Calcareous tube-dwelling encrusting polychaetes from a lower-middle Miocene sedimentary succession, Cairo-Suez District, Egypt

(e.g. Gosselin & Sewell 2013) from the Permian (Sanfilippo et al. 2017) to the present day (e.g. Rouse & Pleijel 2001). Most tube-building polychaete worms are benthic and sedentary suspension feeders (e.g. Díaz-Castañeda & Reish 2009). Serpulid-like calcareous tubes displayed a rapid diversification throughout the Jurassic and Cretaceous until the Holocene (Jäger 1983, 2004, 2012, 2014; Ippolitov 2007a, b, 2010; Sklenář et al. 2013; Ippolitov et al. 2014; Kočí & Ledvák 2014; Kočí et al. 2017). They secrete and inhabit a permanent calcareous tube that can be attached to both biogenic and inorganic hard substrates. They are most commonly found as post-mortem encrusters (e.g. Garberoglio & Lazo 2011, Sklenář et al. 2013, El-Sabbagh & El Hedeny 2016, El-Sabbagh et al. 2016, Veselská et al. 2021) but may also be colonizers of living hosts (in vivo; e.g. El Hedeny et al. 2021). Hard substrates in the modern oceans are often heavily encrusted by polychaetes. They are common in all marine settings, ranging from the intertidal down to hadal depths (e.g. Hill 2013, Ippolitov et al. 2014). In addition, they were important encrusting organisms in the geological past (e.g. El-Sabbagh & El Hedeny 2016, El-Sabbagh et al. 2016). Hence, the study of ancient representatives could provide information on palaeoecology and palaeoenvironment. Sediments of the lower‒middle Miocene succession exposed in the Cairo-Suez District yield a significant polychaete assemblage, which, together with bivalves (oysters, pectinids and others), gastropods and echinoids, constitute the characteristic fossil assemblage in that area. Other common fossils include corals and bryozoans. So far, little attention has been paid to fossil calcareous tubedwelling encrusting polychaetes in Egypt (e.g. El-Sabbagh & El Hedeny 2016, El-Sabbagh et al. 2016). Therefore, this