Skeletons of Norian corals from the aragonite Konservat-Lagerstätte in Alakir Çay, Turkey are commonly considered to be exceptionally preserved. However, one example of Pachysolenia cylindrica shows that although aragonite is the dominant mineral phase (about 86.2%), the distribution of microscale diagenetic features in the skeleton complicate its usage as a paleoenvironmental archive. We used a density separation technique to isolate aragonite-enriched powders of skeletal material, which compared to powders of bulk skeleton (∼8.3% more calcite than aragonite-enriched powders), exhibit higher Sr/Ca (by an average of 0.27 mmol/mol), lower Mg/Ca (by an average of 1.34 mmol/mol), and lower δ¹⁸O (by an average of 0.28‰). In addition, paleo-sea surface temperatures calculated using values from bulk measurements are 1.1–3.4 °C colder (3.3–3.4 °C for Sr/Ca and 1.1–2.0 °C for δ¹⁸O) than temperatures calculated from the density-separated, aragonite-enriched powders. These data suggest that the presence of about 13.8% of secondary calcite can influence the robustness of geochemical proxies and that density separation is an effective tool for recovering the original geochemical signal from diagenetically altered samples.

The lower part of the Wilkes Formation (uppermost Miocene) exposed along lower Salmon Creek in Lewis County, Washington, consists of volcaniclastic-dominated deposits. The section contains a stacked series of volcanic runout mudstone beds overlain by more distal runout mudstone beds, interlayered with carbonaceous mudstone and lignite-woodmat beds that are in turn overlain by poorly sorted volcaniclastic mudstone and sandstone. The section contains a record of forested lowlands inundated by volcanic mudflows, followed sequentially by rising water level associated first with deposition in swamp and lake-margin environments and later by deposition in a lake environment. The lakebed sediments contain common siderite concretions of varied form, including coprolite-shaped concretions that are confined to lakebed deposits. The volcanic mudflow deposits are similar to deposits of mudflows-lahars of modern Cascades stratovolcanoes. Two volcanic ash fall beds contained within lignites in the middle of the section yield ⁴⁰Ar/³⁹Ar radiometric dates. After separation of plagioclase crystals into populations of cloudy appearance (inherited) and clear appearance (newly crystallized), a best age of 6.13 ± 0.08 Ma is determined for the lower ash bed. Sediments contain abundant and well-preserved pollen and spores that document botanical changes progressing from Nyssa-dominated to Taxodium-dominated to mixed forest assemblages. The existence of Taxodium and other warm-climate taxa in the Wilkes Formation indicates the presence of a wet, warm temperate climate in the Puget lowlands during the latest Miocene.

Thousands of lingulid brachiopods were found clustered beneath hundreds of individual valves of the strophomenid brachiopod Rafinesquina in the Upper Ordovician of Ohio. This association suggested a relationship between the two brachiopods, but the nature of this relationship was unclear. We utilized serial thin sectioning to examine these brachiopods and to determine the origin of the bed in which they were found. Sedimentary structures, mixed taphonomies, and stratigraphic and paleogeographic setting suggest that the lingulids occupied a hiatal concentration that had previously been reworked, but not significantly transported, by tropical storms. The final burial event was a storm that exhumed living lingulids along with disarticulated Rafinesquina shells from the same sediments. Neither living nor dead shells were transported, but were reworked locally, then reburied together. The lingulids then burrowed upward to escape, but most were trapped by the concave-downward Rafinesquina shells that had been redeposited above them. This finding offers the first documented example of negative ecosystem engineering and taphonomic feedback in the fossil record, as well as the oldest documented lingulid escape traces. It also suggests that taphonomic feedback can be subdivided into live-dead interactions that occur under normal background depositional conditions and those that occur during periodic short-lived sediment-reworking events, such as storms and tsunamis.

We compared sponge spicules occurring in surface sediments with those of a living sponge community in a shallow-water reef environment of Bocas del Toro archipelago, Panama, with the goal of evaluating how faithfully spicular analysis reflects the living sponge community. Most megasclere morphotypes present in living species are also found in sediment. On the contrary, microscleres are underrepresented in the sediment samples. Apart from spicules that belong to taxa that live at present in the area, some morphotypes found in the sediment have no equivalent in the known living community. Forty species of living sponges have been recognized in the study area, but 9 (22%) do not produce mineral spicules and, therefore, are not recorded in sediment. Sediment spicules suggest the presence of 22 taxa, thus, loss of information in the process of fossilization is average to considerable, with most living taxa identified also with sediment spicules. Some morphotypes are abundant in sediment (i.e., ovoid spicules) even though the sponges bearing them are rare or absent, thus suggesting either preferential preservation or recent disappearances of taxa producing them. As transport did not play a significant role during the fossilization process, spicular analysis—when all limitations and constraints are considered—is a tenable tool in the reconstruction of former sponge communities, but not of the share of various sponge species. Spicular analysis may also help reveal the presence of cryptic and excavating species that are often overlooked in traditional studies.

