Utelga heinckei ( Attems, 1897 ) Karling, 1954

Diez, Yander L., Monnens, Marlies, Aguirre, Rosa Isabel, Yurduseven, Rana, Jouk, Philippe, Van Steenkiste, Niels W. L., Leander, Brian S., Schockaert, Ernest, Reygel, Patrick, Smeets, Karen & Artois, Tom, 2021, Taxonomy and phylogeny of Koinocystididae (Platyhelminthes, Kalyptorhynchia) with the description of three new genera and twelve new species, Zootaxa 4948 (4), pp. 451-500 : 487

Utelga heinckei ( Attems, 1897) Karling, 1954

( Fig. 20A–C )

Known distribution. Western coast of USA, North Sea, Skagerrak, Irish Sea, Irish Atlantic coast ( Karling 1980 and references therein). Skagerrak ( Willems et al. 2007). Galapagos Islands ( Reygel et al. 2011). British Columbia, Canada ( Van Steenkiste & Leander 2018).

New records and material. Observations on live specimens. One whole mount (HU XIII.4.31) from Las Sardinas (19°56’24”N; 76°46’41”W), Santiago de Cuba, Cuba (June 21, 2017), on Cladophoropsis macromeres covered by silt, 0.7 m deep, salinity 32 ‰. One whole mount (HU XIII.4.32) and one serially-sectioned specimen (HU XIII.4.33) from Mala (29°05’0.53”N; 13°26’59”W), Lanzarote, Canary Islands (October 8, 2011), medium coarse calcareous sand, from a very steep slope, 48 m deep, salinity 35 ‰.

Remarks. The morphology of our specimens corresponds with the description of Karling (1980). Live specimens about 1 mm long, unpigmented, with a pair of eyes. The proboscis is about 10% of the body length. It shows the typical koinocystidid construction (see Brunet 1972; Karling 1980), without a juncture sphincter. The pharynx is located in the first body half. The testes lie caudal to the pharynx and ventral to the vitellaria. Two elongated ovaries are situated at the level of the copulatory bulb.

Copulatory bulb surrounded by a sheath of strong circular muscles. At the distal end of the copulatory bulb three sclerotised hooks ( Fig. 20A–C ) occur, which differ from each other in size. The largest hook is 13–14 μm long (n = 2) and 5–6 μm wide proximally (n = 2). The smaller hooks are 4–6 μm long (x̄ = 5 μm; n = 4) and 2–4 μm wide proximally (x̄ = 3 μm; n = 4).

Figures

FIGURE 20. Hooks in species of Utelga. A–C, Utelga heinckei. D–E, Utelga pseudoheinckei (specimen from Sardinia). A–B, specimen from Cuba. C, specimen from Lanzarote. All with proximal end toward top of figure.