SSP4.1

Only a small percentage of all life that ever existed is preserved in the rock record. Some animals and environments are particularly unlikely to fossilize—e.g., soft-bodied organisms and high-energy habitats—biasing fossil deposit faunal composition and resultant inferences about macroevolution and macroecology. To estimate the extent of information loss caused by non-preservation we compared diversity data in over 20,000 modern marine assemblages (Ocean Biogeographic Information System; OBIS) with fossil occurrence data (Paleobiology Database; PBDB) to yield a global assessment of assemblage-level fossilization potential as it varies across depth, habitats, and environments. We used two different metrics, taxon fossilization potential and within-environment fossilization potential, to assess the proportion of taxa in a modern community with PBDB occurrences or with PBDB occurrences in the same environment, respectively. Averaged across all 20,000+ marine assemblages, mean taxon fossilization potential is 38% and mean values vary between environments: from 34% in shallow and deep water, 44% in coral reefs, 51% on seamounts, to 15% in pelagic assemblages. Mean within-environment fossilization potential, in contrast, does not exceed 32% (in shallow water), a lower value than that obtained in other studies, and may approach zero (on seamounts and pelagic environments). Differences between these two metrics indicate the large control of environment on fossilization potential. Our results provide a means to include and compare palaeoecological dynamics across a broader range of settings in the fossil record, while accounting for differences in fossilization potential among environments.

How to cite: Shaw, J., Briggs, D., and Hull, P.: Insights from big data into the fossilization potential of marine communities, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-578, https://doi.org/10.5194/egusphere-egu21-578, 2021.

The search for fossil biomolecules often requires combining many techniques to properly characterize their chemical composition. Recently, it was suggested in 6 papers that conventional Raman spectroscopy (i.e., equipped with a 532 nm laser as the excitation source under continuous illumination) can be used alone to identify diverse remnants or derivatives of biomolecules in animal fossils, with important implications for both evolutionary events and fossilization processes. Unfortunately, the reported claims are not supported by the spectroscopy data provided, which actually result from instrumental artefacts and data processing. Here, we outline the limitations of Raman spectroscopy with respect to the identification of biomolecules in fossil materials, and then describe in detail the origin of the misinterpreted signal. Conventional Raman spectroscopy alone cannot be used to identify fossil biomolecules. Instead, non-conventional Raman spectroscopy, mass spectrometry and infrared and X-ray absorption spectroscopy techniques, are successfully used by paleontologists to identify fossil biomolecules that help understanding both the history of life and the mechanisms of fossilization.

How to cite: Alleon, J. and Gueriau, P.: How not to study fossil biomolecules, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14476, https://doi.org/10.5194/egusphere-egu21-14476, 2021.

Reconstructing ancient community assemblages and the ecological relationships between extinct organisms is a major challenge due to the shortcomings of the fossil record. The uncertainty surrounding the life habits of extinct organisms has proven to be a major hurdle for our understanding of the evolution of ecosystem structure through time. One such period of interest is the Mesozoic Marine Revolution (MMR), where escalation is proposed to have driven major changes in marine food webs which led to the establishment of modern marine ecosystem structure. The timing of the MMR is heavily debated, with proposals ranging from an Early Triassic to a Cretaceous/Cenozoic origin. We present a meta-community analysis of the Peterborough Member (Callovian, UK) with the aim of constraining the timing of the MMR. We assigned traits (i.e. body size, feeding mode, motility, tiering) that define interactions in modern systems to all fossil organisms and used rules based on foraging behaviour to model meta-community food web structure. We then compare the modelled Peterborough Member food webs with those of well-constrained modern marine ecosystems to shed light on whether modern marine ecosystem was established by the end of the Middle Jurassic.

How to cite: Pavey, T., Shaw, J. O., Beckerman, A. P., and Dunhill, A. M.: Modelling marine ecosystem structure from palaeoecological trait data in the Middle Jurassic Peterborough Member (UK), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12201, https://doi.org/10.5194/egusphere-egu21-12201, 2021.