In the western North Atlantic and Gulf of Mexico, isotope sclerochronology and field studies of the hard clams, Mercenaria mercenaria and M. campechiensis, collected across a latitudinal gradient show patterns in the seasonal timing of slow versus fast shell incremental growth. It is unknown, however, if similar patterns exist in the eastern North Atlantic. The European limpet, Patella vulgata, is abundant in rocky shore communities and archaeological deposits along the eastern North Atlantic. As such, it is a potentially valuable archive for paleoclimate and archaeological research. We used isotope sclerochronology to identify the seasonal timing of annual growth line formation in shells from the cold- and warm-temperate zones and at the boundary between these zones. Four shells from the cold-temperate zone (United Kingdom and Norway), five shells from the warm-temperate zone (Spain), and six shells from the boundary (near the English Channel) were analyzed. The isotopic records represent between two and eight years of growth. Cold-temperate shells formed annual lines in winter, and warm-temperate shells produced annual lines in summer. A mixed pattern was found at the boundary. This pattern in the seasonal timing of slowed growth across a latitudinal gradient is similar to that shown in studies of Mercenaria in the western North Atlantic. Thermal tolerance is the most likely mechanism for the observed changes in the timing of annual growth line formation with latitude.

Several methods have been developed to standardize frequencies of failed shell-crushing predation preserved as repair scars on the shells of mollusks to account for factors known to influence the accumulation of repairs. Our understanding of the potential biases inherent in repair frequency analyses, however, remains incomplete due to a lack of systematic comparison and evaluation of available methods. Here we examine the effects of three different types of data standardization—body size, shape, and exposure time to enemies—on the calculation of repair frequency for a hypothetical data set of 1,000 specimens of a marine gastropod species that varies across its geographic range in morphology and life history. We based assumptions for the ecological parameters (e.g., variation in growth rates and morphology) of our model system on literature reports of living marine gastropod species. We initially structured our unstandardized data set to show equivalent repair frequencies throughout the species' geographic range. Subsequent standardization of this data set by size, shape, and exposure time revealed a progressively stronger spatial pattern, with higher repair frequencies to the south. This finding suggests that the comparison of unstandardized data may be misleading. The continued use and development of standardization methods should both enhance our ability to detect ecologically meaningful signals, and facilitate unbiased tests of hypotheses concerned with the importance of shell-crushing predators in ecology and evolution.

Domichnial and domichnial-fodinichnial burrows of ground beetles (Coleoptera: Carabidae) belonging to the genera Bembidion and Harpalus, respectively, and pupichnial burrows of Melolontha (Coleoptera: Melolonthinae: Scarabaeidae) occur in sandy to muddy nonvegetated or partly vegetated substrate on a well-drained, rarely flooded alluvial plain of the Dunajec River (Sandomierz Basin, southern Poland). The burrows show a characteristic morphology, with a straight or curved shaft and a horizontal to oblique terminal chamber. The Bembidion and Harpalus burrows are similar and show a wide range of morphological variability, including forms in which the terminal chamber is poorly outlined. Their inclination changes from oblique (most common) on horizontal surfaces to horizontal in steep scarps. The Melolontha burrows are larger, with vertical shafts and strongly elongated chambers. The Melolontha and Harpalus burrows occupy vegetated areas in more distal areas, the Bembidion stephensii burrows occur in the intermediate environments with respect to the river channel, while the B. quadrimaculatum is present in more proximal, nonvegetated or poorly vegetated flood plain and scarps of the river channel. Comparison with the trace fossil Macanopsis indicates that ground beetles and scarab beetles should be included as possible tracemakers (as well as spiders, wasps, or millipedes as presented in the literature) of Macanopsis in continental settings. These traces occur in environmental conditions typical of the Coprinisphaera ichnofacies, mainly in soils above the groundwater table.