Miocene Clypeaster from Valencia (E Spain): Insights into the taphonomy and ichnology of bioeroded echinoids using X-ray micro-tomography

摘要: Abstract Taphonomic analysis and X-ray micro-tomography (μCT) were applied to Clypeaster specimens from the Miocene of Fuente del Jarro (Valencia, Spain). This enabled identification various preservational features, including encrustation, bioerosion, abrasion post-depositional cracking. Approximately 15% studied affected by encrusters and/or borers. Of particular interest was a single intensely-bored specimen preserving numerous cross-cutting bioerosion structures. These structures exhibit distinctive morphology consisting clavate or flask-shaped chambers with circular oval cross-section, narrow neck region near figure-of-eight-shaped aperture chimney extending outside test. The excellent preservation characteristic morphology, as revealed μCT scan, coupled observation that (in some cases) articulated bivalve shells are still present within chambers, allows for tracemaker boring Rocellaria , reaffirming these tube-dwelling animals borers, burrowers crypt-builders. trace fossils described herein semi-endoskeletal dwellings, representing combination through plates echinoids, bioturbation in form burrowing into sediment infill carbonate secretion resulting crypt. morphologies different dwellings influenced limited available space echinoid tests. study confirms importance relatively stable thick benthic islands Cenozoic sandy littoral settings. high degree multiple colonizations, well uniform orientation burrows, suggests long-term position this secondary substrate at surface.