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Kear, Benjamin P.
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Publications (10 of 90) Show all publications
Poropat, S. F., Martin, S. K., Tosolini, A.-M. P., Wagstaff, B. E., Bean, L. B., Kear, B. P., . . . Rich, T. H. (2018). Early Cretaceous polar biotas of Victoria, southeastern Australia: an overview of research to date. Alcheringa, 42(2), 157-229
Open this publication in new window or tab >>Early Cretaceous polar biotas of Victoria, southeastern Australia: an overview of research to date
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2018 (English)In: Alcheringa, ISSN 0311-5518, E-ISSN 1752-0754, Vol. 42, no 2, p. 157-229Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2018
Keywords
Australia, Victoria, Cretaceous, Dinosaur Cove, Koonwarra, palaeoclimate, palaeobiogeography
National Category
Other Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-359678 (URN)10.1080/03115518.2018.1453085 (DOI)000435661800002 ()
Available from: 2018-09-06 Created: 2018-09-06 Last updated: 2018-09-06Bibliographically approved
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
Keywords
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
Den Boer, W. & Kear, B. P. (2018). Is the fossil rat-kangaroo Palaeopotorous priscus the most basally branching stem macropodiform?. Journal of Vertebrate Paleontology, 38(2), Article ID e1428196.
Open this publication in new window or tab >>Is the fossil rat-kangaroo Palaeopotorous priscus the most basally branching stem macropodiform?
2018 (English)In: Journal of Vertebrate Paleontology, ISSN 0272-4634, E-ISSN 1937-2809, Vol. 38, no 2, article id e1428196Article in journal (Refereed) Published
Place, publisher, year, edition, pages
TAYLOR & FRANCIS INC, 2018
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-356332 (URN)10.1080/02724634.2017.1428196 (DOI)000432213400003 ()
Funder
Swedish Research Council
Available from: 2018-07-26 Created: 2018-07-26 Last updated: 2018-07-26Bibliographically approved
Sachs, S., Jagt, J. W. M., Niedzwiedzki, R., Kedzierski, M., Jagt-Yazykova, E. A. & Kear, B. P. (2018). Turonian marine amniotes from the Opole area in southwest Poland. Cretaceous research (Print), 84, 578-587
Open this publication in new window or tab >>Turonian marine amniotes from the Opole area in southwest Poland
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2018 (English)In: Cretaceous research (Print), ISSN 0195-6671, E-ISSN 1095-998X, Vol. 84, p. 578-587Article, review/survey (Refereed) Published
Abstract [en]

A few isolated plesiosaurian and mosasauroid squamate teeth were collected from the Opole area in southwest Poland during the late nineteenth century. Calcareous nannofossil analysis of their associated rock matrix indicates an early Turonian age (nannofossil zone UC7; Mytiloides ex gr. labiatus and Inoceramus apicalis inoceramid zones), which is significant because this constitutes a globally enigmatic interval of marine amniote evolution. The Opole plesiosaurian teeth are attributable to polycotylids, but an indeterminate mesopodial was also recovered. They are similar to specimens from the Cenomanian–Turonian in the Saxonian Cretaceous Basin of Germany and the Chalk succession of England, but differ from polycotylid remains found in the coeval Bohemian Cretaceous Basin of the Czech Republic, which are far more robust. The mosasauroid tooth crown from Opole compares favourably with dentary and maxillary teeth of a number of Turonian yaguarasaurines and basal russellosaurines, but in having well-developed carinae and a smooth labial and strongly folded/markedly striated lingual tooth surfaces it can be differentiated from taxa such as Yaguarasaurus columbianus (Colombia), Romeosaurus fumanensis and R. sorbinii (both Italy) and ‘Mosasaurusgracilis (England). However, a single record from the Bohemian Cretaceous Basin may refer to a conspecific form. All this suggests a potential for slight compositional differences between Cenomanian–Turonian marine amniote assemblages across central and northern Europe, although otherwise these regions probably constituted a common faunal belt bordering the Tethys Ocean.

Keywords
Plesiosauria, Mosasauroidea, Late Mesozoic, Central Europe, Taxonomy, Comparisons
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-352921 (URN)10.1016/j.cretres.2017.12.002 (DOI)000426412900046 ()
Available from: 2018-06-08 Created: 2018-06-08 Last updated: 2018-06-08Bibliographically 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
Keywords
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
Keywords
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.

Keywords
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.

Keywords
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
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