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Kear, Benjamin P.
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Publications (10 of 87) Show all publications
Pardo-Perez, J. M., Kear, B. P., Gomez, M., Moroni, M. & Maxwell, E. E. (2018). Ichthyosaurian palaeopathology: evidence of injury and disease in fossil 'fish lizards'. Journal of Zoology, 304(1), 21-33
Open this publication in new window or tab >>Ichthyosaurian palaeopathology: evidence of injury and disease in fossil 'fish lizards'
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2018 (English)In: Journal of Zoology, ISSN 0952-8369, E-ISSN 1469-7998, Vol. 304, no 1, p. 21-33Article in journal (Refereed) Published
Abstract [en]

The documented record of ichthyosaurian paleopathologies reveals an array of injury-related bone modifications and instances of disease evidenced through multiple clades, skeletal regions and body-size classes from the Middle Triassic to middle Cretaceous. Examples include traumatic injuries, as well as a high incidence of articular diseases, including avascular necrosis. Forelimb pathologies are particularly abundant (65% of total reported), and the glenoid region seems to have been especially prone to articular disease. In contrast, pathologies affecting the vertebral column are comparatively underrepresented (6% of reported pathologies). Also notable is the disproportionate commonality of osteopathologies in ichthyosaurian taxa between 2 and 6m in length (54%), as opposed to demonstrably larger (31%) or smaller bodied (15%) species. Furthermore, osteopathologies are almost exclusively described from skeletally mature individuals, and are best known from taxa of Jurassic age (78%), versus those from the Triassic (15%) or Cretaceous (7%); this likely reflects biases in the ichthyosaurian fossil record through time. Ichthyosaurs evince remarkable similarities in the types of observed skeletal damage relative to other ecologically similar marine amniotes - especially cetaceans and mosasaurid squamates, all of which potentially exhibited equivalent palaeoecological and/or behavioural adaptations for life in aqueous environments. Notably, however, the unusually low frequency of vertebral pathologies in ichthyosaurs is peculiar, and requires further investigation to establish significance.

Place, publisher, year, edition, pages
WILEY, 2018
Keyword
palaeobiology, ichthyosauria, Mesozoic, Reptilia, avascular necrosis, osteotrauma, palaeopathology
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-341317 (URN)10.1111/jzo.12517 (DOI)000419517600004 ()
Available from: 2018-02-09 Created: 2018-02-09 Last updated: 2018-02-09Bibliographically approved
Sachs, S., Hornung, J. J. & Kear, B. P. (2017). A New Basal Elasmosaurid (Sauropterygia: Plesiosauria) From The Lower Cretaceous Of Germany. Journal of Vertebrate Paleontology, 37(4), Article ID e1301945.
Open this publication in new window or tab >>A New Basal Elasmosaurid (Sauropterygia: Plesiosauria) From The Lower Cretaceous Of Germany
2017 (English)In: Journal of Vertebrate Paleontology, ISSN 0272-4634, E-ISSN 1937-2809, Vol. 37, no 4, article id e1301945Article in journal (Refereed) Published
Abstract [en]

Here we report on a new basal elasmosaurid plesiosaurian, Lagenanectes richterae, gen. et sp. nov., from the Lower Cretaceous (probably Upper Hauterivian) of Germany. The material includes a partial skull (cranium and mandible), the atlas-axis complex, additional cervical vertebrae, caudal vertebrae, an ilium, and limb elements. The basioccipital and atlas intercentrum are pathologically deformed, probably due to an osteomyelitic infection. Two potential autapomorphies were found in the mandible: (1) the alveolar margin at the symphysis is laterally expanded with the rostral-most alveoli being markedly procumbent and situated along the lateral margins of the dentaries; and (2) the ventral midline at the symphysis is produced into a prominent wedge-shaped platform indented by numerous irregular pits. Lagenanectes richterae, gen. et sp. nov., also shows a number of typical elasmosaurid traits, including a longitudinal lateral ridge on the cervical vertebral centra (although a ventral notch is absent) and teeth with oval cross-sections. Lagenanectes richterae, gen. et sp. nov., is one of the best-preserved plesiosaurians from the Lower Cretaceous of Europe.

