| 1. |
- Kear, Benjamin P., et al.
(författare)
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Bandicoot fossils and DNA elucidate lineage antiquity amongst xeric-adapted Australasian marsupials
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Bandicoots (Peramelemorphia) are a unique order of Australasian marsupials whose sparse fossil record has been used as prima facie evidence for climate change coincident faunal turnover. In particular, the hypothesized replacement of ancient rainforest-dwelling extinct lineages by antecedents of xeric-tolerant extant taxa during the late Miocene (-10 Ma) has been advocated as a broader pattern evident amongst other marsupial clades. Problematically, however, this is in persistent conflict with DNA phylogenies. We therefore determine the pattern and timing of bandicoot evolution using the first combined morphological + DNA sequence dataset of Peramelemorphia. In addition, we document a remarkably archaic new fossil peramelemorphian taxon that inhabited a latest Quaternary mosaic savannah-riparian forest ecosystem on the Aru Islands of Eastern Indonesia. Our phylogenetic analyses reveal that unsuspected dental homoplasy and the detrimental effects of missing data collectively obscure stem bandicoot relationships. Nevertheless, recalibrated molecular clocks and multiple ancestral area optimizations unanimously infer an early diversification of modern xeric-adapted forms. These probably originated during the late Palaeogene (30-40 Ma) alongside progenitors of other desert marsupials, and thus occupied seasonally dry heterogenous habitats long before the onset of late Neogene aridity.
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| 2. |
- Poropat, Stephen F., et al.
(författare)
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Early Cretaceous polar biotas of Victoria, southeastern Australia : an overview of research to date
- 2018
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Ingår i: Alcheringa. - : TAYLOR & FRANCIS LTD. - 0311-5518 .- 1752-0754. ; 42:2, s. 157-229
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Tidskriftsartikel (refereegranskat)abstract
- Although Cretaceous fossils (coal excluded) from Victoria, Australia, were first reported in the 1850s, it was not until the 1950s that detailed studies of these fossils were undertaken. Numerous fossil localities have been identified in Victoria since the 1960s, including the Koonwarra Fossil Bed (Strzelecki Group) near Leongatha, the Dinosaur Cove and Eric the Red West sites (Otway Group) at Cape Otway, and the Flat Rocks site (Strzelecki Group) near Cape Paterson. Systematic exploration over the past five decades has resulted in the collection of thousands of fossils representing various plants, invertebrates and vertebrates. Some of the best-preserved and most diverse Hauterivian-Barremian floral assemblages in Australia derive from outcrops of the lower Strzelecki Group in the Gippsland Basin. The slightly younger Koonwarra Fossil Bed (Aptian) is a Konservat-Lagerstatte that also preserves abundant plants, including one of the oldest known flowers. In addition, insects, crustaceans (including the only syncaridans known from Australia between the Triassic and the present), arachnids (including Australia's only known opilione), the stratigraphically youngest xiphosurans from Australia, bryozoans, unionoid molluscs and a rich assemblage of actinopterygian fish are known from the Koonwarra Fossil Bed. The oldest knownand only Mesozoicfossil feathers from the Australian continent constitute the only evidence for tetrapods at Koonwarra. By contrast, the Barremian-Aptian-aged deposits at the Flat Rocks site, and the Aptian-Albian-aged strata at the Dinosaur Cove and Eric the Red West sites, are all dominated by tetrapod fossils, with actinopterygians and dipnoans relatively rare. Small ornithopod (=basal neornithischian) dinosaurs are numerically common, known from four partial skeletons and a multitude of isolated bones. Aquatic meiolaniform turtles constitute another prominent faunal element, represented by numerous isolated bones and articulated carapaces and plastrons. More than 50 specimensmostly lower jawsevince a high diversity of mammals, including monotremes, a multituberculate and several enigmatic ausktribosphenids. Relatively minor components of these fossil assemblages are diverse theropods (including birds), rare ankylosaurs and ceratopsians, pterosaurs, non-marine plesiosaurs and a lepidosaur. In the older strata of the upper Strzelecki Group, temnospondyl amphibiansthe youngest known worldwideare a conspicuous component of the fauna, whereas crocodylomorphs appear to be present only in up-sequence deposits of the Otway Group. Invertebrates are uncommon, although decapod crustaceans and unionoid bivalves have been described. Collectively, the Early Cretaceous biota of Victoria provides insights into a unique Mesozoic high-latitude palaeoenvironment and elucidates both palaeoclimatic and palaeobiogeographic changes throughout more than 25 million years of geological time.
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| 3. |
- Abel, Pascal, et al.
(författare)
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An anhanguerian pterodactyloid mandible from the lower Valanginian of Northern Germany, and the German record of Cretaceous pterosaurs
- 2021
-
Ingår i: Acta Palaeontologica Polonica. - : Polska Akademia Nauk Instytut Paleobiologii (Institute of Paleobiology, Polish Academy of Sciences). - 0567-7920 .- 1732-2421. ; 66:3, s. S5-S12
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Tidskriftsartikel (refereegranskat)abstract
- The record of Cretaceous pterosaur remains from Germany is sparse. The material recovered to date includes the fragmentary holotypes of Targaryendraco wiedenrothi and Ctenochasma roemeri, as well as a few isolated pterodactyloid teeth and some indeterminate skeletal elements, together with a plaster cast of a large Purbeckopus manus imprint. Here, we report the discovery of a pterodactyloid pterosaur mandible from lower Valanginian strata of the Stadthagen Formation in the Lower Saxony Basin of Northern Germany. Based on the size and spacing of its alveoli, this fossil is attributable to the cosmopolitan Early Cretaceous pteranodontoid clade Anhangueria. Moreover, it represents the first and only known pterosaur from the Valanginian of Germany and is one of only a handful Valanganian pterosaur occurrences presently recognized worldwide. In addition to the approximately coeval Coloborhynchus clavirostris from the Hastings Bed Group of southern England, the Stadthagen Formation pterosaur mandible is among the stratigraphically oldest identifiable anhanguerians.
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| 4. |
- Alhalabi, Wafa A., et al.
(författare)
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Recovering lost time in Syria : New Late Cretaceous (Coniacian-Santonian) elasmosaurid remains from the Palmyrides mountain chain
- 2024
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Ingår i: Cretaceous research (Print). - : Elsevier. - 0195-6671 .- 1095-998X. ; 159
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Tidskriftsartikel (refereegranskat)abstract
- Despite its relatively limited vertebrate fossil record, Syria currently records the largest number of documented Mesozoic marine reptile occurrences among the Middle Eastern countries. In particular, the phosphatic deposits of the Palmyrides mountain chain have yielded fossils of aquatic squamates, bothremydid and chelonioid marine turtles, as well as elasmosaurid plesiosaurs. Nevertheless, new discoveries have not been reported for the last two decades. Here, we describe the partial skeleton of an elasmosaurid plesiosaur from Syria, which comprises the middle and posterior cervical series, together with articulated pectoral, dorsal and anterior caudal parts of the vertebral column, with associated rib fragments. The fossil was excavated from Coniacian-Santonian phosphatic deposits of the Al Sawaneh el Charquieh mines, in the central part of the southwestern Palmyrides, about 200 km northeast of Damascus. The specimen can be assigned to Elasmosauridae based on the cervical centra morphology and, although incomplete, is significant because it not only represents likely the oldest, but also the currently most complete plesiosaur skeleton recovered from the Middle East. (c) 2024 Elsevier Ltd. All rights reserved.