The most numerous and diversified Middle Miocene gastropod collection from Northern Croatia, housed at the Croatian Natural History Museum (CNHM), comes from the Zaprešić Brijeg locality near Zagreb. The gastropod-bearing horizon of the Middle Miocene (Langhian, Badenian) age is today no longer visible on the surface, not only in this area but also in other parts of Northern Croatia. The description of the Zaprešić Brijeg locality and fossil collecting methods can be found in the museum archives and published papers. According to these data, gastropods were collected from "sandstones" during the first half of the 20th century (Gorjanović-Kramberger 1894; Šuklje 1929). Among more than 11000 stored gastropod shells from this locality 45 belong to marine, 2 to marine/brackish and 2 to brackish gastropod families. Some families comprise only one or a few representatives, while other are much more common, such as Potamididae (4459 shells), Nassariidae (2428 shells), Clavatulidae (1813 shells), Turritellidae (1253 shells), and Cerithiidae (508 shells). In previously published papers on the Zaprešić Brijeg gastropod fauna (e.g., Gorjanović-Kramberger 1894; Šuklje 1929; Pavlovsky 1957, 1960) the focus was mostly on the taxonomical aspect. While examining the collection, we observed numerous drilling predation marks in a shape of drill holes on marine gastropod shells and provided numerical analysis of predation marks on some common families (Bošnjak et al., submitted). The aim of this study is to continue the division of gastropod families by their palaeoecology (infauna, epifauna) and feeding type (carnivores, suspension feeders, detritivores and grazers), in order to better understand the palaeoenvironmental conditions during the Middle Miocene (Badenian, Langhian) in this area. Non-marine gastropod taxa indicate the freshwater influx and the vicinity of hinterland. Such a rich museum collection can provide further insight into the palaeoecology of the southwestern margin of the Central Paratethys, even though the original fossiliferous horizon is no more available in the field.

References:

Bošnjak, M., Sremac, J., Karaica, B., Mađerić, I. & Jarić, A. (submitted): Mollusk mortal kombat: drilled Middle Miocene gastropods from the south-western margin of the Central Paratethys, Croatia.

Gorjanović-Kramberger, D. (1894): Geology of Samoborsko gorje Mt. and Žumberak Mt. Rad Yugoslav Academy of Sciences and Arts, 120, 1–82. (in Croatian)

Šuklje, F. (1929): Die Mediterranfauna des Zaprešić Brijeg in der Samoborska gora in Kroatien. Bulletin de l'institut geologique de Zagreb, III, 1–52. (in Croatian with German summary)

Pavlovsky, M. (1957): Ein Beitrag zur Kenntnis Miozäner Gastropoden von Zaprešić-Brijeg bei Samobor. Geološki vjesnik, 10 (1956), 51–56. (in Croatian with German summary)

Pavlovsky, M. (1960): Neue Elemente der Fauna von Zaprešić-Brijeg bei Samobor. Geološki vjesnik, XIII (1959), 213–216. (in Croatian with German summary)

How to cite: Bošnjak, M. and Sremac, J.: Middle Miocene gastropods from the southwestern margin of the Central Paratethys, Croatia: Museum collection's insight, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12861, https://doi.org/10.5194/egusphere-egu21-12861, 2021.

Marine biodiversity is controlled by depth, climate, and ocean connectivity. The early Miocene marine fauna of the proto-Mediterranean is particularly important because this is the time when the connection with the Indo-Pacific realm was disrupted , and the marine biodiversity hotspot shifted toward the southeast, marking the onset of a subtropical gradually oligotrophic regime in the proto-Mediterranean Sea. The Mesohellenic basin in particular, at the northern part of the proto-Mediterranean, was located at the intersection with the Paratethys epicontinental sea. Therefore, the fauna in this area was influenced by the conditions in both basins. In this study, we present the mollusc and fish fauna of the Aquitanian Mesohellenic basin and discuss its paleobiogeographic and evolutionary implications. Comparisons and assessment of faunal similarities of the proto-Mediterranean and adjacent provinces is carried out using ordination methods to treat available data from relevant publications and the Paleobiology Database (PBDB).

This research has been co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Programme “Human Resources Development, Education and Lifelong Learning 2014–2020” in the context of the project “Mollusc and fish migrations in the dynamic environments of the early to middle Miocene in the Mediterranean” (MIS 5047960). 

How to cite: Koskeridou, E., Agiadi, K., and Thivaiou, D.: Early Miocene mollusc and fish biodiversity at the Proto-Mediterranean–Paratethys marine corridor, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2593, https://doi.org/10.5194/egusphere-egu21-2593, 2021.

