A new vertebrate track site in the Lower Permian Wellington Formation in north-central Oklahoma is described wherein tracks are found on a single dolomite bedding plane that can be traced along more than 1.6 km of disconnected outcrops. In excess of 1,400 tetrapod tracks, including 16 trackways, are documented. Because of extramorphological factors, it was not possible to identify ichnogenera with certainty, but five distinct morphotypes are described, and their possible affinities with known Permian ichnotaxa are given. All tracks appear to be undertracks of vertebrates walking on all fours, wading on their back legs, or swimming. It is proposed that one of these morphotypes was made by a web-footed trackmaker. Aspects of the ichnofauna and lithologic features suggest a lacustrine paleoenvironment for the track site, and could warrant further subdivision of the redbed ichnofacies.

With the exception of the Neogene, it is difficult in much of the fossil record to measure range offset; that is, the difference in age between the first or last occurrence of a species in a local section and its time of origination or extinction within the sedimentary basin. A coupled simulation that incorporates a model of sedimentary basin fill, a random-branching model of evolution, and a model of the ecological characteristics of species is used here to explore stratigraphic and ecologic controls on range offset. Median values of range offset in much of the fossil record are predicted to range from several hundred k.y. to a few m.y., for a wide variety of stratigraphic architectures and species ecologies. Higher than average values of range offset are favored by unconformities of long duration, rapid facies changes of large magnitude, persistent monotonic trends in facies change, increased facies specificity of species, and decreased species abundance. These model predictions can be used as a guide for interpreting field data on first and last occurrences, such as evaluating zones of likely high or low biostratigraphic precision. Similarly, these results can be used to evaluate the support for paleobiological interpretations of local radiations, migrations, and extinction episodes.

Predation was examined using experimentally deployed shells along two transects representing shallow shelf (15 to 30 m), outer shelf (70 m) and bathyal (100 m to 267 m) habitats in the Bahamas. Lethal breakage on experimentally tethered shells was not restricted to the shallow-shelf (≤ 30 m), but could occur to outer shelf (70 m) and upper slope (≥ 88 m) depths. However, significantly more shells were preyed on at shallow-shelf depths (≤30 m) than at deeper depths (≥ 70 m) for both transects. Predation was not restricted to shelf sites (≤ 70 m), and predator-induced damage, such as peeled shells or last whorl remnants, could be encountered to a depth of 195 m. However, significantly more predation occurred at shelf rather than slope (≥ 88 m) depths for both transects. Although the experimental shells were exotic species, they were preyed upon at differing frequencies depending upon transect location and depth. It appears that morphology alone may not account for the differences in predation. Long-term deployment (six years) of shells enhanced the likelihood of predation, but short term deployment (one or two years) did not. Molluscivorous predators in the Caribbean are highly diverse and are not restricted to the shallow shelf, but occur in outer shelf to slope settings. Therefore, evolutionary-ecological conclusions based on predation with depth should not be tied to a single site, to a few depths, or to a single predator, as habitat heterogeneity and patchiness in predator and prey distributions may vary.

Mollusc shells of several species were deployed on racks and on the seafloor for up to two years on eutrophic and mesotrophic reefs in the Java Sea, a modern epeiric sea. Taphonomic indicators of shell preservation decreased during the study, but some ligament, periostracum, and shell color persisted throughout. Shell fragmentation was negligible except for species with easily chipped margins; weight loss was less than 5% for sturdy shells and up to 15% for shells with chipped margins. Shells deployed in mesh bags on the sediment surface had low encrustation and bioerosion, probably because of partial or complete burial. Areal encrustation on shells in bags was greater at the mesotrophic site than the eutrophic site, but animal encrustation and biovolume of encrusters was greater at the eutrophic site.

