ABSTRACTCrinoids are diverse and well-known from the Permian of Timor, but the literature has failed to document the numerous specimens of crinoid pluricolumnals from the fauna, many showing unusual morphology or yielding palaeoecological information. A curious and instructive specimen demonstrates the relationship between a living Permian crinoid and coeval invasive, pit-forming, invertebrates in detail. The pit-former is not preserved; most likely it was unmineralized or, if mineralized, then the shell simply dropped out. The infesting organism made pits assigned to the ichnospecies Oichnus paraboloides Bromley. The pit-former was unusually site selective. Either (1) one spatfall attached to just one side of the elevated (either up-current or down-current) or recumbent column and each individual centered their pits on the sutures between adjacent columnals; or (2) a single individual migrated along the column. The living crinoid showed an extreme reaction to this infestation. Excess stereom growth on the side of the pits transformed what was a circular column by addition of a thick, triangular ridge on the pitted side.

ABSTRACTBeaconites capronus is a winding meniscate backfilled trace fossil differentiated from comparable ichnotaxa Taenidium and Ancorichnus on the basis of its distinct and unornamented burrow lining. Typically, horizontal to subhorizontal B. capronus also includes vertical pipes, which serve as a point of entry for endobenthic deposit feeding activity. The burrows do not self-cross but often display secondary successive branching potentially indicating coprophagous feeding strategies in lower nutrient sediment. Beaconites capronus material is examined and discussed from the Carboniferous offshore transition zone deposits near Howick, United Kingdom. Samples were collected and analyzed using high-resolution serial grinding and modeling techniques documenting fine detail in three dimensions. As the burrows are actively backfilled and do not maintain a connection to the sediment water interface the trace making organism must have a method of coping with the low oxygen porewater conditions. Four methods are considered herein, as follows: 1) revisiting the sediment-water interface; 2) creating periodic shafts; or 3) employing the use of obligate anaerobic metabolism. Based on the material presented herein, an emended ichnospecific diagnosis is provided.

ABSTRACTSeveral new Early Cretaceous tracksites from the Lower Cretaceous Xiagou Formation of Gansu Province (China) with tracks of large sauropods and ornithopods are described. Previously reported bird tracks were missing due to human negligence. The studied specimens are preserved as impressions and shallow and deep natural track casts. These dinosaur tracks are first reported from the Jiuquan area in the Changma Basin, matching well with the skeletal record of diverse non-avian dinosaur-bird faunas of this region. Moreover, they add new data to the dinosaur ichnofaunas of the Lanzhou-Minhe Basin (Gansu Province) and indicate a wide distribution of dinosaur-bird assemblages in the Early Cretaceous. Regarding morphology, sauropod, and ornithopod tracks from the Lanzhou-Minhe Basin and the Jiuquan area are very similar to each other. Titanosauriform trackmakers are assumed for the sauropod tracks and possibly iguanodontids have left the large, tridactyl ornithopod tracks. Of particular interest are well-preserved, deep natural track casts of large ornithopods and sauropods preserving ridges and grooves as well as striation marks on the lateral sides of the casts that allow the reconstruction of complex pathways of the foot within the substrate. One particular sauropod pes–manus track cast even indicates lateral and vertical sliding within the sediment because of the presence of “double impressions of digits” on the bottom.

ABSTRACTThis study constitutes the first comprehensive description and analysis of trace fossils produced by insects on bone from a faunal assemblage in the Cradle of Humankind, South Africa. A total of 9,500 bone fragments from Cooper's D were visually inspected for evidence of insect trace fossils. Fifty-three specimens with insect traces were identified and analysed using optical microscopy at low magnifications. Analysis revealed frass and coprolites preserved on some bones, and nine morphologically distinctive traces. Circular boreholes associated with a crescent-shaped excavation are attributed to a new ichnogenus Munitusichnus pascens, while ellipsoid surface borings (pupation chambers) are assigned to a new ichnospecies Cubiculum cooperi. Evidence suggests that traces were produced by more than one agent at different stages during the taphonomic process. Modification either took place whilst bones were sub-aerially exposed, at the point of final deposition, or post-burial of the remains. Munitusichnus pascens and Cubiculum cooperi represent the first ichnotaxa in bone from the Cenozoic of African.

ABSTRACTAbout a hundred dinosaur tracks, mostly preserved as isolated footprints, have been recorded at a single site within the borders of the Waterberg National Park, Otjozondjupa Region, north-central Namibia. They are found in an interdune setting within the Lower Jurassic Etjo Formation and represent medium-sized theropods with slender digits and high projection of digit three. From an ichnotaxonomic point of view, the Namibian tracks are intermediate in morphology between Grallator (which is known to occur at other localities within the same Etjo Formation) and Anchisauripus, being otherwise in a size range that is usually considered typical for the latter ichnotaxon or even for Eubrontes. The Waterberg tracks do not match the allometric growth model proposed by Olsen et al. (1998) for the Early Jurassic theropod track assemblage of the North American Connecticut Valley, and they highlight the difficulties of consistently discriminating between theropod ichnotaxa in the Grallator-Anchisauripus-Eubrontes plexus. The Waterberg ichnosite adds important data to our understanding of the ichnological diversity of the Etjo Formation, raising to three the dinosaur localities in Namibia with revised and updated ichnofaunas. The dinosaur ichnofauna from Namibia, of which the Waterberg tracksite is a basic component, shows high ichnotaxonomic similarity with coeval assemblages from the northern hemisphere. This points to an overall homogeneity of the global ichnofaunistic composition, even at lower latitudes.

