Marphysa kinbergi McIntosh 1910

Marphysa kinbergi McIntosh, 1910 (Figures 6, 7)

Marphysa kinbergi McIntosh 1910: 451, pl. 74–83, fig. 9; Orensanz 1975: 103, pl. 6; Campoy 1982: 753.

Holotype, 1921.5.1.2021, off Cape Finisterre, Spain, Northeast Atlantic Ocean, M 9, 148 m, hard bottom with sandy mud, Lat./Log. 42.7333 / –9.3833, Porcupine Expedition, coll. McIntosh.

Type material in poor condition. Incomplete specimen (NHM-1921.5.1.2021) with 53 chaetigers; L10 = 7.4 mm, W10 = 2.3 mm, TL = 23.17 mm. Body cylindrical, light pink in colour (Figure 6A). Prostomium slightly bilobed anteriorly, as long as wide, with five prostomial appendages. Prostomium (1.2 mm) slightly shorter than peristomium (1.3 mm).

Prostomial appendages in a horseshoe pattern, longer than prostomium, similar thickness. Palps shorter than antennae, digitiform, reaching middle of second peristomial ring. Antennae tapering, median antenna slightly longer than lateral antennae. Lateral antennae reaching middle of chaetiger 2, median antenna reaching front of chaetiger 3. Palpophores and ceratophores short, wider than long. Palpostyles and ceratostyles without articulations. Eyes absent. Peristomium cylindrical with two distinct rings; anterior ring (0.8 mm) longer than posterior one (0.5 mm). Peristomial cirri absent.

Maxillary apparatus with five pairs of maxillae. Maxillary formula = 1 + 1; 5 + 6; 6 + 0; 3 + 6; 1 + 1.

Branchiae pectinate, from chaetiger 15 to 30, longer than dorsal cirri; 10 filaments at first one, up to 24 at chaetiger 27, stems tapering; filaments tapering, similar in size and thickness.

Anterior dorsal cirri cylindrical, longer than parapodia after chaetiger 2 to chaetiger 11, twice as long as parapodia after chaetiger 11 to chaetiger 20; elongated and spindle shaped in median parapodia (between chaetigers 21 and 40), tapering, filament shaped in posterior parapodia (between chaetigers 41 and 53). First ventral cirri small and conical, basally slightly inflated; postbranchial ventral cirri reduced to small swellings (between chaetigers 32 and 53).

Prechaetal lobes as transverse fold in all chaetigers. Postchaetal lobes rounded in all chaetigers, decreasing gradually until becoming inconspicuous (Figure 7).

Supra-acicular chaetae with six to eight limbate in all chaetigers and two or three pectinate chaetae in all chaetigers except anterior ones. Subacicular chaetae with eight to ten compound spiniger chaetae. Limbate chaetae slender, marginally smooth (Figure 6B); one type pectinate chaetae present from postbranchial segments, heterodont, marginal teeth longer than others, shafts narrow, thick, with eight to ten teeth (Figure 6D); compound spiniger chaetae with smooth and tapering blade approximately 190 µm long (Figure 6C, F); shafts inflated. Compound falciger chaetae absent. Aciculae black with pale tips, two or three per parapodia, distally blunt. Subacicular hooks from chaetiger 37, dark brown with light tips, unidentate (Figure 6E), distally blunt or slightly curved.