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An isolated exopod in uncompressed three−dimensional “Orsten”−type preservation from the Cambrian of Australia represents a new species of Marrellomorpha, Austromarrella klausmuelleri gen. et sp. nov. The exopod is composed of at least 17 annuli. Each of the proximal annuli carries a pair of lamellae: one lamella on the lateral side and one on the median side. The distal annuli bear stout spines in the corresponding position instead of lamellae, most likely representing early ontogenetic equivalents of the lamellae. The new find extends the geographical range of the taxon Marrellomorpha. Additionally, it offers a partial view into marrellomorph ontogeny. The occurrence of a marrellomorph fragment in “Orsten”−type preservation provides new palaeo−ecological insights into the possible connections between the “Orsten” biotas and other fossil Lagerstätten. Finding such connections is necessary for understanding the complex ecosystems of early Palaeozoic times.
Secondarily phosphatised olenid trilobites from organic−rich limestones (orsten) in the Furongian (Upper Cambrian) of Västergötland, south−central Sweden, are described and illustrated. All trilobites originate from the Peltura scarabaeoides Zone and were collected on the western slope of Kinnekulle. Only the dorsal exoskeletons have become secondarily phosphatised, and the ventral appendages are not preserved. Yet the material is otherwise remarkably well preserved and reveals the morphology of the olenid trilobites in greater detail than hitherto known. Species belonging to the genera Ctenopyge, Sphaerophthalmus, Parabolina, and Peltura are identified, and several juvenile specimens are present in the material. The material is disarticulated and fragmentary, and it has only been possible to identify a few specimens to species level. In addition to chaetognaths and conodonts, the trilobites are associated with pelmatozoan columnals, a possible camaroid, and fossils of uncertain affinities. These fossils, along with a probable conulariid fragment from the Peltura minor Zone, are also described and discussed. The presence of a benthic fauna of pelmatozoans, and possible conulariids and camaroids, indicates that at least parts of the Peltura zones were deposited during dysoxic rather than anoxic periods. Moreover, the sea floor must have been firm enough to allow colonisation by sessile organisms.
Colonies of boring ctenostome bryozoans and microborings of “fungi” that occur in the Early Devonian (Lochkovian, ~416 Ma) of Podolia, western Ukraine, have soft−tissue preserved by phosphatization. These comprise exceptional three−dimensional body walls of feeding zooids with probable parietal muscles inserted on the cystid wall, and setigerous collars twisted within the vestibulum. The presence of collars in this Early Devonian ctenostomes proves the existence of this feature for more than 416 Ma of ctenostome evolution. Phosphatized remains of the zooid walls are interpreted as relicts of the originally chitinous cystid walls. This is the first record of soft−tissue fossilization in a boring bryozoan. The presence of cavities (specialized heterozooids), empty or filled with laminated calcium phosphate, is also documented in bryozoans for the first time. These cavities are interpreted as “store−rooms” in which the bryozoans accumulated nutrients. The new taxon, Podoliapora doroshevi gen. et sp. nov. is described. In additional, phosphatised fungi−like endoliths co−occur with bryozoans.
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