Diversity and ecology of sponges in the Early Ordovician Fezouata Biota, Morocco

摘要: Abstract Sponges form a significant component of the diversity Tremadocian (Early Ordovician) Fezouata Biota in Anti-Atlas Morocco, but are distributed intermittently and have so far received only limited attention. New material reveals high undescribed taxa (a total at least 27 species), including numerous representatives protomonaxonid groups such as Leptomitidae, Piraniidae “Choiidae”. Some these show unusually complex skeletal architecture, represent derived variations their lineages relative to those Cambrian Burgess Shale-type faunas, although most species assignable described families. Reticulosan sponges rare Biota, usually fragmentary. The palaeoecology sponge fauna is unusual, with known from single sites (frequently bedding planes), often abundant where they occur. It very for two be found on same slab, or precisely horizon. With some protomonaxonid, particular planes crowded individuals that rarely, if ever, isolated. Only (Pirania auraeum Botting, 2007 an hazeliid) levels, not assemblages; this may relate differences reproductive strategy. dense, monospecific populations can best explained through repeated colonisation events frequently hostile environment, rather than representing range different stable communities.