Unanereismacgregori Day, 1962.

https://www.marinespecies.org/polychaeta/aphia.php?p=taxdetails&id=129384.

Day (1962).

Dorsal cirrus terminally attached to dorsal notopodial ligule on posterior chaetigers; dorsal notopodial ligule not markedly broader on posterior chaetigers (minimal diagnosis). Notochaetae sesquigomph falcigers present; prostomium anterior margin entire (secondary diagnosis).

Antennae present (described as having a single antenna but this is here assumed to be a mistake; likely a developmental anomaly or simply missing). Tentacular belt greater than length of chaetiger 1.

Jaws with dentate cutting edge.

Maxillary ring of pharynx with papillae absent. Maxillary ring paragnaths present. Area II conical paragnaths present; III conical paragnaths present; III rod-like paragnaths absent; IV paragnaths present; IV conical paragnaths present; IV rod-like paragnaths absent. Oral ring papillae absent. Oral ring paragnaths absent.

Dorsal notopodial ligule markedly elongate on posterior chaetigers; not markedly broader on posterior chaetigers; not markedly reduced on posterior chaetigers. Dorsal cirrus not sub-terminally attached to dorsal notopodial ligule on posterior chaetigers; terminally attached to dorsal notopodial ligule on posterior chaetigers; not terminally attached throughout all chaetigers.

Neuropodial prechaetal lobe present; extending beyond postchaetal lobe (at least in anterior chaetigers). Neuropodial postchaetal lobe present; projecting beyond end of the acicular ligule; flattened. 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. Ventral neuropodial ligule on posterior chaetigers short, up to half length of acicular neuropodial ligule.

Notochaetae: homogomph spinigers present; sesquigomph falcigers present; blade distally bifid. Neurochaetae dorsal fascicle: heterogomph spinigers absent; homogomph spinigers present; heterogomph falcigers in anterior chaetigers present; on posterior chaetigers present. Neurochaetae ventral fascicle: heterogomph spinigers present; homogomph spinigers absent; heterogomph falcigers present; heterogomph falcigers blade terminally bifid.

Unanereis Day, 1962 was described from a single specimen found in the tube of a species of Terebellidae. A second species, U.zghali Ben Amor, 1980, from a vertical rocky substrate including dendrophyllid coral Astroidescalycularis and algae Corallinamediterranea but without an obvious host, has been described from the Mediterranean (Ben Amor 1980). As noted by several studies, the validity of Unanereis is doubtful and the genus may represent developmental anomalies in specimens belonging to Ceratonereis or Solomononereis (Bakken and Wilson 2005; Santos et al. 2005; Bakken et al. 2022).