The depositional environment of the Upper Ordovician Harding Sandstone of central Colorado has been debated since Charles Walcott first described its pteraspidomorph agnathans. Although most previous workers have favored a marine setting for the Harding based on the presence of marine invertebrates and burrows, some have argued for a fluvial or estuarine habitat for these primitive vertebrates. This study presented here is the first regional, comprehensive analysis of the depositional environments and sequence stratigraphy of the Harding Sandstone. The Harding contains deposits from an array of coastal environments, including transition zone, shoreface, bay/lagoon, washover fan, and bayhead delta. Features of these environments suggest that the Harding was deposited on a microtidal coast with low wave energy. Within the study area, two depositional sequences are developed, and each apparently lacks a lowstand systems tract. The Harding contains numerous flooding surfaces, which preclude any attempt to interpret the Harding as a single depositional environment. Flooding surfaces commonly display evidence of stratigraphic condensation, including burrowed firmgrounds, concentrations of pteraspidomorph plates, and dolomitic cementation. Pteraspidomorph remains are associated most commonly with shoreface facies, are uncommon in bay/lagoon facies, and are absent from bayhead-delta facies. Collectively, these occurrences argue for a shallow-marine habitat for these primitive vertebrates.

Three loose blocks, rich in dinosaur footprints, were found in a small pier at Mattinata (Gargano Promontory, Foggia, Italy), most probably quarried from the Upper Jurassic Sannicandro Formation. All of the footprints in the blocks are ascribed to medium-sized theropod trackmakers. Recent track discoveries from both the Early Cretaceous San Giovanni Rotondo Limestone and the Late Cretaceous Altamura Limestone, as well as this new discovery, reveal the consistency of terrestrial associations along the southern margin of the Tethys Ocean in the peri-Mediterranean area at the end of Jurassic through Cretaceous times. The presence of these dinosaur-track-rich levels within marine sediments of the Apulia Platform underlines the relevance of dinosaur footprints as a means of constraining paleogeographic reconstructions.

This study presents a new, reliable method of dental microwear analysis, which is applied to one of the largest published primate databases and to a Miocene hominoid, Ouranopithecus macedoniensis. Phase I and phase II molar facets were considered. A strict protocol during the molding and casting steps enabled the capture of sharp photographs using light stereomicroscopy. A semi-automatic method allows the quantification of the microwear features on digitized photographs.

Inter-specific analysis on extant primates enabled recognition of three clusters. Primates feeding on soft fruits and leaves and having a low incidence of pitting on molar facets constitute the first cluster. A second group composed of the three sub-species of Papio, differs from the others by a high incidence of pitting and scratching on both molar facets. This is related to the consumption of abrasive graminoids and hard items. Pan troglodytes troglodytes and Pongo pygmaeus have an intermediate microwear pattern and constitute a third group. Ouranopithecus macedoniensis is close in dental microwear pattern to the three sub-species of Papio. This suggests the importance of the consumption of hard and abrasive items. Intra-specific analysis of dental microwear variations within a population of Pongo pygmaeus reveals no significant differences related to sex and molar-wear stage. According to these results, this alternative method appears to be repeatable, and therefore reliable, for paleodiet characterization of fossil primates.

Both the timing and nature of early Metazoan evolution remain controversial, with complementary, and sometimes conflicting, evidence from molecular data and fossil occurrences. Exceptionally preserved embryos from the Neoproterozoic and early Phanerozoic remain an important source of direct evidence: fossil embryos of complex organisms at a relatively advanced stage of development provide a test of hypotheses based on comparative embryology and the evolutionary development of living forms. Understanding how these fossils are preserved, and what morphological changes are induced by decay, is essential to interpreting the evidence that they provide for early metazoan evolution. A range of decay experiments was performed on eggs of living arthropods to explore the controls on their mineralization and likely fossilization. Surface mineralization occurred within one month, mainly in calcium carbonate or in a combination of calcium carbonate and calcium phosphate. There was no enhancement of mineralization with increased phosphate or calcium concentrations, or with changing oxic/anoxic conditions, and mineralization occurred both in the absence and presence of an associated carcass. The eggs showed remarkable resistance to decay, indicating that an extended time-period (more than a year) would be available for mineralization and fossilization in some settings. Where sediment was available, it could become attached to the egg surface, replicating the morphology in a fashion analogous to mineralization. The interior of the eggs was not mineralized in the experiments. The degree of mineralization was very variable, reflecting conditions both in the natural environment and in the fossil record.

Ordination is a common tool for reconstructing paleoecological gradients for ordering samples and taxa along one or more axes of variation in faunal composition. The primary source of variation, known as the primary gradient, commonly is highly correlated with water depth in marine systems, and elevation or moisture in terrestrial systems. When ordination sample scores are plotted stratigraphically, they commonly reveal long-term patterns of variation related to changes in this primary gradient, and these patterns have proved useful in regional correlation. In addition, ordination scores display high-frequency, high-amplitude patterns of variation unrelated to this primary gradient. The origin of this high-frequency variation has been enigmatic, but recently has been argued to reflect faunal patchiness. Numerical modeling of ordination scores derived from the Upper Ordovician Kope Formation of the Cincinnati, Ohio area is used here to demonstrate that such high-frequency patterns of variation indeed can arise from the presence of faunal patchiness along ecological gradients. The magnitude of this variation is controlled by the peak-abundance distribution of fossil taxa as well as the abundance distribution of a taxon at any given position along the primary gradient. Replicate sampling or moving averages should be employed to control for this high-frequency variation before ordination sample scores can be treated as a suitable proxy for environmental factors such as water depth, elevation, or moisture.

Dasycladalean green algae show marked fluctuation in genus and species biodiversity from the Carboniferous to the Pliocene. Diversity lows (<10 species) alternate with peaks (>70 species) over periods of ∼20–50 Myr. Relatively few taxa are recorded for the earliest Carboniferous, Early Triassic, Early to Mid-Jurassic, Late Cretaceous, and Pliocene. Diversity maxima occur in the Permian, Early Cretaceous, and Paleocene. With the exception of the Late Cretaceous, biodiversity broadly tracked temperature from the Carboniferous to the Pliocene. Diversity minima generally correspond with low sea level, and diversity maxima with periods of intermediate sea level. Dasycladaleans were most diverse when their main habitats—warm shallow seas—were most extensive. This observation does not preclude the influence of additional important factors on dasycladalean evolutionary history, but it suggests a strong link between long-term patterns of dasycladalean diversity and global fluctuations in temperature and sea level.

This paper provides an estimate of the temporal nature and environmental implications of bioturbation in upper-foreshore and backshore deposits resulting from the burrowing activity of talitrid amphipods at Waterside Beach, Bay of Fundy, Canada. Short-term preservation potential is assessed by comparing shore-normal variations in burrow morphologies and densities to grain-size distribution, and hydraulic and eolian processes. The intensity and distribution of burrowing is linked to depositional environment and provides a temporal framework for bioturbation indices in ancient upper-foreshore and backshore deposits.

Bioturbation in foreshore and backshore successions provides a means for predicting short-term, autocyclic processes in the rock record, in that: (1) the initial occurrence of burrowing marks the transition from the foreshore to the backshore, and (2) the degree of bioturbation may be used to predict depositional rates and processes. At Waterside, bioturbation indices (BI) of two or less indicate a single season of colonization; BIs of two (upper end of range) and higher suggest multiple seasons of colonization. A high BI may indicate that the backshore environment was protected from wave reworking or erosion (particularly during storms) and/or was subjected to minor eolian sedimentation.