Laonice cf. quadridentata  

Prostomium blunt, anteriorly truncate or rounded, anterior margin with entire anterior margin. Lateral horns absent. Caruncle present, continuing back to chaetiger distinct caruncle which merges into a mid-dorsal ridge that extends well into the middle body region, usually until the end of the fragment. Occipital antenna present (distinct, finger-like, arising at the posterior part of the prostomium behind the eyes). Nuchal organ long, extending back more than one segment, extending posteriorly to chaetiger 4–15 (as double ciliary bands running along each side of the carunel and the middorsal ridge). Eyes present; 2 eyes (one pair of two large reddish to dark brown patches across the middle of the prostomium; sometimes almost touching each other). 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. 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. Neuropodial lobe of chaetiger 2 rounded, approximately symmetrical. Neuropodial lobes of posterior chaetigers a single lobe. Interparapodial pouches present. Interparapodial pouches on chaetigers 6–13 (beginning 6–13, continuous until end of fragment). Chaetigers 2–4 similar, not strongly differentiated. Chaetiger 5 unmodified, similar to subsequent chaetigers. Posterior modified notochaetae absent. Notopodial hooded hooks absent. Neurochaetae of chaetiger 1 simple capillaries similar to those of subsequent chaetigers. Neuropodial hooded hooks present, first present on chaetiger 26–33. 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. 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:
Greaves, Meißner & Wilson. 2011. New Laonice species (Polychaeta: Spionidae) from western and northern Australia. Zootaxa 2903: 1-20