National Category
Other Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-340179 (URN)10.1080/02724634.2017.1301945 (DOI)000413534100002 ()
Available from: 2018-01-26 Created: 2018-01-26 Last updated: 2018-01-26Bibliographically approved
Sachs, S., Wilmsen, M., Knueppe, J., Hornung, J. J. & Kear, B. P. (2017). Cenomanian-Turonian marine amniote remains from the Saxonian Cretaceous Basin of Germany. Geological Magazine, 154(2), 237-246
Open this publication in new window or tab >>Cenomanian-Turonian marine amniote remains from the Saxonian Cretaceous Basin of Germany
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2017 (English)In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 154, no 2, p. 237-246Article in journal (Refereed) Published
Abstract [en]

The Saxonian Cretaceous Basin constitutes an important source of rare Late Cretaceous marine amniote fossils from Germany. It is also historically famous, having been documented in a series of monographic works published by the distinguished German palaeontologist Hanns Bruno Geinitz in the nineteenth century. The most productive rock units include the upper Cenomanian Dolzschen Formation and upper Turonian Strehlen and Weinbohla limestones (lower Strehlen Formation). A survey of curated specimens recovered from these deposits has now identified isolated teeth of probable polycotylid and elasmosaurid plesiosaurians, as well as several humeri that are referred to protostegid marine turtles. The Saxonian Cretaceous Basin formed a continuous epeiric seaway with the Bohemian Cretaceous Basin during late Cenomanian - Turonian time. A western connection to the North Sea Basin also existed via the North German and Munsterland Cretaceous basins. The Mesozoic marine amniote remains from these regions therefore record a coeval northern European fauna that was probably homogeneous across the northern peri-Tethyan margin during Late Cretaceous time.

Place, publisher, year, edition, pages
CAMBRIDGE UNIV PRESS, 2017
Keyword
Plesiosauria, Protostegidae, Late Cretaceous, central Europe
National Category
Geosciences, Multidisciplinary
Identifiers
urn:nbn:se:uu:diva-320844 (URN)10.1017/S0016756815001004 (DOI)000395444700003 ()
Available from: 2017-04-26 Created: 2017-04-26 Last updated: 2017-04-26Bibliographically approved
Paulina-Carabajal, A., Sterli, J., Georgi, J., Poropat, S. F. & Kear, B. P. (2017). Comparative neuroanatomy of extinct horned turtles (Meiolaniidae) and extant terrestrial turtles (Testudinidae), with comments on the palaeobiological implications of selected endocranial features. Zoological Journal of the Linnean Society, 180(4), 930-950
Open this publication in new window or tab >>Comparative neuroanatomy of extinct horned turtles (Meiolaniidae) and extant terrestrial turtles (Testudinidae), with comments on the palaeobiological implications of selected endocranial features
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2017 (English)In: Zoological Journal of the Linnean Society, ISSN 0024-4082, E-ISSN 1096-3642, Vol. 180, no 4, p. 930-950Article in journal (Refereed) Published
Abstract [en]

Turtles are one of the least explored clades of reptiles with respect to palaeoneuroanatomy. Few detailed descriptions of endocranial features such as the brain morphology or inner ear exist for extant and extinct forms. In this contribution, we present the first CT-based reconstructions of endocranial morphology (brain and inner ear) and the nasal cavities in the terrestrial horned meiolaniid (Meiolaniidae) turtles Niolamia argentina and Gaffneylania auricularis from the Eocene of Patagonia, as well as Meiolania platyceps from the Pleistocene of Lord Howe Island, Australia. In addition, these exclusively Gondwanan Cenozoic taxa are contrasted with cranial endocasts of multiple extant testudinoids, thereby providing the largest sample of digital comparative endocranial data assembled for extinct and living turtles to date. Our study thus adds much needed anatomical information on turtle palaeoneurology. Aspects of meiolaniid palaeobiology are discussed; in particular, the hypertrophied nasal cavity might not to be related to olfactory acuity, but rather perhaps adaptation to arid climatic conditions, and/or intraspecific behaviours.

