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  • 1.
    ACOSTA HOSPITALECHE, Carolina
    et al.
    División Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque s/n, B1900FWA, La Plata, Argentina.
    HAGSTRÖM, Jonas
    Swedish Museum of Natural History, Department of Paleobiology.
    REGUERO, Marcelo
    División Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque s/n, B1900FWA, La Plata and Instituto Antártico Argentino (Dirección Nacional del Antártico), 25 de mayo 1143, San Martín, Argentina.
    Historical perspective of Otto Nordenskjöld´s Antarctic fossil penguin collection and Carl Wiman’s contribution2017In: Polar Record, ISSN 0032-2474, E-ISSN 1475-3057, Vol. 53, no 4, p. 364-375Article in journal (Refereed)
    Abstract [en]

    The early explorer and scientist Otto Nordenskjöld, leader of the Swedish South Polar Expedition of 1901–1903, was the first to collect Antarctic penguin fossils. The site is situated in the northeastern region of Seymour Island and constitutes one of the most important localities in the study of fossilised penguins. The task of describing these specimens together with fossilised whale remains was given to Professor Carl Wiman (1867–1944) at Uppsala University, Sweden. Although the paradigm for the systematic study of penguins has changed considerably over recent years, Wiman's contributions are still remarkable. His establishment of grouping by size as a basis for classification was a novel approach that allowed them to deal with an unexpectedly high morphological diversity and limited knowledge of penguin skeletal anatomy. In the past, it was useful to provide a basic framework for the group that today could be used as ‘taxon free’ categories. First, it was important to define new species, and then to establish a classification based on size and robustness. This laid the foundation for the first attempts to use morphometric parameters for the classification of isolated penguin bones. The Nordenskjöld materials constitute an invaluable collection for comparative purposes, and every year researchers from different countries visit this collection.

  • 2.
    Bomfleur, Benjamin
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Ferraguti, Marco
    Dipartimento di Bioscienze, Universita` degli Studi di Milano, Milano, Italy.
    Reguero, Marcelo
    Divisio´n Paleontologı´a de Vertebrados, Museo de La Plata, La Plata, Argentina.
    McLoughlin, Stephen
    Swedish Museum of Natural History, Department of Paleobiology.
    Fossilized spermatozoa preserved in a 50-myr-old annelid cocoon from Antarctica2015In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, no 20150431, p. 1-5Article in journal (Refereed)
    Abstract [en]

    The origin and evolution of clitellate annelids—earthworms, leeches and their relatives—is poorly understood, partly because body fossils of these delicate organisms are exceedingly rare. The distinctive egg cases (cocoons) of Clitellata, however, are relatively common in the fossil record, although their potential for phylogenetic studies has remained largely unexplored. Here, we report the remarkable discovery of fossilized spermatozoa preserved within the secreted wall layers of a 50-Myr-old clitellate cocoon from Antarctica, representing the oldest fossil animal sperm yet known. Sperm characters are highly informative for the classification of extant Annelida. The Antarctic fossil spermatozoa have several features that point to affinities with the peculiar, leech-like ‘crayfish worms’ (Branchiobdellida). We anticipate that systematic surveys of cocoon fossils coupled with advances in non-destructive analytical methods may open a new window into the evolution of minute, soft-bodied life forms that are otherwise only rarely observed in the fossil record.

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  • 3. BUONO, Monica
    et al.
    FERNANDEZ, Martha
    REGUERO, Marcelo
    MARENSSI, Sergio
    SANTILLANA, Sergio
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Eocene basilosaurid whales from the La Meseta Formation, Marambio (Seymour) Island, Antarctica2016In: Ameghiniana, ISSN 0002-7014, E-ISSN 1851-8044, Vol. 53, no 3, p. 296-315Article in journal (Refereed)
    Abstract [en]

    Basal fully aquatic whales, the basilosaurids are worldwide known from Bartonian–Priabonian localities, indicating that this group was widely distributed during the late middle Eocene. In the Northern Hemisphere, fossils of basilosaurids are abundant, while records in the Southern Hemisphere are scarce and, in some cases (i.e., Antarctica), doubtful. The presence of basilosaurids in Antarctica was, until now, uncertain because most of the records are based on fragmentary materials that preclude an accurate assignment to known archaeocete taxa. Here we report the findings of mandibles, teeth, and innominate bone remains of basilosaurids recovered from the La Meseta Formation (TELM 4 Lutetian–Bartonian and; TELM 7 Priabonian), in Marambio (Seymour) Island (James Ross Basin, Antarctic Peninsula). These findings confirm the presence of Basilosauridae in the marine realm of Antarctica, increasing our knowledge of the paleobiogeographic distribution of basilosaurids during the middle–late Eocene. In addition, one of these records is among the oldest occurrences of basilosaurids worldwide, indicating a rapid radiation and dispersal of this group since at least the early middle Eocene.

  • 4. Davydenko, Svitozar
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Gol'din, Pavel
    A small whale reveals diversity of the Eocene cetacean fauna of Antarctica2021In: Antarctic Science, ISSN 0954-1020, E-ISSN 1365-2079, Vol. 33, no 1, p. 81-88Article in journal (Refereed)
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  • 5.
    Davydenko, Svitozar
    et al.
    Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Gol'din, Pavel
    anon, anon
    A small whale reveals diversity of the Eocene cetacean fauna of Antarctica2021In: Antarctic Science, ISSN 0954-1020, E-ISSN 1365-2079, Vol. 33, no 1, p. 81-88Article in journal (Refereed)
    Abstract [en]

    Cetacean fossils have been recorded from middle and late Eocene deposits on Seymour Island since the beginning of the twentieth century and include fully aquatic Basilosauridae and stem Neoceti. Here, we report a small cetacean vertebra tentatively referred to as Neoceti from the late Eocene of Seymour Island. It shows a mosaic of traits, some of which are characteristic of early Neoceti (anteroposteriorly long transverse processes; a ventral keel on the ventral side of the centrum; thin pedicles of the neural arch), whereas others are shared with Basilosauridae (low-placed bases of the transverse processes). However, some traits are unique and may be autapomorphic: presence of separate prezygapophyses on the vertebra at the thoracic/lumbar boundary and a proportionally short centrum. Both traits imply a fast swimming style, which is characteristic of modern dolphins rather than Eocene cetaceans. Thus, this specimen can be identified as Neoceti indet., with some hypothetical odontocete affinities. Along with a few other Eocene whale taxa, it seems to be among the earliest known members of Neoceti on Earth. The finding of small and fast-swimming Neoceti in Antarctica also demonstrates early diversification of cetaceans and ecological niche partitioning by them dating back as early as the late Eocene.

