Pectinaria Lamarck 1818

Pectinaria sp.

Figs 35–36, Table 3

Material examined. Australia: Queensland: AM W.2648, 1 spec., Murray Island, Torres Strait, 09°33’S 144°03’E, coll. M. Ward, Oct 1928; AM W.2615, 1 spec., Great Barrier Reef, Low Isles, 16°23’S 145°34’E, coll. G.P. Whitley W. Boardman, Aug 1928; AM W.100, 1 spec., off South Mission Beach, Dunk Island, 17°57’S 146°09’E, coll. E.J. Banfield, Feb 1910; AM W.3117, 1 spec., Hayman Island, Whitsunday Pass, 20°03’S 148°53’E, coll. F.A. McNeill, Jan 1934; AM W.3028, 1 spec., Whitsunday Group, 20°03’S 148°53’E, coll. F.A. McNeill, Jan 1933; AM W.4292, 1 spec., Black Island, near Langford Reef, Whitsunday Group, 20°05’S 148°54’E, shallow water, coll. N. Coleman, Nov 1969; AM W.2649, 1 spec., Lindeman Island, Whitsunday Pass, 20°27’S 149°02’E, 16 m, coll. M. Ward, Jan 1929.

Description. Based on all specimens examined. Preserved specimen pale reddish in colour, conical in shape (Fig. 35A – B). Body length 27.0 – 76.0 mm including paleae and scaphe, width 8.8 – 18.5 mm at cephalic regions.

Cephalic veil trapezoidal, anterior margin wider and straight, free from operculum, with 20 – 28 smooth cirri on anterior margin and 2/3 of lateral margins, 5 – 6 pairs of long cirri on lateral margins (Fig. 35A, C). Pair of earshaped lobes adjacent to both sides of dorsal base of cephalic veil. Buccal tentacles with wide longitudinal grooves, arising posterior to cephalic veil (Fig. 35C).

Operculum semicircular; dorsal and lateral margin well developed, smooth; ventral margin (opercular ridge) with 10 – 13 pairs of golden paleae, most broken, curved dorsally, with blunt tips (Fig. 35A – B, D).

First pair of tentacular cirri short with annuli, not extending beyond tips of paleae, arising from connection of opercular margin and paleal ridge (Fig. 35B, D). Pair of small ventral lappets present behind tentacular cirri near cephalic veil on segment 1 (Fig. 35C). Ventral region of segment 1 covered by buccal tentacles and ventral lobes of segment 2 (Fig. 35A, C).

Second pair of tentacular cirri short not extending beyond opercular margin, with annuli, on latero-median connecting ridge on segment 2, inserted more dorsally than 1 st pair of tentacular cirri (Fig. 35A, D). Segment 2 with ventral lobes as pair of narrow lateral lobes separated by grooves from base of 2 nd pair of tentacular cirri, and pair of broad mid-ventral lobes about 3x as wide as ventro-lateral lobes. Segment 2 with pair of dorso-lateral lobes, about 1/3 width of segment 2 dorsally, connected to base of 2 nd pair of tentacular cirri (Fig. 35D).

Comb-like branchiae on segments 3 – 4, consisting of series of dense, flat lamellae (Fig. 35A – B). Branchiae on segment 3 larger and inserted more ventrally than those on segment 4 (Fig. 35B). Pair of dorso-lateral glandular pads present adjacent to branchiae on segments 3 and 4, about 1/4 width of sement 3 dorsally (Fig. 35D).

Distinct ventral glandular lobes present on segments 3 – 6, becoming progressively more lateral and broader on segments 3 – 5 (Fig. 35A – B). Hump present near branchiae on segment 4. Segment 3 with broad ventral lobe, higher at mid-line. Segment 4 with damaged ventral lobes. Segment 5 with pair of ventro-lateral lobes and mid-ventral lobe about 1/3 width of ventro-lateral lobes, separated from those by shallow grooves. Segment 6 with damaged ventral lobes, with mid-ventral gap covered with papillae (Fig. 35A).

Notopodia other than those of segment 1 which bear paleae, on segments 5 – 21 (17 pairs), each bearing two kinds of chaetae; one winged, bordered with serrations along distal portion; other stout and straight, tapering to pointed tip (Figs 35A – B; 36A – B, D). Neuropodia, 13 pairs on segments 8 – 20, each with slightly raised torus with transverse row of uncini; each uncinus with U-shaped peg embedded into torus, several rows of minor teeth, and two longitudinal rows of major teeth, each with of 7 – 8 teeth (Figs 35B; 36C). Segment 21 with pair of ventrolateral lobes near notopodia (Fig. 35A – B).

Scaphe ovoidal, flattened dorsally, divided into two anterior narrow lobes and four posterior larger broad and rounded lobes on each lateral margin (Fig. 35B). Anal flap triangular tongue, with smooth margin and short anal cirrus (Fig. 35G). Scaphal hooks 7 – 10 pairs, amber, with pointed tips, strongly curved dorsally, inserted anterior to dorsal margin of scaphe (Fig. 35F).

Tube with wide opening, slightly curved, made of fine sand and rocks (Fig. 35E).

Methyl Green stained body distinctly green on cirri of cephalic veil, ventral lobes of segments 2–6, dorsolateral lobes of segment 2, dorso-lateral pads of segments 3–4, ventro-lateral regions adjacent to neuropodia, lateral regions between segment 21 and scaphe, margins of scaphe, and ventro-lateral regions on posterior end of scaphe (Fig. 35).

Distribution. NE Queensland (Fig. 1).

Habitat. Found in shallow waters.

Remarks. The anterior ventral lobes of these old and large specimens, collected from Queensland between 1910 – 1969, are damaged, and most paleae have been broken. These specimens are similar to P. brevispinis Grube, 1878 from the Philippines in having paleae with blunt tips; scaphal hooks with bent tips; with similar ranges of number of paleae, scaphal hooks and cirri of cephalic veil; the last two lobes of scaphe are large and round; scaphal hooks located under the dorsal margin of scaphe; and with similar tubes. They are also similar to P. antipoda in having blunt tipped paleae, dorso-lateral lobes on segment 2, the shape of scaphe, scaphal hooks not present on the dorsal margin of scaphe, 7 – 10 pairs of scaphal hooks and two longitudinal rows of major uncinial teeth. But P. antipoda differs from these variable specimens in not having continuous papillae on ventral lobes of segment 6, and it has relative broad dorso-lateral lobes on segment 2, scaphal hooks markedly curved, and a robust tube made of black and yellow sand. Specimens of P. antipoda, except for several small specimens from Lizard Island, have not been collected from Queensland waters since 1969. These specimens are also very similar to P. carnosus from the same location, as they all have the blunt paleae, dorso-lateral lobes on segment 2 and segment 6 without continuous papillae on ventral lobes. But they are different from P. carnosus because the latter has extremely swollen ventral lobes on segment 6 and an anal flap without anal cirrus. So, these specimens are identified as Pectinaria sp. In order to identify these specimens, additional complete specimens need to be collected from Queensland waters, from locations other than around Lizard Island, to examine the arrangement of papillae on the ventral lobes of segment 6 and determine if they belong to P. antipoda or an undescribed species. On the Great Barrier Reef, sampling of soft sediments has been limited with more emphasis on reefs rather than inter-reefal habitats.