The fossiliferous strata of the Maastrichtian-aged Lance Formation in Wyoming, although broadly coeval with the better-known Hell Creek Formation, remain comparatively understudied. A detailed examination of a recently discovered Edmontosaurus annectens bonebed in the Lance Formation opened a new window into the last Cretaceous terrestrial ecosystems of present-day North America. This locality, which yielded a wealth of vertebrate remains but also macro-, meso-, and micro-palaeobotanical remains, now serves as a focal point for renewed paleoecological analysis of the Lance Formation. This study presents palynological and mesofossil data from sediments associated with the Edmontosaurus bonebed, with particular emphasis on a peculiar aquatic palynoflora. Notably high abundances of Azolla, an ecologically restricted aquatic fern, were recovered from multiple stratigraphic levels within and surrounding the bonebed horizon. The presence of Azolla megaspores, along with other freshwater-indicative palynomorphs such as Pediastrum, Botryococcus, and Gunnera, supports deposition in a freshwater floodplain setting with densely vegetated still-water bodies. Moreover, the concentration of Azolla and associated aquatic palynoflora in and around the bonebed horizon may offer new insights into the paleoecology of Edmontosaurus, including potential habitat preferences and feeding behaviors. Stratigraphic analysis of the floral assemblages below, within, and above the bonebed also suggests notable shifts in plant community composition over time, possibly linked to environmental changes in the latest Maastrichtian. This integrated paleoecological and palynological perspective enhances our understanding of the Lance Formation ecosystems, and underscores the importance of expanding research beyond more extensively studied rock units like the Hell Creek Formation.

Understanding the evolution of hybodontiforms, a diverse group of shark-like chondrichthyans ranging from the Late Devonian to the Late Cretaceous, is challenging, as most species are only known from their teeth. The genus Hybodus, established in the 19th century based on both dental and skeletal material from the Early Jurassic Lias Group (UK), has traditionally been regarded as one of the most speciose hybodontiforms, encompassing numerous nominal species from across the globe and spanning a stratigraphic range from the Early Permian to the Late Cretaceous. However, recent research has revealed that Hybodus, as historically defined, represents an unnatural assemblage of unrelated species characterized by unspecialized multicuspid teeth. Here, we present preliminary results from an ongoing study of abundant, largely undescribed fossil material referred to Hybodus, including articulated and whole-bodied specimens from some of the world's most productive Jurassic vertebrate sites. Our findings provide evidence for restricting Hybodus to its type species, H. reticulatus from the Early Jurassic Lias Group, and further bolster the hypothesis that Jurassic hybodontids were ecological generalists exhibiting an arrested evolutionary trajectory.

Solider beetles (Cantharidae) are relatively well known in the fossil record. Yet, not many fossil larvae of this group have been reported, despite the importance of this developmental phase. The larval phase of solider beetles is different from that of many other beetles, as in some species the early larvae (“pre-larvae”) differ from the later larvae. Therefore, the development of Cantharidae is possibly associated to hypermetamorphosis, a developmental pattern with early larvae being different in morphology and fulfilling different ecological functions than the later larvae. This type of differentiation between life stages has been thought to be a driving force in the evolution of beetles and other holometabolans (wasps, butterflies, etc.). Details of the evolution of this developmental pattern should therefore be informative for improving our understanding of evolutionary response to ecological selective pressures, and fossils could provide details for a well-resolved reconstruction. Unfortunately, so far only three fossil larvae of Cantharidae have been reported. Here we add 44 new specimens from Baltic and Kachin (Myanmar/Burma) amber and one new adult specimen in Baltic amber. Together with fossil and extant specimens from the literature we assembled a dataset of over 300 specimens, immatures and adults. Shape analyses and measurements were performed to investigate the change over time (evolution) of the change over time (ontogeny) on a quantitative level. Our results indicate a higher diversity of extant forms of Cantharidae, but also fossil morphologies could be recognised that are absent in the modern-day fauna, indicating certain losses of diversity.

