A revision ofSabella,BispiraandStylomma(Polychaeta: Sabellidae)

Abstract

Sabellais rediagnosed to include only species that have spiralled fascicles of abdominal chaetae, first thoracic shield with straight anterior border and radioles that lack composite eyes and flanges.Spirographis spallanzaniiis synonymous withSabella penicillus. The type of the genus is discussed and a neotype designated. The only other species retained inSabellaareS. pavoninaandS. discifera(=Branchiomma linaresi, once misplaced inMegalomma, but abdominal fascicles ofMegalommaform transverse rows). Most species formerly placed inSabellaare transferred toBispira, having C-shaped fascicles of abdominal chaetae, first thoracic shield with a «W»-shaped anterior border and, in most species, radioles with paired composite eyes and flanges.Bispira, withB. volutacornisas the type species, is rediagnosed to includeB. crassicornis,B. fabricii,B. melanostigma,B. tricyclia,B. viola,B. manicata,B. porifera,B. mariae,B. elegans,B. brunnea,B. guinensis,B. secusolutus,B. wireni,B. oatesiana,B. spirobranchia,B. pacifica,B. monroi, andB. turneri, many of which are described fully for the first time. Only five of these form bispiral crowns (bispirality is useful only specifically and occurs in other genera) and one,B. tricyclia, has a unispiral crown.Sabella palmataQuatrefages, the type ofStylommais redescribed and its synonyms discussed. This genus has abdominal fascicles like those ofBispira, but radiolar eyes like those ofMegalomma. The relative advantages of chaetal arrangement and eye position are discussed.