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  • 6. DOGUZHAEVA, Larisa
    et al.
    BENGTSON, Stefan
    REGUERO, Marcelo
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    An Eocene orthocone from Antarctica shows convergent evolution of internally shelled cephalopods2017In: PLOS ONE, E-ISSN 1932-6203, Vol. 12, no 3, article id e0172169Article in journal (Refereed)
    Abstract [en]

    Background

    The Subclass Coleoidea (Class Cephalopoda) accommodates the diverse present-day internally shelled cephalopod mollusks (Spirula, Sepia and octopuses, squids, Vampyroteuthis) and also extinct internally shelled cephalopods. Recent Spirula represents a unique coleoid retaining shell structures, a narrow marginal siphuncle and globular protoconch that signify the ancestry of the subclass Coleoidea from the Paleozoic subclass Bactritoidea. This hypothesis has been recently supported by newly recorded diverse bactritoid-like coleoids from the Carboniferous of the USA, but prior to this study no fossil cephalopod indicative of an endochochleate branch with an origin independent from subclass Bactritoidea has been reported.

    Methodology/Principal findings

    Two orthoconic conchs were recovered from the Early Eocene of Seymour Island at the tip of the Antarctic Peninsula, Antarctica. They have loosely mineralized organic-rich chitin-compatible microlaminated shell walls and broadly expanded central siphuncles. The morphological, ultrustructural and chemical data were determined and characterized through comparisons with extant and extinct taxa using Scanning Electron Microscopy/Energy Dispersive Spectrometry (SEM/EDS).

    Conclusions/Significance

    Our study presents the first evidence for an evolutionary lineage of internally shelled cephalopods with independent origin from Bactritoidea/Coleoidea, indicating convergent evolution with the subclass Coleoidea. A new subclass Paracoleoidea Doguzhaeva n. subcl. is established for accommodation of orthoconic cephalopods with the internal shell associated with a broadly expanded central siphuncle. Antarcticerida Doguzhaeva n. ord., Antarcticeratidae Doguzhaeva n. fam., Antarcticeras nordenskjoeldi Doguzhaeva n. gen., n. sp. are described within the subclass Paracoleoidea. The analysis of organic-rich shell preservation of A. nordenskjoeldi by use of SEM/EDS techniques revealed fossilization of hyposeptal cameral soft tissues. This suggests that a depositional environment favoring soft-tissue preservation was the factor enabling conservation of the weakly mineralized shell of A. nordenskjoeldi.

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  • 7. ENGELBRECHT, Andrea
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    REGUERO,, Marcelo
    KRIWET, Jürgen
    A new sawshark, Pristiophorus laevis, from the Eocene of Antarctica with comments on Pristiophorus lanceolatus2016In: Historical Biology, ISSN 0891-2963, E-ISSN 1029-2381Article in journal (Refereed)
  • 8. ENGELBRECHT, Andrea
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    REGUERO, Marcelo
    KRIWET, Jürgen
    Eocene squalomorph sharks (Chondrichthyes, Elasmobranchii) from Antarctica2017In: Journal of South American Earth Sciences, ISSN 0895-9811, E-ISSN 1873-0647Article in journal (Refereed)
  • 9. ENGELBRECHT, Andrea
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    REGUERO, Marcelo
    KRIWET, Jürgen
    New carcharhiniform sharks (Chondrichthyes, Elasmobranchii) from the early to middle Eocene of Seymour Island, Antarctic Peninsula2017In: Journal of Vertebrate Paleontology, ISSN 0272-4634, E-ISSN 1937-2809Article in journal (Refereed)
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  • 10. ENGELBRECHT, Andrea
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    REGUERO, Marcelo
    KRIWET, Jürgen
    Revision of Eocene Antarctic carpet sharks (Elasmobranchii, Orectolobiformes) from Seymour Island, Antarctic Peninsula2016In: Journal of Systematic Palaeontology, ISSN 1477-2019, E-ISSN 1478-0941Article in journal (Refereed)
  • 11. ENGELBRECHT, Andrea
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    REGUERO, Marcelo
    KRIWET, Jürgen
    Skates and Rays (Elasmobranchii, Batomorphii) from the Eocene La Meseta and Submeseta formations, Seymour Island, Antarctica2019In: Historical Biology, ISSN 0891-2963, E-ISSN 1029-2381Article in journal (Refereed)
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  • 12.
    FRIIS, Else Marie
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    IGLESIAS, Ari
    Instituto de Investigaciones en Biodiversidad y Ambiente INIBIOMA (CONICET-UNCO), San Carlos de Bariloche, Argentina.
    REGUERO, Marcelo
    División Paleontología de Vertebrados, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata – CONICET, Buenos Aires, Argentina.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Notonuphar antarctica, an extinct water lily (Nymphaeales) from the Eocene of Antarctica2017In: Plant Systematics and Evolution, ISSN 0378-2697, E-ISSN 1615-6110, Vol. 303, no 7, p. 969-980Article in journal (Refereed)
    Abstract [en]

    A new genus and species, Notonuphar antarctica, is described from the Eocene of Seymour (Marambio) Island, the Antarctic Peninsula and assigned to the Nymphaeales based on well-preserved seeds. This is the first record of a water lily from Antarctica and the first record of a Gondwanan plant with close link to the genus Nuphar (Nymphaeaceae), which is restricted today to the Northern Hemisphere. Critical features for systematic placement of Notonuphar are the presence of a germination cap with closely spaced hilar scar and micropyle, anatropous, bitegmic and exotestal seed organization, exotesta composed of one cell layer of high sclerenchymatic palisade-shape cells, mesotesta of smaller, low parenchymatic cells, a few cell layers deep, and a thin tegmen. The seeds of Notonuphar are particularly similar to seeds of extant and fossil Nuphar in the straight, unfolded anticlinal wall of the exotestal cells and the presence of a narrow zone of exotestal tissue between hilum and micropyle. Other seed features including the very tall exotestal cells and strongly thickened cell walls of exotesta also link Notonuphar to Brasenia and related fossil taxa (Cabombaceae). This character mosaic observed in Notonuphar corroborates the transitional position of Nuphar between Cabombaceae and Nymphaeaceae. Notonuphar is the only member of Nymphaeales recorded from Antarctica and so far the only fossil seeds of Nymphaeales known from the Southern Hemisphere. The discovery of this extinct Gondwanan taxon with features suggesting close relationship with extant Northern Hemisphere genus Nuphar is a further evidence for the relictual nature of the extant group.

