Trigonostomum armatum, (Jensen, 1878)

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 : 285-286

TRIGONOSTOMUM ARMATUM ( JENSEN, 1878)

GAMBLE, 1900

( FIGS 5B , 8A , 9B , 10B; TABLE 1)

Alternative species name: trigonostomum-armatum

Kylosphaera armata Jensen, 1878: 7 , 12, 14, 17, 45– 47, t. 3, figs 14–22.

Hyporhynchus armatus Graff, 1882: 337 ; Gamble, 1893: 466–467; Attems, 1897: 228, t. 2, fig. 26.

Trigonostomum armatum Gamble, 1900: 813 ; Southern, 1912: 3, 9; Graff, 1913: 305–307, fig. 265; Southern, 1915: 34; Meixner, 1924b: 89, 94, 96, 99–100, 102; 1925: 256; Steinböck, 1931: 13, 23; Southern, 1936: 45, 57; Steinböck, 1938: 13, 22; Ax, 1952: 90– 91, fig. 1; Westblad, 1954: 9.

Known distribution: Norway ( Jensen, 1878; Graff, 1882; Westblad, 1954), English Channel ( Gamble, 1893), North Sea ( Attems, 1897; Meixner, 1924b, 1925), Ireland ( Gamble, 1893, 1900; Southern, 1912, 1915, 1936), Faeroe Islands ( Steinböck, 1931), Iceland ( Steinböck, 1938), Baltic Sea ( Ax, 1952).

New localities: Norway, Bergen, Karlsög, on algae, 9 July 1953 , Westblad (coll. SMNH). Norway, Trondheim, Munkholmen , in sand, 45–50 m deep, 22 July 1955 . Westblad (coll. SMNH). Norway, Leröy-Buröy , in fine-grained sand, 5–7 m deep, 1 August 1968 , Karling (coll. SMNH; type locality) . United Kingdom, Plymouth, Salcombe, Saltstone, on algae, 11 July 1949, Westblad (coll. SMNH). Sweden, Gullmaren, Gåsövik, sheltered bay on brown algae, 19 August 2001 . France, Wimereux, Langue du Chien, on algae, 20 October 1999 . Curaçao (Dutch Antilles), Playa Canoa, on green algae, 10 December 1998 . Curaçao (Dutch Antilles), Dam di Cabicuchi , ‘Spaanse water’, on Turbinaria -like algae, 14 and 30 December 1998 and 5 January 1999 . Australia, New South Wales, Arrawarra, south of the marine station, on Sargassum sp., 1 November 1997 . New Caledonia, Nouméa, Nouville, on algae in a lagoon, 10 August 2003 . South Georgia, Cumberland Bay, May Creek , on seaweed, 9 May 1902 (coll. SMNH).

Material examined: Several individuals studied alive. Neotype ( SMNH, no. 46427) from Norway. Whole mounts from France (1), Australia (1), New Caledonia (1), Curaçao (10) and South Georgia ( SMNH, no. 46448). Serially sectioned specimens from Sweden (3), Curaçao (1), Norway ( SMNH, no. 46425–6) and Plymouth ( SMNH, nos. 46419–20).

Diagnosis: Trigonostomum species with coiled copulatory organ, with one whole spire. Stylet 158–434 Mm long, enveloped by the mantle over its entire length. Mantle distally split into two spiny plates with terminal hook. Bursal appendage 50–149 Mm long, with two tubules, proximally curved over 270∞ and with straight distal part.

Figures

Figure 5. Schematic representation of the copulatory organ of the representatives of group 2, showing the different number of spires (dashed lines indicate the location of the mantle plates). A, T. franki sp. nov. (1/ spire). B, T. armatum. (11/ 2 2 spires). C, T. setigerum. (21/ spires). D, T. australis sp. nov. (31/ spires). E, T. galapagoensis sp. nov. (41/ spires). F, 2 2 2 T. tori sp. nov. (51/ spires).

Figure 8. A, rostral spot in T. armatum (whole mounted specimen from Curaçao). B, dorsal stripe in T. setigerum (whole mounted specimen from Greece). C, bursal appendage of T. tori sp. nov. (from the paratype). D, constricted distal tubes of bursal appendage (arrow indicates constriction) in T. setigerum (specimen from Bermuda). E, copulatory organ of T. denhartogi comb. nov. (specimen from New Caledonia). F, copulatory organ of T. spinigerum sp. nov. (from the holotype). G, habitus of T. franki sp. nov. (live specimen from New Caledonia). H, bursal appendage of T. spinigerum sp. nov. (from the holotype). I, head region of T. franki sp. nov. showing both epidermal and subepidermal pigment (live specimen from New Caledonia). Scale bars: A, B = 200 Mm. C-F = 20 Mm. H = 10 Mm.

Figure 9. Copulatory organ of the representatives of group 2. A, T. franki sp. nov. (specimen from Curaçao) B, T. armatum (specimen from Curaçao). C, T. setigerum (from the neotype). D, T. australis sp. nov. (from the holotype). E, T. galapagoensis sp. nov. (from the holotype; after Ehlers and Ax, 1974: fig. 13C). F, T. tori sp. nov. (from the holotype). Scale bars: A-D, F = 20 Mm.

Figure 10. Copulatory organs and bursal appendages of the representatives of group 2. A, T. franki sp. nov. A1, 3 copulatory organ; A2, 4 bursal appendage (A1, 2 from the holotype; A3, 4 from a specimen from Kenya). B, T. armatum sp. nov. B1, 3 copulatory organ; B2, 4 bursal appendage (B1, 2 specimen from France; B3, 4 specimen from Curaçao). C, T. setigerum: C1 copulatory organ; C2 bursal appendage (specimen from Kenya). D, T. australis sp. nov. D1 copulatory organ; D2 bursal appendage (from the holotype). E, T. tori sp. nov. E1 copulatory organ; E2 bursal appendage (from the holotype).