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Taxonomy
Laonice lemniscata Greaves, Meißner & Wilson, 2011
SUMMARY
Prostomium blunt, anteriorly truncate or rounded, anterior margin with entire anterior margin or bifid, with anterior margin indented (prostomium is either rounded or very slightly indented). Lateral horns absent. Caruncle present, continuing back to chaetiger 9–10 (the caruncle is continuous with the prostomium, narrows at about the level of the 2nd chaetiger, and then extends back to the 9th or 10th chaetiger; difficult to determine due to split dorsum). Occipital antenna present (long). Nuchal organ long, extending back more than one segment, extending posteriorly to chaetiger 15–16 (long, u-shaped, appears continuous with the peristomium, runs the length of the caruncle). Eyes present; 4 eyes (appear as 1 pair; 1 dark brown pair, edged anteriorly and laterally by a lighter cresent-shaped pair). Palps simple, lacking basal sheath. The caruncle/nuchal organ structure is similar that to that illustrated for Laonice petersenae. Palps missing from all specimens. 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 continue to near posterior end of body. Dorsal branchiae continuous. Dorsal branchiae free and separate from notopodial lamellae throughout, all simple (but distinctly ciliated on inner margin). First branchiae without process at base on anterior face. Dorsal branchiae longest on median chaetigers, decreasing in length anteriorly and posteriorly (branchiae on chaetiger 2 are approximately the same height as the free section of the notopodial lobe, by about the 7th chaetiger they are about 2 times the height of the free section of the notopodial lobe, and in the posterior half of the specimen they are up to 3 times the height of the free portion of the lobes (due to the smaller size of the notopodial lobe; the branchiae are longest in the anterior third of the specimen). Accessory branchiae arising from posterior part of notopodium absent. Ventral branchiae absent. Chaetiger 3 without filament at base of branchiae. Dorsal crests present; first dorsal crest present on chaetiger 10 (initially separated by nuchal organ/caruncle then full crests from about setiger 15, ciliated). Ventral crests absent. Chaetiger 1 notopodium present. Chaetiger 1 notochaetae 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 9–61 (starting between 9 and 12 and continuing posteriorly to end of fragment). Notopodial postchaetal lobes - reduced on chatiger 1; leaf-like, slightly poined until about chaetiger 4, then becoming more rounded and gradually reducing to a small round lobe. Neuropodial postchaetal lobes - leaf-like from chaetiger 1; dorsally rounded and ventrally pointed until about he 15th chaetiger, then rounded and reducing in size; very small by about the 25th chaetiger. 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 17–22 (4–5 per fascicle). Neuropodial hooded hooks with accessory tooth or teeth above the main fang, 2 accessory teeth (tridentate) (bi- or tri-; tooth above main fang may or may not have smaller apical tooth). Shaft of neuropodial hooded hooks of constant thickness, lacking a constriction. Neuropodial sabre chaetae present, in ventral-most positions, first on chaetiger(s) 10–11 (1–2 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:
Greaves, Meißner & Wilson. 2011. New Laonice species (Polychaeta: Spionidae) from western and northern Australia. Zootaxa 2903: 1-20