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| 5. |
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| 6. |
- Barrett, Paul M., et al.
(författare)
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Ankylosaurian dinosaur remains from the Lower Cretaceous of southeastern Australia
- 2010
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Ingår i: Alcheringa. - : Informa UK Limited. - 0311-5518 .- 1752-0754. ; 34:3, s. 205-217
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Tidskriftsartikel (refereegranskat)abstract
- The Eumeralla and Wonthaggi formations (Otway and Strzelecki groups, respectively: late Hauterivian to Albian) of Victoria, Australia, have yielded diverse dinosaur faunas. Here we report a set of unassociated isolated specimens from these units including teeth, dorsal vertebrae, ribs and osteoderms of an indeterminate ankylosaurian dinosaur.
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| 7. |
- Barrett, Paul M., et al.
(författare)
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Opalized archosaur remains from the Bulldog Shale (Aptian : Lower Cretaceous) of South Australia
- 2010
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Ingår i: Alcheringa. - : Informa UK Limited. - 0311-5518 .- 1752-0754. ; 34:3, s. 293-301
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Tidskriftsartikel (refereegranskat)abstract
- Terrestrial reptile remains are very rare in the Lower Cretaceous of South Australia, but include the holotype of the small theropod Kakuru. Here, we review this taxon and other archosaur specimens collected from the Bulldog Shale (Aptian) of Andamooka and Coober Pedy. Kakuru possesses no unique characters or character state combinations and is regarded as a nomen dubium, representing an indeterminate tetanuran theropod. Two other specimens (a left metatarsal and astragalus) can be referred to Dinosauria, but the identity of several other specimens (phalanges and a centrum) can only be resolved to the level of an indeterminate archosaur.
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| 8. |
- Bazzi, Mohamad, et al.
(författare)
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Feeding ecology has shaped the evolution of modern sharks
- 2021
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Ingår i: Current Biology. - : Cell Press. - 0960-9822 .- 1879-0445. ; 31:23, s. 5138-5148.e4
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Tidskriftsartikel (refereegranskat)abstract
- Sharks are iconic predators in today’s oceans, yet their modern diversity has ancient origins. In particular, present hypotheses suggest that a combination of mass extinction, global climate change, and competition has regulated the community structure of dominant mackerel (Lamniformes) and ground (Carcharhiniformes) sharks over the last 66 million years. However, while these scenarios advocate an interplay of major abiotic and biotic events, the precise drivers remain obscure. Here, we focus on the role of feeding ecology using a geometric morphometric analysis of 3,837 fossil and extant shark teeth. Our results reveal that morphological segregation rather than competition has characterized lamniform and carcharhiniform evolution. Moreover, although lamniforms suffered a long-term disparity decline potentially linked to dietary “specialization,” their recent disparity rivals that of “generalist” carcharhiniforms. We further confirm that low eustatic sea levels impacted lamniform disparity across the end-Cretaceous mass extinction. Adaptations to changing prey availability and the proliferation of coral reef habitats during the Paleogene also likely facilitated carcharhiniform dispersals and cladogenesis, underpinning their current taxonomic dominance. Ultimately, we posit that trophic partitioning and resource utilization shaped past shark ecology and represent critical determinants for their future species survivorship.
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| 9. |
- Bazzi, Mohamad, et al.
(författare)
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Southern higher-latitude lamniform sharks track mid-Cretaceous environmental change
- 2022
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Ingår i: Gondwana Research. - : Elsevier. - 1342-937X .- 1878-0571. ; 103, s. 362-370
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Tidskriftsartikel (refereegranskat)abstract
- The mid-Cretaceous (Albian and Cenomanian, 113–93.9 Myr) marked a transformative interval of shark evolution during which lamniforms (mackerel sharks) diversified as dominant marine predators. Yet, their radiation dynamics relative to major biotic turnovers delimiting the Albian–Cenomanian and Cenomanian–Turonian boundaries are incompletely understood. Here, we use the high-resolution dental fossil record of lamniforms to track changing morphological disparity and tooth size through a succession of mid-Cretaceous shark assemblages from higher-palaeolatitude (up to ∼ 58°S) settings in Australia. Our geometric morphometric analyses and evolutionary model fitting reveal stable disparity throughout the late Albian–late Cenomanian. By contrast, lamniform disparity increased in the early Turonian, which might reflect local habitat differences and/or intraspecific variability through heterodonty. Nevertheless, clade-specific partial disparity increases are evident among small-bodied carchariids, and couple with a trend towards larger teeth as a proxy for body-size in coeval anacoracids. We correlate these signals with recovery after the Oceanic Anoxic Event 2, which severely disrupted latest Cenomanian marine ecosystems and apparently instigated disjunct responses in shark communities occupying epeiric versus outer neritic environments.
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| 10. |
- Bazzi, Mohamad, et al.
(författare)
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Static Dental Disparity and Morphological Turnover in Sharks across the End-Cretaceous Mass Extinction
- 2018
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Ingår i: Current Biology. - : CELL PRESS. - 0960-9822 .- 1879-0445. ; 28:16, s. 2607-2615
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Tidskriftsartikel (refereegranskat)abstract
- The Cretaceous-Palaeogene (K-Pg) mass extinction profoundly altered vertebrate ecosystems and prompted the radiation of many extant clades [1, 2]. Sharks (Selachimorpha) were one of the few larger-bodied marine predators that survived the K-Pg event and are represented by an almost-continuous dental fossil record. However, the precise dynamics of their transition through this interval remain uncertain [3]. Here, we apply 2D geometric morphometrics to reconstruct global and regional dental morphospace variation among Lamniformes (Mackerel sharks) and Carch-arhiniformes (Ground sharks). These clades are prevalent predators in today's oceans, and were geographically widespread during the late Cretaceous-early Palaeogene. Our results reveal a decoupling of morphological disparity and taxonomic richness. Indeed, shark disparity was nearly static across the K-Pg extinction, in contrast to abrupt declines among other higher-trophic-level marine predators [4, 5]. Nevertheless, specific patterns indicate that an asymmetric extinction occurred among lamniforms possessing lowcrowned/triangular teeth and that a subsequent proliferation of carcharhiniforms with similar tooth morphologies took place during the early Paleocene. This compositional shift in post-Mesozoic shark lineages hints at a profound and persistent K-Pg signature evident in the heterogeneity of modern shark communities. Moreover, such wholesale lineage turnover coincided with the loss of many cephalopod [6] and pelagic amniote [5] groups, as well as the explosive radiation of middle trophic-level teleost fishes [1]. We hypothesize that a combination of prey availability and post-extinction trophic cascades favored extant shark antecedents and laid the foundation for their extensive diversification later in the Cenozoic [7-10].
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| 11. |
- Bazzi, Mohamad, et al.
