Palaeontologia Electronica palaeo-electronica.org Hidden subsurface garden on own faeces – the trace fossil Tubulichnium rectum (Fischer-Ooster, 1858) from the Cretaceous-Palaeogene deep-sea sediments Alfred Uchman and Andreas Wetzel ABSTRACT Tubulichnium rectum (Fischer-Ooster, 1858) is an oblique to horizontal, unbranched, blind ending tube having margins densely lined with ellipsoidal muddy pellets. It occurs in fine sandy to muddy, siliciclastic and marly deep-sea sediments mostly from Turonian to Eocene times. It was probably produced by “worm”-like organ- isms, which fed on organic-rich sediment deposited seasonally or episodically on the sea floor. The faecal pellets were stored in the deep parts of the burrow within the anoxic zone beyond the depth that other burrowers usually penetrate. During periods of food shortage, the pellets were utilized as a supplementary nutrition source. Such behaviour in constructing and using a cache is interpreted as an adaptation to increased competition for food in the deep sea after the Cenomanian. Alfred Uchman. Institute of Geological Sciences, Jagiellonian University, Gronostajowa 3a, PL 30-387 Kraków, Poland;
[email protected] Andreas Wetzel. Geologisches Institut, Universität Basel, Bernoullistrasse 32, CH-4056 Basel, Switzerland;
[email protected] Keywords: ichnology; ichnotaxonomy; autocoprophagy; cache; flysch; turbidites Submission: 26 April 2017 Acceptance: 4 August 2017 INTRODUCTION oligotrophy, efficiency of these strategies is chal- lenging in the deep-sea, where supply of organic Trace fossils record variable strategies of matter is, on average, rather low and commonly feeding by their producers, which include system- strongly fluctuating (e.g., Lutz et al., 2007; Arndt et atic utilization of deposits in horizontal, vertical, or al., 2013).