Palaeoscolecid worms from the Lower Ordovician Fezouata Lagerstätte, Morocco: Palaeoecological and palaeogeographical implications Emmanuel L.O. Martin a, ⁎ ,1 , Rudy Lerosey-Aubril b, ⁎ ,1 , Jean Vannier a a UMR CNRS 5276 Laboratoire de Géologie de Lyon, Terre, Planètes, Environnement (LGLTPE), Géode, campus de la Doua, Université Lyon 1, 2 rue Dubois, 69622 Villeurbanne cedex, France b Division of Earth Sciences, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia abstract article info Article history: Received 31 October 2015 Received in revised form 1 April 2016 Accepted 4 April 2016 Available online 9 April 2016 The Lower Ordovician Fezouata Lagerstätte from Morocco (central Anti-Atlas, Zagora area) has yielded abundant and diverse soft-bodied fossils. Most described taxa were epibenthic or pelagic, so that little is known about the endobenthic components of the fauna. Here we report the discovery of a locally abundant element of the biota, a palaeoscolecid worm, which may have played an important ecological role in the community. Palaeoscolecids had a long, annulated body with an eversible tooth-bearing pharynx. They probably represent stem priapulids, but unlike them, they were protected by biomineralized (phosphatic) microscopic plates covering most of the body. These sclerites are commonly found isolated within SSF assemblages, thus considerably extending the fossil record of the group that ranges from the Cambrian Series 2 (Stage 3) to the upper Silurian. Like priapulids, palaeoscolecids might have been important bioturbators, contributing to the substrate colonization in the lower Palaeozoic. The discovery of abundant material (38 specimens) in the Fezouata Shale (Lower Ordovician, Morocco) allows us to reconsider their possible lifestyle, habitat and feeding habits. All the specimens belong to Palaeoscolex? tenensis, a species previously only known from a fragment of cuticle from the Floian of Bohemia (Czech Republic). Some exhibit remains of the gut and aboral spines, features that are highly informative with regard to the ecology of these extinct organisms, but rarely preserved. The phosphatic nature of the plates is dem- onstrated by compositional analyses and interpreted with regard to the diagenetic context of the Fezouata Shale as primary. We also hypothesize that (at least) some palaeoscolecids were makers of Tomaculum-type ichnofossils, which are elongate clusters of faecal pellets, and show that they ingested a notable amount of sed- iment during the normal course of feeding. The presence of Palaeoscolex? tenensis in the Lower Ordovician of Morocco further documents the great faunal similarities between Perunica and northern Gondwana at that time. © 2016 Elsevier B.V. All rights reserved. Keywords: Epibenthic lifestyle Deposit feeding Primary phosphatisation Tomaculum Gondwana Perunica 1. Introduction The Lower Ordovician Fezouata Lagerstätte in the vicinity of Zagora (central Anti-Atlas, Morocco) has yielded rich assemblages of biomineralised and non-biomineralised organisms. These are predomi- nantly composed of arthropods (e.g. anomalocaridids, chelicerates, cheloniellids, marrellomorphs, trilobites), echinoderms (asterozoans, blastozoans, crinoids, edrioasteroids, stylophorans) and graptolites, but also include brachiopods, bryozoans, conulariids, lobopodians, mol- luscs (e.g. bivalves, cephalopods, gastropods, halwaxiids, hyolithoids), and sponges (Van Roy et al., 2010, 2015a; Lefebvre et al., 2016a-in this issue). The overwhelming majority of these animals lived at or close to the water-sediment interface as vagile or sessile members of epibenthic communities. The water column was also home to large filter-feeding anomalocaridids that probably fed on zooplankton (Van Roy and Briggs, 2011; Van Roy et al., 2015b), including diverse planktonic graptolites (Gutiérrez-Marco and Martin, 2016-in this issue). The ex- ceptional preservation of these animal communities may have been fa- cilitated by episodes of oxygen-depletion within the superficial layers of the sea floor, preventing scavenging and slowing down decay (Van Roy et al., 2010, 2015a; Martin et al., in press). This hypothesis of hypoxic/ anoxic episodes at the sea floor permitting exceptional preservation questions the view of a permanent habitability of bottom sediment in the Fezouata, as do the huge differences between beds in terms of bio- turbation. Indeed, some horizons display abundant subhorizontal or penetrative 3-dimensional burrows (Van Roy et al., 2010; Martin et al., in press), whereas others are barren of trace fossils. Palaeoscolecid worms, which are locally abundant in the Fezouata Shale, might have represented major bioturbators of the sediment according to Huang et al. (2014). Although many described palaeoscolecid taxa are known from acid dissolution of limestones (Botting et al., 2012), they also inhabited environments dominated by siliciclastic sedimentation (Robison, 1969; Conway Morris and Robison, 1986; Kraft and Mergl, 1989; Zhang and Pratt, 1996; Botting et al., 2012). This contribution aims to discuss the life habits and feeding ecologies of palaeoscolecids Palaeogeography, Palaeoclimatology, Palaeoecology 460 (2016) 130–141 ⁎ Corresponding authors. E-mail addresses: emmanuel.martin@univ-lyon1.fr (E.L.O. Martin), leroseyaubril@gmail.com (R. Lerosey-Aubril), jean.vannier@univ-lyon1.fr (J. Vannier). 1 These authors equally contributed to this paper and are both corresponding authors. http://dx.doi.org/10.1016/j.palaeo.2016.04.009 0031-0182/© 2016 Elsevier B.V. All rights reserved. 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