Amphictene favona, 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 : 102-105

Amphictene favona n.sp.

Figs. 2A–B, 3A–C, 4A–B, 5A–B, 6, Tables 1, 6

Amphictene crassa .– Hartman, 1966a: 363–364. Not A. crassa Grube, 1870 .

Type material. HOLOTYPE: AM W 25611, 40 mm long, 14 & 10 mm wide . PARATYPES: 2, BMNH 2001.70 – 71 *, 68–69 mm long, 13–17 & 6–7 mm wide; 3, LACM-AHF POLY 2060 *, 54–59 mm long, 14–17 & 5 mm wide; 3, USNM 187084*, 35–68 mm long, 10–21 & 5–8 mm wide; 11, AM W25403*, 40–72 mm long, 10–15 & 4–10 mm wide. All material collected by Pat Hutchings, 28.vi.1994 .

Type locality. Western Australia: Abrohlos I., Wallabi Group, holotype 28°32'35.4"S 113°46'32.4"E paratypes collected from 28°32'35.4"S 113°46'32.4"E to 28°36'31.2"S 113°44'56.4"E, 45–47 m, in amongst white bleached algal nodules (Rhodoliths) .

Additional material examined. WESTERN AUSTRALIA: S of islets near Gun I., South Group , 28°53'S 113°52'E, 9.iv.1976, 2, WAM 49-96 *; 8 km NW of Gun I., South Group , 28°53'S 113°52'E, 11.v.1960, 56.7– 64 m, coral rubble, sponge and seaweed, 3, WAM 48-96 *; Point Samson , 20°38'S 117°12'E, 26.ix.1972, low tide, sandy mud, 1, AM W5493 *; between Broome and Wallal , 18°58'S 122°14'E, ix. 1931, 13 m, 1, AM W2842 *; Ashmore Reef , 12°15'S 123°00'E, 11.ix.1986, reef flat, 1, WAM 41-96 *. QUEENSLAND: No. 2, Sandbank, Michaelmas Reef, near Cairns, 16°35'S 146°02'E, 7.viii.1971, 1, AM W25404 ; vi.1926, 1, AM W2317 *, 1, AM W2318 *; Brampton I., 20°49'S 149°17'E, 1949, 1, AM W5611 *; Hayman I., 20°03'S 148°53'E, 1, AM W3150 *; One Tree I., 23°30'30"S 152°05'E, 4.x. 1967, 1 m, 1, AM W25405 *. Material examined varied from 35 to 97 mm long & 10 to 16 & 10 to 6 mm wide .

n. r. character not recorded.

* Only a selection of records are given based on the literature to indicate distribution of species; however distributions outside the region of the type locality require verification.

a [ auricoma ] Widely recorded from Sweden and Norway ( Malmgren, 1866, 1867); Gulf of Naples ( Claparède, 1868); North Sea ( Fauvel, 1927); Swedish west coast, 20–30 m ( Hessle, 1917); Atlantic Ocean, Arctic Sea, Northern Pacific Ocean ( Nilsson, 1928); Mediterranean Sea ( Annenkova, 1929); Scandinavia ( Holthe, 1986). Notochaetae with finely denticulate tips. Considerable variation recorded for this species.

b [ auricoma mediterranea] Nilsson (1928) synonymised Amphictene auricoma described by Claparède (1868), Marenzeller (1874) and Panceri (1875); and P. auricoma described by Grube (1850, 1861, 1864) and Lo Bianco (1893) with his new subspecies, all records from the Mediterranean Sea. Not recorded since.

c [ capensis ] Recorded from S & E coast of Africa in 1298 m ( Nilsson, 1928; Day, 1955, 1967). Some notochaetae with finely serrated tips.

d [ crassa ] Recorded from New Caledonia, Palau, Sri Lanka ( Nilsson, 1928), India ( Fauvel, 1953). Record by Hartman (1966a) from Sydney referred to A. favona (this study).

e [ japonica ] Also recorded by Imajima & Hartman (1964) from Japan. Some notochaetae with finely denticulate tips.

f [ souriei ] Known only from original description– distinguished by 4 large tubercules on the dorsum at level of branchiae. Some notochaet ae with finely denticulated tips.

Other material examined. Holotype of Pectinaria (Amphictene) crassa Grube, 1870 , ZMB 5704 , New Caledonia .

Description. Preserved specimen pale cream to grey in colour. Body, robust and solid.Tube forming slightly tapered cylinder, resembling a tusk, composed of cemented shell fragments.

Rim of cephalic veil with 28 long cirri; cirri basally triangular, tapering to form thread-like terminal filaments. Cephalic veil completely free from operculum forming dorsal semi-circular lobe, which covers the bases of numerous peristomial palps. Raised opercular margin well developed, crenulated with 62 triangular lappets. Operculum with 12 pairs of paleae, short, golden, subacute, curved dorsally, without extended tips ( Fig. 2A).

