Two new species of an atypical group of Pseudobranchiomma Jones (Polychaeta: Sabellidae)

The genus Pseudobranchiomma Jones, 1962 can be divided into three groups: ( A) those with paired serrated flanges along all or most of the crown radioles, as in the type species P. emersoni Jones, 1962; ( B) those with such flanges only on the distal parts of the radioles; ( C) those with flanges reduced or absent ( without serrations) as in two new species described here from Florida and Italy. Group C also contains Pseudobranchiomma longa (Kinberg, 1867), P. punctata (Treadwell, 1906) and P. minima ( Nogueira & Knight-Jones, 2002). Lists of species ( and their synonyms) in the other two groups are given, and scissiparity, thoracic length, chaetal arrangements and types of radiolar eyes are discussed.