| 1. |
- Huldtgren, Therese, et al.
(författare)
-
Fossilized nuclei and germination structures identify Ediacaran ‘animal embryos’ as encysting protists.
- 2011
-
Ingår i: Science. - Washington, DC : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 334:6063, s. 1696-1699
-
Tidskriftsartikel (refereegranskat)abstract
- Globular fossils showing palintomic cell cleavage in the Ediacaran Doushantuo Formation, China, are widely regarded as embryos of early metazoans, although metazoan synapomorphies, tissue differentiation, and associated juveniles or adults are lacking. We demonstrate using synchrotron-based x-ray tomographic microscopy that the fossils have features incompatible with multicellular metazoan embryos. The developmental pattern is comparable with nonmetazoan holozoans, including germination stages that preclude postcleavage embryology characteristic of metazoans. We conclude that these fossils are neither animals nor embryos. They belong outside crown-group Metazoa, within total-group Holozoa (the sister clade to Fungi that includes Metazoa, Choanoflagellata, and Mesomycetozoea) or perhaps on even more distant branches in the eukaryote tree. They represent an evolutionary grade in which palintomic cleavage served the function of producing propagules for dispersion.
|
|
| 2. |
- Ivarsson, Magnus, et al.
(författare)
-
Introducing palaeolithobiology
- 2021
-
Ingår i: GFF. - London : Taylor & Francis. - 1103-5897 .- 2000-0863. ; 143:2-3, s. 305-319
-
Tidskriftsartikel (refereegranskat)abstract
- A growing literature of deep but also surficial fossilized remains of lithobiological life, often associated with igneous rocks, necessitates the unfolding of a sub-discipline within paleobiology. Here, we introduce the term paleolithobiology as the new auxiliary sub-discipline under which fossilized lithobiology should be handled. We present key criteria that distinguish the paleolithobiological archive from the traditional one and discuss sample strategies as well as scientific perspectives. A majority of paleolithobiological material consists of deep biosphere fossils, and in order to highlight the relevance of these, we present new data on fungal fossils from the Lockne impact crater. Fungal fossils in the Lockne drill cores have been described previously but here we provide new insights into the presence of reproductive structures that indicate the fungi to be indigenous. We also show that these fungi frequently dissolve and penetrate secondary calcite, delineating the role lithobionts plays in geobiological cycles. We hope that the formalization of the sub-discipline paleolithobiology will not only highlight an overlooked area of paleobiology as well as simplify future studies of endo- and epilithic fossil material, but also improve our understanding of the history of the deep biosphere.
|
|
| 3. |
- Kouchinsky, Artem, et al.
(författare)
-
A Middle Cambrian fauna of skeletal fossils from the Kuonamka Formation, northern Siberia.
- 2011
-
Ingår i: Alcheringa. - : Informa UK Limited. - 0311-5518 .- 1752-0754. ; 35:1, s. 123-189
-
Tidskriftsartikel (refereegranskat)abstract
- An assemblage of mineralized skeletal fossils containing molluscs, hyoliths, chancelloriids, protoconodonts, lobopods, paleoscolecids, bradoriids, echinoderms and hexactinellid sponges is described from the middle Cambrian part of the Kuonamka Formation, exposed along the Malaya Kuonamka and Bol’shaya Kuonamka rivers, northern Siberian Platform. The sampled succession is attributed to the Kuonamkites and lower Tomagnostus fissus–Paradoxides sacheri biozones of the Amgan Stage of Siberia, correlated with Series 3, Stage 5—lower Drumian Stage of the IUGS chronostratigraphical scheme for the Cambrian. This work complements descriptions of molluscs from the same samples published by Gubanov et al. (2004) with additional material. It contains forms in common with coeval faunas from Australia, China, Western Gondwana, Avalonia, Laurentia and Baltica, increasing potential for global biostratigraphic correlation and understanding of palaeogeographic connections.
|
|
| 4. |
- Skovsted, Christian B., et al.
(författare)
-
The problematic early Cambrian fossil Tumulduria incomperta represents the detached ventral interarea of a paterinid brachiopod.
- 2014
-
Ingår i: Acta Palaeontologica Polonica. - : Polska Akademia Nauk Instytut Paleobiologii (Institute of Paleobiology, Polish Academy of Sciences). - 0567-7920 .- 1732-2421. ; 59:2, s. 359-365
-
Tidskriftsartikel (refereegranskat)abstract
- The organophosphatic early Cambrian (Terreneuvian, Cambrian Stage 2) fossil Tumulduria incomperta has been problematic ever since its original description in 1969. Comparison of abundant specimens from the Lower Cambrian of Siberia with co-occurring brachiopod valves show that T. incomperta represents the central portion of the ventral interarea of a paterinid brachiopod similar to Cryptotreta neguertchenensis, and that the domed central portion of typical Tumulduria specimens represents the ridge-like pseudodeltidium of the interarea.
|
|
