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Den Boer, W., Campione, N. E. & Kear, B. P. (2019). Climbing adaptations, locomotory disparity and ecological convergence in ancient stem 'kangaroos'. Royal Society Open Science, 6(2), Article ID 181617.
Open this publication in new window or tab >>Climbing adaptations, locomotory disparity and ecological convergence in ancient stem 'kangaroos'
2019 (English)In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, no 2, article id 181617Article in journal (Refereed) Published
Abstract [en]

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.

Keywords
Macropodoidea, Balbaridae, Nambaroo, Dendrolagus, gait evolution, Miocene
National Category
Other Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-383891 (URN)10.1098/rsos.181617 (DOI)000465432900031 ()30891280 (PubMedID)
Funder
Swedish Research Council, 2011-3587
Available from: 2019-05-28 Created: 2019-05-28 Last updated: 2019-05-28Bibliographically approved
Reiss, S., Scheer, U., Sachs, S. & Kear, B. P. (2019). Filling the biostratigraphical gap: First choristoderan from the Lower - mid-Cretaceous interval of Europe. Cretaceous research (Print), 96, 135-141
Open this publication in new window or tab >>Filling the biostratigraphical gap: First choristoderan from the Lower - mid-Cretaceous interval of Europe
2019 (English)In: Cretaceous research (Print), ISSN 0195-6671, E-ISSN 1095-998X, Vol. 96, p. 135-141Article in journal (Refereed) Published
Abstract [en]

Choristodera is a Glade of extinct aquatic reptiles whose fossils have been found in freshwater and marginal marine deposits from Europe, Asia and North America. The European record is the most extensive, spanning at least the Middle Jurassic to early Miocene, and incorporates the stratigraphically oldest and youngest members of the group. Despite this, there is an unexplained-70 myr gap in European choristoderan fossil occurrences. Here we fill this hiatus with the discovery of an isolated choristoderan dorsal vertebra from the lower Cenomanian 'Rotkalk' red limestone facies of the Essen Greensand Formation in Wilhelm/Ruhr, North Rhine-Westphalia, western Germany. This specimen represents the first identifiable European choristoderan from the Kimmeridgian-Campanian interval, and displays a diagnostic state combination including an amphiplatyan centrum with synapophyses on the transverse processes that are level with the neurocentral suture. The palaeobiogeographical distribution of choristoderans thus likely transected the entire Laurasian landmass throughout the Cretaceous, with perceived stratigraphical interstices being a result of incomplete sampling. 

Place, publisher, year, edition, pages
ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2019
Keywords
Choristodera, Palaeobiogeography, Mid-Cretaceous
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-380431 (URN)10.1016/j.cretres.2018.12.009 (DOI)000461127800012 ()
Available from: 2019-03-29 Created: 2019-03-29 Last updated: 2019-03-29Bibliographically approved
Kundrát, M., Nudds, J., Kear, B. P., Lu, J. & Ahlberg, P. (2019). The first specimen of Archaeopteryx from the Upper Jurassic Mornsheim Formation of Germany. Historical Biology, 31(1), 3-63
Open this publication in new window or tab >>The first specimen of Archaeopteryx from the Upper Jurassic Mornsheim Formation of Germany
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2019 (English)In: Historical Biology, ISSN 0891-2963, E-ISSN 1029-2381, Vol. 31, no 1, p. 3-63Article in journal (Refereed) Published
Abstract [en]

From an initial isolated position as the oldest evolutionary prototype of a bird, Archaeopteryx has, as a result of recent fossil discoveries, become embedded in a rich phylogenetic context of both more and less crownward stem-group birds. This has prompted debate over whether Archaeopteryx is simply a convergently bird-like non-avialan theropod. Here we show, using the first synchrotron microtomographic examination of the genus, that the eighth or Daiting specimen of Archaeopteryx possesses a character suite that robustly constrains it as a basal avialan (primitive bird). The specimen, which comes from the Mornsheim Formation and is thus younger than the other specimens from the underlying Solnhofen Formation, is distinctive enough to merit designation as a new species, Archaeopteryx albersdoerferi sp. nov., but is recovered in close phylogenetic proximity to Archaeopteryx lithographica. Skeletal innovations of the Daiting specimen, such as fusion and pneumatization of the cranial bones, well vascularized pectoral girdle and wing elements, and a reinforced configuration of carpals and metacarpals, suggest that it may have had more characters seen in flying birds than the older Archaeopteryx lithographica. These innovations appear to be convergent on those of more crownward avialans, suggesting that Bavarian archaeopterygids independently acquired increasingly bird-like traits over time. Such mosaic evolution and iterative exploration of adaptive space may be typical for major functional transitions like the origin of flight.