(författare)
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Tooth morphology elucidates shark evolution across the end-Cretaceous mass extinction
- 2021
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Ingår i: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 19:8
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Tidskriftsartikel (refereegranskat)abstract
- Sharks (Selachimorpha) are iconic marine predators that have survived multiple mass extinctions over geologic time. Their prolific fossil record is represented mainly by isolated shed teeth, which provide the basis for reconstructing deep time diversity changes affecting different selachimorph clades. By contrast, corresponding shifts in shark ecology, as measured through morphological disparity, have received comparatively limited analytical attention. Here, we use a geometric morphometric approach to comprehensively examine tooth morphologies in multiple shark lineages traversing the catastrophic end-Cretaceous mass extinction-this event terminated the Mesozoic Era 66 million years ago. Our results show that selachimorphs maintained virtually static levels of dental disparity in most of their constituent clades across the Cretaceous-Paleogene interval. Nevertheless, selective extinctions did impact apex predator species characterized by triangular blade-like teeth. This is particularly evident among lamniforms, which included the dominant Cretaceous anacoracids. Conversely, other groups, such as carcharhiniforms and orectolobiforms, experienced disparity modifications, while heterodontiforms, hexanchiforms, squaliforms, squatiniforms, and dagger synechodontiforms were not overtly affected. Finally, while some lamniform lineages disappeared, others underwent postextinction disparity increases, especially odontaspidids, which are typified by narrow-cusped teeth adapted for feeding on fishes. Notably, this increase coincides with the early Paleogene radiation of teleosts as a possible prey source, and the geographic relocation of disparity sampling "hotspots," perhaps indicating a regionally disjunct extinction recovery. Ultimately, our study reveals a complex morphological response to the end-Cretaceous mass extinction and highlights an event that influenced the evolution of modern sharks.
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| 12. |
- Black, Karen H., et al.
(författare)
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A New Species of the Basal "Kangaroo'' Balbaroo and a Re-Evaluation of Stem Macropodiform Interrelationships
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:11, s. e112705-
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Tidskriftsartikel (refereegranskat)abstract
- Exceptionally well-preserved skulls and postcranial elements of a new species of the plesiomorphic stem macropodiform Balbaroo have been recovered from middle Miocene freshwater limestone deposits in the Riversleigh World Heritage Area of northwestern Queensland, Australia. This constitutes the richest intraspecific sample for any currently known basal "kangaroo'', and, along with additional material referred to Balbaroo fangaroo, provides new insights into structural variability within the most prolific archaic macropodiform clade - Balbaridae. Qualitative and metric evaluations of taxonomic boundaries demonstrate that the previously distinct species Nambaroo bullockensis is a junior synonym of B. camfieldensis. Furthermore, coupled Maximum Parsimony and Bayesian phylogenetic analyses reveal that our new Balbaroo remains represent the most derived member of the Balbaroo lineage, and are closely related to the middle Miocene B. camfieldensis, which like most named balbarid species is identifiable only from isolated jaws. The postcranial elements of Balbaroo concur with earlier finds of the stratigraphically oldest balbarid skeleton, Nambaroo gillespieae, and suggest that quadrupedal progression was a primary gait mode as opposed to bipedal saltation. All Balbaroo spp. have low-crowned bilophodont molars, which are typical for browsing herbivores inhabiting the densely forested environments envisaged for middle Miocene northeastern Australia.
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| 13. |
- Borinder, Niclas H., et al.
(författare)
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Postcranial osteology of the basally branching hadrosauroid dinosaur Tanius sinensis from the Upper Cretaceous Wangshi Group of Shandong, China
- 2021
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Ingår i: Journal of Vertebrate Paleontology. - : Taylor & Francis. - 0272-4634 .- 1937-2809. ; 41:1
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Tidskriftsartikel (refereegranskat)abstract
- Tanius sinensis was one of the first dinosaur species to be named from China. It was established on a partial skeleton recovered by a joint Sino-Swedish expedition in 1923. The fossils were excavated from Upper Cretaceous strata of the Jiangjunding Formation (Wangshi Group) in Shandong Province, and although their discovery dates back almost 100 years, they have not been reassessed in detail since their initial description in 1929. This omission is critical because T. sinensis is now recognized as one of the stratigraphically youngest non-hadrosaurid hadrosauroid taxa. Here, we re-evaluate the postcranial osteology of T. sinensis as a prelude to an anatomical and phylogenetic revision of the species. We examined the holotype and all currently referred specimens of T. sinensis first-hand, and identified a unique postcranial character state combination incorporating tall dorsal neural spines, a reduced postacetabular ridge on the ilium, a fully enclosed flexor tunnel formed by the distal condyles of the femur, and a lunate proximal end on metatarsal III. Comparisons with other species of Tanius confirm that: (1) T. chingkankouensis is a nomen dubium erected on non-diagnostic composite material; (2) T. laiyangensis was established on indeterminate hadrosaurid remains that are not attributable to Tanius; and (3) the anecdotal assignments of Bactrosaurus prynadai and Tsintaosaurus spinorhinus to Tanius cannot be substantiated. Close inspection of the holotype caudal vertebra further reveals a possible healed bite trace consistent with a prey-predator interaction. Lastly, our calculated average body mass estimate for T. sinensis of between 2091-3533 kg suggests that it was one of the largest non-hadrosaurid hadrosauroids.
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| 14. |
- Borinder, Niclas H., et al.
(författare)
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Reassessment of the earliest documented stegosaurian fossils from Asia
- 2016
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Ingår i: Cretaceous research (Print). - : Elsevier BV. - 0195-6671 .- 1095-998X. ; 68, s. 61-69
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Tidskriftsartikel (refereegranskat)abstract
- In 1929, the famous Swedish palaeontologist Carl Wiman documented the first unequivocal stegosaurian dinosaur fossils from Asia. His material comprised an isolated dermal spine, together with a dorsal vertebra that was briefly described but never figured. Since then these remains have languished in obscurity, being noted in some stegosaur review articles but often ignored altogether. However, recent auditing of the Museum of Evolution palaeontological collection at Uppsala University in Sweden has led to the rediscovery of Wiman's original specimens, as well as two additional previously unrecognised stegosaurian dorsal vertebrae. All of these bones derive from the Lower Cretaceous (Berriasian-Valanginian) Mengyin Formation of Shandong Province in eastern China, and are morphologically compatible with the stratigraphically proximal stegosaurian taxon Wuerhosaurus from the Valanginian-Albian Tugulu Group in the Xinjiang Uyghur Autonomous Region of Western China. Wirnan's seminal stegosaurian fossils thus expand current palaeobiogeographical distributions, and contribute to the otherwise enigmatic record of Early Cretaceous stegosaurian occurrences.
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| 15. |
- Bremer, Oskar, et al.
(författare)
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CT-scan of Parasaurolophus tubicen from the Sternberg Collection (Uppsala University)
- 2011
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Ingår i: The 2nd Wiman Meeting. Carl Wiman's Legacy: 100 Years of Swedish Palaeontology. ; , s. 4-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In 1922, Carl Wiman, head of the then Palaeontological Institute at Uppsala University, received a series of crates containing dinosaur remains from the Upper Cretaceous (upper Campanian–Maastrichtian) Kirtland Formation of New Mexico, U.S.A. The specimens had been collected in 1921 by the famous American fossil hunter, Charles H. Sternberg, during a commissioned 5 month field expedition to the in the San Juan Basin. Arguably, one of the most significant specimens recovered was the partial skull of the spectacular crested hadrosaur Parasaurolophus tubicen. The holotype (PMU 24925) comprises the massive crest and neurocranium, together with parts of the pareital, frontal, prefrontals, postorbitals, squamosals and exoccipitals. The right quadrate is also preserved in articulation with the quadratojugal and pterygoid; the right jugal, maxilla, pterygoid, ectopterygoid and the anterior section of the lacrimal make up the facial region of the skull. Wiman was the first to propose that the crest of Parasaurolophus functioned as a vocalization structure. This study aims to investigate the functional morphology of the crest in this hadrosaur, in conjunction with endocranial anatomy, using CT-scanning and 3D modelling of the intracranial chambers. Comparisons with other specimens of Parasaurolophus will permit reconstruction of sensory capabilities in this 'classic' dinosaur taxon.
