• We conclude, that the late Oligocene fauna from the Neža locality inhabited a shallow marine, near shore facies. High influx of organic detritus based on rich plant remains, but calm environment without strong currents that would significantly disturb post-mortem taphocoenosis. The shallow depth is supported by the present ichthyofauna, which apart from predominant specimens of clupeid fish, consists of sygnathid and centriscid species having a bathymetrical preference for shallow near-shore bottoms with seagrass meadows (Ahnesjö and Craig, 2011; Nelson et al., 2016). Such interpretation of palaeoenvironment fits well with the presence of hymenosomatid crabs, as most extant species inhabit shallow water environment.

• The Cenozoic sequence starts with the upper Oligocene Trbovlje Formation, which discontinuously overlies Triassic rocks. Basal horizons comprise conglomerates and sandstones, grading upwards into greyish coloured marls and marly limestones. An economically important coal seam occurs within the marly beds (Bechtel et al., 2004) and palynological analysis has identified species of Cupressaceae within the main coal seam (Bruch,1998; Križnar, 2000) with a likely transition to reed marshes in the upper part. The marls and marly limestones above the coal layer are fossiliferous, yielding a diverse fish fauna (Bittner, 1884; Križnar, 2015; Križnar and Lorencon, 2021), crustaceans (Buckeridge et al., 2020; Kovalchuk et al., 2023; herein), molluscs (Bittner, 1884), as well as abundant plant remains (Lorencon, 2019).

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•Four mass accumulations of fish remains (probably a mass mortality event) were identified at different levels within the section, as well as two beds from which the presented decapod specimens originated