Lysilla Malmgren, 1866

Nogueira, João Miguel Matos, Hutchings, Pat & Carrerette, Orlemir, 2015, Polycirridae (Annelida, Terebelliformia) from Lizard Island, Great Barrier Reef, Australia, Zootaxa 4019 (1), pp. 437-483 : 443

Genus Lysilla Malmgren, 1866

Lysilla .— Hutchings & Glasby 1986: 325.

Type-species. Lysilla loveni Malmgren, 1866 , by original designation.

Diagnosis. Transverse prostomium attached to dorsal surface of upper lip; basal part as thick horseshoe-shaped crest; distal part restricted to base of upper lip, with flaring lobes and sometimes also a mid-dorsal process. Buccal tentacles of three types, short tentacles thin, uniformly cylindrical, intermediate ones spatulated, long buccal tentacles spatulated or more specialised, with uniformly cylindrical peduncle distally widening towards cylindrical swelling and pointed to blunt tip. Peristomium forming lips; upper lip large, frequently circular and convoluted, folded into three lobes; short and swollen lower lip, only mid-ventral and usually button-like. Segments biannulated throughout, segment 1 reduced, usually visible dorsally and ventrally, laterally covered by expanded prostomium. Segment 2 distinctly short, narrower than following segments, with rectangular or pentagonal midventral shield at beginning of mid-ventral groove, sometimes extending anteriorly through segment 1 until near posterior margin of lower lip. Body wall papillate throughout, papillae distinctly larger and more abundant on ventro-lateral pads of anterior segments; pads usually from segment 2 to last with notopodia. Notopodia beginning from segment 3, extending for few segments; bilobed, elongate notopodia, lobes about same size; notochaetae throughout usually with distinctly narrow wings, acicular, wings inconspicuous under light microscopy, only visible under SEM; pinnate chaetae sometimes present. Neuropodia absent. Nephridial and genital papillae usually present, at anterior bases of all notopodia. Pygidium smooth or with rounded ventral papilla.

Remarks. The genera Lysilla and Amaeana are very similar, the only difference being the presence of neuropodia bearing acicular spines in the latter genus, while neuropodia and neurochaetae are absent in Lysilla . As a consequence, incomplete specimens are unidentifiable unless neuropodia are present, and possibly some species of Lysilla described from incomplete material may in fact belong to Amaeana . This has already happened with A. apheles ( Hutchings, 1974) , originally described as a species of Lysilla and transferred to Amaeana when complete specimens were found ( Hutchings & Glasby 1986; Nogueira et al. 2015). Prior to this study four species were known from Australia.