Paratomella rubra Rieger and Ott, 1971

(Figs. 30)

Material. Living specimens in squeeze preparation; whole mounts for fluorescence imaging of musculature.

Locality. As Ilhas, São Sebastião, São Paulo, Brazil, from subtidal fine-grained sand (23°47’16.0”S, 45°42’31.2”W).

Description. Living specimens ~ 1.5 mm long and 70 m wide (Fig. 30 A). Elongate, filiform body with blunt posterior end. Posterior end with adhesive haptocilia. Body color bright red in transmitted light (Figs. 30 A–C). Mouth opening on ventral surface, anterior half of body. Sexual forms with testes and male copulatory organ positioned anterior to ovaries and eggs. Male gonopore opens to a large ciliated antrum that leads to a muscular, sperm-filled seminal vesicle and associated penis needles (Fig. 30 C).

Remarks. Paratomella rubra is a cosmopolitan species. Although all the specimens we collected were sexual forms, the species can also be found in asexual paratomizing chains of two (Creze 1978).