Lumbrineris pinaster, Martins, Roberto, Carrera-Parra, Luis F., Quintino, Victor & Rodrigues, Ana Maria, 2012

Martins, Roberto, Carrera-Parra, Luis F., Quintino, Victor & Rodrigues, Ana Maria, 2012, Lumbrineridae (Polychaeta) from the Portuguese continental shelf (NE Atlantic) with the description of four new species, Zootaxa 3416, pp. 1-21 : 15-17

Lumbrineris pinaster sp. nov.

Figure 5

Material examined. Type material: Holotype ( MNHN TYPE 1541) western Portuguese continental shelf (off Tagus Estuary, Lisbon), site PC115, 38º35.368ʹ N 9º25.567ʹ W, in mud, 97.7 m. Paratypes: ECOSUR0131, 1 specimen, site PC187. MB29-000234, 1 specimen, site PC203. MB29-000235, 10 specimens, site G19(2). MB29- 0 0 0 236, 3 specimens, site G28(1). MB29-000237, 3 specimens, site G28(2). DBUA 0 1318.01, 3 specimens, site G22(1). DBUA 0 1318.02, 10 specimens, site G19(2). Additional material: site G19(2), 9 specimens; site G22(1), 17 specimens; site PC114, 4 specimens; site PC118, 1 specimen; site PC187, 9 specimens; site PC188, 1 specimen; site PC195, 2 specimens; site PC201, 1 specimen; site PC208, 1 specimen; site PC229, 1 specimen; site ALG86, 6 specimens; site G25(3), 12 specimens; site G28(1), 15 specimens; site G28(2), 31 specimens.

Description. Holotype incomplete with 101 chaetigers, LT= 18.1 mm, L10= 1.6 mm, W10= 0.4 mm. Prostomium conical, as long as wide, with a pair of nuchal organs, ventrally with short buccal lips. Peristomium half the length of prostomium, with two rings; anterior ring 0.75 of total peristomial length ( Fig. 5 A).

All parapodia well developed, first four smaller than following ones. Prechaetal lobe rounded with globular protuberance directed dorsally, increasing in size gradually from chaetigers 1 to 12, preserving shape and size to end; always smaller than postchaetal lobe. Postchaetal lobe auricular from parapodia 1 to 13, gradually transforming to digitiform lobe, clearly visible from parapodium 30; longer in posterior parapodia ( Fig. 5 B–D). Short rounded dorsal cirri in all parapodia.

Composite multidentate hooded hooks in chaetigers 1–10, 2–3 per chaetiger, with long blade, up to 7 teeth, all of similar size ( Fig. 5 E). Simple multidentate hooded hooks of two types; from chaetiger 11 to 22, with long hood, up to 7 teeth, proximal tooth slightly largest ( Fig. 5 F); from chaetiger 23 with short hood, up to 5 teeth, proximal tooth largest. Preacicular hook with a section that is twice as large as the postacicular hook ( Fig. 5 G-H). Dorsal limbate chaetae in chaetigers 1–41, ventral limbate chaetae in chaetigers 1–12. Aciculae yellow, aristate, up to two per chaetiger.

Pygidium with terminal anus and two pairs of anal cirri (paratype MB29-000234).

Mandible divided for about half its length. Maxillary apparatus with five pairs of maxillae; maxillary carriers as long as MI, anterior end constricted. MI forceps-like with well-developed attachment lamella. MII as long as MI, with wide connecting plates slightly developed; with four teeth of similar size. MIII unidentate, followed by a knob,.MIV unidentate with a well-developed plate. MV free, prominent, lateral to MIV and MIII ( Fig. 5 I).

Variations. The specimens examined ranged in L10 from 1.3 to 2.5 mm, in W10 from 0.4 to 0.7 mm, and varied in the following features: the last composite multidentate hooded hooks were observed from chaetiger 7 to 12; the first simple multidentate hooded hooks with long hood from chaetiger 8 to 13; the first simple multidentate hooded hooks with short hood from chaetiger 19 to 35; the end of ventral limbate from chaetiger 10 to 15; and the end of dorsal limbate from chaetiger 36 to 45 (cf. Table 2).

Reproduction. Mature specimens were only found in October. The male gametes of Lumbrineris pinaster sp. nov. are located posteriorly to chaetiger 37 (paratypes MB29-000235, MB29-000236, MB29-000237, DBUA 0 1318.01, DBUA 01318.02); they have a long tail and a subspherical nucleus with diameter between 2.5 and 3 µm. The female gametes cells are located from parapodia 38 (paratypes MB29-000235, MB29-000236, MB29-000237, DBUA 0 1318.01, DBUA 01318.02), the morphology is globular with diameter from 98 µm to 147 µm.

Distribution and habitat. This species occurred only on the southern Portuguese continental shelf and off the Tagus Estuary at shelf depths. It was mainly found at nearly 50 m depth (cf. Table 3 ). The species shows a preference for mud, very fine and fine sands. Sediments are characterized by high fines, biogenic and TOM contents (averaging, 39.7%, 6.4% and 4.7% respectively) (cf. Table 3 ). Although the northwestern deeper shelf is dominated by finer sediments ( Martins et al. 2012), the species was not recorded there. It is possible that the Lisbon/Cascais canyons, located in the western margin, could set a barrier to the distribution of this species. It is expected that Lumbrineris pinaster sp. nov. might also occur in the Gulf of Cádiz muddy area (southwestern Spain), which is a continuation of the extensive mud patch present in the southern Portuguese shelf.

Type locality: Off the Tagus Estuary (Lisbon), Portugal.

Etymology. The specific name was derived from the Maritime Pine seed ( Pinus pinaster ) which has a peculiar wing, resembling the Maxillae IV of this Lumbrineris .

Discussion. Lumbrineris pinaster sp. nov. belongs to the same group of species as L. lusitanica sp. nov. characterized by having an unidentate MIII, followed by a knob. Lumbrineris pinaster sp. nov. and L. lusitanica sp. nov. differ from L. amboinensis , L. grandis , L. futilis and L. reunionensis by having yellow aciculae, whereas they are black or dark red in all the other. Additionally, L. pinaster sp. nov. differs from L. amboinensis , L. grandis , and L. lusitanica sp. nov. by having composite multidentate hooded hooks with long rather than short blade. Furthermore, L. pinaster sp. nov. differs from all these species by having preacicular SMHH twice as big as postacicular SMHH, while the other species have SMHH of similar size. Among all Lumbrineris species with MIII unidentate followed by a knob, L. pinaster sp. nov. is unique by having postchaetal lobe auricular in anterior parapodia.

Figures

FIGURE 5. Lumbrineris pinaster sp. nov. Paratype (ECOSUR 0131) A, anterior end, dorsal view; B, parapodium 3, frontal view; C, parapodium 13, frontal view; D, parapodium 153, frontal view; E, composite multidentate hooded hook, from parapodium 3; F, simple multidentate hooded hook with long hood, from parapodium 13; G, preacicular simple multidentate hooded hook with short hood, from parapodium 79; H, postacicular simple multidentate hooded hook with short hood, from parapodium 79; I, maxillae III and IV, dorsal view. Scale bars: A, 0.4 mm; B, C, 0.5 mm; D, I, 0.025 mm; E, F, 0.012 mm.