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  • 13. Gelfo, Javier
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Lorente, Malena
    López, Guillermo
    Reguero, Marcelo
    The oldest mammals from Antarctica, early Eocene of La Meseta Formation, Seymour Island2014In: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 58, p. 101-110Article in journal (Refereed)
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  • 14.
    Hara, Urszula
    et al.
    Polish Geologi cal Institute – Nati onal Research Institute.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Hagström, Jonas
    Swedish Museum of Natural History, Department of Paleobiology.
    Reguero, Marcelo A.
    Museo de La Plata, Di vi sion Paleontol ogia de Vertebrados.
    Eocene bryozoan assemblages from the La Meseta Formation of Seymour Island, Antarctica2018In: Geological Quarterly, ISSN 1641-7291, E-ISSN 2082-5099, Vol. 62, no 3, p. 705-728Article in journal (Refereed)
    Abstract [en]

    Early to Late Eocene bryozoans from the La Meseta Formation of Seymour Island were collected at two localities within the Cucullaea I Allomember (Telm4 and Telm5) on the northwestern side of the island and in two localities within the Submeseta Allomember (Telm6 and Telm7) on the northeastern side. This fauna is represented by cyclostomes of the suborders Tubuliporina and Cerioporina and suborders of Neocheilostomata, among which nine species have been recognized. The following new species are introduced: Micropora nordenskjoeldi sp. nov., Lunulites marambionis sp. nov., Otionellinaantarctica sp. nov. and Otionellina eocenica sp. nov. Some other taxa recognized in the studied material, such as Reticrescis plicatus, Uharella seymourensis and Celleporaria mesetaensis, were previously described from the lower most (Telm1) or uppermost parts (Telm6–7), thus their stratigraphical ranges within the La Meseta Formation are extended. The diverse...

  • 15.
    JADWISZCZAK, Piotr
    et al.
    Institute of Biology, University of Bialystok, Bialystok, Poland;.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    An enigmatic fossil penguin from the Eocene of Antarctica2017In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 36, no 1, article id 1291086Article in journal (Refereed)
    Abstract [en]

    Tarsometatarsi are key skeletal elements in penguin palaeontology. They constitute, among others, type specimens of all 10 widely accepted species of fossil penguins from the Eocene La Meseta Formation on Seymour Island (Graham Land, Antarctic Peninsula). Here, we report on a recently collected large-sized tarsometatarsus from this formation that represents a new morphotype. We are convinced that the morphotype corresponds to a new species, but the material is too scarce for a taxonomic act. Undoubtedly, the bone discussed here is a valuable addition to our knowledge on diversity of early penguins.

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  • 16. Jadwiszczak, Piotr
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Aspects of diversity in early Antarctic penguins2011In: Acta Palaeontologica Polonica, ISSN 0567-7920, E-ISSN 1732-2421Article in journal (Refereed)
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  • 17. JADWISZCZAK, Piotr
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    First partial skeleton of Delphinornis larseni Wiman, 1905, a slender-footed penguin from the Eocene of Antarctic Peninsula2019In: Palaeontologia Electronica, ISSN 1935-3952, E-ISSN 1094-8074Article in journal (Refereed)
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  • 18. JADWISZCZAK, Piotr
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    First report on quill pits in early penguins2016In: Antarctic Science, ISSN 0954-1020, E-ISSN 1365-2079Article in journal (Refereed)
  • 19.
    Jadwiszczak, Piotr
    et al.
    Faculty of Biology, University of Bialystok, Bialystok, Poland.
    Reguero, Marcelo
    Instituto Antártico Argentino, Campus Miguelete, Buenos Aires, Argentina.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    A new small-sized penguin from the late Eocene of Seymour Island with additional material of Mesetaornis polaris2021In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 143, no 2-3, p. 283-291Article in journal (Refereed)
    Abstract [en]

    Here, we report on two tarsometatarsi assignable to relatively small-sized Eocene Antarctic penguins, housed in the palaeozoological collections of Naturhistoriska riksmuseet, Stockholm. The Priabonian fossils were collected by museum staff during two joined Argentinean and Swedish expeditions from the Submeseta Formation on Seymour Island, Antarctic Peninsula. One specimen represents a new early sphenisciform, Marambiornopsis sobrali gen. et sp. nov., the sixth small-sized tarsometatarsus-based penguin species known from the Antarctic Eocene. Micro-CT scanning revealed the presence of quite large and essentially empty metatarsal medullary cavities. The second fossil can unequivocally be assigned to Mesetaornis polaris. The specimen represents only the second record of this species and supposedly a relatively young bird. Micro-CT scanning showed that in M. polaris the metatarsal medullary cavities are less developed than in M. sobrali – the cortical and trabecular bone tissues left rather little room for significant hollow spaces. Both specimens also differ in overall density of their trabecular networks.

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  • 20.
    JADWISZCZAK, Piotr
    et al.
    Faculty of Biology University of Bialystok Bialystok Poland.
    SVENSSON‐MARCIAL, Anders
    Department of Clinical Science Intervention and Technology at Karolinska Institute Stockholm Sweden.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    An integrative insight into the synsacral canal of fossil and extant Antarctic penguins2022In: Integrative Zoology, ISSN 1749-4869, E-ISSN 1749-4877, ISSN 1749-4877, Vol. 18, no 2, p. 237-253Article in journal (Refereed)
    Abstract [en]

    The lumbosacral-canal system in birds most likely operates as a sense organ involved in the control of balanced walking and perching, but our knowledge of it is superficial. Penguins constitute interesting objects for the study of this system due to their upright walking, but only the Humboldt penguin, Spheniscus humboldti, and some incomplete fossil penguin synsacra have been studied in this respect. Here, we give an integrative comparative insight into the synsacral canal of extant Emperor penguin, Aptenodytes forsteri, Adelie penguin, Pygoscelis adeliae, and Eocene giant Anthropornis and/or Palaeeudyptes Antarctic penguins, using computed tomography imaging and associated data-extraction methodologies, complemented by analytical approaches ranging from geometric morphometrics to modularity, curvature, and wavelet analyses. We document that the variability in the number of synsacro-lumbar vertebrae is evolutionarily conserved, and all studied synsacra possess osteological correlates of the lumbosacral-canal system. We also found that Eocene and extant Antarctic penguins were separable on the basis of the main direction of the shape-related (size-independent) variability within said system, and A. forsteri was unique in the entire studied set in terms of the relative cranial shift of this compound structure. Moreover, we suggest that the evolutionary processes, shaping both the terrestrial posture and gait, were responsible, in extant penguins, for the increased simplicity and stability of the synsacral canal cross-sectional periodic patterns, as well as pave the way for the lumbosacral-canal system modularity characterized by reduced atomization/complexity.

