Eunice imogena (Monro 1924)

Eunice imogena (Monro, 1924)

Nicidion imogena Monro, 1924:61–62, figs. 22–24.

MATERIAL EXAMINED.—Holotype, BM(NH) ZK 1924.1.28.91, Hotspur Bank, off the coast of Brazil, 16°S, 36°W.

COMMENTS ON MATERIAL EXAMINED.—The holotype was originally described as consisting of 108 setigers and being 25 mm long; the current specimen, labeled as type, is larger, as indicated below. It is unclear how this discrepancy has arisen: it is here assumed that a simple lapsus has taken place and that specimen here described in fact is the holotype.

DESCRIPTION.—Holotype incomplete, of unknown sex, with 138 setigers; length 30 mm; maximal width 2 mm at setiger 10; length through setiger 10, 3.5 mm.

Prostomium (Figure 56j) distinctly shorter and narrower than peristomium, as deep as of peristomium. Prostomial lobes frontally rounded, somewhat flattened dorsally; median sulcus very deep. Eyes behind bases of A-I, kidney-shaped, black. Antennae in horseshoe, evenly spaced, similar in thickness. Ceratophores ring-shaped in all antennae, without articulations. Ceratostyles medially inflated with irregular notches, but without articulations. A-I to middle of anterior peristomial ring; A-II and A-III to posterior end of peristomium. Peristomium longer than prostomium, cylindrical. Separation between rings distinct on all sides; anterior ring ~ of total peristomial length. Peristomial cirri barely to front edge of posterior peristomial ring, digitiform, without articulations.

Maxillary formula 1+1, 5+5, 7+0, 6+9, and presumably 1+1; Mx V apparently absent in preparation (see comment below). Distal tooth of both Mx II with small subdistal notches, indicating possible presence of reduced sixth tooth.

Branchiae absent.

Anterior neuropodial acicular lobes short, distally rounded, becoming sessile in median and posterior setigers (Figure 56n); aciculae emerging above midline. Pre- and postsetal lobes low, transverse folds. Anterior ventral cirri digitiform, becoming basally inflated by setiger 10. Ventral cirri retaining inflated bases through rest of body, but inflated bases increasingly retracted into body wall. Narrow tips short and button-shaped in median setigers, becoming distinct and tapering in far posterior setigers. Anterior notopodial cirri tapering and about twice as long as ventral cirri, increasing in length through median setigers. Notopodial cirri reduced in length from about setiger 50, becoming short and tapering in far posterior setigers, located well above neuropodia on body wall. Notopodial cirri without articulations.

Pectinate setae (Figure 56m) tapering, flat. Both marginal teeth longer than other teeth; ~10 teeth present. Shafts of compound falcigers (Figure 56l) slender, distally strongly inflated, marginally strongly serrated; distinct beak present. Appendages very short, with nearly parallel sides; heads small, bidentate. Both teeth similar in size. Proximal teeth slender, tapering, directed laterally. Distal teeth tapering, directed laterally. Guards symmetrically rounded, marginally serrated; mucros absent. Pseudocompound falcigers and compound spinigers absent. Aciculae (Figure 56n) single, with black core and clear sheath, thick, distally tapering, straight; cross-sections round. Subacicular hooks (Figure 56k) with black core and clear, nearly translucent heads, bidentate. Hooks first present from setiger 50, present in all setigers thereafter, always single (except for replacements). Hooks with distinctly bent necks; heads distinct. Proximal teeth larger than distal teeth, curved, directed laterally. Distal teeth triangular, tapering, directed distally.

UNKNOWN MORPHOLOGICAL FEATURES.—Relationship between Mx III and left Mx IV; pygidium and anal cirri.

EXPECTED STATES OF SELECTED UNKNOWN FEATURES.—Mx III short and forming part of distal arc with left Mx IV.

CHARACTERS USED IN PREPARATION OF KEY NOT SCORED.—Inappropriate Characters: 22, 31–42, 56, 60. Unknown Characters: 1, 2.

ASSUMED STATES FOR PURPOSE OF PREPARING KEY.—None.