Subadyte pellucida (Ehlers 1864)

Subadyte pellucida (Ehlers, 1864)

Polynoe pellucida Ehlers, 1864:105, pl. 2: fig. 10; pl. 3: figs. 5, 7–13; pl. 4: figs. 1–3.

Hermadion fragile Claparède, 1868:383, pl. 5: fig. 2.

Scalisetosus communis.—Cuénot, 1912:40.

Scalisetosus pellucidus.—Fauvel, 1923:74, fig. 27a–f [synonymy].—Spooner et al., 1957:112.—Bellan, 1960:6; 1964:29.—Guille, 1965:286.—Hamond, 1966:388.—Hartmann-Schröder, 1971:69, fig. 21a–e.

Harmothoe crosetensis.—Monro, 1930:57 [part; not McIntosh, 1885].

Scalisetosus sp.—Hartman, 1939:6, fig. 1f–k.

Subadyte pellucida.—Pettibone, 1969a:8, fig. 4a–e [synonymy].—Intes and Le Loeuff, 1975:274.—Hartmann-Schröder, 1977:68.—Barel and Kramers, 1977:54.—Campoy, 1982:52.

Adyte pellucida.—Tebble and Chambers, 1982:63, figs. 5a, 20c,d, 56b.

MATERIAL EXAMINED.—SOUTH ATLANTIC OCEAN: South Africa: Simon's Town, False Bay, Basin of H.M. Dockyard, 0–2 m, Discovery sta 90, 10 Jul 1926, 1 specimen (BMNH; mixed with Harmothoe crosetensis by Monro, 1930).

EASTERN PACIFIC OCEAN: Galápagos Islands: James Island, Sullivan Bay, shore and tide-pool collecting, W.L. Schmitt, collector, Presidential cruise sta 13, 24 Jul 1938, 1 specimen (USNM 20517, as Scalisetosus sp. by Hartman, 1939). Isla Isabella, Tagus Cove, in Amphiroa mat, Feb 1978, W.D. Hope, collector, 1 specimen (USNM 75375).

DESCRIPTION OF SPECIMEN FROM GALÁPAGOS ISLANDS (USNM 20517, as Scalisetosus sp. by Hartman, 1939).—Body flattened, elongate-oval, with 40 segments, last one minute, 14 mm long, 3 mm wide including setae. Elytra 15 pairs, on segments 2, 4, 5, 7, then on alternate segments to 23, 26, 29, and 32. Elytra oval, delicate, transparent, dotted with oval sensory papillae and some larger papillae, with “veins” eminating from place of attachment to elytrophores (Figure 1B; Hartman, 1939, fig. 1g,h).

Prostomium bilobed, with minute cephalic peaks and 2 pairs of small eyes in posterior half of prostomium; ceratophore of median antenna in anterior notch, style absent; ceratophores of lateral antennae inserted ventrally, with short papillate styles; palps long, tapering; tentaculophores of first segment lateral to prostomium, without setae, each with pair of dorsal and ventral papillate tentacular cirri (Figure 1A; Hartman, 1939, fig. 1f). Second or buccal segment with small nuchal lobe, first pair of elytrophores, biramous parapodia, and papillate ventral buccal cirri longer than following ventral cirri (Figure 1A,C).

Parapodia biramous, notopodium short, conical, with projecting acicular lobe on lower side; neuropodium with long conical presetal acicular lobe from which tip of aciculum projects, and shorter rounded postsetal lobe (Figure 1C–E). Notosetae subequal in width to neurosetae, with spinose pouches and blunt tips, shorter ones with entire tips, longer ones with minute bifid tips (Figure 1F; Hartman, 1939, fig. 1j). Neurosetae each with basal semilunar pocket and distal spinose region, upper ones longer than lower ones, all with bifid hooked tip (Figure 1G; Hartman, 1939, fig. 1i,k). Dorsal cirri with cylindrical cirrophores on posterior sides of notopodia and long papillate styles; ventral cirri short, tapered (Figure 1E).

BIOLOGY.—Subadyte pellucida has been reported on the discs or arms of two species of Ophiothrix: (1) O. fragilis (Abildgaard) from Plymouth, England (Spooner et al., 1957), including postlarvae in the plankton (7–12 setigers); Norfolk, England (Hamond, 1966); NE Atlantic (Barel and Kramers, 1977); English Channel (Bellan, 1964); Arcachon, France (Cuénot, 1912); Portugal (Bellan, 1960); Iberian Peninsula (Campoy, 1982); and (2) O. quinquemaculata (Delle Chiaje) from the Mediterranean by (Bellan, 1964); Banyuls, France (Guille, 1965), including many young stages (15–20 setigers).

Some records of S. pellucida were indicated as free-living or their associations were not noted. The species also is commensal with asteroids.

DISTRIBUTION.—Eastern Atlantic Ocean, North Sea, English Channel, Adriatic and Mediterranean Seas, West and South Africa; Indian Ocean, Bay of Bengal; Eastern Pacific Ocean, Galápagos Islands. Intertidal to 100 meters (Pettibone, 1969a).

Subadyte pellucida is a scale worm widely reported from the Indian, Pacific and North Atlantic Oceans from the intertidal zone to depths of about 800 m.