Trigonostomum messoplanoides, Artois, Vermin & Schockaert, 2000

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 : 289

TRIGONOSTOMUM MESSOPLANOIDES ARTOIS ET AL., 2000

( FIG. 6B )

Alternative species name: trigonostomummessoplanoides

Trigonostomum messoplanoides Artois et al., 2000: 104–105 , fig. 1.

Known distribution: Weddell Sea, Antarctica ( Artois et al., 2000).

Material examined: Holotype ( LUC, no. 207).

Diagnosis: Trigonostomum species with stylet 225 Mm long, proximally bent over 270∞. Mantle with stylet 75 Mm long, flagelliform spine surrounding only the distal part of the stylet. Bursal appendage 22 Mm long, with a proximal ring and two distal tubes.

Remarks: The copulatory organ of T. messoplanoides resembles that of some species of Messoplana ( Artois et al., 2000) , for instance M. elegans ( Luther, 1948) Den Hartog, 1966 , M. helgolandica Ax, 1971 , M. pacifica Karling, 1986 and M. rugata Ehlers, 1974 . However, the presence of a ventral invagination clearly confirms that it is a species of Trigonostomum .

Figures

Figure 6. Copulatory organs and bursal appendages of the representatives of group 1A. A, T. venenosum: A1, 3 copulatory organ; A2, 4 bursal appendage. (A1, 2 specimen from Norway, neotype; A3,4 specimen from Sardinia). B, T. messoplanoides: B1 copulatory organ; B2 bursal appendage. (from the holotype; after Artois et al., 2000).