Malmgreniella taylori Pettibone 1993

Malmgreniella taylori

Hermadion sp.—Behre, 1950:14.

Polynoid B.—Taylor, 1971:89, fig. 2D–I.

Harmothoe, sp.—Wass, 1972:116.—Boesch, 1977:254.

Harmothoe lunulata.—Dauer, 1980:487 [not Delle Chiaje, 1830].

Malmgreniella sp. A.—Weston, 1984:21–20, figs. 21–13, 14a–g.

MATERIAL EXAMINED.—NORTHWESTERN ATLANTIC OCEAN: Virginia: York River, 9 m, mud, detritus, Nov-Dec 1960, M. Wass, collector, 11 specimens (USNM 55088). York River, mud, Jan-Mar 1961, M. Wass, collector, 16 specimens (USNM 55089). Rappahanock Shoals Channel, silty clay, 20 Nov 1963, M. Wass, collector, 1 specimen (USNM 55090). Chesapeake Bay and York River, 2–13 m, silty bottom, 1964, M. Wass, collector, 15 specimens (USNM 55091, as Harmothoe sp. by Wass, 1972, and Boesch, 1977). York River, 9 m, silty sand, on brittle star Amphiodia atra (Stimpson), Feb 1970, D. Boesch, collector, 6 paratypes (USNM 55078). Southern portion of Chesapeake Bay, 21 m, May 1976, D. Weston, collector, 1 specimen (USNM 55092). North Carolina: Wrightsville Sound, 23 Jun 1967, muddy sand, on oral disc of brittle star Amphiopholis gracillima (Stimpson), A.B. McCrary, collector, paratype (USNM 55076). Georgia: Sapelo Island, 31°23′N, 81°12′W, about 7 m, Apr 1970, A.S. Leiper, collector, 5 paratypes (USNM 55077).

GULF OF MEXICO: Florida: Tampa Bay, 1963, J.L. Taylor, collector, holotype (USNM 55073) and 5 paratypes (USNM 55074; LACM; as Polynoid B by Taylor, 1971). Hillsborough Bay, Tampa Bay, sand and shells, 7 May 1975, S.L. Santos, collector, 11 paratypes (USNM 55075). Alabama: Mouth of Mobile Bay, 30° 14′N, 88°03′W, Mobile Oil sta 051A, 154E,F, 6.1–8.2 m, sandy and grey mud, Jul-Aug 1978, 10 specimens (USNM 70077-8). About 3 miles SE of Dauphin Island, 30°11′N, 88°07′W, 13 m, Continental Shelf Assoc. sta 14, 18 Sep 1981, 1 specimen (USNM 71738). Louisiana: Grande Isle, 1934, 1 specimen (USNM 21379, as Hermadion sp. by Behre, 1950). Texas: Corpus Christi Bay, 27°45′ to 57′N, 97°00′ to 20′W, shelly clay and slightly shelly with fine sandy mud, sta 122, 127, 141, 142, 147, 152, Jun 1974 to Apr 1975, J.S. Holland and N.J. Maciolek, collectors, 202 specimens (USNM 55079-87). South Texas Outer Continental Shelf (STOCS) sta III-4, Spr 1976, 26°58′N, 97°20′W, 15 m, sand, 1 specimen (USNM 89682, as Malmgreniella sp. A by Weston, 1984). Off Texas, IXTOC Oil Spill sta N-40, 5 Dec 1979, 28°14′N, 96°29′W, 10 m, sand-silt-clay, 1 specimen (USNM 89683).

SOUTHWESTERN ATLANTIC OCEAN: Brazil: Bay of Flamengo, São Paulo, 23°27′S, 45°06′W, 12 m, Jan 1963, L. Forneris, collector, 15 specimens (USNM 55093).