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  • 21.
    Jarochowska, Emilia
    et al.
    GeoZentrum Nordbayern, Fachgruppe Paläoumwelt, University of Erlangen-Nürnberg, Erlangen, Germany.
    Bremer, Oskar
    Department of Organismal Biology, Uppsala University, Uppsala, Sweden.
    Yiu, Alexandra
    GeoZentrum Nordbayern, Fachgruppe Paläoumwelt, University of Erlangen-Nürnberg, Erlangen, Germany.
    Märss, Tiiu
    Department of Geology, Tallinn University of Technology, Tallinn, Estonia.
    Blom, Henning
    Department of Organismal Biology, Uppsala University, Uppsala, Sweden.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology. Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden.
    Vajda, Vivi
    Swedish Museum of Natural History, Department of Paleobiology. Department of Geology, Lund University, Sweden.
    Revision of thelodonts, acanthodians, conodonts, and the depositional environments in the Burgen outlier (Ludlow, Silurian) of Gotland, Sweden2021In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 143, no 2-3, p. 168-189Article in journal (Refereed)
    Abstract [en]

    Ludfordian strata exposed in the Burgen outlier in eastern Gotland, Sweden record a time of initial faunal recovery after a global environmental perturbation manifested in the Ludfordian Carbon Isotope Excursion (LCIE). Vertebrate microfossils in the collection of the late Lennart Jeppsson, hosted at the Swedish Museum of Natural History, hold the key to reconstruct the dynamics of faunal immigration and diversification during the decline of the LCIE, but the stratigraphic relationships of the strata have been debated. Historically, they had been placed in the Burgsvik Formation, which included the Burgsvik Sandstone and the Burgsvik Oolite members. We revise the fauna in the Jeppsson collection and characterize key outcrops of Burgen and Kapellet. The former Burgsvik Oolite Member is here revised as the Burgen Oolite Formation. In the Burgenoutlier, back-shoal facies of this formation are represented and their position in the Ozarkodina snajdri Biozone is supported. The shallow-marine position compared to the coeval strata in southern Gotland isreflected in the higher δ13C carb values, reaching +9.2‰. The back-shoal succession includes high-diversity metazoan reefs, which indicate a complete recovery of the carbonate producers as the LCIE declined. The impoverishment of conodonts associated with the LCIE in southern Gotland might be a product of facies preferences, as the diverse environments in the outlier yielded all 21 species known from the formation. Fish diversity also returned to normal levels as the LCIE declined, with a minimum of nine species. In line with previous reports, thelodont scales appear to dominate samples from the Burgen outlier.

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  • 22.
    Jovells-Vaqué, Sílvia
    et al.
    Department of Geology and Palaeontology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovak Republic;Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Cerdanyola del Vallés, Barcelona, Spain.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    The aberrant hamster Melissiodon (Cricetidae, Rodentia) from the early Miocene of Echzell and other German and French localities2022In: Historical Biology, ISSN 0891-2963, E-ISSN 1029-2381, Vol. 35, no 6, p. 821-831Article in journal (Refereed)
    Abstract [en]

    Melissiodon is a rare cricetid with a long stratigraphic range, present from the Oligocene until the Miocene, only found in western and central Europe except some specimens recovered in Anatolia. What makes Melissiodon special is its unique dental and mandible morphology that has led to many questions regarding its relationship to other cricetid genera and its type of diet. In this work, we have studied new material attributed to Melissiodon from the German localities Echzell (MN4) and Petersbuch (MN3 and MN4), and from the French locality Beaulieu (MN3). Moreover, we compared these specimens with the already published material from other localities across western and central Europe during the early Miocene (MN3 and MN4). In conclusion, the studied specimens and the comparison with other material from different European localities allow us to ascribe this new material as Melissiodon dominans, a widely dispersed species across Europe during the early Miocene.

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  • 23.
    Kalthoff, Daniela C.
    et al.
    Swedish Museum of Natural History, Department of Zoology. Department of Zoology Swedish Museum of Natural History Stockholm Sweden.
    Fejfar, Oldrich
    Geological‐Paleontological Institute Karls University Prague Czech Republic.
    Kimura, Yuri
    Department of Geology and Paleontology National Museum of Nature and Science Tsukuba Japan;Institut Català de Paleontologia Miquel Crusafont Universitat Autònoma de Barcelona Barcelona Spain.
    Bailey, Bruce E.
    Division of Vertebrate Paleontology University of Nebraska State Museum Lincoln Nebraska USA.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology. Department of Paleobiology Swedish Museum of Natural History Stockholm Sweden.
    Incisor enamel microstructure places New and Old World Eomyidae outside Geomorpha (Rodentia, Mammalia)2022In: Zoologica Scripta, ISSN 0300-3256, E-ISSN 1463-6409, Vol. 51, no 4, p. 381-400Article in journal (Refereed)
    Abstract [en]

    The lower incisor enamel microstructure of the fossil rodent family Eomyidae was believed to be three-layered and highly derived but rather uniform throughout the clade. Here, we describe a new four-layered schmelzmuster in Eomyidae consisting of a three-fold portio interna with longitudinal oriented, uniserial Hunter-Schreger bands and a one-fold portio externa, accounting for a unique enamel microstructure character combination in Rodentia. This new schmelzmuster type has developed early in eomyid evolution and is detectable already in the late Eocene (Chadronian) of North America. In European eomyids, it first occurs in the early Miocene (MN 3), implying that this four-layered schmelzmuster was not present in all members of the family but restricted to species included in Eomyini and some genera currently considered Eomyidae incertae sedis within Eomyidae. Additionally, our analysis recognizes three taxa with schmelzmuster divergent from all other eomyids. Incisor enamel microstructure does not advocate a close phylogenetic relationship of Eomyidae to either fossil or extant Heteromyidae and Geomyidae, nor to fossil Heliscomyidae and Florentiamyidae. Our results rather support the view that Eomyidae are placed outside Geomorpha.

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  • 24.
    Kalthoff, Daniela C.
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Biomechanical adaptations for burrowing in the incisor enamel microstructure of Geomyidae and Heteromyidae (Rodentia: Geomyoidea)2021In: Ecology and Evolution, E-ISSN 2045-7758, Vol. 11, p. 9447-9459Article in journal (Refereed)
    Abstract [en]

    The enamel microstructure of fossil and extant Geomyoidea (Geomyidae, Heteromyidae) lower incisors incorporates three- or two-layered schmelzmusters with uniserial, transverse Hunter-Schreger bands having parallel and perpendicular or exclusively perpendicular oriented interprismatic matrix. Phylogenetically, these schmelzmusters are regarded as moderately (enamel type 2) to highly derived (enamel type 3). Our analysis detected a zone of modified radial enamel close to the enamel–dentine junction. Modified radial enamel shows a strong phylogenetic signal within the clade Geomorpha as it is restricted to fossil and extant Geomyoidea and absent in Heliscomyidae, Florentiamyidae, and Eomyidae. This character dates back to at least the early Oligocene (early Arikareean, 29 Ma), where it occurs in entoptychine gophers. We contend that this specialized incisor enamel architecture developed as a biomechanical adaptation to regular burrowing activities including chisel-tooth digging and a fiber-rich diet and was probably present in the common ancestor of the clade. We regard the occurrence of modified radial enamel in lower incisors of scratch-digging Geomyidae and Heteromyidae as the retention of a plesiomorphic character that is selectively neutral. The shared occurrence of modified radial enamel is a strong, genetically anchored argument for the close phylogenetic relationship of Geomyidae and Heteromyidae on the dental microstructure level.

