Ichthydium tanytrichum Balsamo, 1982

Kånneby, Tobias, Todaro, Antonio & Jondelius, Ulf, 2009, One new species and records of Ichthydium Ehrenberg, 1830 (Gastrotricha: Chaetonotida) from Sweden with a key to the genus, Zootaxa 2278, pp. 26-46 : 32

Ichthydium tanytrichum Balsamo, 1982

( Figures 7A, B ; Table 4)

Localities: Ånnsjön, Jämtland, Sweden (63º15.637’N; 12º27.090’E).

Material: 1 specimen.

Remarks: Ichthydium tanytrichum is short and plump with a long tong-shaped furca. The Swedish specimen was an adult specimen of 126 µm in total body length and agrees well with descriptions provided by Balsamo (1982). The bi-keeled scales anchoring the posterior bristles as well as the large rectangular ventral terminal scales and the four pairs of long ventral ciliary tufts in the trunk region were clearly visible. Balsamo (1982) reports a total body length of only 74–76 µm for I. tanytrichum . In our opinion the specimens found by Balsamo (1982) were probably sub-adults based on the fact that the original drawing of this species was depicted without an egg, and most important the length of the pharynx is proportionally too long compared to total body length, a trait that is typical for sub-adult animals. PhIJ at U27; ASB at U18; PSB at U71.

Associated gastrotrich fauna: Aspidiophorus tetrachaetus Kisielewski, 1986 , Chaetonotus armatus Kisielewski, 1981 , C. heideri Brehm, 1917 and C. polyspinosus Greuter, 1917 .

Figures

FIGURE 7. A – D) Subgenus Forficulichthys continued; E) Subgenus Pseudichthydium; F – H) Incertae sedis. A) Ichthydium tanytrichum dorsal and B) ventral view. C) I. skandicum n. sp. dorsal and D) ventral view. E) I. balatonicum dorsal view. F) I. chaetiferum ventral view. G) I. cyclocephalum dorsal and H) ventral view. A – D, original; E, modified from Schwank (1990); F, modified from Kisielewski (1991); G, H, modified from Grünspan (1908). Scale bars: 20 µm.