The vertebrate fauna from the Lower Cretaceous Patuxent Formation of Virginia is composed of a single partial fish impression from the James River at Dutch Gap and a diverse tetrapod ichnofauna from near Fredericksburg that includes trace fossils made by frogs, turtles, theropods, sauropods, ankylosaurs, and ornithopods. The footprints occur on overbank deposits preserved locally within a fluvial braided-stream sequence that formed near the western border of the Early Cretaceous Atlantic Coastal Plain.

A palaeocommunity of large Conichnus conicus, a conical, cone-in-cone shaped burrow, created by sea anemones, occurs in medium-grained, crossbedded, well-sorted sandstone in the middle part of the Cretaceous Guneri Member of the Bhuj Formation in India. The trace fossil Conichnus is considered to be a common element of the Skolithos ichnofacies and is interpreted to reflect equilibrium movement in response to substrate aggradation. In the present study, three different varieties of Conichnus conicus are distinguished based on morphology and internal fabric. Community dynamics and burrowing behavior are revealed by inter-burrow relationships, burrow initiation levels and sedimentology. Three types of behavior are envisaged: retrusive equilibrium, protrusive equilibrium response, and escape behavior. Palaeocommunity dynamics show that the tracemakers consisted of only adult organisms that initiated burrows during neap tides and are adapted to feed effectively during weak flow conditions. The occurrence of Conichnus palaeocommunity in the Guneri Member indicates the tidal conditions in a fully marine setting. Results presented herein may aid in the understanding of palaeocommunity dynamics in other shallow marine sequences.

Cretaceous tetrapod (dinosaur and pterosaur) tracks from Zhaojue County in Sichuan Province are locally very abundant. Large scale quarrying operations at the Sanbiluoga Copper Mine site have produced extensive exposures, and track material for detailed study. However, natural track-bearing outcrops also occur at a site in Jiefang Township. The traditions of the local Yi people, indigenous to the area, attribute such tracks to Zhigealu, a central creator hero-ancestor, who made the footprints while riding his heavenly steed through the area. Through seeing tracks exposed by quarrying the local people offered these legend-based interpretations, and reported the Jiefang site which was previously unknown to scientists from outside the area. Thus, it is important to pay attention to local legends about track makers since they may lead directly to significant fossil footprint discoveries. Thereby paleontology and ichnological research can benefit largely from archeological sciences as well as from oral narratives from the local people. The recently discovered sauropod trackway from Jiefang is an excellent example. It comprises 16 pes-manus sets arranged in a narrow-gauge pattern. A peculiarity is the combination of this feature with morphological characteristics known from typical wide-gauge Brontopodus trackways suggesting a tentative assignment to cf. Brontopodus. The discovery enlarges the distribution and diversity of Brontopodus-like trackways and their producers in the Cretaceous Sichuan Basin.

The use of X-ray microtomography (micro-CT) to evaluate the contrasts in permeability associated with bioturbation in two- and three-dimensions (2D and 3D) is investigated in this article. Core analysis, spot-permeametry measurements, and petrographic thin-sections of the six different datasets from Western Canada (Debolt Formation, Wabamun Group, and Medicine Hat Member) and offshore Norway (Ula Formation, Lysing Formation, and Nise Formation) show that the trace fossils commonly modify the permeability and porosity of the reservoir through sediment reworking and diagenesis of the sediment. In this study, micro-CT techniques are used to analyze the X-ray attenuation associated with bioturbation in siliciclastics and carbonates. Because X-ray attenuation represents the transmissivity or absorptivity of a sample to the incident X-rays, each of which is related to sediment composition and sediment densities, micro-CT images are integrated with sedimentological data and petrographic data to identify the trace fossils and matrix in 2D and 3D. Due to the difference in sediment grain size and sorting (i.e., porosity) within the burrows and matrix, analysis of the X-ray attenuations allows for their delineation in 2D cross-sectional images. When processed as 3D volumes, the micro-CT images show the complexity in burrow connectivity and burrow orientations within a sample. More importantly, the 3D volumes help show the distribution of porosity that can be linked to measured permeability values within a sample. Quantification of the heterogeneous burrow fabric on reservoir and resource quality is made from these processed micro-CT images.

A complex microboring trace of fungal affinity is described in shells as a new ichnotaxon Saccomorpha stereodiktyon isp. nov. and compared with the earlier established ichnotaxon Saccomorpha terminalis Radtke, 1991. The new trace is characterized by a three-dimensional network of tunnels composed of a bifurcate horizontal (parallel to substrate surface) network with an upright (perpendicular to surface) system of tunnels and by the formation of cylindrical to multilobate terminal sporangial swellings. The new trace shares with Saccomorpha terminalis Radtke, 1991 the terminal position of sporangial swellings but differs from this ichnotaxon by its complexity in spatial arrangement, segmented construction, and ramification of tunnels. The horizontal parts of the network in the new taxon adhere to the substrate surface and regularly produce thinner tunnels that explore the interior of the substrate, allowing the producer to participate in digestion of organic lamellae incorporated in the shell. Microborings similar to the new trace fossil have been observed in modern bivalve shells of the Atlantic Ocean, North Sea, Adriatic Sea and Red Sea at depths ranging from the intertidal down to 1,550 m. The fossil record of the trace reaches back to the Jurassic and the type material stems from a Lower Oligocene oyster shell. The study shows that complex microboring traces reflect both behaviour and developmental strategy of their makers.