Fouling polychaete worms from the southern Gulf of California: Sabellidae and Serpulidae

Members of the tubicolous polychaete families, Sabellidae and Serpulidae, constitute two of the most important groups in the marine fouling biota. This paper describes three fouling sabellids and six serpulids from the southern Gulf of California and provides information about the reproductive biology of these species. The invasive species, Branchiomma bairdi and Ficopomatus miamiensis, are established in the southern Gulf of California as self-sustaining populations outside of their native range of the Caribbean Sea. Hull fouling is considered the most probable vector for the translocation of B. bairdi to the eastern Pacific, while the presence of F. miamiensis is most likely due to shrimp aquacultural activities. Hydroides elegans is probably an invasive species in the study area and is common as fouling on ships and piers in the Caribbean, Gulf of Mexico, the Turkish Levantine coast, Hawaii and California. Hydroides brachyacanthus has been widely recorded in the Mexican Pacific. Demonax pallidus and Megalomma coloratum constitute new records for Mexico. Hydroides elegans, H. recurvispino and Vermiliopsis multiannulata are new records for the Mazatlan port. Hydroides cruciger, H. brachyacanthus, H. elegans, H. recurvispina and Megalomma coloratum have separate sexes without sexual dimorphism. Branchiommo bairdi and D. pallidus are simultaneous hermaphrodites, although asexual reproduction via scissiparity is documented in B. bairdi. Sperm morphology (spherical nucleus, rounded or subtriangular cap-like acrosome and a long flagellum) suggests that the species recorded here are free-spawners with external fertilisation or ect-aquasperm type. This taxonomic effort is greatly enhanced by the integration of synonymies, characterisations and image collections with annotations archived in Morphbank.