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  • 25.
    Kim, Sora
    et al.
    Department of Life and Environmental Sciences, University of California, Merced, CA, USA.
    Zeichner, Sarah
    Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.
    Colman, Albert
    Department of Earth, Environment, and Planetary Sciences, Rice University, Houston, TX, USA.
    Scher, Howie
    Department of Earth, Ocean, and Environment, University of South Carolina, Columbia, SC, USA.
    KRIWET, JÜRGEN
    Department of Paleontology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria..
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Huber, Matthew
    Department of Earth, Atmosphere, and Planetary Sciences, Purdue University, West Lafayette, IN, USA.
    Probing the ecology and climate of the Eocene Southern Ocean with sand tiger sharks Striatolamia macrota2020In: Paleoceanography and Paleoclimatology, ISSN 2572-4517, E-ISSN 2572-4525, Vol. 35, no 12, article id e2020PA003997Article in journal (Refereed)
    Abstract [en]

    Many explanations for Eocene climate change focus on the Southern Ocean—where tectonics influenced oceanic gateways, ocean circulation reduced heat transport, and greenhouse gas declines prompted glaciation. To date, few studies focus on marine vertebrates at high latitudes to discern paleoecological and paleoenvironmental impacts of this climate transition. The Tertiary Eocene La Meseta (TELM) Formation has a rich fossil assemblage to characterize these impacts; Striatolamia macrota, an extinct (†) sand tiger shark, is abundant throughout the La Meseta Formation. Body size is often tracked to characterize and integrate across multiple ecological dimensions. †S. macrota body size distributions indicate limited changes during TELMs 2–5 based on anterior tooth crown height (n = 450, mean = 19.6 ± 6.4 mm). Similarly, environmental conditions remained stable through this period based on δ18OPO4 values from tooth enameloid (n = 42; 21.5 ± 1.6‰), which corresponds to a mean temperature of 22.0 ± 4.0°C. Our preliminary εNd (n = 4) results indicate an early Drake Passage opening with Pacific inputs during TELM 2–3 (45–43 Ma) based on single unit variation with an overall radiogenic trend. Two possible hypotheses to explain these observations are (1) †S. macrota modified its migration behavior to ameliorate environmental changes related to the Drake Passage opening, or (2) the local climate change was small and gateway opening had little impact. While we cannot rule out an ecological explanation, a comparison with climate model results suggests that increased CO2 produces warm conditions that also parsimoniously explain the observations.

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  • 26.
    KIMURA, Yuri
    et al.
    Department of Geology and Paleontology, National Museum of Nature and Science.
    CASANOVAS-VILAR, Isaac
    Institut Català de Paleontologia Miquel Crusafont, ICTA-ICP.
    MARIDET, OLIVIER
    JURASSICA Museum, Route de Fontenais 21, CH-2900 Porrentruy, Switzerland.
    KALTHOFF, Daniela
    Swedish Museum of Natural History, Department of Zoology.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    TOMIDA, Yukimitsu
    The Eomyidae in Asia: Biogeography, diversity and dispersals2020In: Fossil Imprint, Vol. 76, no 1, p. 181-200Article in journal (Refereed)
    Abstract [en]

    In Asia, the first find of an eomyid rodent was reported almost one century after the first studies of the family Eomyidae in North America and Europe. Since then, eomyid rodents have been increasingly found in Asia particularly over the past two decades. Here, we review the Asian record of this family at the genus level. Currently, 22 species within 14 genera were reported from Asia, including seven endemic genera and rare materials of apeomyine eomyids. Eomyids emphasize the palaeogeographic importance of Asia in considering intercontinental dispersal events of small mammals. With newly compiled data for Asian eomyids, we also compare genus-level diversity trends through time among North America, Europe, and Asia. Despite data standardizations limited with respect to potential biases in the fossil record, we found that the Asian eomyid diversity closely follows ecological shifts induced by climate changes. In general, Asian eomyid genera disappeared earlier than their European counterparts. We suggest that this pattern is not dictated by differences in the quality of the fossil record and is related to the expansion of drier habitats over large areas of Asia.

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  • 27. KIMURA, Yuri
    et al.
    TOMIDA, Yukimitsu
    Kalthoff, Daniela
    Swedish Museum of Natural History, Department of Zoology.
    CASANOVAS-VILAR, Isaac
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    A new endemic genus of eomyid rodents from the early Miocene of Japan2019In: Acta Palaeontologica Polonica, ISSN 0567-7920, E-ISSN 1732-2421Article in journal (Refereed)
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  • 28. Kriwet, Jürgen
    et al.
    Engelbrecht, Andrea
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Reguero, Marcelo
    Pfaff, Cathrin
    Ultimate Eocene (Priabonian) chondrichthyans (Holocephali, Elasmobranchii) of Antarctica2016In: Journal of Vertebrate Paleontology, ISSN 0272-4634, E-ISSN 1937-2809Article in journal (Refereed)
    Abstract [en]

    ABSTRACT—The Eocene La Meseta Formation on Seymour Island, Antarctic Peninsula, is known for its remarkable wealth of fossil remains of chondrichthyans and teleosts. Chondrichthyans seemingly were dominant elements in the Antarctic Paleogene fish fauna, but decreased in abundance from middle to late Eocene, during which time remains of bony fishes increase. This decline of chondrichthyans at the end of the Eocene generally is related to sudden cooling of seawater, reduction in shelf area, and increasing shelf depth due to the onset of the Antarctic thermal isolation. The last chondrichthyan records known so far include a chimeroid tooth plate from TELM 6 (Lutetian) and a single pristiophorid rostral spine from TELM 7 (Priabonian). Here, we present new chondrichthyan records of Squalus, Squatina, Pristiophorus, Striatolamia, Palaeohypotodus, Carcharocles, and Ischyodus from the upper parts of TELM 7 (Priabonian), including the first record of Carcharocles sokolovi from Antarctica. This assemblage suggests that chondrichthyans persisted much longer in Antarctic waters despite rather cool sea surface temperatures of approximately 5C. The final disappearance of chondrichthyans at the Eocene–Oligocene boundary concurs with abrupt ice sheet formation in Antarctica. Diversity patterns of chondrichthyans throughout the La Meseta Formation appear to be related to climatic conditions rather than plate tectonics.

  • 29. Li, Zhaoyu
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Dormice (Rodentia, Gliridae) from the Middle Miocene of Hambach 6C, Northwest Germany2023In: Geobios, ISSN 0016-6995, E-ISSN 1777-5728, Vol. 78, p. 15-31Article in journal (Refereed)
    Abstract [en]

    Glirid dental material is described from the Middle Miocene channel fill of the Hambach open-cast lignite mine in northwestern Germany. The fauna Hambach 6C shows a high diversity with seven species in six genera: Glirudinus undosus, Muscardinus thaleri, Muscardinus sansaniensis, Miodyromys aegercii, Paraglirulus werenfelsi, Microdyromys koenigswaldi, and Paraglis astaracensis, which are characteristic taxa in Middle Miocene European localities. Regarding the faunal composition and high diversity, the Hambach 6C assemblage is closest to that of the MN 5 locality Schönenberg in southern Germany, but also shares many taxa with late Middle Miocene faunas. The species richness of glirids, combined with other vertebrate remains in Hambach 6C indicates a warm, humid forested environment during the Mid-Miocene Climate Optimum (MCO).