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| 16. |
- Byrne, Hannah, et al.
(författare)
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Coprolite diversity reveals a cryptic ecosystem in an early Tournaisian lake in East Greenland : Implications for ecosystem recovery after the end-Devonian extinctio
- 2022
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier. - 0031-0182 .- 1872-616X. ; 605
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Tidskriftsartikel (refereegranskat)abstract
- The early Tournaisian (Carboniferous) stage represents a key episode in the evolution of vertebrates. It follows the end-Devonian Hangenberg extinction event, which led to a major perturbation to both terrestrial and aquatic vertebrate ecosystems, and resulted in a significant restructuring of assemblages. However, few faunal associ-ations of this age have been described, and our understanding of faunal turnover across the Devonian -Carboniferous boundary remains poor. In this paper, we present an analysis of coprolite material from early Tournaisian lacustrine facies at Celsius Bjerg on Ymer o in East Greenland, which overlies the world-famous latest Devonian tetrapod-bearing localities. Fifty-five coprolite specimens (defined as a single coprolite or a piece of shale containing coprolites) were analysed using propagation phase-contrast synchrotron micro -tomography (PPC-SR mu CT). Through a study of external morphology, shape and size combined with information about internal structures, we categorise coprolite morphotypes, and interpret their origin. Notably, we identify a greater number of coprolite morphotypes compared to vertebrate taxa known from skeletal material, indicating the existence of a cryptic ecosystem that has not yet been recovered as body fossils. Vertebrate diversity in the immediate aftermath of the end-Devonian extinction is inferred to have been higher than expected, and might have included transient faunal elements within an open system, perhaps involving marine basin connections. Our results show that coprolites offer an alternative fossil data source, revealing diversity that is otherwise not always captured by the skeletal record.
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| 17. |
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| 18. |
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| 19. |
- Byrne, Hannah
(författare)
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Novel approaches to the environments and ecosystems of the fish-tetrapod transition
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The fish-tetrapod transition is one of the most important evolutionary events in Earth’s history, giving rise to terrestrial vertebrates around 390 million years ago. It set the stage for a series of evolutionary events that ultimately resulted in modern-day terrestrial vertebrates including ourselves. The fish-tetrapod transition occurred during the Middle Palaeozoic and although it has been the subject of intense study over the last century, many questions remain unanswered. In this thesis, novel techniques were used to help elucidate certain aspects of the fish-tetrapod transition. The first project sought to use numerical tidal simulations to test the premise of a hypothesis that large tides occurred during the Middle Palaeozoic and acted as a driver for the evolution of lungs and limbs. The simulations produced for the Late Silurian-Late Devonian revealed unusually large tides during the Late Silurian, thus the origin of lungs, supporting the hypothesis that deoxygenated tidal pools could have been the setting for this evolutionary step. The following three projects used propagation phase-contrast synchrotron microtomography (PPC-SRμCT) to analyse new tetrapod material from the terminal Famennian (latest Devonian) and coprolite material from the earliest Tournaisian of Greenland (earliest Carboniferous), spanning a mass extinction event (the Hangenberg crisis) believed to have impacted early tetrapod diversity. Spectacular data sets were generated using this technique, with analysis of the tetrapod material revealing the presence of new taxa, making East Greenland home to the greatest known diversity of tetrapods in the world during the Devonian. Synchrotron scanning allowed for the accurate determination of coprolite morphotypes from a post-Hangenberg crisis lake deposit, revealing greater diversity among the coprolites compared with vertebrate body fossil taxa and thus demonstrating that the fauna contained additional taxa not captured by the body fossil record. Most of the large coprolites are non-spiral and were probably produced by a large aquatic tetrapod. One large coprolite is spiral and is postulated to have been produced by a chondrichthyan. Virtual reconstructions of several coprolites were generated using the scan data. The largest coprolites were full of actinopterygian and acanthodian remains, showing that the probable tetrapod was a proficient aquatic predator. Another large coprolite contained remains of two new body fossil taxa; an actinopterygian and small tetrapod. The coprolite data challenge our initial interpretation of a low-diversity lake fauna, revealing instead a complex ecosystem immediately after a major mass extinction event. Tetrapods and chondrichthyans appear to have been the apex predators in this ecosystem. This thesis demonstrates the capabilities of two novel analytical techniques, tidal simulation and synchrotron microtomography, to uncover previously inaccessible information about the fish-tetrapod transition and its environmental-ecological context.
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| 20. |
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| 21. |
- Den Boer, Wendy, et al.
(författare)
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Climbing adaptations, locomotory disparity and ecological convergence in ancient stem 'kangaroos'
- 2019
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Ingår i: Royal Society Open Science. - : The Royal Society. - 2054-5703. ; 6:2
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Tidskriftsartikel (refereegranskat)abstract
- Living kangaroos, wallabies and rat-kangaroos (Macropodoidea) constitute the most ecologically diverse radiation of Australasian marsupials. Indeed, even their hallmark bipedal hopping gait has been variously modified for bounding, walking and climbing. However, the origins of this locomotory adaptability are uncertain because skeletons of the most ancient macropodoids are exceptionally rare. Some of the stratigraphically oldest fossils have been attributed to Balbaridae-a clade of potentially quadrupedal stem macropodoids that became extinct during the late Miocene. Here we undertake the first assessment of balbarid locomotion using two-dimensional geometric morphometrics and a correlative multivariate analysis of linear measurements. We selected the astragalus and pedal digit IV ungual as proxies for primary gait because these elements are preserved in the only articulated balbarid skeleton, as well as some unusual early Miocene balbarid-like remains that resemble the bones of modern tree-kangaroos. Our results show that these fossils manifest character states indicative of contrasting locomotory capabilities. Furthermore, predictive modelling reveals similarities with extant macropodoids that employ either bipedal saltation and/or climbing. We interpret this as evidence for archetypal gait versatility, which probably integrated higher-speed hopping with slower-speed quadrupedal progression and varying degrees of scansoriality as independent specializations for life in forest and woodland settings.
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| 22. |
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| 23. |
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| 24. |
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| 25. |
- Einarsson, Elisabeth, et al.
(författare)
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A mid-Campanian marine extinction event – possible evidence from the Kristianstad Basin of southern Sweden
- 2011
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Ingår i: The 2nd Wiman Meeting. Carl Wiman's Legacy: 100 Years of Swedish Palaeontology. ; , s. 7-8
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Potential traces of a mid-Campanian (83–73 Ma) marine extinction event have been documented as sequential faunal turnover in shallow coastal calcareous sands and calcarenite strata at the Åsen locality in the Kristianstad Basin of southern Sweden. The depositional succession at Åsen is conformably divided into the latest-early Campanian Belemnellocamax mammillatus belemnite Zone (a lateral equivalent of the northern European Belemnitella mucronata senior/Gonioteuthis quadrata gracilis Zone), and an overlying earliest-late Campanian Belemnellocamax balsvikensis Zone. The stratigraphically older B. mammillatus Zone assemblages comprise storm-accumulated remains (associated with coquina beds and oyster banks) that include selachians, chimaeroids, bony fish (pachycormiforms, pycnodontids, and teleosts), dyrosaurid crocodilians, elasmosaurid and polycotylid plesiosaurs, mosasaurs (mosasaurines, halisaurines, tylosaurines, and plioplatecarpines), and cheloniid sea turtles. Coeval invertebrates comprise abundant belemnites, bivalves, brachiopods, and echinoderms. This rich biodiversity abruptly declines up-sequence through the oyster bed layer and into the B. balsvikensis Zone; this is characterised by a sandier facies, which is exceptionally poor in reptile remains and manifests only small teleosts and sharks. Benthic molluscs and brachiopods also decline in abundance while worm tracks and decapod crustaceans (crabs) make a first appearance. Although, this observed change clearly corresponds to an environmental shift, it also correlates with a recognised trans-Atlantic mid-Campanian extinction event that affected warm-temperate to sub-tropical palaeolatitudinal belt assemblages in North America, and might have been part of a broader global phenomenon.
