Ferns were among the first broadleaved plants in the fossil record. We assessed fern-arthropod interactions in modern ferns (Monilophyta) as a model for comparison with damage on ferns in the fossil record. We found that the functional feeding groups of margin feeding, hole feeding, surface feeding, piercing and sucking, oviposition, mining, and galling was present on 13 species of ferns at elevations ranging from 750 to 900 meters along mountain slopes of the Brazilian Atlantic Rainforest. We recognized 17 damage types (DTs), including one new DT, and provide implications for interpreting damage on leaves in the fossil record. Nine fossil DTs with modern analogues were found on ferns. Evaluation of damage on modern ferns demonstrate that the variation in the abundance and damage signatures of external feeding, piercing and sucking, galling, and mining enhances understanding of damage patterns on fossil leaves. The taphonomic implications to fossil plant-insect interactions are provided based on the sampling of modern arthropod damage and the preservation biases on ferns. Arthropod remains that are poorly attached to ferns, such as silk webs, eggs, and spider egg sacs, as well as insect exuviae, pupae, and body parts, might provide an important feature for arthropod preservation associated with fern leaves in the plant fossil record. This integrative method demonstrates that DT signatures on modern ferns indicate that ferns are an important host plant for herbivorous arthropods. Consequently, the same importance of ferns as host plants of arthropod herbivores likely was present in deep time.

A phoronid-like hederelloid that formed a symbiotic association with the rugosan coral Entelophyllum has been found in the Pridoli Series of Estonia. The skeletons of the hederelloid and rugosan are partially intergrown. The hederelloid apertures are located at the margin of the rugosan calice. The hederelloid lophophore was likely placed between the tentacles of the coral polyp, indicating a positive or at least a neutral co-existence. In extant corals, polyps can be retracted into the calice either during the day or night. If the rugose coral was similar to modern corals in this respect, it may have helped in the co-existence with the hederelloid and allowed feeding at different times. It is possible that the hederelloid soft tissues were protected against smaller predators by the stinging cells of the rugosan tentacles. The history of symbiosis in hederelloids is similar to that of tentaculitoids, in which symbiotic relationships also appeared early in their evolution. To date, Entelophyllum is the only colonial rugosan known to have formed symbiotic associations during the Silurian.

The fossil record spanning the latest Ediacaran and earliest Cambrian is characterized by the proliferation of small, mineralized organisms that comprise the well-known and abundant deposits of small shelly fauna. Many of these fossils are tubular or conical forms with simple morphologies, and thus present difficulties in both taxonomic and phylogenetic interpretation. This study investigates a community of poorly preserved shelly tubicolous organisms in two fossiliferous slabs from the Soltanieh Formation, northern Iran. Analysis of the taphonomy of this fossil assemblage using thin-section petrography, scanning electron microscopy, and energy dispersive X-ray spectroscopy, suggests a two-part preservational pathway involving phosphatic replacement of the shell wall and separate, diagenetically later infillings of void space with either phosphatic or calcium carbonate cements. In parallel with the taphonomic study and given the difficulty in assigning the observed fossils taxonomically, morphometrics of the shelly organisms were also explored. Biometric measurements were collected from high-resolution photomosaic images of the slab-surface fossils, as well as from a three-dimensional volume of the interior of one of the slabs generated via X-ray tomographic microscopy. Statistical analysis of these measurements revealed a separation of the fossils into two morphologically distinct groups of conical and tubular forms, which we characterize respectively as ‘conomorphs’ and ‘tubomorphs’. Based on previous studies of fossils from the Soltanieh Fm., we can offer tentative generic-level assignment to Anabarites and Cambrotubulus to at least some of the fossils present, though these are dependent on views in thin section rather than morphometric distinction. Cumulatively, we provide a conservative, taxonomy-free approach for detailing the morphology and preservation of poorly preserved fossils from the Ediacaran–Cambrian transition.

Taphonomic analysis is a useful tool to assess the intensity of alteration of skeletal remains and to help characterize depositional conditions as well as completeness and resolution of fossil assemblages. We herein introduce TAPHOGRAPH, an Excel spreadsheet script (a R code is also available), for the production of taphonomic diagrams to characterize the taphonomy of skeletal remains. The graphical representation depicts four taphonomic factors (fragmentation, abrasion, bioerosion, and encrustation) as a cumulative curve that allows visualization and comparison of the degree and variability of taphonomic alteration for different hard part types from one or more samples in a single diagram. The TAPHOGRAPH methodology is highly flexible, and can be used to assess the relative influence of mechanical versus biological (versus chemical) taphonomic alteration. The TAPHOGRAPH approach can guide inferences about hydraulic regimes, residence time at the seafloor, and intensity of different taphonomic processes.

Pleistocene large carnivores from the Pampean Region have been studied almost always based on bone remains. Here we report the first coprolite of a large carnivore from the Late Pleistocene of the Pampean Region, Argentina. The coprolite was found associated with megafauna bone remains and it shows the typical shape and size of a carnivorous mammal, with a length of 240 mm and a maximum diameter of 39.59 mm. The coprolite contains two bones of the autopodium of an artiodactyl, and numerous dermal ossicles of giant terrestrial sloths. The coprolite's composition, size, and shape allow us to discard ursids, canids, and small felids. Ursid and canid feces contain abundant plant remains, which are absent in the coprolite described here. Feces of extant felids are smaller than the coprolite here as they do not exceed 130 mm in length and 30 mm in diameter. Based on size, shape, and bone inclusions, the discovered coprolite may be attributed to the Machairodontinae saber-toothed felid Smilodon. If correctly identified, this coprolite sheds light on predatory habits of Smilodon.