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  • 30.
    Li, Zhaoyu
    et al.
    Swedish Museum of Natural History, Department of Paleobiology. Northwest University.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Zhang, Yunxiang
    Northwest University.
    Xie, Kun
    Northwest University.
    Li, Yongxiang
    Northwest University.
    New Material of Schizotheriine Chalicothere (Perissodactyla, Chalicotheriidae) from the Xianshuihe Formation (Early Miocene) of Lanzhou Basin, Northwest China2022In: Journal of mammalian evolution, ISSN 1064-7554, E-ISSN 1573-7055, Vol. 29, no 4, p. 877-889Article in journal (Refereed)
    Abstract [en]

    A new schizotheriine mandible from the early Miocene Xianshuihe Formation in Lanzhou Basin, Northwest China is described here. Compared with other contemporaneous taxa, the lower jaw is most similar to Borissiakia betpakdalensis from Kazakhstan based on mandibular morphology and dental features, except for a much smaller body size which is hardly explained by intraspecific variation and suggests it represents a smaller body-sized species of Borissiakia. The type specimen of Phyllotillon huangheensis, from the same strata of the Lanzhou Basin, shares characters with the new specimen in the lower cheek teeth and the tapered morphology of the anterior horizontal ramus. Differences between both are reflected in the height of the ramus, especially the level of the symphysis, which may be an expression of sexual dimorphism. Therefore, schizotheriine mandibles from the early Miocene of Lanzhou Basin are regarded as the same taxon, and both are recognized as Borissiakia huangheensis. The occurrence of a chalicothere and other large perissodactyls may suggest that a certain amount of open woodland was distributed across the basin and that the paleoclimate might have been more humid during the early Miocene.

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  • 31.
    Loch, Carolona
    et al.
    University of Otago, Dunedin.
    BUONO, Monica
    Instituto Patagónico de Geología y Paleontología, CONICET, Puerto Madryn.
    KALTHOFF, Daniela
    Swedish Museum of Natural History, Department of Zoology.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    FERNANDEZ, Martha
    Universidad Nacional de La Plata, CONICET, La Plata.
    Enamel microstructure in Eocene cetaceans from Antarctica (Archaeoceti and Mysticeti)2020In: Journal of mammalian evolution, ISSN 1064-7554, E-ISSN 1573-7055, Vol. 27, p. 289-298Article in journal (Refereed)
    Abstract [en]

    Modern baleen whales have no adult teeth, whereas dolphins and porpoises have a homodont and polydont dentition, with simplified enamel microstructure. However, archaic cetaceans (archaeocetes and early mysticetes and odontocetes) had a complexand ornamented dentition, with complex enamel microstructure as in terrestrial mammals. This study describes the morphology of teeth and enamel microstructure in two fossil cetaceans from Antarctica: a basilosaurid archaeocete from the La Meseta Formation (middle Eocene); and Llanocetus sp. from the Submeseta Formation (late Eocene), one of the oldest mysticetes known. The two teeth analyzed were lower premolars, with transversely compressed triangular crowns composed of a main cuspand accessory denticles. The enamel microstructure of the basilosaurid and Llanocetus sp. is prismatic with Hunter-Schreger bands (HSB) and an outer zone of radial enamel. In the basilosaurid, the enamel is relatively thin and measures 150–180 μm, whereas in Llanocetus sp. it is considerably thicker, measuring 830–890 μm in the cusp area and 350–380 μm near the crown base. This is one of the thickest enamel layers among cetaceans, extinct and living. Structures resembling enamel tufts and lamellae were observed in both fossils at the enamel-dentine junction (EDJ) and extending along the thickness of the enamel layer, respectively. The presence of HSB and biomechanical reinforcing structures such as tufts and lamellae suggests prominent occlusal loads during feeding, consistent with raptorial feeding habits. Despite the simplification or absence of teeth in modern cetaceans, their ancestors had complex posterior teeth typical of most mammals, with a moderately thick enamel layer with prominent HSB.

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  • 32.
    Macaluso, Loredana
    et al.
    Dipartimento di Scienze della Terra Via Valperga Caluso 35 10125 Turin Italy.
    Villa, Andrea
    Institut Català de Paleontologia Miquel Crusafont Universitat Autònoma de Barcelona Edifici ICTA‐ICP, c/ Columnes s/n Campus de la UAB, 08193 Cerdanyola del Vallès Barcelona Spain.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    A new proteid salamander (Urodela, Proteidae) from the middle Miocene of Hambach (Germany) and implications for the evolution of the family2021In: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 65, no 1, article id e12585Article in journal (Refereed)
    Abstract [en]

    Members of the urodele family Proteidae currently account for eight extant species within two genera and at least four extinct species within three genera. The clade has a clear disjunct geographical range, with the extinct Paranecturus and the extant Necturus in North America and the extinct Mioproteus and the extant Proteus in Europe and Asia. A recent phylogenetic analysis supported a Eurasian clade including both fossil and living species found east of the Atlantic Ocean. However, the finding of a new proteid salamander, herein named Euronecturus grogu, from the Miocene of western Germany sheds new light on the evolution of this family, challenging the idea of all Eurasian members of the group deriving from a single lineage separated from the North American ones at least prior to the Oligocene. This new proteid taxon is based on five isolated atlases found in late Orleanian (MN 5) sediments in Hambach 6C, and displays features that are unknown in any other proteid, such as the presence of secondary dorsal crests, small and posteriorly-directed postzygapophyses, and (in at least some specimens) a wide and deep ventral fossa between the anterior cotyles. A phylogenetic analysis recovered the new taxon in an earl ybranching position within Proteidae, sister to all other proteids but the late Maastrichtian Paranecturus. It thus suggests the presence in Europe of a second proteid lineage, currently known only in the middle Miocene, that appears unrelated to the Mioproteus–Proteus clade.

