| 1. |
- van de Kamp, Thomas, et al.
(författare)
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Parasitoid biology preserved in mineralized fossils
- 2018
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723.
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Tidskriftsartikel (refereegranskat)abstract
- About 50% of all animal species are considered parasites. The linkage of species diversity to a parasitic lifestyle is especially evident in the insect order Hymenoptera. However, fossil evidence for host–parasitoid interactions is extremely rare, rendering hypotheses on the evolution of parasitism assumptive. Here, using high-throughput synchrotron X-ray microtomography, we examine 1510 phosphatized fly pupae from the Paleogene of France and identify 55 parasitation events by four wasp species, providing morphological and ecological data. All species developed as solitary endoparasitoids inside their hosts and exhibit different morphological adaptations for exploiting the same hosts in one habitat. Our results allow systematic and ecological placement of four distinct endoparasitoids in the Paleogene and highlight the need to investigate ecological data preserved in the fossil record.
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| 2. |
- ACOSTA HOSPITALECHE, Carolina, et al.
(författare)
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Historical perspective of Otto Nordenskjöld´s Antarctic fossil penguin collection and Carl Wiman’s contribution
- 2017
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Ingår i: Polar Record. - Cambridge. - 0032-2474 .- 1475-3057. ; 53:4, s. 364-375
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- BUONO, Monica, et al.
(författare)
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Eocene basilosaurid whales from the La Meseta Formation, Marambio (Seymour) Island, Antarctica
- 2016
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Ingår i: Ameghiniana. - 0002-7014 .- 1851-8044. ; 53:3, s. 296-315
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 4. |
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| 5. |
- Davydenko, Svitozar, et al.
(författare)
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A small whale reveals diversity of the Eocene cetacean fauna of Antarctica
- 2021
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Ingår i: Antarctic Science. - Cambridge : Cambridge University Press. - 0954-1020 .- 1365-2079. ; 33:1, s. 81-88
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Tidskriftsartikel (refereegranskat)abstract
- 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. |
- Daxner-Höck, Gudrun, et al.
(författare)
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A synthesis of fauna, palaeoenvironments and stratigraphy of the Miocene Tagay locality (Olkhon Island, Lake Baikal, Eastern Siberia)
- 2022
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Ingår i: Palaeobiodiversity and Palaeoenvironments. - : Springer Science and Business Media LLC. - 1867-1594 .- 1867-1608. ; 102:4, s. 969-983
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Tidskriftsartikel (refereegranskat)abstract
- We report about the Early Miocene Tagay fauna of Olkhon Island, the largest island of the Baikal Lake. The Tagay fauna is of high scientific importance because of the diversity of fishes, amphibians, lizards, snakes, turtles, manifold birds and mammals. The lithology, geochemistry and the fossil record along the Tagay-1 section allow reconstruction of various palaeoenvironments, i.e. open water, shallow lakes with adjacent wetlands, riverine woodlands, and also forested and dry habitats. The fossil record, lithology and geochemical sediment-analyses suggest a temperate palaeoclimate with short humid and dry periods. The small mammal record and the magnetic polarity pattern of the upper part of section Tagay-1 correlate with the subchrons C5Cn.2r – C5Cn.1r of Chron C5C and the late Burdigalian Stage of the Geologic Time Scale (GTS2000). The corresponding age range of the Tagay fauna is ~16.5 to ~16.3 Ma.
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| 7. |
- Daxner-Höck, Gudrun, et al.
(författare)
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Cricetodontinae (Rodentia, Mammalia) of the Miocene Tagay fauna (Olkhon Island, Lake Baikal, Eastern Siberia)
- 2022
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Ingår i: Palaeobiodiversity and Palaeoenvironments. - : Springer Science and Business Media LLC. - 1867-1594 .- 1867-1608. ; 102:4, s. 885-895
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Tidskriftsartikel (refereegranskat)abstract
- The collection of fossil Rodentia from the Miocene Tagay fauna comprises Aplodontidae, Mylagaulidae, Sciuridae, Gliridae, Castoridae, Eomyidae and Cricetodontinae. Represented by three taxa the Cricetodontinae dominate the rodent assemblage of the Tagay fauna. The fossils were collected by wet-screening of test samples along the section Tagay-1 at Tagay Bay of Olkhon Island. Here, we report on the medium-sized Democricetodon cf. lindsayi, the very small Democricetodon sp. and the large Gobicricetodon filippovi. The primitive dental pattern of D. cf. lindsayi and G. filippovi suggest archaic members of the genera, and an age around the Early/Middle Miocene transition.
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| 8. |
- Daxner-Höck, Gudrun, et al.
(författare)
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Geology and lithology of the Tagay-1 section at Olkhon Island (Lake Baikal, Eastern Siberia), and description of Aplodontidae, Mylagaulidae and Sciuridae (Rodentia, Mammalia)
- 2022
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Ingår i: Palaeobiodiversity and Palaeoenvironments. - : Springer Science and Business Media LLC. - 1867-1594 .- 1867-1608. ; 102:4, s. 843-857
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Tidskriftsartikel (refereegranskat)abstract
- Excavations along the Tagay-1 section shed light into the composition of small mammal assemblages of the Tagay site. The present paper focuses on the geology and geomorphology of Olkhon Island, the lithology and fossil evidence along the Tagay-1 section and descriptions of the aplodontid, mylagaulid and sciurid rodents. The described fossils are isolated teeth of four taxa, Ansomys sp. (Aplodontidae), Lamugaulus olkhonensis Tesakov and Lopatin, 2015 (Mylagaulidae), Sciuridae indet. and Spermophilinus debruijni nov. spec. (Sciuridae). The archaic tooth pattern of these rodents suggests an age around the Early/Middle Miocene transition.
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| 9. |
- Daxner-Höck, Gudrun, et al.
(författare)
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Gliridae and Eomyidae (Rodentia) of the Miocene Tagay fauna (Olkhon Island, Lake Baikal, Eastern Siberia)
- 2022
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Ingår i: Palaeobiodiversity and Palaeoenvironments. - : Springer Science and Business Media LLC. - 1867-1594 .- 1867-1608. ; 102:4, s. 859-871
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Tidskriftsartikel (refereegranskat)abstract
- The small mammals Myomiminae indet. (Gliridae), Leptodontomys cf. gansus Zheng and Li, 1982 (Eomyidae) and the new species Keramidomys sibiricus nov. spec. (Eomyidae) are described. They were collected from six layers of the middle to upper part of the Tagay-1 section on Olkhon Island. The glirid Myomiminae indet. is represented by only a few isolated teeth, the small eomyid Leptodontomys cf. gansus by a mandible with two teeth, and the second small eomyid Keramidomys sibiricus nov. spec. by several isolated teeth and a mandible. The ancestral tooth characteristics of Keramidomys sibiricus nov. spec. indicate an early evolutionary stage of Keramidomys in Asia. The suggested age of the assemblage is Early/Middle Miocene transition.
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| 10. |
- DOGUZHAEVA, Larisa, et al.
(författare)
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An Eocene orthocone from Antarctica shows convergent evolution of internally shelled cephalopods
- 2017
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Ingår i: PLOS ONE. - San Fransisco : Public Library of Science (PLoS). - 1932-6203. ; 12:3
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe 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 findingsTwo 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/SignificanceOur 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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