Conidae is a very diverse family of carnivorous gastropods with over 900 extant species, that present beautiful colour patterns. These patterns can be useful to biologists for the systematic approach, but lack usually in fossil samples, when they are only observed in natural light. Therefore conid species were difficult to distinguish.
To resolve that problem, we use ultraviolet light to reveal the colour patterns of these fossil shells. Here, we present the second part of a PhD project that attempts to clarify the diversity of the Tortonian Conidae from Crete, Greece. The first part of this project already revealed eleven species of Conilithes Swainson, 1840 and Conus (Kalloconus) da Motta, 1991 five of them being new. In the second part, we found seventeen species, of those seven are considered as new. Among them, ten are attributed to Conus (Lautoconus) Monterosato, 1923 and three in Conus (Plagioconus) Tucker & Tenorio, 2009. Finally, a group of four species with special characteristics is discussed and is proposed as a new subgenus.
This project will greatly enrich the knowledge of the family in  the Tortonian of Eastern Proto-Mediterranean. The results will be compared to similar faunas from the Middle-Miocene to Pliocene of Europe, in order to assess the biogeography of this family.

How to cite: Psarras, C., Koskeridou, E., and Merle, D.: Tortonian Conidae of Crete. New species revealed under UV light. Subgenera Conus (Lautoconus), Conus (Plagioconus) and a possible new subgenus., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2543, https://doi.org/10.5194/egusphere-egu21-2543, 2021.

Grotta del Cavallo, a well-known Paleolithic site in Southern Italy (Nardò, Apulia), preserves one of the most important Italian Middle Paleolithic sequences. Its stratigraphic succession records the presence of Neanderthals from Marine Isotope Stage (MIS) 7 to 3, providing substantial insights on their lifeways. Here we present the taxonomic and taphonomic analysis of the bird assemblages associated to Neanderthal occupation. The rich avifaunal assemblages allowed paleoenvironmental and paleoclimatic reconstructions, noticeably improving the reconstruction of the landscape that was exploited by Neanderthals throughout the last glacial-interglacial cycles. Based on the bird taxa identified in the assemblages, Grotta del Cavallo was mainly surrounded by extensive grasslands and shrublands, with scattered open woodland and rocky outcrops, during MIS 7, 6 and 3. The coastal plain, that is currently underwater due to Holocene relative sea-level rise, hosted wetlands in the cooler periods, when it was exposed. In the cool-temperate climatic phase attributed to MIS 3, bird taxa of water and wet environments proportionally increased, as well as coverage-based rarefied richness values. This is possibly due to the expansion of wetland areas, linked to more humid conditions, or to the shorter distance of the wetland settings from the cave, compared to MIS 6 (glacial period). A consequent higher heterogeneity of the landscape is retained to drive the increased richness. The sampling effort allowed to retrieve bird taxa that provided significant paleoclimatic insights, such as Branta leucopsis, an arctic breeder, and other species currently spread at higher altitudes, that reinforce previously obtained geochemical derived inference of climate conditions cooler than the present ones. The bird assemblages also provided the first occurrence ever of Larus genei, the first Italian occurrence of Emberiza calandra, the oldest Italian occurrence of Podiceps nigricollis, and the occurrence of Sylvia communis (a species rarely retrieved in the fossil record). Ordination analyses of the bird dataset detected the drivers of taphonomic degradation and the agents responsible for the accumulation of the avian bones: modifications are mainly due to physical sin- and post-depositional processes, whereas accumulation is mainly attributed to short-range physical processes of sediment accumulation, feeding activities of nocturnal raptors and, to a lesser extent, human activities. In detail, traces found on a few bones suggest that Neanderthals introduced some of the birds in the cave with alimentary purposes, providing the earliest Italian evidence of bird exploitation ever.

How to cite: Carrera, L., Scarponi, D., Martini, F., Sarti, L., and Pavia, M.: Neanderthal landscapes and subsistence strategies during late Quaternary glacial-interglacial periods: insights from the avian assemblages of Grotta del Cavallo (Apulia, Southern Italy), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10115, https://doi.org/10.5194/egusphere-egu21-10115, 2021.