Early Cretaceous terrestrial environments from inner paleo-Asia are poorly studied. Here we report new data from the Tevshiin Govi opencast lignite mine (TSG; Choir-Nyalga Basin; Aptian-Albian) from central Mongolia. The TSG contains a thick, lignite-rich succession assigned to the Khukhteeg Formation, which bears an exceptionally well-preserved fossil flora composed of various pine and redwood species as well as representatives of extinct seed plants. In order to reconstruct the conditions during peat formation, we used a combined approach including coal petrology and palynology, complemented by geochemical measurements (TOC, TS, δ¹³C_org) and brGDGT-based palaeothermometry. The investigated lignites show maceral compositions with high amounts of mineral detritus, which are dominated by huminite. Calculated maceral indices are indicating a topogenous mire setting. The variability of the GWI_AC indicates regular flooding of the peat. The stratigraphic trend in δ¹³C_org covaries with fusinite content, suggesting that short-lived events such as peat fires had a pronounced effect on the δ¹³C_org signature. Palynological observations show a strong dominance of pollen produced by Cupressaceae and Pinaceae, which is in accordance with the macrofossil findings. No angiosperm pollen was observed. The brGDGT data exhibit mean annual air temperatures of around 10°C (± 3°C), which is slightly cooler than previously thought. Overall, the TSG site reveals a paleoenvironment that was mainly forested with conifers with an understory of pteridophytes and strongly influenced by fluvial processes. During phases of peat formation, the environment was either covered by water or regularly flooded. Overall low inertinite contents reveal varying intensities of peat fires.

Both Lagerstätten were discovered many years ago and the two most unusual echinoderms in each were described: in Lagerstätte (‘archive’) I the armoured holothurian Prokrustia; in Lagerstätte (‘archive’) II the ophiocistioid Rotasaccus. Both Lagerstätten are burial (obrution) deposits. Due to the rarity of their very special echinoderms they represent important ‘natural archives’.

Natural archive I: In layers of the higher Talacasto Fm. (Lower Devonian) in the Precordillera (western Argentina) numerous obbrution Lagerstätten with diverse, very well preserved echinoderms were found, in one of them numerous specimens of the large Prokrustia which is completely skeletonised with large plates. Possibly, by new analytical methods the still unknown pharyngeal ring typical of holothurians will be detected. Special geopetal positions of Prokrustia will be will be discussed as unsuccessful attempts of escape lethal obrution.

Natural archive II: In finely laminated layers of the Wiedenest-Fm. (upper Middle Devonian of the Sauerland, eastern Rhenish Massif) there are several layers with some almost complete holothurians, but above all with thousands of jaw apparatuses (‘lanterns’ as in echinoids, but with typical, serially arranged angular teeth, "goniodonts") of Rotasaccus (a genus of the very rare echinoderm group Ophiocistioidea). As in some holothurians, its body wall of Rotasaccus is skeletonised with microscopic wheels, the wall of its very large podia with sieve plates. New ideas about the way of life of Rotasaccus are being discussed. Further important structures could possibly be visualised by using newer analytical methods on skeletons that partly are still calcitic.

Investigating ecosystems of the past is understandably different from studying modern-day ones. Many properties of now-gone ecosystems can only be indirectly inferred, where in modern ecosystems observations or measurements would provide a direct access (though being less easy for hardly accessible ecosystems, e.g. in the deep sea). Indirect access to fossil ecosystems is provided by the life habits of the extinct organisms that have been living in these ecosystems, such as aspects of their feeding behaviour or their life history strategies. The life habits of an extinct organism can finally be inferred by reconstructing the functional morphology, based on the morphological details observed in fossils in comparison to modern counterparts. Such investigations gain precision when exceptionally well-preserved fossils are studied, like those of the Lower Devonian Rhynie and Windyfield chert. These deposits preserve a diverse range of representatives of Euarthropoda, partly with terrestrial, partly with aquatic, non-marine lifestyle. Among aquatic forms, especially crustacean fossils have become known, such as the famous Lepidocaris rhyniensis. The preservation of the crustacean fossils provides details of their feeding apparatus down to the sub-micron-range, including different types of setal structures. Based on these observations, we can infer that crustaceans in the Rhynie and Windyfield chert performed a variety of different life habits. The biota thus contained a rich and differentiated non-marine aquatic fauna already 400 million years ago.