Malmgreniella pierceae Pettibone 1993

Malmgreniella pierceae

Malmgreniella sp. C.—Weston, 1984:21, 22, figs. 21-17,18a–g.

MATERIAL EXAMINED.—NORTHWESTERN ATLANTIC OCEAN: Georgia: Off Georgia, 31°03′N, 80°26′W, 34 m, Texas Instruments, R/V Pierce sta 5E, 16 May 1977, holotype (USNM 61750). 31°01′N, 80°17′W, 40 m, sta 5F, 16 May 1977, paratype (USNM 61762). Same, 30 Aug 1977, 3 paratypes (USNM 61763-4). 30°59′N, 80°08′W, 46 m, sta G, 25 Feb 1977, paratype (USNM 61304).

GULF OF MEXICO: Panama: Caribbean coast, Galeta Reef, 11 m, 4 Oct 1980, on brittle star Amphiura cf. fibulata Koëhler, G. Hendler, collector, 1 specimen (USNM 133561). Florida: as Malmgreniella sp. C by Weston, 1984: Southwest Florida (SOFLA) sta 20, Nov 1980, Jul 1981, 25°17′N, 82°09′W, 22 m, coarse sand, 2 specimens (USNM 89690-1). Mississippi-Alabama-Florida (MAFLA) sta 2422, off Apalachicola River, 29°30′N, 84°27′W, medium fine sand, 1 specimen (USNM 89689).

DESCRIPTION.—Holotype 10 mm long, 3 mm wide including setae, with 37 segments. Large paratype (USNM 61762) 13 mm long, 4 mm wide, with 37 segments. Two smaller paratypes 3–6 mm long, 2 mm wide, with 33 segments. Body flattened, tapering slightly anteriorly and more so posteriorly, without color. Fifteen pairs of oval elytra, without tubercles and papillae, colorless (Figure 32C),

Bilobed prostomium with subtriangular anterior lobes, without distinct peaks, with 2 pairs of rather large eyes on posterior half, and with some scattered pigment spots; ceratophore of median antenna in anterior notch, with style about length of prostomium; lateral antennae with distinct ceratophores inserted terminoventrally, converging midventrally, with short subulate styles; palps stout, tapered; tentaculophores without setae, dorsal and ventral tentacular cirri similar to median antenna; antennae and tentacular cirri minutely papillate (Figure 32A,B; Weston, 1984, fig. 21-18a). Segment 2 with long ventral buccal cirri similar to tentacular cirri.

Parapodium biramous, with notopodium shorter than neuropodium; notopodium rounded, with projecting acicular lobe on lower side; larger neuropodium with subconical presetal acicular lobe with very small bulbous supraacicular process, with shorter, rounded postsetal lobe (Figure 32D,E; Weston, 1984, fig. 21-18b). Notosetae numerous, forming radiating bundle, about same width as neurosetae, short to long, slightly curved, with tapering blunt tips, appearing smooth but finely spinose along convex border (Figure 32F; Weston, 1984, fig. 21-18c). Neurosetae moderate in number, forming fan-shape bundle; upper neurosetae with long spinose regions and entire, bare tips; some larger middle neurosetae with shorter spinose regions and bifid tips, with secondary tooth very long and slender; lower neurosetae shorter with less prominent spinose rows and entire, slightly hooked tips (Figure 32G–I; Weston, 1984, fig. 21-18d–g). Dorsal cirri with cylindrical cirrophores, wider basally and long styles extending beyond tips of neurosetae, with scattered micropapillae; dorsal tubercles nodular; ventral cirri short, tapered, with scattered micropapillae on upper side (Figure 32E). Pydigium small, rounded, between posterior pair of small parapodia.

BIOLOGY.—Malmgreniella pierceae was collected on the brittle star Amphiura cf. fibulata Koëhler on Galeta Reef, Panama, by G. Hendler.

ETYMOLOGY.—The species is named for the collecting ship R/V Pierce.

DISTRIBUTION.—Northwest Atlantic Ocean, off Georgia; Caribbean coast of Panama; Gulf of Mexico, off Florida. In 11–46 meters.