Trace fossils are direct records of organism activity and are often abundant where body fossils are absent. Because the responsible tracemaker taxon often cannot be identified, trace fossils are named and classified in an independent parataxonomy called ichnotaxonomy. In vertebrate track ichnotaxonomy, only morphological features related to anatomy should be used, although behaviour, substrate properties and preservation also contribute to the shape of the track. Because of these multiple sources of variation, and the continuous rather than discrete nature of morphological features, ichnotaxonomy involves many subjective decisions that make rigorous quantitative analyses difficult.

Deep learning is a promising approach to the study of trace fossils and can be used to independently test ichnotaxonomy and its conclusions. Here I present a novel similarity learning approach where different models are trained on dinosaur tracks of the same morphotype and locality, modern bird tracks of known species, and/or synthetic data, with the aim of autonomously learning anatomically relevant features. New tracks can be plotted based on these features, revealing clusters that are conceptually similar to, but independent of, traditional ichnotaxa. The models suggest widespread oversplitting of dinosaur ichnotaxa and major inconsistencies in ichnotaxa definitions. They confirm that the dinosaurian ichnofauna of East Asia differs significantly from that of Europe and North America in the Lower Cretaceous. However, this difference does not appear to result from a geographic isolation of East Asia, as commonly assumed, but from the absence of an ecomorphotype in Europe and North America.

The Lower Devonian Hunsrück Slate exhibits a remarkable diversity of stalked crinoids, with approximately 61 species from 31 genera, representing all major Paleozoic taxa. Among them are forms with highly branched or unbranched arms, with or without pinnules. Prominent anal tubes or spines are present in many species. The calyces are typically small, and the stalks relatively slender and of varying lengths.

This study investigates the composition of this crinoid community, assessing whether the individuals coexisted in competition or if the community structure provides benefits to them. The latter is assumed, because the great variety of different forms, especially in the construction and branching of the arms, indicates that these crinoids possessed a wide food spectrum.

To test this hypothesis, the model of niche differentiation by Ausich (1980) is applied. The most important parameters are column length, which indicates the level of filtration above the seafloor, and filtration fan density, from which information about the food particle selection can be derived.

Fossil material from the Lehmann Collection at the University of Bonn was investigated. Radiographs were taken of the specimens to make all structures visible. Filtration fan densities were calculated for as many genera and species as possible. The results reveal clear differences between the taxa depending on their typical arm-branching patterns and presence or absence of pinnules. To advance this study, column lengths, and more parameters, such as arm width or ambulacral groove width, will be included in the niche differentiation analysis.

The Remigiusberg lagerstaette is an outstanding fossil site with abundant and diverse aquatic and terrestrial biota from the base of the Rotliegend in the Saar-Nahe Basin, SW Germany. It refers to an about 50 m thick succession of fluvio-lacustrine sediments of the Remigiusberg Formation (Gzhelian–Asselian, Pennsylvanian–Permian boundary) that is exposed by an active quarry near Kusel, Rhineland-Palatinate. Between 2022 and 2023, during long-term excavations by the Urweltmuseum GEOSKOP, a total of six chondrichthyan egg capsule remains were found in paleotropical delatic mudstones of a silting distributary channel.

The compressed specimens, showing transverse rhombic pattern, are composed of eight bands, were originally about 55 mm long and 12 mm wide at their widest points. According to size, shape and banding characteristics they belong to the fossil chondrichthyan egg capsule morphotype Palaeoxyris. According to the size measurements, size ratios, pedicle shape with transverse band pattern, and the number, width and breadth pattern of the bands these specimens can be assigned to Palaeoxyris carbonaria, SCHIMPER 1850 (synonym = P. appendiculata). This is the most common Paleozoic Palaleoxyris species, known so far from the Late Carboniferous (Westphalian–Stephanian) of paleoequatorial Europe and North America. The capsules are assigned to hybodontid sharks as the most probable producers. Thus they indirectly prove their existence in the Remigiusberg ecosystem, while skeletal remains or teeth are absolute rarities. In addition, these new findings double the number of known shark egg capsule fossils from the Saar-Nahe Basin and increase the number of herein known Palaleoxyris specimens to eight.