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| 26. |
- Einarsson, Elisabeth, et al.
(författare)
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Mosasaur bite marks on a plesiosaur propodial from the Campanian (Late Cretaceous) of southern Sweden
- 2010
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Ingår i: GFF. - : Informa UK Limited. - 1103-5897 .- 2000-0863. ; 132:2, s. 123-128
-
Tidskriftsartikel (refereegranskat)abstract
- Although plesiosaurs and mosasaurs co-existed for about 35 million years at the end of the Cretaceous, the fossil record documenting interactions between these two groups of marine reptiles is meagre. The discovery of deeply incised scars on a limb bone of an immature polycotylid plesiosaur from the latest early Campanian (in the European two-fold division of the Campanian Stage) of the Kristianstad Basin, southern Sweden, is thus significant because it represents a rare example of predation or scavenging on an immature polycotylid plesiosaur by a large mosasaur.
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| 27. |
- Frauenfelder, Timothy G., et al.
(författare)
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New Ankylosaurian Cranial Remains From the Lower Cretaceous (Upper Albian) Toolebuc Formation of Queensland, Australia
- 2022
-
Ingår i: Frontiers in Earth Science. - : Frontiers Media S.A.. - 2296-6463. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Australian dinosaur research has undergone a renaissance in the last 10 years, with growing knowledge of mid-Cretaceous assemblages revealing an endemic high-paleolatitude Gondwanan fauna. One of its most conspicuous members is ankylosaurs, which are rare but nonetheless occur in most Australian dinosaur-bearing formations spanning the uppermost Barremian to lower Cenomanian. Here we describe a partial ankylosaur skull from the marine Toolebuc Formation exposed near Boulia in western Queensland, Australia. This skull represents the oldest ankylosaurian material from Queensland, predating the holotype of Kunbarrasaurus ieversi, which was found in the overlying Allaru Mudstone. The ankylosaur skull is encased in a limestone concretion with the maxillary tooth rows preserved only as impressions. Synchrotron radiation X-ray tomography was used to non-destructively image and reconstruct the specimen in 3D and facilitate virtual preparation of the separate cranial bones. The reconstruction of the skull revealed the vomer, palatines, sections of the ectopterygoids and maxillae, and multiple teeth. The palate has posteriorly positioned choanae that differs from the more anterior placement seen in most other ankylosaurians, but which is shared with K. ieversi, Akainacephalus johnsoni, Cedarpelta bilbeyhallorum, Gobisaurus domoculus, and Panoplosaurus mirus. Phylogenetic analyses place the new cranial material within the recently named basal ankylosaurian clade Parankylosauria together with K. ieversi. This result, together with the anatomical similarities to the holotype of K. ieversi, permits its referral to cf. Kunbarrasaurus sp. This specimen elucidates the palatal anatomy of Australian ankylosaurs and highlights one of the most ubiquitous components of Australian mid-Cretaceous dinosaur faunas.
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| 28. |
- Garcia-Navas, Vicente, et al.
(författare)
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The geography of speciation in dasyurid marsupials
- 2020
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Ingår i: Journal of Biogeography. - : WILEY. - 0305-0270 .- 1365-2699. ; 47:9, s. 2042-2053
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To determine the effects of competition and divergence time on morphological dissimilarity and geographical range overlap between dasyurid species at both regional and local scales. Our hypothesis is that speciation in this group has been largely allopatric at regional scale, but involved morphological divergence at local scale through sympatric character displacement.Location: Australia, New Guinea and surrounding islands.Taxon: Dasyurid (Dasyuridae) marsupials, 67 species.Methods: Geographical range overlap was quantified using polygons representing the outer limits of species distributions. Local-scale range overlap was quantified as the degree of co-occurrence of two taxa across a set of ecological survey plots representing 83 sampled communities. Phylogenies were generated using a novel DNA dataset, with divergence times estimated via total-evidence dating incorporating fossils. Morphological divergence was determined using body mass and lower molar row length as proxy traits for reconstructing niche exploitation.Results: Sister species pairs were found to be sympatric in 52% (11/21) of cases. Range overlap tended to increase with node age, which supports the hypothesis that mammalian speciation is routinely allopatric. We detected no evidence of character displacement with increasing range overlap between sister species pairs. However, a negative relationship was observed between morphological divergence in body mass and range overlap across all sampled taxa, suggesting that selection in sympatry is convergent, while divergent selection occurs in allopatry. Local-scale co-occurrences revealed no trace of species aversion, indicating that competition has not impacted on the spatial distribution of dasyurids.Main conclusions: Despite moderate levels of sympatry through time, our results evince low rates of spatial co-occurrence between dasyurid species. Although this may be indicative competitive exclusion, the lack of character displacement suggests that biotic interactions have likely not acted as a dominant driver of phenotypic evolution in this radiation. We alternatively posit that abiotic factors including aridity and geographical connectivity have more feasibly propagated character convergence, and led to both niche conservatism and speciation in this ubiquitous australidelphian clade.
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| 29. |
- Georgalis, Georgios L., et al.
(författare)
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New material of Laophis crotaloides, an enigmatic giant snake from Greece, with an overview of the largest fossil European vipers
- 2016
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Ingår i: Swiss Journal of Geosciences. - : Springer Science and Business Media LLC. - 1661-8726 .- 1661-8734. ; 109:1, s. 103-116
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Tidskriftsartikel (refereegranskat)abstract
- Laophis crotaloides was described by Richard Owen as a new and very large fossil viperid snake species from Greece. The type material is apparently lost and the taxon was mostly neglected for more than a century. We here describe a new partial viperid vertebra, collected from the same locality and of equivalent size to the type material. This vertebra indicates that at least one of the three morphological characters that could be used to diagnose L. crotaloides is probably an artifact of the lithographer who prepared the illustration supporting the original description. A revised diagnosis of L. crotaloides is provided on the basis of the new specimen. Despite the fragmentary nature of the new vertebra, it confirms the validity of L. crotaloides, although its exact relationships within Viperidae remain unknown. The new find supports the presence of a large viperid snake in the early Pliocene of northern Greece, adding further data to the diversity of giant vipers from Europe.
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| 30. |
- Georgalis, Georgios L., et al.
