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Ornithischians represent one of the three major radiations of dinosaurs. Throughout their evolutionary history, exceeding 134 million years, ornithischians evolved considerable diversity and morphological disparity, expressed especially through the cranial and osteodermal features of their most distinguishable representatives. The new study provides detailed nomenclatural revision of Ornithischia; it reviews the recent and historical use of 76 ornithischian clade names and establishes their phylogenetic definitions in accordance with the newly implemented International Code of Phylogenetic Nomenclature. Additionally, it introduces five new clade names: two for robustly supported clades of later-diverging hadrosaurids and ceratopsians, one uniting heterodontosaurids and genasaurs, and two for clades of nodosaurids. The study marks a key step towards a formal phylogenetic nomenclature of ornithischian dinosaurs.

Stable isotopes and predation marks shed new light on ammonoid habitat depth preferences

Ammonoids are extinct cephalopods with external shells which predominated in late Paleozoic and Mesozoic marine ecosystems. Habitat depth belongs to crucial parameters of their palaeoecology and is essential for understanding of ammonoid evolution and extinction. In order to reconstruct the habitat depth preferences of a Late Cretaceous scaphitid ammonoid from Poland, we applied a combination of stable isotope data from aptychi (calcitic elements of ammonoid lower jaw) and co-occurring foraminifera with an analysis of predation marks preserved on scaphitid specimens. Our results document a change in depth preferences of the scaphitid studied and suggest that ammonoids could have been more flexible in their depth related behaviour than anticipated.

Caption to illustration 1: The inferred shift in habitat depth preferences of Hoploscaphites constrictus along with shallowing of the sea at the Chełm site, Poland.
Caption to illustration 2: Positions of studied scaphitids and foraminifera in the water column of the shallowing Maastrichtian sea, based on mean palaeotemperatures gained from δ¹⁸O data from their fossils.
Work financed by the National Science Centre, Poland (Grant 2015/19/B/ST10/02033).

The results of new research on the giant siliceous basal spicule of the deep water sponge Monorhaphis chuni complemente and partially undermine previous observations and interpretations of the structure of these spicules. We identified and described four morphologically and structurally different layers/zones in its construction, explained their relations, and proposed their functional role. As a result, we proposed a new model of growth of the basal spicule of Monorhaphis chuni, substantially different from the model that is currently accepted. At the same time, we showed that the spicule of Monorhaphis cannot be a structural model for other spicules of hexactinellid sponges, because of its unique function which determines its structure..

The authors described coralliths (unattached coral colonies passively rotated by water movement) constructed by tabulate corals (an extinct group of Palaeozoic anthozoans). They have been found in the Devonian of Jaźwica, Kowala, and Miłoszów in the Holy Cross Mountains (Poland). The majority of coralliths are known from very shallow environments, whereas the material described here is from deeper settings, a rare situation among both Recent and fossil anthozoans. Analogous coralliths are reported from the Wistari Channel (Southern Great Barrier Reef, Australia).

Our combined morphological and taxonomic study has clarified the taxonomy and biogeography of Cassidulinidae benthic foraminifera in the area of the Scotia Sea and West Antarctica. It has also demonstrated how the complex interplay between environmental changes driven by the tectonics, climate and oceanography throughout the Cenozoic have influence the evolution and biogeography of this important foraminiferal family. Our data suggest, for example, that the Late Miocene to Pliocene warming (7 to 5 Ma) could have been a period during which biogeographic barriers across the Drake Passage were breached. Currently, Antarctica is experiencing similar climate change and, with the ongoing warming and the southward shift of marine currents, it is increasingly exposed to species invasion. Studies with a geological perspective, such as ours, can provide a broader context for how these environmental changes might refashion communities and biogeographic patterns in this critical region.

The object of the paper is to show how using modern technology (neutron tomography, fluorescence) allows extracting more information from Late Cretaceous plant fossils from Sweden compared to classical methods. Neutron tomography allowed preparing a 3-D visualisation of a fossil cone of the conifer Fricia nathorstii even if the major part of the cone is embedded in a large piece of hard sandstone. The newly described Meliolinites scanicus is the oldest known (and the first pre-Cenozoic) representative of the fungal order Meliolales (division Ascomycota, class Sordariomycetes).


A single image of the fossil cone extracted from the mobile 3-D visualisation (McLoughlin et al. 2021, fig. 4F). The full film.

Hydrothermal vent communities are associations of animals living in deep sea around sulphide chimneys. Their feeding strategies are based on chemosynthesis by microbial primary producers. Molecular phylogenetic divergence estimates indicate that many of the dominant vent taxa arose during the Cenozoic and Cretaceous; however, the fossil record of vent communities is exceptionally poor. One occurrence of such Cretaceous vent communities is known from an ophiolite in Cyprus. The Cyprus vent communities consist of worm tubes and numerous abyssochrysoid gastropods. All gastropods belong new species and one new genus Cyprioconcha is also described. The gastropod fauna contains the first representatives of Desbruyeresia, Hokkaidoconcha, Ascheria and Paskentana from hydrothermal vents, and also the youngest representative of the latter genus in any environment. This fauna is just one of two hydrothermal vent communities known containing other fossils than worm tubes in the Mesozoic times.

 
We have applied a novel approach that uses the Nd isotope composition (combined with rare earth element analyses and carbon and oxygen isotope measurements) to trace the former composition and migration pathways of the seeping fluids, which interacted with magmatic intrusions in organic rich sedimentary basins. These fluids and termogenic methane were responsible for the formation of authigenic seep carbonates at place of the fluid release at the sea bottom (so-called hydrocarbon seeps). We studied four mid-Cretaceous methane-seep deposits of the Basque-Cantabrian Basin and reconstructed their architecture and origin during the opening of the Bay of Biscay, a process that caused numerous intrusions of magmatic matter into thick sediment cover and formed several hydrocarbon seeps on the sea floor. This in turn allowed to develop rich chemosynthetic communities on a deep sea floor, which is usually poor in biological life.

Papiliograptus retimarginatus n. sp. is reported from the praedeubeli/deubeli Biozone, upper Homerian of the Bartoszyce IG-1 drill core of Poland, Baltica. It is the second species of the genus Papiliograptus Lenz & Kozłowska-Dawidziuk, 2002, belonging to the new retiolitid fauna of the recovery period after the lundgreni Extinction Event. Two characteristic features of the new retiolitid fauna are the development of a geniculum and singular or paired genicular structures. The new form has extremely wide, singular, reticulated genicular processes. It is suggested that these structures may have been an adaptation to prevent the planktonic colony from sinking in the quiet water.

The cross sections of tusks of all elephantimorph proboscideans show well-developed intersecting lines that form a conspicuous net-like structure termed the Schreger pattern. This trait is usually used to discriminate the tusks of elephants from those of mammoths. The new study provides the first assessment of the structure in a Neogene elephantimorph (Zygolophodon turicensis). The results indicate that the appearance of the inner structure of elephantimorph tusks is not associated with their shape and is probably not reflective of phylogenetic affinities. Still, its appearance remains useful for species identification.