A series of excavations in the fossiliferous Blätterton Member of the Hornburg-Formation (Eisleben municipality, Saxony-Anhalt) was carried out between 2022 and 2024 by an international team of scientists, students and volunteers on an area of about 60 m² and covering a thickness of 4.5 meters. The fieldwork included a finestratigraphic documentation and yielded a vast amount of trace fossils – about 2000 specimens that were collected with exact assignment to lithological units; it expanded our knowledge about a crucial middle Permian ichnofauna. The Blätterton Member is dominated by silt- and claystones with some intercalation of laterally tapering bodies of standstone; it represents a succession that is typical for a playa lake environment. Given the muddy substrates that barely show signs of vegetation cover, footprints of larger herbivores are missing. In this aspect, the Blätterton ichnofauna differs from the somewhat younger Mammendorf assemblage, which is marked by tracks of larger tetrapods including herbivores, plant roots and burrows within predominantly sandy substrates that were deposited in a floodplain environment with steppe-like vegetation cover. In the Blätterton succession, however, relatively small tracks of the type Dromopus are abundant. They were produced by reptiles that likely fed on small arthropods, whose abundance and diversity is testified by mass occurrences of arthropod tracks in addition to aquatic insect larvae preserved as body impressions. A second tetrapod footprint type, tentatively referred to the ichnogenus Capitosauroides, is often associated with swimming traces made by the same producers indicating a lifestyle in proximity to small ponds and shallow water bodies.

The Middle Triassic Madygen Formation of southwestern Kyrgyzstan has yielded a remarkably diverse non-marine flora and fauna, but few ichnia. The overlying Rhaetian to Lower Jurassic alluvial-fluvial sediments contain a moderately diverse ichnofossil record in an ephemeral pond that is characterized by the dominance of two types of traces assigned to different arthropod groups. The first type is assigned to Kouphichnium pterodactyli (Winkler) Malz 1964 and linked to xiphosuran tracemakers. This type is well-documented in marine and freshwater environments from the Pennsylvanian onwards. The second type represents a new ichnospecies in the ichnogenus Heteropodichnus Walter 1983 which so far is only known from the Lower Permian of central Germany and northern Italy. Twelve recovered traces of this type show signficant along-track changes in morphology that reflect the transition from swimming to walking locomotion and the dragging or rhythmic beating of the telson. Morphological comparisons indicate Kazachartra as likely tracemakers, in this case specifically Almatium gusevi Chernyshev 1940 which is preserved as fragmentary exuviae in the same horizon and more completely and abundantly in the lacustrine sediments of the underlying Madygen Formation. This find represents the first walking traces of Kazachartra, an order so far only known from the Middle Triassic to Lower Jurassic of China and Central Asia. For the Permian Heteropodichnus a notostracan tracemaker can be suggested.

The trace fossil assemblage is completed by three further types of invertebrate traces, the fish swimming trace Undichna unisulcata Gibert 1999 and rare swimming traces of small tetrapods, Lunichnium rotterodium Walter 1983.

In the Southern Fergana Basin (southwestern Kyrgyzstan), strikingly red siliciclastic Cretaceous strata contrast sharply with surrounding lithologies, including older Triassic to Jurassic terrestrial, and younger Paleogene marine sediments within the Madygen Geopark area (Trubin et al., 2025). These Cretaceous deposits are associated with marginal marine settings, reflecting the marine transition of this complex and long-lived basin and its connection to the Peritethys (Getman et al., 2015).

These Cretaceous deposits lack body fossils and diagnostic sedimentary structures, hindering precise stratigraphic and paleoenvironmental interpretations. However, previously undescribed, exceptionally large ichnofossils, interpreted as burrows, offer rare insights into the Cretaceous of the Southern Fergana Basin. At three sites within the Madygen Geopark area, these structures are remarkable in size, density, and abundance, making them the only known evidence of macrobiotic activity from this time in the region. Despite the absence of body fossils, the burrows preserve sufficient morphological detail to suggest functional significance and potential tracemakers.

Their presence provides a valuable proxy for reconstructing local paleoenvironmental conditions during the Cretaceous and help interpret the extent of the shifting habitat. Moreover, the ichnofossils contribute to the broader understanding of large fossil burrows—an ichnological group often difficult to interpret due to the lack of modern analogs (Bromley et al., 1975). To support further analysis, the ichnofossils were documented using photogrammetry, and selected samples were examined via scanning electron microscopy (SEM). We suggest that the burrows have been produced by crustaceans, as they show strong similarity to the ichnogenus Camborygma (Hasiotis and Mitchell, 1993).