Lygdamis wambiri, Hutchings & Capa & Peart, 2012

Hutchings, Pat, Capa, María & Peart, Rachael, 2012, 3306, Zootaxa 3306, pp. 1-60 : 29-31

Lygdamis wambiri n. sp.

Figures 6B, 11F, G, 16, 17, Table 2.

Material examined. HOLOTYPE: QM G10505*, 26+ mm in length (incomplete), 3 mm in width, 26+ segments (incomplete) . PARATYPES: QM G10338*, 14+ mm in length (incomplete), 2 mm in width, 24+ segments (incomplete), plus one specimen mounted for SEM. All material from Queensland: Moreton Bay, Peel Island , 0.8 km southeast of South West Rocks , 27°30'S, 153°21'E, from shell, grit and sand, 7.62 m, collected vi. 1970, 7 m , and iii.1970.

Additional material examined.? Northern Territory: New Year Island , 10°55'S 133°02'E, 14.x.1982, LWM, 1, NTM W1121 *, from coarse sandy bottom .

Description. Holotype, stout, colourless with golden yellow paleae and dark brown nuchal hooks.Operculum completely divided into two free divergent lobes, longer than wide ( Figs 11F, H, 16A, B) with distal end sloping with two rows of paleae ( Fig. 17B). Outer row with 29 paleae, blades finely textured, colourless, margins straight, symmetrical, tapering to acute tip with small distal denticles ( Fig. 17B, C), inner row with 12 pairs of spines, yellow, smooth and acute tipped ( Fig. 17D); outer paleae longer than inner ( Fig. 17B) but thinner. Opercular papillae, 18 pairs peripheral to outer row of paleae on each lobe, about one third length of outer paleae ( Figs 11G, 16C, 17B). One pair of nuchal hooks present, strongly recurved, margins smooth, convave with pointed tips ( Figs 11F, 16B, C). Tentacular filaments compound, arranged in about 30 horizontal rows ( Fig. 16A, B). Medial organ present at dorsal base of opercular lobes ( Figs 11F, 16A, 17A), palps shorter than a third of opercular lobes. Eyespots absent. Segment 1 with lobe shaped neuropodia ( Fig. 16A), chaetae absent. Segment 2 with three pairs of triangular lateral lobes ( Figs 11F, G, 16B), with fine capillaries with plumose margins and extended fine tips, in compact fascicle, inserted posteriorly to U-shaped buccal organ. Twelve pairs of branchiae present from segment 2. Branchiae with broad base, tapering gently to rounded tip ( Figs 11G, 16B), from chaetiger 7 onwards, triangular, larger in size in anterior abdominal segments, absent from posterior segments of incomplete type material. Segment 3–6 (parathoracic) with chaetae inserted in two transverse rows with eight lanceolate chaetae with frayed twisted tips ( Fig. 17E), and fine capillaries with compact thecae interspersed between them ( Fig. 17E), we suspect that the lanceolate chaetae can retract but not the capillaries. Segments 3–6 with two types of neurochaetae arranged in oblique transverse row, five lanceolate with fine capillaries. Abdominal region with 20 chaetigers, but holotype is incomplete lacking cauda. Notopodia as transverse tori, with numbers of uncini per row decreasing posteriorly, uncini with two vertical rows of teeth, each row with eight teeth. Neuropodia with capillaries arranged in discrete fascicles with compact theca, distal margins becoming more elongate towards tip ( Fig. 17F).

Variation. Paratypes exhibit the following variation, number of rows of tentacular filaments (15–30), outer paleae (27–29 pairs), inner paleae (12–16 pairs). A specimen from Northern Territory is 25 mm in length, 4 mm in width and has 32 pairs of outer paleae, 20 pairs of inner paleae, one pair of hooks, 26 pairs of opercular papillae and parathoracic segments with 6–7 notopodial lanceolate chaetae. This specimen has considerably more inner paleae than the holotype which has 12 pairs and the paratype mounted for SEM has 13. At this stage we are referring the Northern Territory material to the species, Lygdamis wambiri n. sp., as it certainly does not represent either of the other two species of Lygadamis recorded from Australia, but additional material from this locality should be examined to determine if this is correct or whether material from the Northern Territory represents another undescribed species of the genus.

Remarks. Lygdamis wambiri n. sp., is distinguished from other species in the genus by a combination of characters: 27–29 pairs of outer paleae, 12–16 pairs of inner paleae, three pairs of lateral lobes on segment 2 and having straight markedly asymmetrical outer paleae with distally denticulate margins (Table 2).

Lygdamis wambiri n. sp., can be distinguished from the other species of the genus recorded from Australia by the shape of the distal margins of the outer paleae, in L. wambiri n. sp., they are finely denticulate whereas they are smooth in the other Australian species. Lygdamis wambiri n. sp., has short inflated lanceolate notochaetae on parathoracic segments, whereas the two Australian species have longer less inflated lanceolate notochaetae compared to those of the other two species. Lygdamis wambiri n. sp., has branchiae present on posterior segments whereas L. augeneri and L. giardi lack them posteriorly. The only other species which appears to have distal margins of the outer paleae denticulate is L. robinsi Jeldes and Lefevre, 1959 described from off Angola, but this species is poorly known with regard to other characters.

Lygdamis wambiri n. sp., can be separated from other species described from the Indo-Pacific by the number of opercular papillae: L. bhaudi Kirtley, 1994 , described from Madagascar, has 3–4 pairs whereas L.wambiri has 12–17. Lygdamis curvatus ( Johansson, 1922) and L. japonicas Nishi & Kirtley, 1944 , both described from Japan, have smooth distal tips of outer paleae in contrast to the denticulate tips of L. wambiri n. sp. Lygdamis ehlersi Caullery, 1913 , described from Indonesia has only five pairs of outer paleae in contrast to the 27–29 pairs present in the new species.

Distribution. Moreton Bay, Queensland, with a possible record from Northern Territory.

Habitat. Inshore in sheltered shallow waters (around 7 m).

Etymology. The specific name wambiri is an Aboriginal word for the coast ( Endacott 1973) and refers to the extensive coast line of Moreton Bay a shallow protected bay, the type locality of the species.