Trigonostomum breitfussi, (Graff, 1905)

Willems, Wim R., Artois, Tom J., Vermin, Wouter A. & Schockaert, Ernest R., 2004, Revision of Trigonostomum Schmidt, 1852 (Platyhelminthes, Typhloplanoida, Trigonostomidae) with the description of seven new species, Zoological Journal of the Linnean Society 141 (2), pp. 271-296 : 286

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 ).

Figures

Figure 1. Habitus of live animal (Trigonostomum venenosum). Abbreviations: ac, apical tuft of cilia; b, brain; ba, bursal appendage; bu, bursa; cop, copulatory organ; e, eye; gp, common genital pore; i, antero-ventral invagination; m, mouth; ov, ovary; ph, pharynx; rg, rostral rhabdite glands; t, testis; vg, prostate vesicle; vit, vitellary; vs, seminal vesicle.

Figure 3. Reconstruction on sagittal sections of the genital system from the left hand side (T. franki sp. nov.). Abbreviations: ba, bursal appendage; bs, bursal stalk; bu, bursa; cga, common genital atrium; cop, copulatory organ; ds, spermatic duct; fd, female duct; fg, female glands; gp, common genital pore; n, nucleus; od, oviduct; ov, ovary; rh, rhabdite; sd, seminal duct; vg, prostate vesicle; vit, vitellary; vs, seminal vesicle.

Figure 7. Copulatory organs and bursal appendages of the representatives of group 1B, A, T. coronatum: A1 copulatory organ; A2 bursal appendage. (from the neotype). B, T. watsoni sp. nov. B1, 2 copulatory organ; B3 bursal appendage (B1 from the holotype; B2, 3 from the paratype). C, T. penicillatum: C1 copulatory organ; C2 bursal appendage (from the neotype). D, T. lilliei: D1, 3 copulatory organ; D2, 4 bursal appendage. [D1, 2 specimen from Australia; D3, 4 specimen from the USA (neotype = holotype of T. prytherchi)]. E, T. breitfussi: E1 copulatory organ; E2 bursal appendage; E3 section through the bursa and the bursal appendage (different specimens from Sweden; E2, 3 freehand drawings). F, T. mirabile: F1, 2 copulatory organ; F3 bursal appendage (F1, 3 from the neotype; F2 from another specimen from the Black Sea). G, T. nataschae sp. nov. G1 Copulatory organ; G2 Bursal appendage (from the holotype).