Euzonus mammillatus, Santos & Nonato & Petersen, 2004

Santos, Cinthya S. G., Nonato, Edmundo F. & Petersen, Mary E., 2004, Two new species of Opheliidae (Annelida: Polychaeta): Euzonus papillatus sp. n. from a northeastern Brazilian sandy beach and Euzonus mammillatus sp. n. from the continental shelf of southeastern Brazil, Zootaxa 478 (1), pp. 1-12 : 4-6

Euzonus mammillatus sp. n. ( Figs. 4–7 )

Euzonus mamillata [sic] Nonato, 1981: 182­184, figs. 202–203 [Manuscript name not validly published according to the ICZN].

Material originally examined by E.F. Nonato (lost): SE BRAZIL: Rio de Janeiro State: Ilha Grande, Lopes Mendes Bay , 22–43 m, gravel and coarse sand with mud, coll. L. R. Tommasi (3 specimens) .

Holotype: Continental Shelf, SE Brazil: Rio de Janeiro State: 22º57’– 23º00’S; 47º07’– 42º11’W, 45 m, coarse sand, coll. P. Paiva ( MCEM­BPO 1630 ).

Diagnosis. Euzonus with slender body clearly divided into three regions by weak constrictions; body formula 11a+18b+6a = 35 chaetigers. Cephalic region with 2 chaetigers, chaetiger 1 uniramous; thoracic region with 8 chaetigers, last of which (chaetiger 10) with 2+5 mammilliform papillae in a long, dorsoventrally oriented band just above notopodium of each side, reaching nearly to middorsum. Last abranchiate chaetigers uniramous; anal cirri with ventral pair stout, longer than dorsal ones.

Description. Preserved material colorless; color in life unknown. Holotype 6 mm long; material examined by Nonato (1981) up to 30 mm long, all specimens with 35 chaetigers. Body slender, clearly divided into three regions by weak constrictions. Segments of thoracic region fairly well delimited, faintly annulated; segments of abdominal region multiannulate, with segmental limits less distinct. Cephalic region with oval nuchal organs and 2 chaetigers, thoracic region with 8 chaetigers, last of which (chaetiger 10) with 2+5 mammilliform papillae in a long, dorsoventrally oriented band just above notopodium of each side, reaching nearly to middorsum; chaetigers 9–16 with 2 mamilliform papillae more or less anterior to neuropodia, uppermost papilla of which sometimes interramal ( Figs. 4–5 ). Branchiae bifid, with 2 subequal, long smooth, slender branches. Chaetae all capillaries, without distal modification; chaetiger 1 uniramous, with single bundle of chaetae, chaetigers 2­29 biramous; notochaetae of 2–28 only slightly longer and more numerous than neurochaetae; notochaetae of 29 becoming much longer than neurochaetae ( Figs. 6–7 ); chaetigers 29– 34 (= last branchiate + all posterior abranchiate) uniramous, with only very long notochaetae, about twice as long as on chaetiger 28; notochaetae several times as long as those of preceding segments except for chaetiger 34, where they are only about half as long as on chaetigers 30–34. Extent of ventral groove unknown. Pygidium broad at base, tapering to double midventral anal cirri ( Fig. 7 ). Dorsal anal cirri disposed as a V over ventral plate, 12–18 in all, with 6–9 cirri on each side.

Records. Known from Lopes Mendes Bay, Ilha Grande and continental shelf off Rio de Janeiro State, SE Brazil, 22–45 m, coarse sand.

Remarks. Material of Euzonus sp. from southeastern Brazil was referred to as a new species, Euzonus mamillata [sic], by Nonato (1981) in an unpublished thesis, but was never published formally. The original material has been lost and it is therefore not possible to re­examine it or to fix the name on a type from one of the original specimens. According to the new International Code of Zoological Nomenclature (ICZN 1999, effective from 1 January 2000), a species described after 1999 can only be validly described if the name can be fixed on a type specimen (ICZN 1999 Art. 72.3). Dr. Paulo Paiva’s find of new material of the species from the same general area as the worms studied by Nonato makes it possible to fulfill this requirement.

Figures

FIGURES 4–7. Euzonus mammillatus sp. n., specimen from SE Brazil, Rio de Janeiro State, from Nonato (1981): 4. right lateral view of whole body; 5. details of lateral papillae on chaetiger 10 and branchiae; 6. posterior end, dorsal view; 7. posterior end, ventral view.