not as extreme as the modern monsoon. The landscape was heterogeneous, a freshwater alluvial plain bestrode by low energy, meandering rivers, minor lakes and mires. Infrequent, scouring flood events were part of a multi-year cycle of drier and wetter years. The heavily vegetated flood plains supported abundant large herbivores. This was the final infilling of the great Eromanga Basin.
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Affiliation(s)
- Tamara L. Fletcher
- Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, MT, United States of America
- Department of Geography, University of Nevada—Reno, Reno, United States of America
| | - Patrick T. Moss
- School of Earth and Environmental Sciences, University of Queensland, Brisbane, Australia
| | - Steven W. Salisbury
- School of Biological Sciences, University of Queensland, Brisbane, Australia
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8
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Syme CE, Salisbury SW. Taphonomy of Isisfordia duncani specimens from the Lower Cretaceous (upper Albian) portion of the Winton Formation, Isisford, central-west Queensland. R Soc Open Sci 2018; 5:171651. [PMID: 29657771 PMCID: PMC5882695 DOI: 10.1098/rsos.171651] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 02/09/2018] [Indexed: 05/12/2023]
Abstract
Taphonomic analysis of fossil material can benefit from including the results of actualistic decay experiments. This is crucial in determining the autochthony or allochthony of fossils of juvenile and adult Isisfordia duncani, a basal eusuchian from the Lower Cretaceous (upper Albian) distal-fluvial-deltaic lower Winton Formation near Isisford. The taphonomic characteristics of the I. duncani fossils were documented using a combination of traditional taphonomic analysis alongside already published actualistic decay data from juvenile Crocodylus porosus carcasses. We found that the I. duncani holotype, paratypes and referred specimens show little signs of weathering and no signs of abrasion. Disarticulated skeletal elements are often found in close proximity to the rest of the otherwise articulated skeleton. The isolated and disarticulated skeletal elements identified, commonly cranial, maxillary and mandibular elements, are typical of lag deposits. The holotype QM F36211 and paratype QM F34642 were classified as autochthonous, and the remaining I. duncani paratypes and referred specimens are parautochthonous. We propose that I. duncani inhabited upper and lower delta plains near the Eromanga Sea in life. Their carcasses were buried in sediment-laden floodwaters in delta plain overbank and distributary channel deposits. Future studies should refer to I. duncani as a brackish water tolerant species.
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Herne MC, Tait AM, Weisbecker V, Hall M, Nair JP, Cleeland M, Salisbury SW. A new small-bodied ornithopod (Dinosauria, Ornithischia) from a deep, high-energy Early Cretaceous river of the Australian-Antarctic rift system. PeerJ 2018; 5:e4113. [PMID: 29340228 PMCID: PMC5767335 DOI: 10.7717/peerj.4113] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/09/2017] [Indexed: 11/20/2022] Open
Abstract
A new small-bodied ornithopod dinosaur, Diluvicursor pickeringi, gen. et sp. nov., is named from the lower Albian of the Eumeralla Formation in southeastern Australia and helps shed new light on the anatomy and diversity of Gondwanan ornithopods. Comprising an almost complete tail and partial lower right hindlimb, the holotype (NMV P221080) was deposited as a carcass or body-part in a log-filled scour near the base of a deep, high-energy river that incised a faunally rich, substantially forested riverine floodplain within the Australian-Antarctic rift graben. The deposit is termed the 'Eric the Red West Sandstone.' The holotype, interpreted as an older juvenile ∼1.2 m in total length, appears to have endured antemortem trauma to the pes. A referred, isolated posterior caudal vertebra (NMV P229456) from the holotype locality, suggests D. pickeringi grew to at least 2.3 m in length. D. pickeringi is characterised by 10 potential autapomorphies, among which dorsoventrally low neural arches and transversely broad caudal ribs on the anterior-most caudal vertebrae are a visually defining combination of features. These features suggest D. pickeringi had robust anterior caudal musculature and strong locomotor abilities. Another isolated anterior caudal vertebra (NMV P228342) from the same deposit, suggests that the fossil assemblage hosts at least two ornithopod taxa. D. pickeringi and two stratigraphically younger, indeterminate Eumeralla Formation ornithopods from Dinosaur Cove, NMV P185992/P185993 and NMV P186047, are closely related. However, the tail of D. pickeringi is far shorter than that of NMV P185992/P185993 and its pes more robust than that of NMV P186047. Preliminary cladistic analysis, utilising three existing datasets, failed to resolve D. pickeringi beyond a large polytomy of Ornithopoda. However, qualitative assessment of shared anatomical features suggest that the Eumeralla Formation ornithopods, South American Anabisetia saldiviai and Gasparinisaura cincosaltensis, Afro-Laurasian dryosaurids and possibly Antarctic Morrosaurus antarcticus share a close phylogenetic progenitor. Future phylogenetic analysis with improved data on Australian ornithopods will help to test these suggested affinities.