First pair of tentacular cirri arise from posterolateral margin of segment 2. Second pair of tentacular cirri present on segment 3, arise from a connecting ridge, which runs across the venter, margins of which expanded to form thin, flattened, rounded flaps. Segment 2 with posterodorsal lobe present and with scalloped margin. Venter of segments 3 and 4 slightly glandular and smooth. Chaetiger 1 (segment 5) without an anteroventral lobe. Chaetiger 2 with anteroventral lobe large and broad, anterior margin of lobe with contiguous rounded papillae, 24 present ( Fig. 2A).

Two pairs of comb-like stalked branchiae on segments 3 and 4, situated laterally and each consisting of a series of loose, flat lamellae; anterior pair attached more ventrally than posterior pair, larger than posterior pair. Branchiae lie flattened against the body. Large subquadrate glandular flaps present ventrally at base of second pair of branchiae on segment 4.

Chaetigers 1 to 3 (segments 5 to 7) with notopodia only. Chaetigers 4 to 16, biramous with notopodia, neuropodia, notochaetae and neurochaetae. Chaetiger 17 with notopodia and notochaetae only. Chaetigers 1 to 3 and 15 to 17 with both notopodia and notochaetae reduced in length compared to those on chaetigers 4 to 14. All notochaetae smoothwinged capillaries with finely hirsute surfaces and some margins slightly pectinate ( Fig. 4A–B), some notochaetae straight, others with slightly curved tips ( Figs. 3A, 4A–B).

Neuropodia wedge-shaped, slightly glandular, erect tori, with numerous neurochaetae. Neurochaetal uncini with major teeth arranged in two longitudinal rows, each with 8 to 10 teeth, with size of teeth declining basally ( Figs. 3B–C, 5A).

Posterior 5 segments fused to form scaphe broader than long; distinctly separated from preceding abdomen. Scaphe with lobed margins, and an anal flap with a dorsal papilla present ( Fig. 2B). Scaphal hooks present, 16 pairs; broad, blunt, golden-brown ( Fig. 5B).

paratype ( AM W25403). Scales = 5 mm .

Chaetigers 4 to 18 with prominent paired, ventral glandular patches, rectangular with rounded margins. Small thin, film-like flaps present on second prescaphal segment.

Nephridial papillae present on segments 5 and 6 (chaetigers 1 and 2), rounded, situated ventrolaterally below base of second pair of branchiae.

Variation. Some immature individuals have only one pair of nephridial papillae present on chaetiger 1, two pairs present on mature individuals. Within the material examined, the number of cirri on the cephalic veil margin varies between 23 and 28, with larger animals having more cirri than smaller ones. In addition, the number of lappets on the opercular margin varies from 61 to 63 and the number of papillae on the anteroventral lobe of chaetiger 2 varies from 23 to 25; in general the higher counts are present on larger animals. The orientation of the branchiae varies between individuals, some have the branchiae completely flattened against the body whereas in others they are held away from the body. This may be an artifact of preservation, or a real difference among individuals.

Remarks. Amphictene favona n.sp. can be distinguished from all other described species of Amphictene (see Table 1) by the following combination of characters: relatively few cirri on the cephalic veil (23 to 28), large numbers of cirri on the operculum (61 to 63), and 16 pairs of scaphal hooks, with relatively little variation occurring between large and small individuals. The number of pairs of scaphal hooks distinguishes this species from all other described species. Amphictene favona most closely resembles A. capensis ( Pallas, 1776) , A. uniloba n.sp., A. crassa ( Grube, 1870) and A. japonica ( Nilsson, 1928) in terms of sharing one of its diagnostic characters.

Hartman (1966a) recorded Amphictene crassa from Australia, giving no locality data. The specimen was brought into the Australian Museum for identification by a member of the public. Re-examination of this specimen (AM W3802) showed that it is Amphictene favona n.sp. and not A. crassa , so no valid records for the latter species exist from Australian waters. The specimen was most likely collected in New South Wales, extending the known range of the species (but not indicated on Fig. 6, due to the uncertain nature of the record). The individual was compared with the type of A. crassa ( Grube, 1870) (ZMB 5704), which was described from New Caledonia and differs from this species in having fewer pairs of scaphal hooks. The records of this species from Palau, Sri Lanka ( Nilsson, 1928) and those from India ( Fauvel, 1953) may also be misidentifications.

Etymology. The specific name favona refers to the westerly winds, which blow almost continually on the Abrohlos Islands, and is based on the latin word for “west wind”.

Distribution. Northeastern Australia and northwestern Australia (see Fig. 6).

Habitat. Found in depths ranging from intertidal to 64 m, in soft sediments, often in amongst bleached algal nodules and typically associated with coral reefs.