Pectinaria carnosus, Wong, Eunice & Hutchings, Pat, 2015

Wong, Eunice & Hutchings, Pat, 2015, New records of Pectinariidae (Polychaeta) from Lizard Island, Great Barrier Reef, Australia and the description of two new species, Zootaxa 4019 (1), pp. 733-744 : 739-742

Pectinaria carnosus n. sp.

( Figs 5–7 )

Material examined. Holotype: AM W.47431, Lizard Island, Coconut Beach, 14°41'3''S 145°28'12''E, intertidal, coll. P. Hutchings & M. Capa, 25 Aug 2010, CReefs, 22.0 mm long, 11.0 mm wide anteriorly, 6.0 mm wide posteriorly.

Description. Preserved specimen pale cream in colour. Body wide, robust and conical in shape ( Fig. 5 A–B). Anterior width approximately 1/2 length of specimen. Tube straight to slightly curved, composed of cemented shell-like fragments and sand grains.

Rim of cephalic veil with 16 long cirri. Cirri are triangular appendages which rapidly taper. Cephalic veil completely free from operculum, forming a dorsal semi-circle around the numerous buccal tentacles ( Fig. 6 A). Buccal tentacles numerous and with deep medial groove ( Figs 5 A, 6A). Raised opercular margin well developed, smooth ( Fig. 6 B). Operculum with 9 pairs of paleae, yellow-gold, stout, slightly curved dorsally, tips blunt ( Fig. 5 B). Tentacular cirri not observed. Two pairs of comb-like branchiae on segments 3 and 4, situated laterally and consisting of loose flat lamellae. Anterior pair larger and situated more ventrally than posterior pair.

Chaetiger 1 and 2 with anteroventral lobe large and broad, with that of chaetiger 2 larger than that of chaetiger 1; anterior margin of lobes smooth. Nephridial papillae not observed.

Chaetigers 1–3 (segments 5–7) with notopodia and notochaetae only. Chaetigers 4–16 biramous with notopodia, neuropodia, notochaetae and neurochaetae. Chaetiger 17 with only notopodia and notochaetae.

Notochaetae of chaetigers 1–3 and 12–17 reduced in size compared to those of notopodia 4–11. Notochaetae include smooth winged capillaries and thick robust chaetae ( Fig. 7 A–B). Neuropodia wedge shaped, erect and glandular. Neurochaetae with major teeth arranged in 2 rows, 6–10 teeth per row ( Fig. 7 C). Glandular areas present on chaetigers 3–17. Glandular areas from chaetigers 3–8 form prominent strips that are partially joined to anterior edge of corresponding neuropodia ( Fig. 6 B).

Posterior scaphe and abdomen distinctly separated. Posterior 5 segments fused to form a flattened plate or scaphe, broader than long, with crenulated margins ( Fig. 6 C–D). Anal flap present. Scaphal hooks present, 6 pairs, broad, blunt, golden ( Fig. 6 C).

Remarks. This new species Pectinaria carnosus n. sp. is characterised by 9 pairs of stout paleae with blunt tips and 6 pairs of broad and blunt scaphal hooks. Hutchings & Peart (2002) provided a summary of the diagnostic feature of all known species (see Table 4) together with comments on the validity of the type species of the genus. Pectinaria carnosus n. sp. most closely resembles P. belgica Hutchings & Peart, 2002 (described from Sweden), P. antipoda and P. dodeka .

Pectinaria carnosus n. sp. can be distinguished from P. antipoda by the absence of large rounded papillae on the anteroventral lobe of chaetiger 2, which varies from 12 to 19 in P. antipoda . Pectinaria carnosus n. sp. can also be distinguished from the only other Australian species P. dodeka and P. kanabinos by the shape of paleae.

Pectinaria carnosus n. sp. has short stout paleae with blunt tips, as opposed to the acute and needle-like shape in P. dodeka and P. kanabinos .

Etymology. The species name carnosus translates as “fleshy” in Latin and is representative of the general shape of the specimen.

Habitat. Found in amongst coral rubble.

Type locality. Queensland: Lizard Island, Coconut Beach, 14°41'3''S 145°28'12''E. Distribution. Species currently known only from Lizard Island in the intertidal zone.

Figures

FIGURE 5. Pectinaria carnosus n. sp., stained with methyl green, holotype, AM W. 47431. A. Ventral view of entire animal; B. Dorsal view of entire animal. Scale bar: A – B = 1 mm.

FIGURE 6. Pectinaria carnosus n. sp., stained with methyl green, holotype, AM W. 47431. A. Ventral view of anterior end; B. Lateral view of anterior end; C. Posterior end; D. Lateral view of last chaetigers. Abbreviations: avl = anteroventral lobes, br = branchiae, bt = buccal tentacles, cv = cephalic veil, g = glandular area, nec = neurochaetae, noc = notochaetae, or = opercular rim, p = paleae, s = scaphe, sh = scaphal hooks. Scale bar: A – D = 1 mm.

FIGURE 7. Chaetae of Pectinaria carnosus n. sp., holotype, AM W. 47431. A. Notochaetae of chaetiger 1 (above) and chaetiger 6 (below), both with robust chaetae and smooth winged capillaries; B. smooth winged capillary from notochaetae of chaetiger 5 as viewed under a compound microscope; C. Neurochaetal uncini of chaetiger 5, main teeth arranged in 2 rows. Abbreviations: c = smooth winged capillaries. Scale bars: A – B = 0.1 mm, C = 0.01 mm.