(författare)
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Nostimochelone lampra gen. et sp. nov., an EnigmaticNew Podocnemidoidean Turtle from the Early Mioceneof Northern Greece
- 2012
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Ingår i: Morphology and Evolution of Turtles. - Dordrecht : Springer. - 9789400743090 - 9789400743083 ; , s. 277-287
-
Bokkapitel (refereegranskat)abstract
- A new podocnemidoidean turtle, Nostimochelonelampra gen. et sp. nov., was recently recovered fromlittoral marine-estuarine sediments of the lower MioceneZeugostasion Formation, near the village of Nostimo innorthwestern Macedonia, Greece. This new taxon is characterizedby a mosaic of primitive and derived features mostnotably the presence of a broad embayment on the anteriorcarapace margin, which involves both the nuchal (whosewidth[length) and first pair of peripherals, a continuousseries of six markedly elongate and very narrowed hexagonalneural bones, extension of the axillary buttress onto themidline of the anteroposteriorly elongate costal I (leavinga concave scar) and also laterally across the peripheralII-peripheral III suture, medial contact of the humeral scutes(implying a small intergular), and extensive overlap of thepectoral scutes on the entoplastron, probably extending tothe epiplastral-hyoplastral suture. Conclusive phylogeneticplacement of Nostimochelone is difficult to establishbecause the remains are incompletely preserved. Nevertheless,its discovery is significant because it represents boththe first record of a pleurodiran turtle from Greece and alsoone of only a handful of fossil podocnemidoidean occurrencesthus far documented from the Neogene of Europe.
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| 31. |
- Georgalis, Georgios L., et al.
(författare)
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The fossil turtles of Greece : An overview of taxonomy and distribution
- 2013
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Ingår i: Geobios. - : Elsevier BV. - 0016-6995 .- 1777-5728. ; 46:4, s. 299-311
-
Tidskriftsartikel (refereegranskat)abstract
- Turtle remains are common in the Miocene-Holocene deposits of Greece, and are a key focus of the growing research interest in Neogene. herpetofaunas from the Aegean region. Some of the most important finds include one of Europe's stratigraphically youngest pleurodiran taxa, Nostimochelone lampra, from the Early Miocene of Macedonia, together with arguably the richest record of fossil tortoises from the Eastern Mediterranean. This incorporates the presently oldest definitive representatives of the quintessential genus Testudo sensu stricto from the Late Miocene of Attica and Macedonia, and numerous specimens of the colossal (carapace similar to 2 m-length) testudinid Cheirogaster from Late Miocene-Late Pliocene sediments in southern and northern Greece, as well as on the eastern Aegean islands of Samos and Lesvos. Tantalising, but as yet unconfirmed Miocene accounts of the geoemydid Mauremys in Macedonia, and indeterminate emydid-like remains from Euboea, also provide potentially significant range extensions. Although hampered by a historically sparse documentation, the fossil turtles of Greece are a significant resource that record both assemblage changes and the origin of modern lineages.
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| 32. |
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| 33. |
- Haig, David W., et al.
(författare)
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Early Triassic (early Olenekian) life in the interior of East Gondwana : mixed marine-terrestrial biota from the Kockatea Shale, Western Australia
- 2015
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier BV. - 0031-0182 .- 1872-616X. ; 417, s. 511-533
-
Tidskriftsartikel (refereegranskat)abstract
- A new terrestrial marine assemblage from the lower beds of a thin outcrop section of the Kockatea Shale in the northern Perth Basin, Western Australia, contains a range of fossil groups, most of which are rare or poorly known from the Lower Triassic of the region. To date, the collection includes spinose acritarchs, organic-cemented agglutinated foraminifera, lingulids, minute bivalves and gastropods, ammonoids, spinicaudatans, insects, austriocaridid crustaceans, actinopterygians, a temnospondyl-like mandible, plant remains, and spores and pollen. Of these groups, the insects, crustaceans and macroplant remains are recorded for the first time from this unit. Palynomorphs permit correlation to nearby sections where conodonts indicate an early Olenekian (Smithian) age. The locality likely represents the margin of an Early Triassic shallow interior sea with variable estuarine-like water conditions, at the southwestern end of an elongate embayment within the East Gondwana interior rift sag system preserved along the Western Australian margin. Monospecific spinose acritarch assemblages intertwined with amorphous organic matter may represent phytoplankton blooms that accumulated as mats, and suggest potentially eutrophic surface waters. The assemblage represents a mixure of marine and terrestrial taxa, suggesting variations in water conditions or that fresh/brackish-water and terrestrial organisms were transported from adjacent biotopes. Some of the lower dark shaly beds are dominated by spinicaudatans, likely indicating periods when the depositional water body was ephemeral, isolated, or subjected to other difficult environmental conditions. The biota of the Kockatea Shale is insufficiently known to estimate biotic diversity and relationships of individual taxa to their Permian progenitors and Triassic successors, but provides a glimpse into a coastal-zone from the interior of eastern Gondwana. Specialist collecting is needed to clarify the taxonomy of many groups, and comparisons to other Lower Triassic sites are required to provide insights into the pattern of biotic decline and recovery at the end-Permian crisis. (C) 2014 Elsevier B.V. All rights reserved.
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| 34. |
- Hamilton-bruce, Robert J., et al.
(författare)
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A possible succineid land snail from the Lower Cretaceous non-marine deposits of the Griman Creek Formation at Lightning Ridge, New South Wales
- 2010
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Ingår i: Alcheringa. - : Informa UK Limited. - 0311-5518 .- 1752-0754. ; 34:3, s. 325-331
-
Tidskriftsartikel (refereegranskat)abstract
- A diverse non-marine molluscan fauna has been recorded from the Lower Cretaceous (middle-upper Albian), low-energy, fluvial sediments of the Griman Creek Formation at Lightning Ridge in northern New South Wales. We describe a novel addition to this assemblagea probable pulmonate gastropod that manifests features (including shell with an inflated body whorl, expansive aperture, and reduced spire/whorl count) consistent with Succineidae, an extant cosmopolitan family of terrestrial snails. The fossils are assigned to a new genus and species (Suratia marilynae), distinguishable from existing taxa by a combination of traits: shell with sculpturing limited to fine growth lines only, lunate body whorl with a rounded periphery, markedly flattened spire (comprising up to two whorls), which is almost flush with the apical surface and delineated by a deeply impressed sutural 'gutter,' and presence of both a broad columellar plait and distinct columellar fold. The new taxon apparently constitutes the oldest pulmonate remains recorded from Australasia, and extends the known stratigraphical range of succineids back to the Lower Cretaceous in the Southern Hemisphere.
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| 35. |
- Janis, Christine M., et al.
(författare)
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Myth of the QANTAS leap : perspectives on the evolution of kangaroo locomotion
- 2023
-
Ingår i: Alcheringa. - : Taylor & Francis. - 0311-5518 .- 1752-0754. ; 47:4, s. 671-685
-
Tidskriftsartikel (refereegranskat)abstract
- The distinctive QANTAS flying kangaroo' motif of Australia's national airline signifies what many people regard as the pinnacle of kangaroo evolution-a large-bodied marsupial specialized for endurance-hopping. However, while almost all extant macropodoids (the crown group including kangaroos) use hopping gaits to some extent, the fossil record reveals that the locomotory capabilities of extinct macropodoids were comparatively diverse. The earliest recognized Oligocene- middle Miocene macropodoids probably employed quadrupedal bounding, climbing and slower speed hopping as their primary modes of locomotion. Yet, all were apparently small-bodied (<12 kg), with larger-bodied (>20 kg) forms not appearing until the late Miocene coincident with increasing aridity and the spread of openly vegetated habitats. Hopping is functionally problematic at larger body sizes. Consequently, the later radiation of macropodids (kangaroos, wallabies and their relatives) achieved an optimal mass for efficient higher-speed hopping at similar to 35 kg, with a theorized extreme limit of similar to 140-160 kg. Modern kangaroos otherwise approach the peak mass range for such gaits at similar to 50-90 kg, with the gigantic Pliocene-Pleistocene species of Protemnodon (giant wallabies') at similar to 100-160 kg likely being predominantly quadrupedal, and sthenurines (short-faced kangaroos) at similar to 50-250 kg seemingly using bipedal striding. Here, we review the fossil evidence of macropodoid locomotion over the last similar to 25 million years, and present preliminary analyses of limb bone and tarsal metric data. These indicate that the higher-speed endurance-hop-ping typical of modern large-bodied kangaroos was probably rare or absent in all but a few crown macropodoid lineages. The intrinsic gait variability of macropodoids has therefore diminished with Late Pleistocene megafaunal extinctions. As a result, the famous QANTAS flying kangaroo' actually depicts only one of what was once many successful locomotory strategies employed by macropo-doids to conquer a range of terrestrial and arboreal habitats.
