Pisione parapari Moreira, Quintas & Troncoso 2000

Pisione parapari Moreira, Quintas & Troncoso, 2000

Material examined. MB 29 -000243, 1 specimen, site PC 91; MB 29 -000244, 1 specimen, site PC 132 (Table 1). Additional material: 3 specimens, site R 28; 13 specimens, site R 39; 6 specimens, site R 40; 9 specimens, site R 48; 1 specimen, site PC 87; 1 specimen, site PC 90; 42 specimens, site PC 91; 1 specimen, site PC 92; 109 specimens, site PC 132; 8 specimens, site PC 133; 1 specimen, site PC 137; 3 specimens, site PC 138; 1 specimen, site PC 222; 2 specimens, site PC 229; 1 specimen, site G 13 (2); 3 specimens, site G 21 (1); 4 specimens, site ALG 2; 14 specimens, site ALG 9; 2 specimens, site ALG 18; 6 specimens, site ALG 19; 1 specimen, site ALG 30; 1 specimen, site ALG 34; 16 specimens, site ALG 39; 1 specimen, site ALG 42; 1 specimen, site ALG 43; 3 specimens, site ALG 49; 2 specimens, site ALG 51; 3 specimens, site ALG 59; 4 specimens, site ALG 60; 1 specimen, site ALG 62; 5 specimens, site ALG 63; 10 specimens, site ALG 66; 11 specimens, site ALG 68; 2 specimens, site ALG 71; 1 specimen, site ALG 74 (Table 1).

Brief description. Width of 10 th chaetiger from 0.14 to 0.24 mm, total length from 2.24 to 7.60 mm, and total number of chaetigers ranging from 26 to 51. Buccal aciculae protrude obliquely the skin, not exceeding length of chaetiger 1, with a smooth distal margin. Prechaetal lobes entire. Dorsal cirri of chaetiger 2 is 1.3 to 1.6 times longer than the dorsal cirri of chaetiger 3 and following ones (cf. Table 2). All dorsal cirri globular-piriform, with a papilla with pilose tip, except on chaetiger 2 digitiform. Three types of chaetae: one long-bladed compound heterogomph chaeta with curved tip (blade length ranging from 21 to 28 µm; cf. Table 2), three short-bladed compound heterogomph chaetae and one supra-acicular simple chaeta distally bidentate. One stout notoaciculum embedded in all parapodia. Male genitalia with 2 to 3 pairs of copulatory organs appearing on chaetigers 11, 12, 21 (MB 29 -000243) or alternating on chaetigers 10, 18, 19, 20 in additional material (cf. Table 2). Female sexual organs not visible externally. Female gametes globular, with a diameter ranging from 38 µm to 64 µm, 49 µm in average, located in chaetigers 20–43 (MB 29 -000244) or earlier in additional material (19–28), depending on size of specimen. Pygidium with two long anal cirri.

Distribution and habitat. This species occurred in fine gravel (11 %), very coarse (14 %), coarse (63 %) and medium sand (11 %), with low total organic matter content, usually below 1 % of total sediment dry weight and high biogenic content (5.9 % in average). Specimens were recorded mainly in the near shore shelf of the western and southern Portuguese coast, between 3 and 80 m water depth, 24.6 m on average (cf. Table 3). The distribution depth range of this species is expanded since P. parapari was only previously recorded from 8 to 12 m (Moreira et al. 2000). This species was only known in the northern Iberian Peninsula and this study extends its southern limit to the southern sector of the Portuguese continental shelf (Fig. 1).

Remarks. In males, copulatory organs usually appeared in alternate parapodia, but in some cases they appeared in consecutive parapodia, which is not consistent with Moreira et al. (2000).