INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Ichnotaxobases for bone bioerosion structures: a proposal
C.A. PIRRONE; L.A. BUATOIS; R.G. BROMLEY
Congreso; ICHNIA 2012; 2012
Memorial University of Newfoundland
Bioerosion trace fossils in bones are commonly used to infer paleoecologic conclusions. Little has been published on the methodology for naming bioerosion trace fossils in bones, including definition of adequate ichnotaxobases, although their value as direct evidence of species interactions in the fossil record is significant. We define bioerosion trace fossils in bones as biogenic structures that cut or destroy osteologic tissue structures (hard substrate) as the result of mechanical and/ or chemical processes. Most traces found in biologic tissue (bone) are the result of specific ecological niche selection by specialist necrophagous organisms, produced during different stages of decay, as reported in forensic studies. Although the selection of substrate reflects obligate behavior by organisms having specific feeding requirements and that specific biologic tissue (bone) is used as source for those nutrients, adopting substrate as an ichnotaxobase is controversial. We propose the following ichnotaxobases in order to assist in naming traces in bones: general morphology, bioglyphs, filling, branching, pattern of occurrence, and site of emplacement. The most common general morphologies are: pits and holes, chambers, trails, tubes, channels, grooves, striae, and furrows. The main types of bioglyphs are grooves and scratches, which may display different arrangements, such as parallel and opposing or arcuate paired. Nature of the fill may help to recognize origin, composition, and relationship with the surrounding sediment, as well as processes of destruction or consumption of bony tissue. The structure and layout of filling, such as meniscate backfill or pelleted filling, offer information about the bioeroding processes. Branching structures on cortical bone are present in canals and furrows. Where the trace penetrates spongy bone, branching structures are present in tunnels and connecting internal chambers. The common patterns of occurrences are individual, paired, grouped, overlapping, lined, and arcuate. The site of emplacement may be in cortical or spongy bone, articular surfaces, internal bone microstructures, and external bone anatomical structures.