The Bogda Mountains, Xianjiang Uygur Autonomous Region, western China, expose an uppermost Permian–Lower Triassic succession of fully continental strata deposited across three graben (half graben) structures in the mid-paleolatitudes of Pangea. A cyclostratigraphy scheme developed for the succession is subdivided into three low-order cycles (Wutonggou, Jiucaiyuan, Shaofanggou). Low-order cycles are partitioned into 1838 high-order cycles based on repetitive environmental changes, and their plant taphonomic character is assessed in > 4700 m of high-resolution, measured sections distributed across ∼ 100 km. Four taphonomic assemblages are represented by: permineralized wood (both autochthonous and allochthonous), megafloral adpressions (?parautochthonous and allochthonous) identifiable to systematic affinity, unidentifiable (allochthonous) phytoclasts concentrated or disseminated on bedding, and (autochthonous) rooting structures of various configurations (carbon films to rhizoconcretions). Their temporal and spatial occurrences vary across the study area and are dependent on the array of depositional environments exposed in any particular locality.

Similar to paleobotanical results in other fully continental basins, megafloral elements are rarely encountered. Both wood (erect permineralized stumps and prostrate logs) and adpressions are found in < 2% of meandering river and limnic cycles, where sediment accumulated under semi-arid to humid conditions. The absence of such assemblages in river-and-lake deposits is more likely related to physical or geographical factors than it is to an absence of organic-matter contribution. With such a low frequency, no predictable pattern or trend to their occurrence can be determined. This is also true for any horizon in which rooting structures are preserved, although paleosols occur in all or parts of high-order cycles developed under arid to humid conditions. Physical rooting structures are encountered in only 23% of these and are not preserved equally across space and time. Allochthonous phytoclasts are the most common taphonomic assemblage, preserved in association with micaceous minerals on bedding in fine-grained lithofacies. The consistency of phytoclast assemblages throughout the succession is empirical evidence for the presence of riparian vegetation during a time when models propose the catastrophic demise of land plants, and does not support an interpretation of vegetational demise followed by long-term recovery across the crisis interval in this basin. These mesofossil and microfossil (palynological) assemblages offer the best opportunity to understand the effects of the crisis on the base of terrestrial ecosystems.

We report the occurrence of abundant dipteran puparia of Phormia regina, the black blow fly, in association with an early historic-age bison skeleton excavated near Carson City, Nevada. Cut marks on some of the bones indicate that the bison was butchered and probably skinned by humans. Radiocarbon dating provides two possible age intervals for the death of the bison: (1) latest seventeenth to early eighteenth century or (2) early nineteenth to early twentieth century; we consider the more recent age to be more plausible. The purpose of this study is to explore how the presence of puparia of this well-studied, necrophagous fly species can be used to help constrain the season of death and inform the interpretation of the taphonomic history of the bison.

The life cycle of P. regina requires a minimum of 8.8 days within a temperature range of 14°C to 35°C, so the bison carcass must have been exposed to the air for at least that long within that temperature range. However, of the thousands of recovered puparia, 35% remain closed and did not produce adult flies; of this cohort, only a tiny percentage exhibit small exit holes attributable to parasitoid wasps. Cold temperatures, and not parasitoid wasps, are the most probable cause of the high pupal mortality. Climate data for the region, along with P. regina temperature constraints and streamflow and flooding records for the Carson River watershed, indicate that the bison died and was colonized by black blow flies in the spring, when night-time temperatures were low. A short time later the skinned and butchered skeleton was buried by floodplain sediments. Blow fly puparia can contribute useful information for the taphonomic analysis of vertebrate fossil sites.

Diverse modifications of the original morphological features occur throughout the taphonomic history of osteological remains, which may lead in erroneous interpretations about the formation of an accumulation as well as taxonomic misidentifications. Here, we present a neo-taphonomic study in order to analyze and interpret the modifications generated by digestion on osteoderms of the armadillo Dasypus novemcinctus obtained from scats produced by Puma concolor. Results reveal intense breakage and modifications of the articular and broken edges, dorsal surface, bone tissues, and ornamentation pattern of the osteoderms. This work describes for the first time the modifications caused by digestion in armadillo osteoderms, improving the knowledge of preservation of this type of skeletal element and providing a modern analog that can be used to distinguish archeological and paleontological accumulations formed by predators from those generated by other processes. The recognition that digestion modifies the original ornamentation pattern is particularly significant because ornamentation features are used in nearly all taxonomic and phylogenetic studies of fossil cingulates. We use this new information to re-evaluate osteoderms recovered from carnivore coprolites of the classic Middle Miocene La Venta site (Colombia), which formed the basis for recognizing and characterizing the dasypodid species Nanoastegotherium prostatum. We highlight the importance of knowing with certainty the origin and taphonomic history of remains since, in the particular case of cingulates, taxonomic identification also has important biostratigraphic, paleoecological, paleoenvironmental, and paleobiogeographical implications.

Dinosaur eggshell fragments, from the Upper Jurassic Brushy Basin Member of the Morrison Formation, Utah, were examined using Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive Spectroscopy, and Raman Spectroscopy. Analyses revealed that the mammillary tips on the shell interior contain carbonaceous residue. Comparison under the FESEM of these shells with modern bird shells, including some samples heated to diagenetic temperatures, indicate that the residue is degraded organic compounds (DOC). Bird egg membrane is composed of interlaced collagen fibers. Features observed on, and common to, modern bird and dinosaur egg fragments include: (1) irregular-shaped calcium carbonate grains “floating” in an organic matrix; (2) three-dimensional organic fiber matrix; (3) external calcium carbonate molds of fibers in the mammillary bodies; and in heated specimens, (4) carbonaceous residue with ovate to circular pores. However, unlike birds' eggs, the dinosaur eggs contain a calcium carbonate tube around fibrous organic material that emerges from the tube and spreads laterally in a ‘puddle-like’ deposit. The sizes of circular organic matrix pores of the dinosaur egg fragments are significantly smaller than those in the bird shells. Gallus gallus domesticus eggshell membranes heated to diagenetic temperatures resulted in alteration of collagen fibers to gel-like substances. The organic matrix with ovate to circular pore openings and the puddle-like deposits in the dinosaur egg fragments are interpreted as the product of membrane thermal diagenesis. The recognition of carbonaceous residue of the shell membrane on dinosaur shell fragments opens newfound opportunities to explore DOC associated with fragmental dinosaur eggs.