Eunice aciculata (Treadwell 1922)

Eunice aciculata (Treadwell, 1922)

Leodice aciculata Treadwell, 1922:143–144, figs. 24–25; pl. 3: figs. 7–13.

Eunice afra.—Hartman, 1956:282 [in part, not Eunice afra Peters, 1854].

MATERIAL EXAMINED.—Holotype, AMNH 1528, Suva Harbor, Fiji, April 1920, in rocks outside the entrance light, in crevices made by boring echinoids, coll. Treadwell.

DESCRIPTION.—Holotype complete, of unknown sex, with 202 setigers; total length 129 mm; maximal width 4.5 mm at setiger 15; length through setiger 10, 11 mm; width at setiger 10, 4.0 mm. Anterior body ventrally flattened with highly convex dorsum; posterior body ventrally flattened, tapering toward the posterior end. Anal cirri unknown.

Prostomium (Figure 3a) less than half as long and distinctly narrower than peristomium; as deep as the depth of the peristomium. Prostomial lobes frontally obliquely truncate; dorsally flattened; median sulcus deep. Prostomium sloping towards front and laterally. Eyes present; behind bases of A-I. Antennae in a horseshoe, evenly spaced, similar in thickness. Ceratophores cylindrical in all antennae, confluent with prostomium, without articulations. Ceratostyles short, thick, digitiform; all similar in thickness and shape; wrinkled, but without articulations. A-I to middle of first peristomial ring; A-II to front edge of second peristomial ring; A-III incomplete. Peristomium cylindrical. Separation between rings distinct dorsally and ventrally; anterior ring of total peristomial length. Peristomial cirri to middle of first peristomial ring, nearly ovate, without distinct articulations.

Jaws not available for examination.

Branchiae present, pectinate, distinctly longer than notopodial cirri (Figure 3e), not reduced in mid-body region, erect. Branchiae from setiger 18 to setiger 190. Branchiae present to near posterior end, present on more than 65% of total number of setigers. First and last 10 branchiae single filaments. Maximum number of filaments 5, reached at setiger 32; number of filaments decreasing slowly over next 100 segments. Posterior to setiger 150, 2 filaments in each branchia (except in last 10). Branchial stems tapering, longer than filaments. Filaments digitiform, about as long as notopodial cirri.

Neuropodial acicular lobes distally rounded with aciculae emerging dorsal to midline. Presetal lobes low transverse folds. First 20 postsetal lobes free, triangular, projecting barely beyond acicular lobes. Median and posterior postsetal lobes folds following outline of acicular lobes. Ventral cirri thick and tapering from wide bases in first 15–20 setigers. Median ventral cirri basally inflated; basal inflated region indistinct, ovate, noticeable in setigers 20–50; digitiform free tips present. Posterior ventral cirri without basal inflation, digitiform. Notopodial cirri thick and digitiform in anterior setigers, slowly reduced in thickness, but retaining similar shape in all setigers, without articulations.

Slender, marginally smooth limbate setae projecting beyond compound falcigers in all setigers. All pectinate setae (Figure 3c) flat, distally flaring, with slender, cylindrical shafts; one marginal tooth distinctly longer and thicker than all other teeth; a total of about 15 teeth present. Shafts of compound falcigers (Figure 3b) slender, distally distinctly inflated with distinct distal beaks, marginally finely and indistinctly serrated, with internal oblique striations. Appendages tapering towards distinct head, bidentate. Proximal teeth triangular and directed laterally, as large as distal tooth; distal teeth tapering, directed laterally. Guards distally symmetrically rounded, cutting edge finely serrated, without mucro. Pseudocompound falcigers and compound spinigers absent. Neuropodial aciculae dark brown, distally blunt, geniculate. Separation of acicular cores and sheaths indistinct. Cross-section of aciculae round. Notopodial aciculae clear, slender. Subacicular hooks (Figure 3d) dark brown, bidentate. Separation of cores and sheaths indistinct. Hooks first present from setiger 22, present in all setigers thereafter, always single (except for replacements). Hooks distally obliquely tapering; both teeth directed distally; proximal teeth larger than distal teeth.

UNKNOWN MORPHOLOGICAL FEATURES.—Pygidium and anal cirri; jaw structure.

EXPECTED STATES OF SELECTED UNKNOWN FEATURES.—MX III forming arc with left MX IV; MX VI absent.

CHARACTERS USED IN PREPARATION OF KEY NOT SCORED.—Inappropriate Characters: 56, 58, 59. Unknown Characters: None.

ASSUMED STATES FOR PURPOSE OF PREPARING KEY.—None.