Key for the species of Spirobranchus recorded in Brazil

1. Radiolar lobes forming 2-8 whorls in spiral .......................... S. giganteus

1’. Radiolar lobes in 1 whorl or semicircular ...............................................2

2. Spirobranchus - type chaetae present...................................... S.tetraceros

2’. Collar chaetae all limbate or absent.......................................................3

3. Operculum with flat or convex,bilobed endplate;ocelli or ocelar clusters absent on radioles;tube with 3 keels and alveoli................. S.minutus

3’. Operculum with concave, funnel-shape endplate; paired ocelar clusters present on radioles;tube with1 pointed keel and transversal ridges... ................................................................................ S.lirianeae sp.nov.