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Affiliation(s)
- Matthew C. Herne
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Alan M. Tait
- School of Earth, Atmosphere and Environment, Monash University, Melbourne, VIC, Australia
| | - Vera Weisbecker
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Michael Hall
- School of Earth, Atmosphere and Environment, Monash University, Melbourne, VIC, Australia
| | - Jay P. Nair
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
| | | | - Steven W. Salisbury
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
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Romilio A, Hacker JM, Zlot R, Poropat G, Bosse M, Salisbury SW. A multidisciplinary approach to digital mapping of dinosaurian tracksites in the Lower Cretaceous (Valanginian-Barremian) Broome Sandstone of the Dampier Peninsula, Western Australia. PeerJ 2017; 5:e3013. [PMID: 28344899 PMCID: PMC5363262 DOI: 10.7717/peerj.3013] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 01/23/2017] [Indexed: 11/20/2022] Open
Abstract
The abundant dinosaurian tracksites of the Lower Cretaceous (Valanginian-Barremian) Broome Sandstone of the Dampier Peninsula, Western Australia, form an important part of the West Kimberley National Heritage Place. Previous attempts to document these tracksites using traditional mapping techniques (e.g., surface overlays, transects and gridlines combined with conventional photography) have been hindered by the non-trivial challenges associated with working in this area, including, but not limited to: (1) the remoteness of many of the tracksites; (2) the occurrence of the majority of the tracksites in the intertidal zone; (3) the size and complexity of many of the tracksites, with some extending over several square kilometres. Using the historically significant and well-known dinosaurian tracksites at Minyirr (Gantheaume Point), we show how these issues can be overcome through the use of an integrated array of remote sensing tools. A combination of high-resolution aerial photography with both manned and unmanned aircraft, airborne and handheld high-resolution lidar imaging and handheld photography enabled the collection of large amounts of digital data from which 3D models of the tracksites at varying resolutions were constructed. The acquired data encompasses a very broad scale, from the sub-millimetre level that details individual tracks, to the multiple-kilometre level, which encompasses discontinuous tracksite exposures and large swathes of coastline. The former are useful for detailed ichnological work, while the latter are being employed to better understand the stratigraphic and temporal relationship between tracksites in a broader geological and palaeoecological context. These approaches and the data they can generate now provide a means through which digital conservation and temporal monitoring of the Dampier Peninsula's dinosaurian tracksites can occur. As plans for the on-going management of the tracks in this area progress, analysis of the 3D data and 3D visualization will also likely provide an important means through which the broader public can experience these spectacular National Heritage listed landscapes.
