Ichthydium Ehrenberg 1830

Kolicka, Małgorzata, Kisielewski, Jacek, Nesteruk, Teresa & Zawierucha, Krzysztof, 2013, Gastrotricha from the Poznań Palm House — one new subgenus and three new species of freshwater Chaetonotida (Gastrotricha), Zootaxa 3717 (2), pp. 231-279 : 270

Genus: Ichthydium Ehrenberg 1830

Typus generis: Ichthydium podura (Müller, 1773) Terra typica : Denmark

In view of the different geneses of cuticle construction, the genus Ichthydium is clearly considered to be polyphyletic and artificial taxon (Kisielewski 1997a; Kieneke et al. 2008; Kånneby et al. 2009; 2013) and encompasses 34 nominal freshwater species and 1 nominal marine species.

It is present in benthic, interstitial and peryphytic habitats.

Character Specimen Body length 135.0 Pharynx length 33.8 Width of anterior pharynx thickening (a) 7.8

Width of pharynx narrowing that follows anterior thickening (n) 5.8

Width of pharynx at its middle length (m) 6.0

Width of posterior pharynx thickening (p) 8.2

Length of cephalic cilia 7.2–19.6 Hypostomium length?

Cephalion length 5.1

Cephalion width 13.8 Diameter of mouth ring 4.6

Furca length 14.5 Length of adhesive tube 6.1

Length keels transformed into spines 3.6

Neck scale length 3.4–4.3 Neck scale width 1.3–1.9 Trunk scale length 4.4–5.4 Trunk scale width 1.9–2.3 Anterior sensory bristles length 8.3

Posterior sensory bristles length 7.0

Number of cephalic cilia in one tuft 5 (anterior); 4 (posterior) Number of separated cephalic tufts 4

Number of scales in longitudinal row 26

Total number of longitudinal alternating rows of scales 24

Pharynx formula a 23.1 Pharynx formula n 17.2 Pharynx formula m 17.8 Pharynx formula p 24.3 Ratio of scale distribution 92.3