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  • 33.
    MARRAMÀ, GIUSEPPE
    et al.
    Department of Paleontology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria..
    ENGELBRECHT, ANDREA
    Department of Paleontology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria..
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    REGUERO, MARCELO A.
    Division Paleontologia de Vertebrados, Museo de La Plata, Paseo del Bosque s/n, 81900 FWA La Plata, Argentina.
    KRIWET, JÜRGEN
    Department of Paleontology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria..
    THE SOUTHERNMOST OCCURRENCE OF BRACHYCARCHARIAS (LAMNIFORMES, ODONTASPIDIDAE) FROM THE EOCENE OF ANTARCTICA PROVIDES NEW INFORMATION ABOUT THE PALEOBIOGEOGRAPHY AND PALEOBIOLOGY OF PALEOGENE SAND TIGER SHARKS2018In: Rivista italiana di paleontologia e stratigrafia, ISSN 0035-6883, E-ISSN 2039-4942Article in journal (Refereed)
    Abstract [en]

     The first record of one of the most common and widespread Paleogene selachians, the sand tiger shark Brachycarcharias, in the Ypresian strata of the La Meseta Formation, Seymour Island, Antarctica, is provided herein. Selachians from the early Eocene horizons of this deposit represent the southernmost Paleogene occurrences in the fossil record, and are represented by isolated teeth belonging to orectolobiforms, lamniforms, carcharhiniforms, squatiniforms and pristiophoriforms. The combination of dental characters of the 49 isolated teeth collected from the horizons TELMs 2, 4 and 5 supports their assignment to the odontaspidid Brachycarcharias lerichei (Casier, 1946), a lamniform species widely spread across the Northern Hemisphere during the early Paleogene. The unambiguous first report of this lamniform shark in the Southern Hemisphere in the Eocene of the La Meseta Formation improves our knowledge concerning the diversity and paleobiology of the cartilaginous fishes of this deposit, and provides new insights about the biotic turnovers that involved the high trophic levels of the marine settings after the end-Cretaceous extinction and before the establishment of the modern marine ecosystems.

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  • 34.
    McLoughlin, Stephen
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Bomfleur, Benjamin
    Swedish Museum of Natural History, Department of Paleobiology.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Reguero, Marcelo
    División Paleontología de Vertebrados, Museo de La Plata, Paseo del Bosque s/n, B1900FWA La Plata, Argentina.
    Fossil clitellate annelid cocoons and their microbiological inclusions from the Eocene of Seymour Island, Antarctica2016In: Palaeontologia Electronica, ISSN 1935-3952, E-ISSN 1094-8074, Vol. 19, no 1.11A, p. 1-27Article in journal (Refereed)
    Abstract [en]

    Clitellate annelids have a meagre body fossil record but they secrete proteinaceous

    cocoons for the protection of eggs that, after hardening, are readily fossilized

    and offer a largely untapped resource for assessing the evolutionary history of this

    group. We describe three species of clitellate cocoons (viz., Burejospermum seymourense

    sp. nov., B. punctatum sp. nov. and Pegmatothylakos manumii gen. et sp. nov.)

    from the lower Eocene La Meseta Formation, Seymour Island, Antarctica. The

    cocoons probably derive from continental settings and were transported to, and preserved

    within, nearshore marine to estuarine environments. The cocoons provide the

    first evidence of commensal or parasitic relationships in the Eocene continental ecosystems

    of Antarctica. Moreover, numerous micro-organisms and the oldest fossilized

    examples of animal spermatozoa are preserved as moulds within the consolidated

    walls of the cocoons. Fossil annelid cocoons offer potential for enhanced palaeoenvironmental

    interpretation of sediments, correlation between continental and shallowmarine

    strata, and improved understanding of the development of clitellate annelid

    reproductive traits and the evolutionary history of soft-bodied micro-organisms in general.

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  • 35.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Wirbeltiere aus dem Miozän von Homberg/Ohm (Vogelsberg,Hessen)2010In: Geologisches Jahrbuch HessenArticle in journal (Refereed)
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  • 36.
    Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    FLINK, Therese
    Large apeomyine rodents (Mammalia, Eomyidae) from the early Miocene of Echzell, Germany2018In: Historical Biology, ISSN 0891-2963, E-ISSN 1029-2381Article in journal (Refereed)
    Abstract [en]

    The dental material described in this paper was collected from fossiliferous ash layers of the Vogelsberg volcanic complex at Echzell, Germany. It consists of 32 teeth of a new large Apeomys species, Apeomys oldrichi n. sp., and 19 teeth of Megapeomys lindsayi Fejfar, Rummel and Tomida. Both species are extremely rare faunal elements in the early Miocene of Europe. Apeomys oldrichi n. sp. is the largest known Apeomys species, and occurs in a number of MN 3 – 4 sites in southern Germany and Czech Republic. Megapeomys lindsayi, the largest Eurasian apeomyine, was described on the basis of a single lower premolar. Herein both lower and upper cheek teeth as well as the lower deciduous premolar are described for the first time. In comparison with related populations from other localities, the evolutionary stage of the two apeomyine species clearly indicates a middle Orleanian age (MN 4) for Echzell which concurs with previous studies.

  • 37.
    Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Hagström, Jonas
    Swedish Museum of Natural History, Department of Paleobiology.
    Kaim, Andrzej
    HRYNIEWICZ, Krzysztof
    First shark record (Chondrichthyes, Elasmobranchii) from the Paleogene of Spitsbergen, Svalbard2019In: Polish Polar Research, ISSN 0138-0338, E-ISSN 2081-8262Article in journal (Refereed)
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  • 38.
    Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    HUGUENEY, Marguerite
    A Hystrix Linnaeus, 1758 incisor(Mammalia, Rodentia) from the Early Pleistocene of Senèze, France2017In: Geodiversitas, ISSN 1280-9659, E-ISSN 1638-9395Article in journal (Refereed)
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  • 39.
    Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Hulbert, Richard
    Anchitheriomys Roger, 1898 or Amblycastor Matthew, 1918 (Rodentia, Castoridae)?: Taxonomic implications of a mandible from the Miocene of Florida2010In: Journal of Vertebrate Paleontology, ISSN 0272-4634, E-ISSN 1937-2809Article in journal (Refereed)
  • 40.
    Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Kalthoff, Daniela
    A new species of Amphilagus (Mammalia: Lagomorpha) from the Late Oligocene lake deposits of Enspel (Westerwald, Germany)2010In: Palaeobiodiversity and PalaeoenvironmentsArticle in journal (Refereed)
  • 41.
    Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Liu, Liping
    Swedish Museum of Natural History, Department of Paleobiology.
    Hagström, Jonas
    Swedish Museum of Natural History, Department of Paleobiology.
    A Miocene tetraconodontine (Suidae, Mammalia) from Falkenberg (Halland, Sweden)2019In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, p. 77-81Article in journal (Refereed)
  • 42.
    Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    NIEDZWIEDZKI, Grzegorz
    CRISPINI, Laura
    LÄUFER, Andreas
    BOMFLEUR, Benjamin
    First evidence of a tetrapod footprint from the Triassic of northern Victoria Land, Antarctica2019In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369Article in journal (Refereed)
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  • 43.
    Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    REGUERO, MARCELO A.
    Division Paleontologia de Vertebrados, Museo de La Plata, Paseo del Bosque s/n, 81900 FWA La Plata, Argentina.
    VASILYAN, Davit
    JURASSICA Museum, Route de Fontenais 21, 2900, Porrentruy, Switzerland.
    First fossil frog from Antarctica: implications for Eocene high latitude climate conditions and Gondwanan cosmopolitanism of Australobatrachia2020In: Scientific Reports, E-ISSN 2045-2322, Vol. 10, no 5051, p. 1-11Article in journal (Refereed)
    Abstract [en]

    Cenozoic ectothermic continental tetrapods (amphibians and reptiles) have not been documented previously from Antarctica, in contrast to all other continents. Here we report a fossil ilium and an ornamented skull bone that can be attributed to the Recent, South American, anuran family Calyptocephalellidae or helmeted frogs, representing the first modern amphibian found in Antarctica.