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Affiliation(s)
- Anthony Romilio
- School of Biological Sciences, The University of Queensland , Brisbane , Queensland , Australia
| | - Jorg M Hacker
- Airborne Research Australia, Flinders University of South Australia , Adelaide , South Australia , Australia
| | - Robert Zlot
- Autonomous Systems, CSIRO , Brisbane , Queensland , Australia
| | - George Poropat
- Mine Environment Imaging, CSIRO , Brisbane , Queensland , Australia
| | - Michael Bosse
- Autonomous Systems Lab, ETH Zurich , Zürich , Switzerland
| | - Steven W Salisbury
- School of Biological Sciences, The University of Queensland , Brisbane , Queensland , Australia
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11
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Leahey LG, Molnar RE, Carpenter K, Witmer LM, Salisbury SW. Cranial osteology of the ankylosaurian dinosaur formerly known as Minmi sp. (Ornithischia: Thyreophora) from the Lower Cretaceous Allaru Mudstone of Richmond, Queensland, Australia. PeerJ 2015; 3:e1475. [PMID: 26664806 PMCID: PMC4675105 DOI: 10.7717/peerj.1475] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 11/16/2015] [Indexed: 11/30/2022] Open
Abstract
Minmi is the only known genus of ankylosaurian dinosaur from Australia. Seven specimens are known, all from the Lower Cretaceous of Queensland. Only two of these have been described in any detail: the holotype specimen Minmi paravertebra from the Bungil Formation near Roma, and a near complete skeleton from the Allaru Mudstone on Marathon Station near Richmond, preliminarily referred to a possible new species of Minmi. The Marathon specimen represents one of the world’s most complete ankylosaurian skeletons and the best-preserved dinosaurian fossil from eastern Gondwana. Moreover, among ankylosaurians, its skull is one of only a few in which the majority of sutures have not been obliterated by dermal ossifications or surface remodelling. Recent preparation of the Marathon specimen has revealed new details of the palate and narial regions, permitting a comprehensive description and thus providing new insights cranial osteology of a basal ankylosaurian. The skull has also undergone computed tomography, digital segmentation and 3D computer visualisation enabling the reconstruction of its nasal cavity and endocranium. The airways of the Marathon specimen are more complicated than non-ankylosaurian dinosaurs but less so than derived ankylosaurians. The cranial (brain) endocast is superficially similar to those of other ankylosaurians but is strongly divergent in many important respects. The inner ear is extremely large and unlike that of any dinosaur yet known. Based on a high number of diagnostic differences between the skull of the Marathon specimen and other ankylosaurians, we consider it prudent to assign this specimen to a new genus and species of ankylosaurian. Kunbarrasaurus ieversi gen. et sp. nov. represents the second genus of ankylosaurian from Australia and is characterised by an unusual melange of both primitive and derived characters, shedding new light on the evolution of the ankylosaurian skull.
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Affiliation(s)
- Lucy G Leahey
- School of Biological Sciences, University of Queensland , Brisbane, Queensland , Australia
| | - Ralph E Molnar
- University of California Museum of Paleontology , Berkeley, CA , USA
| | | | - Lawrence M Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University , Athens, OH , USA
| | - Steven W Salisbury
- School of Biological Sciences, University of Queensland , Brisbane, Queensland , Australia
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12
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Hand SJ, Lee DE, Worthy TH, Archer M, Worthy JP, Tennyson AJD, Salisbury SW, Scofield RP, Mildenhall DC, Kennedy EM, Lindqvist JK. Miocene Fossils Reveal Ancient Roots for New Zealand's Endemic Mystacina (Chiroptera) and Its Rainforest Habitat. PLoS One 2015; 10:e0128871. [PMID: 26083758 PMCID: PMC4470663 DOI: 10.1371/journal.pone.0128871] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 05/01/2015] [Indexed: 12/30/2022] Open
Abstract
The New Zealand endemic bat family Mystacinidae comprises just two Recent species referred to a single genus, Mystacina. The family was once more diverse and widespread, with an additional six extinct taxa recorded from Australia and New Zealand. Here, a new mystacinid is described from the early Miocene (19-16 Ma) St Bathans Fauna of Central Otago, South Island, New Zealand. It is the first pre-Pleistocene record of the modern genus and it extends the evolutionary history of Mystacina back at least 16 million years. Extant Mystacina species occupy old-growth rainforest and are semi-terrestrial with an exceptionally broad omnivorous diet. The majority of the plants inhabited, pollinated, dispersed or eaten by modern Mystacina were well-established in southern New Zealand in the early Miocene, based on the fossil record from sites at or near where the bat fossils are found. Similarly, many of the arthropod prey of living Mystacina are recorded as fossils in the same area. Although none of the Miocene plant and arthropod species is extant, most are closely related to modern taxa, demonstrating potentially long-standing ecological associations with Mystacina.
