Acoetes flagelliformis (Wesenberg-Lund 1949)

Acoetes flagelliformis (Wesenberg-Lund, 1949)

Polyodontes flagelliformis Wesenberg-Lund, 1949:261, figs. 4–6.

MATERIAL EXAMINED.—GULF OF IRAN. 13 miles (21 km) S of Bustani, 27°00′N, 53°08′E, 65 m, soft gray-brown mud, sta 50B, 6 Apr 1937, G. Thorson, collector, holotype (UZMC).

TYPE MATERIAL.—Holotype with pharynx fully extended, with 35+ segments, 18+ mm long (30+ mm with pharynx), 7 mm wide with setae.

DESCRIPTION.—Elytra rounded to oval, leaving middorsum uncovered, delicate, with fine network of areolae nearly throughout, without lateral pocket (at least to segment 35) (Figure 62B,D; Wesenberg-Lund, 1949, fig. 4a). Prostomium bilobed with bulbous ommatophores with short neck; median antenna with ceratophore on middle of prostomium, with style extending to tips of ommatophores; lateral antennae inserted ventrally on ommatophores with tips visible dorsally; posterior pair of small sessile eyes anterolateral to ceratophore of median antenna; stout ventral palps tapered, about 1.5 times length of prostomium, with longitudinal rows of short papillae and transversely banded with brown pigment (Figure 62A). Tentacular segment distinct dorsally; tentaculophores lateral to prostomium, each with globular papillae on upper side, 2 acicula, 2 bundles of capillary setae and pair of dorsal and ventral tentacular cirri, slightly longer than median antenna (Figure 62A,D).

Second segment with first pair of elytrophores, ventral buccal cirri longer than following ventral cirri, and biramous parapodia; notopodium small, conical, with bundle of long, finely spinous capillary notosetae; neuropodium larger, with conical presetal acicular lobe, truncate postsetal lobe, and distinct ventral bract; neurosetae slender, capillary (tips broken) (Figure 62E). Distal border of extended pharynx with 15 pairs of border papillae, middorsal and midventral ones on wide bases, much longer than others, dorsal one longer than ventral one; 2 pairs of hooked jaws each with 5–7 lateral teeth (Wesenberg-Lund, 1949, fig. 4a-c).

Third segment with first pair of dorsal cirri, with styles extending to tips of setae; ventral cirri short, subulate; parapodia similar to second segment; upper and lower neurosetae slender, lanceolate, finely spinous; middle neurosetae stout, acicular, aristate (Figure 62F-H). Parapodia of segment 8 larger, with dorsal and ventral cirri about equal in length; upper group of neurosetae slender, lanceolate, finely spinous; lower neurosetae similar to following parapodia; middle acicular neurosetae stout with distal hairs on bases of aristae (Figure 62I-K).

Beginning with segment 9, notopodium wide, flattened, on anterodorsal half of larger neuropodium, with notoaciculum, spinning glands, and fan-shaped bundle of short notosetae extending slightly beyond notopodium; neuropodium with slightly bilobed presetal acicular lobe, truncate postsetal lobe, and anteroventral bract; lower group of neurosetae, within anteroventral bract, slender, wider basally, slightly curved, with longer spines basally and close-set shorter spines distally, with capillary tips; middle row of stout acicular aristate neurosetae with distal hairs and subdistal spines in several rows on one side; upper group of neurosetae, emanating from low anterodorsal bract, hidden by notopodium, of 2 types: (a) long, slender, tapering abruptly to more slender tips, with subdistal long bushy hairs and short spinous rows basally; (b) short (hidden by notopodium), slender, bipinnate (Figure 62L-0; Wesenberg-Lund, 1949, figs. 5, 6a-f). Cirrophores of dorsal cirri wide, inflated, with style wider basally, about as long as ventral cirri; small branchiae on posterior side of parapodia, beginning about segment 6; inflated branchial areas medial to ventral cirri (Figure 62N).

DISTRIBUTION.—Gulf of Iran. In 65 meters.