Place, publisher, year, edition, pages
OXFORD UNIV PRESS, 2017
Keyword
Cranial endocast, Gaffneylania auricularis, inner ear, Meiolania platyceps, nasal cavity, Niolamia argentina, palaeoneurology, terrestrial turtles, Testudinidae, Testudinoidea
National Category
Zoology
Identifiers
urn:nbn:se:uu:diva-335674 (URN)10.1093/zoolinnean/zlw024 (DOI)000409233800009 ()
Available from: 2017-12-20 Created: 2017-12-20 Last updated: 2017-12-20Bibliographically approved
Kear, B., Larsson, D., Lindgren, J. & Kundrat, M. (2017). Exceptionally prolonged tooth formation in elasmosaurid plesiosaurians. PLoS ONE, 12(2), Article ID e0172759.
Open this publication in new window or tab >>Exceptionally prolonged tooth formation in elasmosaurid plesiosaurians
2017 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 2, article id e0172759Article in journal (Refereed) Published
Abstract [en]

Elasmosaurid plesiosaurians were globally prolific marine reptiles that dominated the Mesozoic seas for over 70 million years. Their iconic body-plan incorporated an exceedingly long neck and small skull equipped with prominent intermeshing 'fangs'. How this bizarre dental apparatus was employed in feeding is uncertain, but fossilized gut contents indicate a diverse diet of small pelagic vertebrates, cephalopods and epifaunal benthos. Here we report the first plesiosaurian tooth formation rates as a mechanism for servicing the functional dentition. Multiple dentine thin sections were taken through isolated elasmosaurid teeth from the Upper Cretaceous of Sweden. These specimens revealed an average of 950 daily incremental lines of von Ebner, and infer a remarkably protracted tooth formation cycle of about 2-3 years-other polyphyodont amniotes normally take similar to 1-2 years to form their teeth. Such delayed odontogenesis might reflect differences in crown length and function within an originally uneven tooth array. Indeed, slower replacement periodicity has been found to distinguish larger caniniform teeth in macrophagous pliosaurid plesiosaurians. However, the archetypal sauropterygian dental replacement system likely also imposed constraints via segregation of the developing tooth germs within discrete bony crypts; these partly resorbed to allow maturation of the replacement teeth within the primary alveoli after displacement of the functional crowns. Prolonged dental formation has otherwise been linked to tooth robustness and adaption for vigorous food processing. Conversely, elasmosaurids possessed narrow crowns with an elongate profile that denotes structural fragility. Their apparent predilection for easily subdued prey could thus have minimized this potential for damage, and was perhaps coupled with selective feeding strategies that ecologically optimized elasmosaurids towards more delicate middle trophic level aquatic predation.

National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-318948 (URN)10.1371/journal.pone.0172759 (DOI)000395934400039 ()28241059 (PubMedID)
Funder
Australian Research Council, LP100100339Swedish Research Council, 2011-3637, 2011-3587
Available from: 2017-03-30 Created: 2017-03-30 Last updated: 2017-11-29Bibliographically approved
Sachs, S. & Kear, B. P. (2017). Redescription of the elasmosaurid plesiosaurian Libonectes atlasense from the Upper Cretaceous of Morocco. Cretaceous research (Print), 74, 205-222
Open this publication in new window or tab >>Redescription of the elasmosaurid plesiosaurian Libonectes atlasense from the Upper Cretaceous of Morocco
2017 (English)In: Cretaceous research (Print), ISSN 0195-6671, E-ISSN 1095-998X, Vol. 74, p. 205-222Article in journal (Refereed) Published
Abstract [en]