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Affiliation(s)
- Suzanne J. Hand
- School of Biological, Environmental and Earth Sciences, University of New South Wales, Sydney, New South Wales, Australia
- * E-mail:
| | - Daphne E. Lee
- Department of Geology, University of Otago, Dunedin, New Zealand
| | - Trevor H. Worthy
- School of Biological Sciences, Flinders University, Adelaide, South Australia, Australia
| | - Michael Archer
- School of Biological, Environmental and Earth Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Jennifer P. Worthy
- School of Biological Sciences, Flinders University, Adelaide, South Australia, Australia
| | | | - Steven W. Salisbury
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | | | | | | | - Jon K. Lindqvist
- Department of Geology, University of Otago, Dunedin, New Zealand
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Hanson JO, Salisbury SW, Campbell HA, Dwyer RG, Jardine TD, Franklin CE. Feeding across the food web: The interaction between diet, movement and body size in estuarine crocodiles (Crocodylus porosus). AUSTRAL ECOL 2014. [DOI: 10.1111/aec.12212] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Jeffrey O. Hanson
- School of Biological Sciences; The University of Queensland; Brisbane Qld 4072 Australia
| | - Steven W. Salisbury
- School of Biological Sciences; The University of Queensland; Brisbane Qld 4072 Australia
| | - Hamish A. Campbell
- School of Biological Sciences; The University of Queensland; Brisbane Qld 4072 Australia
| | - Ross G. Dwyer
- School of Biological Sciences; The University of Queensland; Brisbane Qld 4072 Australia
| | - Timothy D. Jardine
- Australian Rivers Institute; Griffith University; Brisbane Queensland Australia
| | - Craig E. Franklin
- School of Biological Sciences; The University of Queensland; Brisbane Qld 4072 Australia
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14
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Abstract
Benson et al. (Brevia, 26 March 2010, p. 1613) reported on an Australian tyrannosauroid, represented by a pubis from the late Early Cretaceous of Victoria. However, our examination of this specimen reveals that the critical character used for this referral is not present. We contend that the bone likely belongs to a currently recognized group of Australian theropod or another group not currently known.
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Affiliation(s)
- Matthew C Herne
- School of Biological Sciences, University of Queensland, Brisbane, QLD 4072, Australia.
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15
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Abstract
Background Tyrannosaurus rex and other tyrannosaurid fossils often display multiple, smooth-edged full-thickness erosive lesions on the mandible, either unilaterally or bilaterally. The cause of these lesions in the Tyrannosaurus rex specimen FMNH PR2081 (known informally by the name ‘Sue’) has previously been attributed to actinomycosis, a bacterial bone infection, or bite wounds from other tyrannosaurids. Methodology/Principal Findings We conducted an extensive survey of tyrannosaurid specimens and identified ten individuals with full-thickness erosive lesions. These lesions were described, measured and photographed for comparison with one another. We also conducted an extensive survey of related archosaurs for similar lesions. We show here that these lesions are consistent with those caused by an avian parasitic infection called trichomonosis, which causes similar abnormalities on the mandible of modern birds, in particular raptors. Conclusions/Significance This finding represents the first evidence for the ancient evolutionary origin of an avian transmissible disease in non-avian theropod dinosaurs. It also provides a valuable insight into the palaeobiology of these now extinct animals. Based on the frequency with which these lesions occur, we hypothesize that tyrannosaurids were commonly infected by a Trichomonas gallinae-like protozoan. For tyrannosaurid populations, the only non-avian dinosaur group that show trichomonosis-type lesions, it is likely that the disease became endemic and spread as a result of antagonistic intraspecific behavior, consumption of prey infected by a Trichomonas gallinae-like protozoan and possibly even cannibalism. The severity of trichomonosis-related lesions in specimens such as Tyrannosaurus rex FMNH PR2081 and Tyrannosaurus rex MOR 980, strongly suggests that these animals died as a direct result of this disease, mostly likely through starvation.
