Kainonereisalata Chamberlin, 1919.

https://www.marinespecies.org/polychaeta/aphia.php?p=taxdetails&id=324852.

Conde-Vela et al. (2018); Chamberlin (1919).

Dorsal cirrophores of chaetigers 5–7 of epitokes modified into flattened elytriform discs (minimal diagnosis). Notochaetae homogomph falcigers present; maxillary ring paragnaths absent; oral ring paragnaths absent; dorsal notopodial ligule not markedly reduced on posterior chaetigers (secondary diagnosis).

Palps anteriorly directed, or ventrally directed. Palpophore barrel-shaped, approximately equal width from base to palpostyle (not overly large compared with palpostyle). Prostomium the antennae are separate but sometimes basally fused in male epitokes. Tentacular cirri articulated.

Jaws with dentate cutting edge.

Maxillary ring of pharynx with papillae absent. Maxillary ring paragnaths absent. Oral ring paragnaths absent.

Dorsal notopodial ligule commences chaetiger 3, or chaetiger 4 (from chaetiger 4 in males, 3 in females); not markedly elongate on posterior chaetigers; not markedly reduced on posterior chaetigers. Prechaetal notopodial lobe present (subconical to digitate in atokes, rounded in epitokes). Dorsal cirrus not sub-terminally attached to dorsal notopodial ligule on posterior chaetigers.

Neuropodial prechaetal lobe absent. Neuropodial postchaetal lobe present; present throughout all chaetigers. Ventral neuropodial ligule of anterior chaetigers present. Ventral neuropodial ligule of anterior chaetigers approx. as long as acicular neuropodial ligule. Ventral neuropodial ligule on posterior chaetigers present.

Notoaciculae on chaetigers 1 and 2 absent. Notochaetae: homogomph spinigers present; homogomph falcigers present (in males, on anterior chaetigers); homogomph falcigers with multidentate blade with two or more small lateral teeth, first and subsequent lateral teeth much smaller than terminal tooth present. Neurochaetae dorsal fascicle: heterogomph spinigers absent; homogomph spinigers present; heterogomph falcigers in anterior chaetigers present. Neurochaetae ventral fascicle: heterogomph spinigers present; homogomph spinigers absent; heterogomph falcigers present; falcigers blade bowed, with convex margin.

Pygidium bilobate. Anal cirri form cirriform or conical.

Dorsal cirrophores of chaetigers 5–7 of epitokes modified into flattened elytriform discs. Natatory epitokal modifications in males commence chaetiger 15. Natatory epitokal modifications in females commence chaetiger 15.

Kainonereis was originally described for an epitokous specimen in which dorsal cirri of chaetigers 5–7 were expanded into elytra-like structures. Unless epitokes are available Kainonereis is not separable from Nicon and Websterinereis (this does not imply that Kainonereis is invalid). A revision by Conde-Vela et al. (2018) redefined the genus and included atokous characters; five species are now recognised and epitokes can be identified using the key of Conde-Vela et al. (2018).