Pettibonesia furcosetosa (Loshamn 1981)

Wilsoniella furcosetosa (Loshamn, 1981)

Harmothoe lunulata.—Orton, 1923:861 [part; large specimens with Amphitrite edwardsii]. [Not Delle Chiaje, 1830.]

Harmothoe sp. nov.—G.M. Spooner, in Plymouth Marine Fauna, 1957:xxxvi, 112 [with Amphitrite edwardsii].

Malmgrenia furcosetosa Loshamn, 1981:5, fig. 1A–I.

Harmothoe furcosetosa.—Tebble and Chambers, 1982:42, fig. 1c, 13a–c, 39.—Hanley, 1987:151, fig. 3G.

MATERIAL EXAMINED.—NORTH ATLANTIC OCEAN: England: Salcombe Estuary near Plymouth, in burrows of Amphitrite edwardsii (Quatrefages), 29 Jul 1956, 26 Mar 1959, 18 Mar 1961, G.M. Spooner, collector, 4 specimens (LCHP S-18–20; USNM 55053). Salcombe, west side, 27 Mar 1971, P.E. Gibbs, collector, 3 specimens (LCHP G-1; USNM 55054). Sweden: Boluslän, Säcken, Tränsholmen, 125 m, L. Almkvist, collector, 6 Apr 1974, holotype of Malmgrenia furcosetosa (NRS 3173). Skagerrak, 58°21′N, 09°11′E, 366 m, clay, Gunnild Expedition sta 14, 1879, paratype of M. furcosetosa (NRS 3174).

TYPE MATERIAL.—Holotype, male with sperm, in 3 pieces, with 39 segments, 38 mm long and 10 mm wide including setae. Paratype, female with eggs, in 3 pieces, with 38 segments, 36 mm long and 9 mm wide. Specimens from Plymouth area with 40–42 segments, 46–56 mm long and 11–13 mm wide.

DESCRIPTION.—Body elongate, flattened ventrally, arched dorsally, tapering slightly anteriorly and more so posteriorly. Body showing brownish pigmentation on posterior regions: dorsally in form of spindle-shape bands between dorsal tubercles and additional smaller intersegmental spots; ventrally in form of narrow anterior transverse bands and wide posterior transverse bands, joining laterally and extending onto parapodia, with spots on cirrophores and styles of ventral cirri (Figure 54J). Elytra 15 pairs, on usual segments, large, covering dorsum, except for posterior 5 or so segments; round, subreniform, and elongate oval, with mottled pigmentation, tending to be darker near place of attachment to elytrophore and large area posterior to it without color; also colorless on anterior part; wide band of microtubercles on anterior part of elytra; except for first pair and some posterior elytra; without papillae, except for some scattered micropapillae (Figure 54E–H; Loshamn, 1981, fig. 1I,J; Tebble and Chambers, 1982, fig. 39).

Bilobed prostomium with anterior lobes without distinct peaks; ceratophore of median antenna large, cylindrical, in anterior notch, with style about 1.5 times length of prostomium; ceratophores of lateral antennae inserted terminoventrally, with styles about half as long as median antenna; eyes rather small, anterior pair anterolateral, barely visible dorsally, slightly larger than posterodorsal pair, palps long, tapered, longer than median antenna; tentaculophores lateral to prostomium, each with small acicular lobe and 0–2 setae on inner side; dorsal and ventral tentacular cirri similar to median antenna; antennae and tentacular cirri with minute papillae; facial tubercle bulbous (Figure 54A,B; Loshamn, 1981, fig. 1A,L; Tebble and Chambers, 1982, fig. 1c; Hanley, 1987, fig. 3G). Segment 2 with first pair of large elytrophores, biramous parapodia, and long ventral buccal cirri lateral to ventral mouth, similar to tentacular cirri (Figure 54A–C); notosetae similar to following segments, only few longer ones tapering to slender tips; neurosetae more slender than following, lower ones with bulbous entire tips, some upper ones with slender secondary tooth (Figure 54D); extended pharynx with 9 pairs of border papillae and 2 pairs of hooked jaws.

Biramous parapodium with notopodium much shorter than neuropodium, rounded, with projecting acicular lobe on lower side; neuropodium with longer subconical presetal acicular lobe, with prominent subtriangular supraacicular process, and shorter rounded postsetal lobe (Figure 55A,B; Loshamn, 1981, fig. 1K). Notosetae very numerous, slightly stouter than neurosetae, with numerous spinose rows, of 2 types: shorter ones, of 3 lengths, tapering to blunt tips; longer ones, extending almost to tips of neurosetae, tapering distally to slender bifid tips, one tooth slightly larger than other, or some with tips entire (Figure 55C; Loshamn, 1981, fig. 1B–D,H; Tebble and Chambers, 1982, fig. 13a–c). Neurosetae very numerous, supraacicular ones with longer spinose regions and bifid tips; upper few with longer secondary tooth (Figure 55D; Loshamn, 1981, fig. 1E); subacicular neurosetae with shorter spinose regions and bifid hooked tips, lower few with entire hooked tips (Figure 55E; Loshamn, 1981, fig. 1F,G). Cirrophores of dorsal cirri cylindrical, bulbous basally, with anterior and posterior orange colored glandular areas, with styles flattened dorsoventrally, tending to curl dorsally and extending beyond neurosetae, with scattered micropapillae; dorsal tubercles nodular, with orange colored glandular areas; ventral cirri short, subulate, with scattered micropapillae (Figures 54A,I, 55B). Pygidium with anus medial to last pair of parapodia, with pair of long anal cirri.

BIOLOGY.—Wilsoniella furcosetosa was collected by G.M. Spooner and P.E. Gibbs in the Plymouth area in the burrows of the terebellid polychaete Amphitrite edwardsii (Quatrefages).

DISTRIBUTION.—North Atlantic Ocean, Great Britain and west coast of Sweden, up to 366 meters.