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Affiliation(s)
- Ewan D. S. Wolff
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
- * E-mail: (EDSW); (SWS)
| | - Steven W. Salisbury
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
- Vertebrate Paleontology, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (EDSW); (SWS)
| | - John R. Horner
- Museum of the Rockies, Montana State University, Bozeman, Montana, United States of America
| | - David J. Varricchio
- Department of Earth Sciences, Montana State University, Bozeman, Montana, United States of America
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Smith ND, Makovicky PJ, Agnolin FL, Ezcurra MD, Pais DF, Salisbury SW. A Megaraptor-like theropod (Dinosauria: Tetanurae) in Australia: support for faunal exchange across eastern and western Gondwana in the Mid-Cretaceous. Proc Biol Sci 2008; 275:2085-93. [PMID: 18544511 DOI: 10.1098/rspb.2008.0504] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The fossil record of Australian dinosaurs in general, and theropods in particular, is extremely sparse. Here we describe an ulna from the Early Cretaceous Eumeralla Formation of Australia that shares unique autapomorphies with the South American theropod Megaraptor. We also present evidence for the spinosauroid affinities of Megaraptor. This ulna represents the first Australian non-avian theropod with unquestionable affinities to taxa from other Gondwanan landmasses, suggesting faunal interchange between eastern and western Gondwana during the Mid-Cretaceous. This evidence counters claims of Laurasian affinities for Early Cretaceous Australian dinosaur faunas, and for the existence of a geographical or climatic barrier isolating Australia from the other Gondwanan continents during this time. The temporal and geographical distribution of Megaraptor and the Eumeralla ulna is also inconsistent with traditional palaeogeographic models for the fragmentation of Gondwana, but compatible with several alternative models positing connections between South America and Antarctica in the Mid-Cretaceous.
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Affiliation(s)
- Nathan D Smith
- Department of Geology, The Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605, USA.
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Abstract
While the crocodyliform lineage extends back over 200 million years (Myr) to the Late Triassic, modern forms-members of Eusuchia-do not appear until the Cretaceous. Eusuchia includes the crown group Crocodylia, which comprises Crocodyloidea, Alligatoroidea and Gavialoidea. Fossils of non-crocodylian eusuchians are currently rare and, in most instances, fragmentary. Consequently, the transition from Neosuchia to Crocodylia has been one of the most poorly understood areas of crocodyliform evolution. Here we describe a new crocodyliform from the mid-Cretaceous (98-95 Myr ago; Albian-Cenomanian) Winton Formation of Queensland, Australia, as the most primitive member of Eusuchia. The anatomical changes associated with the emergence of this taxon indicate a pivotal shift in the feeding and locomotor behaviour of crocodyliforms-a shift that may be linked to the subsequent rapid diversification of Eusuchia 20 Myr later during the Late Cretaceous and Early Tertiary. While Laurasia (in particular North America) is the most likely ancestral area for Crocodylia, the biogeographic events associated with the origin of Eusuchia are more complex. Although the fossil evidence is limited, it now seems likely that at least part of the early history of Eusuchia transpired in Gondwana.
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Affiliation(s)
- Steven W Salisbury
- School of Integrative Biology, The University of Queensland, Brisbane, Australia.
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