Laonice antarcticae Hartman, 1953

Prostomium blunt, anteriorly truncate or rounded, anterior margin with entire anterior margin. Lateral horns present, or absent (horns developed to varying degrees on som specimens). Caruncle present, continuing back to chaetiger 5–12. Occipital antenna present. Nuchal organ short, at most one segment long, extending posteriorly to chaetiger 5–12. Eyes present, or absent; 2–4 eyes. Palps simple, lacking basal sheath. Dorsal ridge connecting bases of branchiae on chaetiger 1 absent. Prominent dorsal collar on setiger 2 absent. Dorsal branchiae present, first present on chaetiger 2. Dorsal branchiae absent from many median and posterior chaetigers, last present on chaetiger 30. Dorsal branchiae free and separate from notopodial lamellae throughout. First branchiae without process at base on anterior face. Accessory branchiae arising from posterior part of notopodium absent. Ventral branchiae absent. Chaetiger 3 without filament at base of branchiae. Dorsal crests absent. Ventral crests absent. Chaetiger 1 notopodium present. Anterior setigers with 2 rows of chaetae. Neuropodial lobe of chaetiger 2 rounded, approximately symmetrical. Neuropodial lobes of posterior chaetigers a single lobe. Interparapodial pouches present. Interparapodial pouches on chaetigers 3–4 (start between setigers 3/4 or 4/5). Chaetigers 2–4 similar, not strongly differentiated. Chaetiger 5 unmodified, similar to subsequent chaetigers. Posterior modified notochaetae absent. Neurochaetae of chaetiger 1 simple capillaries similar to those of subsequent chaetigers. Neuropodial hooded hooks present, first present on chaetiger 21–40 (9–12 per fascicle). Neuropodial hooded hooks with accessory tooth or teeth above the main fang, 2 accessory teeth (tridentate). Shaft of neuropodial hooded hooks of constant thickness, lacking a constriction. Neuropodial sabre chaetae present, in ventral-most positions, first on chaetiger(s) 23–24 (1 per fascicle). Neuropodial spines absent. Embedded bunches of notopodial needle chaetae absent. Pygidium unknown.

Description generated from: Wilson, RS & McDiarmid, H 2013. Spionidae (Polychaeta)- A DELTA database of genera, and Australian species. Version 2; originally published as In RS Wilson, PA Hutchings & CJ Glasby (eds) Polychaetes: An Interactive Identification Guide. CSIRO Publishing, Melbourne.

Additional references:
Hartman, O. 1978. Polychaeta from the Weddell Sea quadrant Antarctica. Antarctic Research Series 26: 125-223; Blake, J.A. 1983. Polychaetes of the family Spionidae from South America, Antarctica, and adjacent seas and islands. Antarctic Research Series 39: 205-287.