First record of serpulid aggregations and possible serpulid reefs from the Aptian (Cretaceous) of Algeria

First serpulid aggregations have been described from the Cretaceous of Africa. The serpulid species Parsimonia cf. antiquata formed fan-shaped small aggregations up to 25 cm in diameter. The serpulids are not preserved in situ, and most of the material may have been derived from nearby larger serpulid reefs. The serpulid reefs presumably occurred in a lagoon or marginal marine environment. The Algerian serpulid accumulations resemble more serpulid limestones in their low faunal diversity than modern serpulid reefs with diverse associating fauna. The lagoons often have muddy or sandy bottoms where the serpulid aggregations could have been the only large hard substrates for larvae to settle. The restricted number of suitable substrates may have supported the growth of aggregations. Rich suspended food resources also likely enhanced the growth of serpulid reefs in the Aptian of Algeria.