Pectinaria dodeka, Hutchings & Peart, 2002

Hutchings, P. & Peart, R., 2002, A Review of the Genera of Pectinariidae (Polychaeta) Together with a Description of the Australian Fauna, Records of the Australian Museum 54, pp. 99-127 : 118-121

Pectinaria dodeka n.sp.

Figs. 11A–B, 12C–D, 13, 14A–B, 15A–C, Tables 4, 6

Pectinaria brevispinis .– Nilsson, 1928: 64–68.– Monro, 1931: 27– 28.– Caullery, 1944: 71. Not Grube, 1878.

Pectinaria antipoda .– Stephenson et al., 1974: 114 (in part). Not Schmarda, 1861.

Type material. HOLOTYPE: 1, AM W 25615*, 27.iii. 1962, 17 mm long, 4 & 2 mm wide . PARATYPE: 1, AM W 19076*, 21 mm long, 4 & 2 mm wide .

Type locality. Queensland: Moreton Bay, Dunwich , 27°30'S 153°24'E, collected 27.iii.1962, no information on habitat available .

Additional material examined. NORTHERN TERRITORY: Darwin Harbour , 12°27'S 130°48'E, 6.vii. 1993, 17 m, 1, NTM W 10399*; Gulf of Carpentaria, Bing Bong, McArthur River , 15°37'S 136°15'E, 2, NTM W7720 *; 1, NTM W 16862*; 1, NTM W 16864 *. QUEENSLAND: Torres Strait, Murray I., 09°33'S 144°03'E, 1, AM W2648 *; Low Isles, Great Barrier Reef, 16°23'S 145°34'E, ii.1929 , 1, BMNH 1931.7 .1.60, ii.1929 , 1, BMNH 1931.7 .1.61, February 1929 ; 1, AM W2615 *; off South Mission Beach, Dunk I., 17°57'S 146°09'E, ii.1910 , 1, AM W100 *; Whitsunday Group, 20°03'S 148°53'E, i.1933 , 1, AM W3028 ; Lindeman I., 20°27'S 149°02'E, 1935, 1, AM W 25446*, in sand*, i. 1928, 16 m, 1, AM W2649 *; Hayman I., Whitsunday Pass, 20°03'S 148°53'E, i.1934 , 1, AM W3117 *; Langford Reef, Black I., 20°05'S 148°54'E, xi.1969 , 1, AM W4292 ; Calliope River, N of Gladstone, 24°01'S 150°59'E, 1974, 4, AM W199312 *; Moreton Bay , Dunwich, 27°25'S 153°20'E, 1967, 1 , QM G5042 *; Stradbroke I., Dunwich, 27°30'S 153°24'E, 4.x.1952 , 1, QM G4080 *; 2.4 km S of South West Rocks, Peel I., 27°30'S 153°21'E, vi.1970 , 3.4 m, sand, mud, shell, 1, QM G 10340*; Brisbane River mouth, 27°22'S 153°11'E, 22.vii.1975 , sand and mud, 3, QM GH2880 *; Middle Banks , 27°13'S 153°19'E, viii 1982 , 4, QM G212177 *; 1.6 km SE of Redcliffe Jetty , 27°15'S 153°08'E, 15.xii.1964 , 4.2 m, shell, grit, 1, QM G5040 *; Bramble Bay , 27°18'S 153°06'E, 29.vi.1972 , 4, QM G 10515; viii.1972 , 2, QM G 10635 *; NEW SOUTH WALES: Lake Macquarie , 36°54'S 149°53'E, vi.1977 , Zostera beds, 2, AM W 17847*; Sydney, Port Jackson , 33°50'S 151°16'E, xi.1925 , 1, AM W1760 *; between Sow & Pigs Shoal and Shark I., 30°52'S 153°00'E, iv.1928 , 4– 5 m, 1, AM W2578 *; 1 km SE of Little Bay, Malabar , 33°59'09"S 151°15'40.2"E, 12.v. 1972, 25 m, 1, AM W6460 *; SE of Malabar , 33°58'7.8"S 151°16'52.2"E, 2.i.1973 , 49– 53 m, 1, AM W6461 *; Jervis Bay , 35°03'S 150°44'E, 23.iv. 1973, 15 m, sand, 1, AM W5617 *; Merimbula Channel, 36°55'S 149°55'E, 4.xii.1975 , Posidonia , on south side of seaward end of central sand bank, 1, AM W 17111*; Lake Merimbula , 36°03'S 151°36'30"E, 25.xi. 1977, 6 m, mud, 1, AM W 19254*; 900 m SW of Narooma Bridge, Wagonga , 36°13'42"S 150°07'30"E, weed beds, 1, AM W 10498 *. VICTORIA: central Bass Strait, 35 km NNE of Cape Wickham , 39°16'00"S 144°05'24"E, 23.xi. 1981, 82 m, sandy shell, 2, MV F 78890 *. Material examined varied from 8 to 80 mm long & 2 to18 & 1 to 8 mm wide .