DESCRIPTION.—Holotype from Tampa Bay (USNM 55073) 9 mm long, 4 mm wide including setae, with 33 segments, and 15 pairs of elytra; three paratypes (USNM 55075) 6–7.5 mm long, 3 mm wide, with 31–32 segments and 14–15 pairs of elytra. Paratype from Wrightsville Sound (USNM 55076) 6 mm long, 2.5 mm wide, with 31 segments and 14 pairs of elytra. Two paratypes from Sapelo Island (USNM 55077) 10 mm long, 3.5–4 mm wide, with 34–35 segments and 15 pairs of elytra. Three paratypes from York River (USNM 55078) 5–9 mm long, 2–4 mm wide, with 29–32 segments and 14–15 pairs of elytra. Larger specimens from Corpus Christi Bay (USNM 55083) 5.5–7 mm long, 2.5–3 mm wide, with 29–30 segments and 14 pairs of elytra; small specimens 1.5–3 mm long, 1–2 mm wide, with 17–24 segments and 8–12 pairs of elytra. Specimens from Brazil (USNM 55093) 6–10 mm long, 3–5.5 mm wide, with 33–35 segments and 15 pairs of elytra.

Body short, flattened, tapering slightly anteriorly and posteriorly, colorless (rose color when living, according to M. Wass, in litt.), sometimes with greyish pigment on ventral side of posterior segments, with segments up to 35. Elytra up to 15 pairs, round, subreniform to oval, smooth, delicate, with prominent “veins,” without tubercles, with marginal fringe of clavate papillae on lateral and posterior borders (all around on first pair), without prominent color pattern but with opaque, denser area around place of attachment to elytrophore, sometimes faintly pigmented in this area and on additional crescent-shape area more medially (Figures 26B–D, 27A–D; Taylor, 1971, fig. 2E; Weston, 1984, fig. 21–14a). Bilobed prostomium with truncate anterior lobes and 2 pairs of minute eyes, anterior pair anterior to greatest width of prostomium and larger than posterior pair, ceratophore of median antenna in anterior notch, with style about as long as prostomium; ceratophores of lateral antennae inserted terminoventrally, with short subulate styles; palps stout, tapered, longer than median antenna; tentaculophores each with single seta on inner side and pair of dorsal and ventral tentacular cirri, similar to median antenna; styles of antennae and tentacular cirri with minute papillae (Figure 26A; Taylor, 1971, fig. 2D; Weston, 1984, fig. 21–14b). Segment 2 with first pair of elytrophores, biramous parapodia, and long ventral buccal cirri similar to tentacular cirri.

Parapodium with short, rounded notopodium with projecting acicular lobe on lower side; longer neuropodium with subconical presetal acicular lobe with bulbous supraacicular process, with shorter rounded postsetal lobe (Figure 26E,F). Notosetae numerous, forming radiating bundle, short to long, about as thick as neurosetae, tapering to blunt tips, with very faint spinose rows (Figure 26G; Weston, 1984, fig. 21–14d). Neurosetae forming fan-shape bundle, upper ones with longer spinose regions and more prominent spines, tapering to short, bare, entire tips (Figure 26I; Weston, 1984, fig. 21–14e); middle and lower neurosetae with shorter spinose regions and long, bare, slightly hooked tips (Figure 26H; Weston, 1984, fig. 21–14f,g). Cirrophores of dorsal cirri cylindrical, with bilobed glandular areas on anterior and posterior sides; styles extending to tips of neurosetae or beyond, with scattered clavate micropapillae; dorsal tubercles nodular; ventral cirri short, tapered (Figure 26F). Pygidium between last pair of parapodia, with pair of long anal cirri.

BIOLOGY.—In Tampa Bay, the type locality, Taylor (1971) reported the species (as Polynoid B) as the most common and widely distributed polynoid in the area. A specimen of M. taylori, filled with large yolky eggs, was taken from the oral disc of the brittle star Amphipholis gracillima (Stimpson) in Wrightsville Sound in June by Anne McCrary. The species was reported as commensal with the common burrowing brittle star Amphiodia atra (Stimpson) in the Chesapeake-York estuary by D.F. Boesch (1977) and in Mobile Bay, Alabama, by D. Weston (1984).

ETYMOLOGY.—The species is named for John L. Taylor, who first described the species (as Polynoid B) in his doctoral dissertation.

DISTRIBUTION.—Western Atlantic Ocean, from Chesapeake Bay to Georgia, Gulf of Mexico, Brazil. Low water to 21 meters.