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| 36. |
- Jirak, Daniel, et al.
(författare)
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A combined MR and CT study for precise quantitative analysis of the avian brain
- 2015
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Brain size is widely used as a measure of behavioural complexity and sensory-locomotive capacity in avians but has largely relied upon laborious dissections, endoneurocranial tissue displacement, and physical measurement to derive comparative volumes. As an alternative, we present a new precise calculation method based upon coupled magnetic resonance (MR) imaging and computed tomography (CT). Our approach utilizes a novel interactive Fakir probe cross-referenced with an automated CT protocol to efficiently generate total volumes and surface areas of the brain tissue and endoneurocranial space, as well as the discrete cephalic compartments. We also complemented our procedures by using sodium polytungstate (SPT) as a contrast agent. This greatly enhanced CT applications but did not degrade MR quality and is therefore practical for virtual brain tissue reconstructions employing multiple imaging modalities. To demonstrate our technique, we visualized sex-based brain size differentiation in a sample set of Ring-necked pheasants (Phasianus colchicus). This revealed no significant variance in relative volume or surface areas of the primary brain regions. Rather, a trend towards isometric enlargement of the total brain and endoneurocranial space was evidenced in males versus females, thus advocating a non-differential sexually dimorphic pattern of brain size increase amongst these facultatively flying birds.
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| 37. |
- Karlsson, Henrik, et al.
(författare)
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The Sternberg Collection at the Museum of Evolution (Uppsala University): a palaeontological and historical resource
- 2011
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Ingår i: The 2nd Wiman Meeting. Carl Wiman's Legacy: 100 Years of Swedish Palaeontology. ; , s. 12-13
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Sternberg Collection at the Museum of Evolution, Uppsala University constitutes the single largest repository of Kirtland Formation vertebrate fossils outside of the U.S.A., and is the core off the most extensive collection of original dinosaur remains in Scandinavia. Its specimens derive from various localities in the San Juan Basin of northwestern New Mexico, and include mainly Late Cretaceous (late Campanian–Maastrichtian) dinosaurs, turtles, crocodiles and fish (teleosts, lepisosteids and mylobatid rays) together with a few middle Paleocene reptiles and mammals. The famous North American dinosaur hunter, Charles H. Sternberg, excavated and shipped the material to Sweden during the summer and autumn of 1921, under a commission from the then director of the Palaeontological Institute and first Professor of Palaeontology at Uppsala University, Carl Wiman. Unusually for the time, Sternberg and his two Navajo assistants made a thorough survey for both display-quality skeletons and much smaller fragmentary remains (including plants); thus the Sternberg Collection comprises an actual assemblage cross-section. Wiman established two new taxa (and wrote four papers) on the basis of his material: the hadrosaurid dinosaur Parasaurolophus tubicen, and goniopholid crocodylian Denazinosuchus kirtlandicus. Later workers have also identified other dinosaurs including hadrosaurs (Kritosaurus sp.), sauropods (Alamosaurus sanjuanensis), and theropods (Bistahieversor seeleyi, Saurornitholestes robustus). This study provides the first comprehensive catalogue of the Museum of Evolution Sternberg Collection and assesses its palaeoecological utility.
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| 38. |
- Kear, Benjamin P., 1975-
(författare)
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A 45-year facelift for Alcheringa
- 2020
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Ingår i: Alcheringa. - : TAYLOR & FRANCIS LTD. - 0311-5518 .- 1752-0754. ; 44:3, s. 341-342
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 39. |
- Kear, Benjamin P., 1975-
(författare)
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A new Nell Ludbrook Special Review
- 2022
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Ingår i: Alcheringa. - : Taylor & Francis. - 0311-5518 .- 1752-0754. ; 46:1, s. 1-2
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 40. |
- Kear, Benjamin P., 1975-, et al.
(författare)
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A palaeobiogeographical synthesis of Australasian Mesozoic marine tetrapods
- 2018
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Ingår i: Alcheringa. - : Taylor & Francis Group. - 0311-5518 .- 1752-0754. ; 42:4, s. 461-486
-
Tidskriftsartikel (refereegranskat)abstract
- Kear, B.P., Fordyce, R.E., Hiller, N. & Siversson, M., December 2017. A palaeobiogeographical synthesis of Australasian Mesozoic marine tetrapods. Alcheringa 42, 461-486. ISSN 0311-5518.THE LAST 15years has witnessed a blossoming of research on Australasian Mesozoic marine tetrapod fossils. Much of this work has focused on amniotes, particularly those from the prolific Lower Cretaceous (Aptian-Albian) Lagerstatten of the Eromanga Basin in central and eastern Australia, and Upper Cretaceous (Campanian-Maastrichtian) sequences of the North and South islands of New Zealand. However, rare and less popularized remains have also been found in Lower Triassic-mid-Cretaceous rocks from Australia, New Zealand and the Chatham Islands, and on the tectonically proximal landmasses of New Caledonia and Timor. Currently identified taxa include estuarine-paralic rhytidostean, brachyopid, capitosaurian and trematosaurian temnospondyls from the earliest Triassic (Induan-Olenekian), Middle-Late Triassic (Anisian-Norian) eosauropterygians, and mixosaurian, shastasaurian and euichthyosaurian ichthyosaurians, Early-Middle Jurassic (Sinemurian-Bajocian) ichthyosaurians, together with plesiosauroid and rhomaleosaurid-like plesiosaurians, and diverse Early (Aptian-Albian) through to Late Cretaceous (Campanian-Maastrichtian) elasmosaurid, leptocleidid, polycotylid, probable cryptoclidid and pliosaurid plesiosaurians, as well as ophthalmosaurid ichthyosaurians, sea turtles incorporating protostegids, and mosasaurid squamates. This faunal succession evidences almost continuous occupation of southern high-palaeolatitude seas, and repeated endemic diversifications (including nascent members of some key lineages) amongst emigrant cosmopolitan clades. The primary dispersal routes are likely to have been peri-Gondwanan, with coastal migrations along the western Tethys and polar margins of the Panthalassan Ocean. However, augmentation by increasing continental fragmentation and seaway corridor connectivity probably occurred from the Middle Jurassic to Late Cretaceous. Latest Cretaceous mosasaurid and elasmosaurid taxa also reveal regional affinities with the emergent western Pacific and Weddellian austral bioprovinces. The extreme rarity, or complete absence, of many major groups prevalent elsewhere in Gondwana (e.g., tanystropheids, Triassic sauropterygians, bothremydid marine turtles, thalattosuchians and dyrosaurid crocodylomorphs) is conspicuous, and might be related to stratigraphical/collecting biases, or the predominantly higher-palaeolatitude, cooler-water Mesozoic palaeogeography of the Australasian region. Although the burgeoning record is substantial, much still awaits discovery and adequate documentation; thus Australasia is still one of the most exciting prospects for future insights into the global history of Mesozoic marine tetrapods.