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2019
Keywords
Aves, Avialae, Tithonian, origin of birds, flight, evolution, development, phylogeny, synchrotron microtomography
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-369376 (URN)10.1080/08912963.2018.1518443 (DOI)000448258500002 ()
Funder
Swedish Research Council
Available from: 2019-01-15 Created: 2019-01-15 Last updated: 2019-01-15Bibliographically approved
Sachs, S., Lindgren, J. & Kear, B. P. (2018). A global perspective on Mesozoic marine amniotes. Alcheringa, 42(4), 457-460
Open this publication in new window or tab >>A global perspective on Mesozoic marine amniotes
2018 (English)In: Alcheringa, ISSN 0311-5518, E-ISSN 1752-0754, Vol. 42, no 4, p. 457-460Article in journal, Editorial material (Other academic) Published
National Category
Archaeology Geology Zoology
Identifiers
urn:nbn:se:uu:diva-380675 (URN)10.1080/03115518.2018.1554197 (DOI)000460705100001 ()
Available from: 2019-04-01 Created: 2019-04-01 Last updated: 2019-04-01Bibliographically approved
Kear, B. P., Fordyce, R. E., Hiller, N. & Siversson, M. (2018). A palaeobiogeographical synthesis of Australasian Mesozoic marine tetrapods. Alcheringa, 42(4), 461-486
Open this publication in new window or tab >>A palaeobiogeographical synthesis of Australasian Mesozoic marine tetrapods
2018 (English)In: Alcheringa, ISSN 0311-5518, E-ISSN 1752-0754, Vol. 42, no 4, p. 461-486Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2018
Keywords
marine reptiles, temnospondyls, Cretaceous, Jurassic, Triassic, faunal change
National Category
Other Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-380511 (URN)10.1080/03115518.2017.1397428 (DOI)000460705100002 ()
Funder
Australian Research CouncilSwedish Research Council
Available from: 2019-04-11 Created: 2019-04-11 Last updated: 2019-04-11Bibliographically approved
Sachs, S. & Kear, B. P. (2018). A rare new Pliensbachian plesiosaurian from the Amaltheenton Formation of Bielefeld in northwestern Germany. Alcheringa, 42(4), 487-500
Open this publication in new window or tab >>A rare new Pliensbachian plesiosaurian from the Amaltheenton Formation of Bielefeld in northwestern Germany
2018 (English)In: Alcheringa, ISSN 0311-5518, E-ISSN 1752-0754, Vol. 42, no 4, p. 487-500Article in journal (Refereed) Published
Abstract [en]

Sachs, S. & Kear, B.P. November 2018. A rare new Pliensbachian plesiosaurian from the Amaltheenton Formation of Bielefeld in northwestern Germany. Alcheringa 42, 487-500. ISSN 0311-5518.We describe a new plesiosaurian from the upper Pliensbachian Amaltheenton Formation of Bielefeld in northwestern Germany. The taxon is based upon an incomplete associated skeleton comprising part of the right mandibular ramus, several teeth, a series of cervical, pectoral, dorsal and caudal vertebrae, as well as ribs, limb girdle elements including a nearly complete right scapula, and various distal limb bones. A unique character state combination serves to distinguish the Amaltheenton Formation remains from other previously documented Early Jurassic plesiosaurians. The most important features are the presence of a longitudinal notch incising the posterior rim of the glenoid fossa and retroarticular process, and a pronounced ventrolateral shelf on the scapula, both of which constitute derived states otherwise shared with Early Cretaceous leptocleidians. However, phylogenetic analysis using a total group' Plesiosauria data-set that specifically accommodates for Pliensbachian taxa unanimously placed the Amaltheenton Formation plesiosaurian among Early-Middle Jurassic pliosaurids. This discovery is significant because it reveals unexpected homoplasy, but also because it establishes what is only the third formally named plesiosaurian taxon thus far documented from Pliensbachian strata worldwide.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2018
Keywords
Plesiosauria, Early Jurassic, pliosaurid, "Pliensbachian gap'
National Category
Other Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-380512 (URN)10.1080/03115518.2017.1367419 (DOI)000460705100003 ()
Available from: 2019-04-11 Created: 2019-04-11 Last updated: 2019-04-11Bibliographically approved
Zaton, M., Niedzwiedzki, G., Rakocinski, M., Blom, H. & Kear, B. P. (2018). Earliest Triassic metazoan bioconstructions from East Greenland reveal a pioneering benthic community in the immediate aftermath of the end-Permian mass extinction. Global and Planetary Change, 167, 87-98
Open this publication in new window or tab >>Earliest Triassic metazoan bioconstructions from East Greenland reveal a pioneering benthic community in the immediate aftermath of the end-Permian mass extinction
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2018 (English)In: Global and Planetary Change, ISSN 0921-8181, E-ISSN 1872-6364, Vol. 167, p. 87-98Article in journal (Refereed) Published
Abstract [en]

