Miocene tidal deposits from Las Grutas, Patagonia, Argentina, superbly preserve cylindrically laminated burrow systems including Asterosoma radiciforme von Otto and three compound ichnospecies of the newly proposed ichnogenus Patagonichnus ; P. calyciformis n. isp.; P. stratiformis n. isp.; and P . thalassiformis n. isp. Together with large, palmate burrows, probably produced by crustacean decapods, they are elite trace fossils. The Patagonichnus burrow systems consist of many distinctive concentrically laminated elementary components including: horizontal and vertical, conical and helicoidal bulbs and swellings; vertical shafts; straight and paired branches; and cone-in-cone structures. Hollow, branched, straight or helicoidal inner lined tubes connect... |