Polycirrus paivai, Garraffoni, André R. S. & Costa, Elisa M., 2003

Garraffoni, André R. S. & Costa, Elisa M., 2003, Two new species of Polycirrus (Polychaeta, Terebellidae) from Abrolhos Archipelago, Brazil, Zootaxa 297, pp. 1-7 : 5

Polycirrus paivai sp. nov. (figs. 5–9)

Holotype: Abrolhos Archipelago, 17° 58’44’’ S, 038° 42’41’’ W, 1 complete specimen, 10 mm in length, 0,72 mm in width, approximately 55 segments, IBUFRJ­0484.

Paratypes: all from Abrolhos Archipelago, IBUFRJ­0485 (1 specimen), IBUFRJ­0486 (3 specimens), IBUFRJ­0487 (1 specimen), MCEM­1304 (1 specimen).

Description. Prostomium laterally expanded and difficult to distinguish dorsally and latterally from the peristomium with only one type of bucal tentacles attached along the distal margin ( Fig. 5 ). Peristomial upper lip trilobate with convoluted lateral lobes, and peristomial lower lip forming a large, wrinkled, cushion­like pentagonal structure. Ventrolateral glandular pads on anterior segments ( Fig. 5 ).

Notopodia from segment 2, 12 pairs with a short and elongate digitiform lobe ( Fig. 6 ). All notochaetae similar in size and arranged in 2 tires: pinnate capillaries and smooth capillaries with narrow wings throughout the body ( Figs 7, 8 ). First neurochaetae from segment 11 and then continuing to the last segment before the pygidium, uncini arranged in a single row with flat base and short thick neck and a characteristic upward projecting button below main fang ( Fig. 9 ). Dental formula MF:3:2, with 9–12 neurochaetae per row, number consistent from all setigers.

Nephridial papillae not observed.

Discussion. Polycirrus paivai is similar to P. parvus and P. paucidens in having uncini with a flat base and short thick neck and a characteristic upward projecting button below main fang and to P. bricrinalis in having 2 types of notochaeta, pinnate and smooth with narrow wings. Polycirrus paivai can be distinguished from above species by the number of the thoracic notopodia, 12.

Distribution. Abrolhos Archipelago, Bahia State, Eastern Brazilian coast, 10 m, associated with calcareous algae.

Etymology. The species is named after two great biologists; Dr. Paulo Cesar de Paiva, who studies polychaetes; and for his father, Antonio Elizeu de Paiva, who was a great Biology teacher.

Figures

FIGURES 5 – 9. Polycirrus paivai n sp.: 5, ventral view of head end; 6, anterior view of notopodium from anterior thorax; 7, capillary notochaeta from anterior thorax; 8, other kind of notochaeta from anterior thorax; 9, laterial view of anterior uncinus. Scale bars 90 m (5), 22. 2 m (6), 9. 9 m (7,9), 20 m (8).