Trigonostomum breitfussi

TRIGONOSTOMUM BREITFUSSI (GRAFF, 1905) MEIXNER 1924

(FIG. 7E)

Alternative species name: trigonostomum-breitfussi.

Hyporcus breitfussi Graff, 1905: 112, t. 3, figs 12–16; 1913: 301–302, figs 261, 262.

Hyporhynchus breitfussi Meixner, 1925: 256.

Trigonostomum breitfussi Meixner, 1924b: 89, 91–94, 96–99, 105, figs 3, 4; Steinböck, 1932: 309; Ax, 1952: 91–92, fig. 2; Westblad, 1954: 9; Armonies & Hellwig-Armonies, 1987: 104, table 5; Joffe & Kotikova, 1989: 70–72, 74–77, 79–82, figs 2, 3, 6 and 7.

Known distribution: Barents Sea (Graff, 1905), Baltic Sea (Ax, 1952), Greenland (Steinböck, 1932), North Sea (Meixner, 1924b, 1925; Ax, 1952; Armonies & Hellwig-Armonies, 1987), Norway (Westblad, 1954).

New locality: Sweden, Gullmaren, Kristineberg, 23, 26 and 27 July 1932, Westblad (coll. SMNH; type locality). Sweden, Gullmaren, on algae, 6 August 1945, Westblad (coll. SMNH). Sweden, Gullmaren, Harpo Bedar, on red algae, 20 m deep, 7 August 2001.

Material examined: Observations on live material from Sweden. Neotype (SMNH, no. 47461). Two whole mounts (SMNH, nos. 47462–3) and two serially sectioned specimens (SMNH, nos. 47469–70) from Sweden.

Diagnosis: Trigonostomum species with copulatory organ ± 62 Mm long. Stylet ± 64 Mm long, proximally bent over, 180∞ and with a crest. Mantle with one blunt plate (shorter than the stylet), surrounds only the distal part of the stylet. Bursal appendage 20– 24 Mm long, proximally with a barrel-like casing and nine or ten distal tubes.

Remarks: The observation of Ax (1952) that there is only one plate-like structure instead of two (Graff, 1905), surrounding the tubiform stylet, can be confirmed. This plate has a spine-like projection at its distal end, which lies close to the stylet but is displaced in highly squeezed animals (Fig. 7E 1). The bursal appendage is short (Graff, 1913 24 Mm; Ax, 1952: 20– 21 Mm), barrel-shaped and consists of nine, maybe ten, short tubes (Fig. 7E 3).