The holotype of Libonectes atlasense is an almost complete skeleton from Upper Cretaceous (mid-Turonian) rocks of the Goulmima area in eastern Morocco. Initial assessment of this specimen in 2005 proposed generic referral based on stratigraphical contemporaneity with Libonectes morgani from the Cenomanian-Turonian of Texas, U.S.A. Nevertheless, relative differences in the profile of the premaxillary-maxillary tooth row, position of the external bony nasal opening, number of teeth and rostrad inclination of the mandibular symphysis, proportions of the axial neural arch, and number of cervical and pectoral vertebrae were used to distinguish between these species. As part of an on-going comparative appraisal of elasmosaurid plesiosaurian osteo-anatomy, we re-examined the type and formally referred material of both L atlasense and L morgani in order to establish species validity, as well as compile a comparative atlas for use in future works. Our inspections revealed that these reportedly distinct species-level fossils are in fact virtually indistinguishable in gross morphology. Indeed, the only substantial difference occurs in relative prominence of the midline keel along the mandibular symphysis, which might be explained by intraspecific variation. Furthermore, our observations permit an amendment to the published generic diagnosis of Libonectes with the confirmation of important states such as the likely presence of a pectoral bar, distocaudad expansion of the humerus, and an epipodial foramen. In addition, novel features include a prominent 'prong-like' ventral midline process on the coracoids, and the development of a median pelvic bar that encloses a central fenestration. The composite remains of L morgani thus constitute one of the most complete elasmosaurid skeletal hypodigms documented worldwide, and evidence a trans-Atlantic distribution for this apparently dispersive species during the early Late Cretaceous.

Keyword
Plesiosauria, Elasmosauridae, Species distinction, Trans-Atlantic distribution, Cenomanian-Turonian
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-322510 (URN)10.1016/j.cretres.2017.02.017 (DOI)000400215200021 ()
Available from: 2017-05-30 Created: 2017-05-30 Last updated: 2017-05-30Bibliographically approved
Niedzwiedzki, G., Bajdek, P., Owocki, K. & Kear, B. P. (2016). An Early Triassic polar predator ecosystem revealed by vertebrate coprolites from the Bulgo Sandstone (Sydney Basin) of southeastern Australia. Palaeogeography, Palaeoclimatology, Palaeoecology, 464, 5-15
Open this publication in new window or tab >>An Early Triassic polar predator ecosystem revealed by vertebrate coprolites from the Bulgo Sandstone (Sydney Basin) of southeastern Australia
2016 (English)In: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 464, p. 5-15Article in journal (Refereed) Published
Abstract [en]

Vertebrate trace fossils often provide a measure of cryptic biodiversity, and are especially pertinent when skeletal remnants are exceptionally rare. The Lower Triassic (lower Olenekian) Bulgo Sandstone at Long Reef in the Sydney Basin of southeastern Australia constitutes just such a deposit, having yielded isolated bones of giant capitosaurian temnospondyls and proterosuchid archosauriforms, together with abundant coprolites that are geochemically rich in elemental phosphate and carbon denoting vertebrate predators. Microstructural analysis of these preserved droppings reveals occasional bone fragments, fish scales, insect cuticles, plant material and bacterial traces (pseudomorph voids), as well as silicate mineral particles. REE concentrations indicate that burial and early diagenesis occurred explicitly within fluvial sediments. Furthermore, external morphological characterization permits attribution of spiral coprolites to chondrichthyan or osteichthyan fishes, polygonal, ovoid spherical and typically flattened feces to temnospondyls, and conspicuously large cylindrical droppings to archosauriforms or other amniote apex predators. Collectively, the Bulgo Sandstone coprolite assemblage thus offers new insights into ecosystem structure and palaeoenvironment in what was an earliest Triassic near polar setting. Such data compliments the documented skeletal record, but indicates a greater range of aquatic and possibly terrestrial carnivores the latter being enigmatically sparse in the Australian Triassic and yet detected here via the hitherto underexplored trace fossil evidence of their ecological presence.