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| 41. |
- Kear, Benjamin P., 1975-, et al.
(författare)
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A review of aquatic vertebrate remains from the Middle-Upper Triassic Jilh Formation of Saudi Arabia
- 2010
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Ingår i: Proceedings of the Royal Society of Victoria. - 0035-9211. ; 122:1, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- A recent field survey of the Middle–Upper Triassic (upper Anisian to lowermost Carnian) paralic marine deposits of the Jilh Formation in central Saudi Arabia has yielded large quantities of vertebrate fossils. These finds prompt a revision of the existing faunal list and include at least one novel stratigraphical occurrence for the Arabian Peninsula. The remains comprise sauropterygian marine reptiles (Psephosauriscus sp., Nothosaurus cf. tchernovi, Nothosaurus cf. giganteus, Simosaurus sp.), a lungfish (Ceratodus sp.),hybodontiform sharks (Hybodus sp.) and saurichthyform actinopterygians (Saurichthys sp.). Palaeobiogeographical assessment reinforces Tethyan affinities for the assemblage and reflects the close proximity of the Arabian region to the ‘Sephardic Realm’, a compositionally distinct circum-Mediterranean faunal province characterized by hypersaline Muschelkalk facies.
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| 42. |
- Kear, Benjamin P., 1975-
(författare)
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A revision of Australia's Jurassic plesiosaurs
- 2012
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Ingår i: Palaeontology. - : Taylor & Francis. - 0031-0239 .- 1475-4983. ; 55:5, s. 1125-1138
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Tidskriftsartikel (refereegranskat)abstract
- Jurassic plesiosaur fossils are exceptionally rarein Australia and currently restricted to a single fragmentaryskeleton (Sinemurian, Razorback beds, Queensland), somearticulated vertebrae (lower Toarcian, Evergreen Formation,Queensland) and a few isolated bones and teeth (Aalenian–Bajocian, Champion Bay Group, Western Australia).These remains are attributable to either indeterminate plesiosaurs,or more specifically to pliosauroids and plesiosauroids,and occur within a variety of fluviatile-lacustrine tocoastal marine depositional settings. Although hampered bytheir incompleteness, Australia’s Jurassic plesiosaurs are significantbecause they include some of the most ancientoccurrences from nonmarine strata, and Gondwanan marinereptiles of a similar age are otherwise very sparselyknown.
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| 43. |
- Kear, Benjamin P., et al.
(författare)
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An introduction to the Mesozoic biotas of Scandinavia and its Arctic territories
- 2016
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Ingår i: Mesozoic Biotas Of Scandinavia And Its Arctic Territories. - : Geological Society. - 9781862397484 ; 434:1, s. 1-14
-
Bokkapitel (refereegranskat)abstract
- The Mesozoic biotas of Scandinavia have been studied for nearly two centuries. However, the last 15 years have witnessed an explosive advance in research, most notably on the richly fossiliferous Triassic (Olenekian-Carnian) and Jurassic (Tithonian) Lagerstatten of the Norwegian Arctic Svalbard archipelago, Late Cretaceous (Campanian) Kristianstad Basin and Vomb Trough of Skane in southern Sweden, and the UNESCO heritage site at Stevns Klint in Denmark - the latter constituting one of the most complete Cretaceous-Palaeogene (Maastrichtian-Danian) boundary sections known globally. Other internationally significant deposits include earliest (Induan) and latest Triassic (Norian-Rhaetian) strata from the Danish autonomous territory of Greenland, and the Early Jurassic (Sinemurian-Pliensbachian) to Early Cretaceous (Berriasian) rocks of southern Sweden and the Danish Baltic island of Bornholm, respectively. Marine palaeocommunities are especially well documented, and comprise prolific benthic macroinvertebrates, together with pelagic cephalopods, chondrichthyans, actinopterygians and aquatic amniotes (ichthyopterygians, sauropterygians and mosasauroids). Terrestrial plant remains (lycophytes, sphenophytes, ferns, pteridosperms, cycadophytes, bennettitaleans and ginkgoes), including exceptionally well-preserved carbonized flowers, are also world famous, and are occasionally associated with faunal traces such as temnospondyl amphibian bones and dinosaurian footprints. While this collective documented record is substantial, much still awaits discovery. Thus, Scandinavia and its Arctic territories represent some of the most exciting
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| 44. |
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| 45. |
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| 46. |
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| 47. |
- Kear, Benjamin P., 1975-, et al.
(författare)
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Earliest Triassic ichthyosaur fossils push back oceanic reptile origins
- 2023
-
Ingår i: Current Biology. - : Elsevier. - 0960-9822 .- 1879-0445. ; 33:5, s. R178-R179
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Tidskriftsartikel (refereegranskat)abstract
- Reptiles first radiated into oceanic environments after the cataclysmic end-Permian mass extinction (EPME)1, 251.9 million years (Ma) ago. The geologically oldest fossils evincing this adaptive transition have been recovered from upper-Lower Triassic (lower Spathian) strata, ∼248.8 Ma2, and postdate a landmark turnover of amphibian-dominated to reptile-dominated marine ecosystems spanning the late Smithian crisis (LSC)3, ∼249.6 Ma4 —less than ∼2.3 Ma after the EPME. Here, we report ichthyopterygian (the group including ‘fish-shaped’ ichthyosaurians1) remains from the Arctic island of Spitsbergen that predate the LSC in later-middle to early-late Smithian5 deposits up to ∼250 Ma. Unexpectedly, however, their large size and spongy internal bone structure indicate a fully pelagic ichthyopterygian1,6. Given this unambiguous occurrence ∼2 Ma after the EPME, these pioneering seagoing tetrapods can now be feasibly recast as mass extinction survivors instead of ecological successors2,3 within the earliest Mesozoic marine predator communities.
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| 48. |
- Kear, Benjamin P., 1975-
(författare)
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Editorial
- 2018
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Ingår i: Alcheringa. - : TAYLOR & FRANCIS LTD. - 0311-5518 .- 1752-0754. ; 42:2, s. 155-156
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 49. |
- Kear, Benjamin P., 1975-
(författare)
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Editorial
- 2019
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Ingår i: Alcheringa. - : Taylor & Francis Group. - 0311-5518 .- 1752-0754. ; 43:4, s. 479-479
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 50. |
- Kear, Benjamin P., et al.
(författare)
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First Dinosaurs from Saudi Arabia
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:12, s. e84041-
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Tidskriftsartikel (refereegranskat)abstract
- Dinosaur remains from the Arabian subcontinent are exceedingly rare, and those that have been documented manifest indeterminate affinities. Consequently the discovery of a small, but diagnostic, accumulation of elements from Campanian-Maastrichtian (similar to 75 Ma) deposits in northwestern Saudi Arabia is significant because it constitutes the first taxonomically identifiable dinosaur material described from the Arabian Peninsula. The fossils include a series of possible lithostrotian titanosaur caudal vertebrae, and some isolated theropod marginal teeth that share unique character states and metric parameters (analyzed using multivariate statistical methods) with derived abelisaurids - this is the first justifiable example of a non-avian carnivorous dinosaur clade from Arabia. The recognition of titanosaurians and abelisaurids from Saudi Arabia extends the palaeogeographical range of these groups along the entire northern Gondwanan margin during the latest Cretaceous. Moreover, given the extreme paucity of coeval occurrences elsewhere, the Saudi Arabian fossils provide a tantalizing glimpse into dinosaurian assemblage diversity within the region.
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