Acinetidae, Stein, 1859

Species of Acinetidae View in CoL View at ENA at Sylt, North Sea.

Küsters (1974) reported four species of Acinetidae collected at Königshafen in the northern part of Sylt in 1969 and 1970 from experimentally exposed artificial substrates, viz, Acineta compressa Claparède & Lachmann, 1858 , A. foetida Maupas, 1881 , A. tuberosa ( Ehrenberg, 1834) , and Loricophrya tuba . These species mentioned by Küsters (1974) did not occur on our kinorhynch specimens of Setaphyes kielensis collected at Königshafen in 1998 or on S. dentatus and S. kielensis collected at Kampen in 1988 and 2016, but a different species, viz, Trematosoma husselae sp. nov. was found 1998 and 2016 at Kampen but not at Königshafen at any time ( Tables 1–4 View TABLE 1 View TABLE 2 View TABLE 3 View TABLE 4 ; Küsters 1974). A suctorian species on the same basibionts and from the same location as in this study was briefly reported before by Neuhaus (2013, p. 331: “ Suctoria, possibly Acineta sp. , are also common ectocommensals on Pycnophyes dentatus and P. kielensis from intertidal mudflats in northern Germany; few to several specimens attach to any free area on the trunk cuticle (Fig. 5.8.1D, E; Neuhaus own obs.)”). It turned out that the identification of the epibiont at that time was erroneous, and we here assign the species to Trematosoma husselae sp. nov.