Keyword
Freshwater fishes, Temnospondyls, Archosauriforms, Olenekian, Palaeoecology, Narrabeen Group
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-311478 (URN)10.1016/j.palaeo.2016.04.003 (DOI)000389109600002 ()
Funder
Australian Research CouncilSwedish Research Council
Available from: 2016-12-29 Created: 2016-12-28 Last updated: 2017-11-29Bibliographically approved
Kear, B. P., Lindgren, J., Hurum, J. H., Milan, J. & Vajda, V. (2016). An introduction to the Mesozoic biotas of Scandinavia and its Arctic territories. In: Mesozoic Biotas Of Scandinavia And Its Arctic Territories: (pp. 1-14). Geological Society
Open this publication in new window or tab >>An introduction to the Mesozoic biotas of Scandinavia and its Arctic territories
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2016 (English)In: Mesozoic Biotas Of Scandinavia And Its Arctic Territories, Geological Society, 2016, p. 1-14Chapter in book (Refereed)
Abstract [en]

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

Place, publisher, year, edition, pages
Geological Society, 2016
Series
Geological Society Special Publication, ISSN 0305-8719 ; 434
National Category
Other Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-299983 (URN)10.1144/SP434.18 (DOI)000377671000001 ()2-s2.0-84969954637 (Scopus ID)9781862397484 (ISBN)
Available from: 2016-08-01 Created: 2016-08-01 Last updated: 2017-01-03Bibliographically approved
Kear, B. P., Aplin, K. P. & Westerman, M. (2016). Bandicoot fossils and DNA elucidate lineage antiquity amongst xeric-adapted Australasian marsupials. Scientific Reports, 6, Article ID 37537.
Open this publication in new window or tab >>Bandicoot fossils and DNA elucidate lineage antiquity amongst xeric-adapted Australasian marsupials
2016 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 37537Article in journal (Refereed) Published
Abstract [en]

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.

National Category
Geosciences, Multidisciplinary
Identifiers
urn:nbn:se:uu:diva-311502 (URN)10.1038/srep37537 (DOI)000388966800001 ()
Funder
Swedish Research Council
Available from: 2016-12-28 Created: 2016-12-28 Last updated: 2017-11-29Bibliographically approved
Zaton, M., Niedzwiedzki, G., Blom, H. & Kear, B. P. (2016). Boreal earliest Triassic biotas elucidate globally depauperate hard substrate communities after the end-Permian mass extinction. Scientific Reports, 6, Article ID 36345.
Open this publication in new window or tab >>Boreal earliest Triassic biotas elucidate globally depauperate hard substrate communities after the end-Permian mass extinction
2016 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 36345Article in journal (Refereed) Published
Abstract [en]

The end-Permian mass extinction constituted the most devastating biotic crisis of the Phanerozoic. Its aftermath was characterized by harsh marine conditions incorporating volcanically induced oceanic warming, widespread anoxia and acidification. Bio-productivity accordingly experienced marked fluctuations. In particular, low palaeolatitude hard substrate communities from shallow seas fringing Western Pangaea and the Tethyan Realm were extremely impoverished, being dominated by monogeneric colonies of filter-feeding microconchid tubeworms. Here we present the first equivalent field data for Boreal hard substrate assemblages from the earliest Triassic (Induan) of East Greenland. This region bordered a discrete bio-realm situated at mid-high palaeolatitude (> 30 degrees N). Nevertheless, hard substrate biotas were compositionally identical to those from elsewhere, with microconchids encrusting Claraia bivalves and algal buildups on the sea floor. Biostratigraphical correlation further shows that Boreal microconchids underwent progressive tube modification and unique taxic diversification concordant with changing habitats over time. We interpret this as a post-extinction recovery and adaptive radiation sequence that mirrored coeval subequatorial faunas, and thus confirms hard substrate ecosystem depletion as a hallmark of the earliest Triassic interval globally.

National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-309809 (URN)10.1038/srep36345 (DOI)000387314500001 ()27821855 (PubMedID)
Funder
Swedish Polar Research Secretariat
Available from: 2016-12-14 Created: 2016-12-07 Last updated: 2017-11-29Bibliographically approved
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