Anisonychidae from Møbjerg et al. 2020: “Unplated, interstitial, marine heterotardigrades. Four claws inserted directly on each of the first three leg pairs, and three claws inserted directly on the fourth pair of legs (in adults). Paired basal hooks on all claws, with the two hooks oriented at right angles to one another. Median cephalic cirrus is always present, but can be reduced. Cephalic appendages include internal and external cirri, lateral cirri (cirri A) and generally also primary clava and flat, often indistinct, secondary clava. Cirri E is always present. Papillae on leg IV are often present, and sensory structures on legs I–III may also be present (presently seen in only one species, Anisonyches mauritianus Grimaldi de Zio, D’Addabbo Gallo, Morone De Lucia & D’Addabbo, 1987). Black eyes are present. Stylets are long, with stylet sheaths; stylet supports are lacking. The three placoids are CaCO3 incrusted. Paired seminal receptacles are present in females. The coiled receptacles open relatively distant from the six-lobed female gonopore. The anal system consists of two lateral lobes connected by a median zig-zag structure, with the anus formed by a small terminal pore.”
Citations:
Møbjerg, N., Jørgensen, A. & Kristensen, R.M. (2020) Ongoing revision of Echiniscoididae (Heterotardigrada: Echiniscoidea), with the description of a new interstitial species and genus with unique anal structures. Zoological Journal of the Linnean Society, 188 (3), 663–680.