Shells elevated on racks were encrusted rapidly at all sites; animal encrustation rates were correlated positively with productivity, and biovolume of encrusters was greater on nearshore eutrophic reefs than on offshore mesotrophic reefs. Bioerosion rates were variable but also tended to be higher at the more productive site. Natural shells also exhibited a positive, though less strong correlation with productivity suggesting that encrustation intensity and shell bioerosion may serve as relative indicators of productivity in the fossil record.

Shell-rich deposits of the Louisiana chenier plain (LCP) include three types: (1) cheniers, Holocene relict shorelines of 10–100 km in length that typically are composed of laterally continuous, planar beds primarily containing poorly sorted bivalves in a sandy matrix; (2) mounds, 3–5 m high, ∼10 m across, anthropogenic structures composed of redeposited sediment that have been formed primarily through depositing basket-loads of nearby chenier sediment; and (3) middens, thin, unstratified lenses that are typically1–3 m long,, although they can be up to 100 m across, often lacking topographic expression, and composed primarily of large Rangia cuneata in a black clay matrix. Middens are deposited on cheniers by humans as refuse. LCP mounds often are recognizable using criteria such as topographic expression, and both middens and mounds often are identifiable through faunal composition and the presence of artifacts. However, efforts to record the cultural history of southwestern Louisiana have been hampered because many LCP mounds are now remnants (mounds that have been excavated for road fill and have lost their original diagnostic topographic expression from mound construction). Further, these archaeological deposits contain many of the same species found in cheniers, may be composed primarily of chenier sediment, and directly overlie cheniers. But, LCP cheniers, middens, and mounds have different depositional histories and it may be possible to develop additional stratigraphic, taxonomic, and taphonomic criteria to distinguish them. Preliminary tests indicate that the following criteria can be used to distinguish among these deposits. LCP cheniers typically are composed of alternating coarse- to fine beds of shell and fine- to medium sand. LCP middens examined are small lenses mainly of one molluscan species and black clay. The LCP mounds examined have a complex stratigraphy of mainly unlayered redeposited chenier sediment. Both mounds and middens exhibit somewhat greater taphonomic alteration (particularly chemical) than cheniers and contain evidence of human occupation, such as pottery fragments, vertebrate remains, and charcoal.

A neoichnological resin cast of modern burrows from a mudflat at Willapa Bay, Washington, reveals much of the architecture of the infaunal community present locally within sediments of this mudflat. The cast structures comprise Psilonichnus-, Skolithos-, Trichichnus-, Chondrites(?)-, Planolites-, Palaeophycus-, and Arenicolites-like burrows. The range of behaviors represented by these structures cannot be classified into an archetypal (Seilacherian) ichnofacies.

The resin cast contains many coeval, composite burrows that may reflect certain commensal relationships. Notable composite associations include: (1) siphon shafts of Mya arenaria that are connected to and descend from crab domiciles; (2) an example of a pair of infaunal Mya arenaria that share a single siphonate shaft; (3) abundant Heteromastus burrows that connect to crab and bivalve burrows; and, (4) Nereis burrows that are connected to crab domiciles. It is suggested that such contemporaneous relationships, if passed into the fossil record, might be misinterpreted as representing tiering or faunal succession. The reported observations provide a new perspective on the potential significance of interpenetrating trace fossils and complex ichnofabrics.

Large mammals, especially Hippopotamus amphibius, have created a distinctive set of traces in a spring-fed freshwater wetland on the margin of the saline-alkaline crater lake in the Ngorongoro Crater, Tanzania. It is comprised of a ∼30 m diameter zone of deep (<2m) bioturbation due to hippo wallowing, surrounded by dendritic to radial hippo trails 1–5 m wide and <0.5 m deep, infilled with organic-rich mud. These trails narrow and thin as they grade into trackways on the lake flat. Tracks and trackways of more terrestrial mammals, such as bovids and equids, are found in the lake flat muds surrounding the hippo-dominated area. Associations of sedimentary structures such as these are important indicators of paleoenvironmental conditions where they are preserved in the sedimentary record, due to the strong affinity of Hippopotamidae for freshwater environments.