RT Journal Article T1 The demosponge Leptomitus cf. L. lineatus,first occurrence from the Middle Cambrian of Spain(Murero Formation, Western Iberian Chain) A1 GarcĂ­a-Bellido Capdevila, Diego AB The Middle Cambrian Murero Formation in the Iberian Chain (NE Spain) has yielded a small collection of softbodied fossils (palaeoscolecid worms, onychophorans, algae), a host of fossils from organisms with mineralized skeletons such as trilobites and brachiopods, and some trace fossils. This paper deals with the description of the only specimen of the demosponge Leptomitus known so far from Spain and its association with the brachiopod Micromitra, showing a probable case of commensalism by the latter over the former. The taphonomical study indicates that there was little or no disarticulation of the sponge spicules and suggests that a rather complex series of alteration processes has occurred since these organisms were buried. PB Instituto de Ciencias de la Tierra "Jaume Almera" (Barcelona) SN 1695-6133 YR 2003 FD 2003 LK https://hdl.handle.net/20.500.14352/59909 UL https://hdl.handle.net/20.500.14352/59909 LA eng DS Docta Complutense RD 9 abr 2025