    The two bone fragments were recovered in Eocene, approximately 40 million years old, sediments on Seymour Island, Antarctic Peninsula. The record of hyperossified calyptocephalellid frogs outside South America supports Gondwanan cosmopolitanism of the anuran clade Australobatrachia. Our results demonstrate that Eocene freshwater ecosystems in Antarctica provided habitats favourable for ectothermic vertebrates (with mean annual precipitation ≥900 mm, coldest month mean temperature ≥3.75 °C, and warmest month mean temperature ≥13.79 °C), at a time when there were at least ephemeral ice sheets existing on the highlands within the interior of the continent.

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  • 44.
    Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Stefen, Clara
    The castorid Steneofiber from NW Germany and its implications for the taxonomy of Miocene beavers2010In: Acta Palaeontologica Polonica, ISSN 0567-7920, E-ISSN 1732-2421Article in journal (Refereed)
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  • 45.
    Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Tomida, Yukimitsu
    National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba, Ibaraki 305-0005, Japan.
    Euroxenomys nanus sp. nov., a minute beaver (Rodentia,Castoridae) from the early Miocene of Japan2018In: Paleontological ResearchArticle in journal (Refereed)
    Abstract [en]

    A recently discovered, incomplete dentary with preserved incisor, premolar and first molar of a minute castorid from the Dota locality, Kani Basin, early Miocene (ca. 18.5 Ma) Nakamura Formation of the Mizunami Group in central Japan, is described as a new species of the trogontheriine beaver Euroxenomys. It represents the first record of Euroxenomys in Asia and one of the oldest records of this genus. Euroxenomys nanus sp. nov. is smaller than the type species, E. minutus from the Miocene of Europe and more hypsodont, but similar in size to E. inconnexus from the Barstovian of Montana. Dota is the first Asian locality with three cooccurring castorids, Youngofiber sinensis, Minocastor godai, and E. nanus.

  • 46.
    Mörs, Thomas
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Tomida, Yukimitsu
    Kalthoff, Daniela
    Swedish Museum of Natural History, Department of Zoology.
    A new large beaver (Mammalia, Castoridae) from the Early Miocene of Japan2016In: Journal of Vertebrate Paleontology, ISSN 0272-4634, E-ISSN 1937-2809Article in journal (Refereed)
    Abstract [en]

    A new early Miocene large castorid, Minocastor godai gen. et sp. nov., from the Dota locality, Gifu Prefecture in central Japan, is described on the basis of dentaries and teeth. The material comes from the Kani basin, where limnofluviatile clay and sandstones of the Nakamura Formation (Mizunami Group) are exposed on the southern (left) bank of the Kiso River. It represents the richest sample of a Miocene small mammal in the Japanese fossil record thus far known. Based on jaw and tooth morphology, this new castorid most likely represents a primitive anchitheriomyine. However, it lacks the marked striations on the incisors that are characteristic of the advanced large, middle Miocene anchitheriomyines like Anchitheriomys and Amblycastor. The new castorid shares this dental feature with other primitive anchitheriomyines from Asia and North America, like Propalaeocastor, Oligotheriomys, and Miotheriomys. For these genera, a new tribe, Minocastorini, is proposed as sister group to the Anchitheriomyini. The incisor enamel microstructure of the new castorid largely exhibits plesiomorphic characters but also apomorphic features such as pseudo-pauciserial Hunter-Schreger bands. Additionally, the outer portion of the enamel band is rather thick in comparison to that of other beavers. Based on the rodent taxa associated with Minocastor godai gen. et sp. nov., Dota can be correlated with European Neogene mammal units MN 3/4. Magnetostratigraphic studies and radiometric dates obtained from the Mizunami Group indicate that Dota is more likely correlated with MN 3, with an absolute age of around 18.5 Ma.

  • 47.
    O'Gorman, José P.
    et al.
    División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA, La Plata, Argentina..
    Coria, Rodolfo A
    cMuseo Carmen Funes, Av. Córdoba 55 (8318), Plaza Huincul, Neuquén, Argentina. .
    Reguero, Marcelo
    División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA, La Plata, Argentina..
    Santillana, Sergio
    dInstituto Antártico Argentino, 25 de Mayo 1143, B1650HMK San Martín, Buenos Aires, Argentina.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Cardenas, Magaly
    fInstituto de Investigaciones en Paleobiología y Geología, Universidad Nacional de Río Negro, Av. Roca 1242 (8332), Gral. Roca, Río Negro Province, Argentina.
    The first non-aristonectine elasmosaurid (Sauropterygia; Plesiosauria) cranial material from Antarctica: new data on the evolution of the elasmosaurid basicranium and palate2018In: Cretaceous research (Print), ISSN 0195-6671, E-ISSN 1095-998XArticle in journal (Refereed)
    Abstract [en]

    Elasmosaurids are a monophyletic group of cosmopolitan plesiosaurs with extremely long necks. Although abundant elasmosaurid material has been collected from the Upper Cretaceous of Antarctica, skull material is extremely rare. Here, new elasmosaurid cranial material from the lower Maastrichtian levels of the Cape Lamb Member (Snow Hill Island Formation) on Vega Island, Antarctica is described. The studied specimen (MLP 15-I-7-6) is a non-aristonectine elasmosaurid but shows a palate morphology characterized by the absence of a posterior interpterygoid symphysis and a posterior plate-like extension of the pterygoids, features previously associated with the  aristonectine palatal structure. The specimen MLP 15-I-7-6 thus provides an indication that these palatal features are also present in non-aristonectine Weddellian elasmosaurids, and makes available additional evidence of the close phylogenetical relationship between the aristonectines and some Weddellian non-aristonectine elasmosaurids.

  • 48. Pineker, Patrick
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Neocometes (Rodentia:Platacanthomyinae) from the early Miocene of Echzell, Germany2011In: Geobios, ISSN 0016-6995, E-ISSN 1777-5728Article in journal (Refereed)
  • 49. Scheyer, Torsten
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    Einarsson, Elisabeth
    First record of soft-shelled turtles (Cryptodira: Trionychidae) from the Late Cretaceous of Europe2012In: Journal of Vertebrate Paleontology, ISSN 0272-4634, E-ISSN 1937-2809Article in journal (Refereed)
  • 50. Schwarzhans, Werner
    et al.
    Mörs, Thomas
    Swedish Museum of Natural History, Department of Paleobiology.
    ENGELBRECHT, Andrea
    REGUERO, Marcelo
    KRIWET, Jürgen
    Before the freeze: Otoliths from the Eocene of Seymour Island, Antarctica, reveal dominance of gadiform fishes (Teleostei)2016In: Journal of Systematic Palaeontology, ISSN 1477-2019, E-ISSN 1478-0941Article in journal (Refereed)
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