Marine benthic ecosystems collapsed during the catastrophic end-Permian mass extinction, and subsequently endured a protracted phase of biotic recovery under harsh environmental conditions. In particular, metazoan reef communities almost totally disappeared and were replaced by microbe-dominated mounds during the latest Permian-earliest Triassic. Here we report the stratigraphically oldest exclusively metazoan bioconstructions from earliest Triassic (mid-Induan) strata in East Greenland - these formed within the first ca 300 ka after the Permian-Triassic boundary. Unlike the multitaxic sponge-microbe and bivalve-based buildups recorded from the Early Triassic peri-paleoequatorial Panthalassan and Tethyan margins, the East Greenland bioaccumulations developed within a restricted Boreal mid-paleolatitude seaway, and comprised a monospecific primary framework of microconchid 'lophophorate tubes with shell fragments and phosphatic debris cemented by biogenic calcite. Prostrate growth of the microconchids likely facilitated their accretion into successive sheet-like biostromes and small bioherms. These are associated with a regional paleoenvironmental shift towards well-oxygenated bottom waters, and locally punctuated sedimentation that created a favorable habitat. Although microconchids were both abundant and geographically widespread throughout the earliest Triassic, such buildups formed solely by these metazoans have not been reported from that time frame outside the Boreal Realm. These apparently flourished in the absence of more stable complex communities, and suggest that a locally variable, rather than ubiquitously sequential revival of metazoan bioconstruction activity took place in the immediate aftermath of the end-Permian extinction. However, these may also suggest that ecological recovery of benthic marine ecosystems following the end-Permian mass extinction might have started earlier in higher paleolatitudes.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2018
Keywords
Microconchids, Boreal Realm, Reefs, Build-ups, Paleoecology, Biotic crisis
National Category
Other Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-361676 (URN)10.1016/j.gloplacha.2018.05.009 (DOI)000438322900007 ()
Funder
Swedish Polar Research SecretariatWallenberg Foundations
Available from: 2018-10-08 Created: 2018-10-08 Last updated: 2018-10-08Bibliographically approved
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
Kear, B. P. (2018). Editorial. Alcheringa, 42(2), 155-156
Open this publication in new window or tab >>Editorial
2018 (English)In: Alcheringa, ISSN 0311-5518, E-ISSN 1752-0754, Vol. 42, no 2, p. 155-156Article in journal, Editorial material (Other academic) Published
Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2018
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-365880 (URN)10.1080/03115518.2018.1478171 (DOI)000435661800001 ()
Available from: 2018-11-20 Created: 2018-11-20 Last updated: 2018-11-20Bibliographically approved
Sachs, S., Hornung, J. J., Lallensack, J. N. & Kear, B. P. (2018). First evidence of a large predatory plesiosaurian from the Lower Cretaceous non-marine 'Wealden facies' deposits of northwestern Germany. Paper presented at 5th International Mosasaur Meeting, 2016, Uppsala Univ, Museum Evolut, Uppsala, SWEDEN. Alcheringa, 42(4), 501-508
Open this publication in new window or tab >>First evidence of a large predatory plesiosaurian from the Lower Cretaceous non-marine 'Wealden facies' deposits of northwestern Germany
2018 (English)In: Alcheringa, ISSN 0311-5518, E-ISSN 1752-0754, Vol. 42, no 4, p. 501-508Article in journal (Refereed) Published
Abstract [en]

Here, we describe the incomplete mandible of a large-skulled pliosauromorph' plesiosaurian from the Lower Cretaceous (Berriasian) of northwestern Germany. The fossil derives from limnic-brackish Wealden facies' deposits of the Deister Formation (Buckeberg Group), and is preserved as a natural mould in fine-grained sandstone. Examination of the original remains, in conjunction with a three-dimensional photogrammetrically digitized cast', revealed a conspicuous rosette of symphyseal alveoli, which would otherwise typically characterize Early-Middle Jurassic macrophagous plesiosaurians including rhomaleosaurids and the pliosaurid Simolestes. The Deister Formation pliosauromorph' represents the first record of a large-bodied plesiosaurian macrocarnivore from the Wealden-facies' strata of Europe, and thus adds a previously unrecognized trophic level of aquatic apex predators to the Early Cretaceous non-marine ecosystems of Europe.

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2018
Keywords
Pliosauromorph, macrocarnivore, Berriasian, Deister Formation, Lower Saxony
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-381935 (URN)10.1080/03115518.2017.1373150 (DOI)000460705100004 ()
Conference
5th International Mosasaur Meeting, 2016, Uppsala Univ, Museum Evolut, Uppsala, SWEDEN
Available from: 2019-04-16 Created: 2019-04-16 Last updated: 2019-04-16Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3128-3141

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