Description. Preserved specimen small, conical-shaped, grey to pale cream in colour, and some black pigmentation present anteriorly. Tube curved, composed of cemented shell-like fragments.

Rim of cephalic veil with 16 long cirri tapering to blunt tip. Cephalic veil completely free from operculum forming dorsal semi-circle around numerous peristomial palps.

Raised opercular margin well developed and smooth. Operculum with 12 pairs of paleae, long, golden brown, subacute, curved dorsally, with compact tips. First pair of tentacular cirri arising from anterior edge of segment 2. Ventral ridge connecting second pair of tentacular cirri on segment 3 incised, forming glandular lobes. Chaetiger 2 with anteroventral lobe large and broad; anterior margin of lobe crenulate, posterodorsal lobe absent ( Fig. 14A).

Two pairs of comb-like stalked branchiae, consisting of loose, flat lamellae. Anterior pair situated more ventrally than posterior pair and larger than posterior pair. Branchiae lie flattened against body on preserved animals.

Chaetigers 1 to 3 (segments 5 to 7) with notopodia and notochaetae only. Chaetigers 4 to 16 with notopodia, neuropodia, notochaetae and neurochaetae. Chaetiger 17 with notopodia and notochaetae only. Notochaetae capillaries with one margin strongly pectinated ( Figs. 11A– B, 15A). Notopodia and notochaetae of chaetigers 1 to 3 and 15 to 18 are slightly reduced in size in comparison to those of chaetigers 4 to 14. Neuropodia wedge shaped, erect with margins becoming rounded posteriorly, glandular. Neurochaetae with major teeth arranged in two rows, 6–10 teeth per row ( Figs. 12C, 15B–C).

Posterior scaphe and abdomen distinctly separated. Posterior 5 segments fused to form a flattened plate or scaphe broader than long, with crenulated margins. Scaphe with an anal flap and dorsal papilla. Eight pairs of scaphal hooks, broad, blunt, brown ( Fig. 12D). Prominent glandular areas present on chaetigers 4 to 17, and ventral areas of segments 1 to 6 also glandular. Triangular gland present between segments 2 and 3, situated mid-ventrally. Segments 3 and 4 with raised glandular anterior margins extending across venter. Paired nephridial papillae on chaetiger 1, inserted ventrally at the base of the second pair of branchiae.

Variation. The number of cirri on the cephalic veil margin varies from 16 to 28, the number of pairs of paleae varies from 11–13, and the number of scaphal hooks varies from 6 to 10 pairs, and this appears to be related to size with larger animals having more cirri, paleae and hooks than smaller individuals. The anterior pair of branchiae in some specimens are of similar size to the posterior pair. The intensity of the glandular areas varies.

Remarks. Pectinaria dodeka n.sp. can be distinguished from all other described species of Pectinaria by the following combination of characters: 16–18 pairs of cirri on the cephalic veil, 11 to 13 pairs of subacute dorsally curved paleae and 6–10 pairs of scaphal hooks (see Table 4). The species most closely resembles another Australian species, P. kanabinos , in terms of the number of cephalic cirri present, but can be distinguished from it by the shape of the paleae: subacute curved dorsally in P. dodeka and acute needle shaped in P. kanabinos . In addition, the shape of the scaphe and the number of pairs of scaphal hooks differs between the two species. The species may be separated from P. antipoda by the lack of rounded papillae on the anterior margin of the anteroventral lobe of chaetiger 2. Many other species have a similar number of paleae, although as is clear from Table 4, some species exhibit a considerable range in the number of pairs present; this may be a function of size of individuals or perhaps an indication that the paleae can be replaced if damaged during feeding. The absolute number of pairs of paleae may not be a useful character.

Material identified as P. brevispinis by Monro (1931) (BMNH 1931.7.1.61; 1931.7.60.) from Low Isles, Queensland has been re-examined and we have referred them to P. dodeka n.sp. as well as material he identified as P. antipoda . Pectinaria dodeka n.sp. can be distinguished from P. brevispinis by the number of cirri on the cephalic veil, 16–28 in P. dodeka and 25–30 on P. brevispinis , and the number and shape of scaphal hooks present.

Material identified as P. antipoda by Stephenson et al. (1974) from Moreton Bay was re-examined and consisted of both P. antipoda and P. dodeka n.sp.

Etymology. The specific name dodeka is from the Greek word for twelve and refers to the number of pairs of paleae present on the holotype.

Distribution. Gulf of Carpentaria, and the east Australian coast ( Fig. 13), often associated with estuarine or sheltered waters.

Habitat. Collected from shallow waters to depths of 82 m, in soft sediments, sometimes associated with seagrass beds. Habitat data are lacking for many specimens.