Eunice bilobata Treadwell 1906

Eunice bilobata Treadwell, 1906

Eunice bilobata Treadwell, 1906:1168–1169, figs. 47, 48.

MATERIAL EXAMINED.—Holotype, USNM 5212, Albatross sta 3871, Auau Channel, between Maui and Lanai islands, 20°52′20″N, 156°41′35″W, 24–79 m, fine white sand, 12 Apr 1902.

COMMENTS ON MATERIAL EXAMINED.—The holotype consists of a well-preserved anterior end and three median fragments, which probably all derive from the same specimen; size and general constitution are similar, but several intermediate sections must be missing, because the fragments do not match well. The description is based on the anterior end only.

DESCRIPTION.—Anterior fragment with 35 setigers; length 18 mm; maximal width 6 mm; length through setiger 10,7 mm. Head and anterior 5–6 segments cylindrical; remainder of fragment dorsoventrally flattened.

Prostomium (Figure 22a) distinctly shorter and narrower than peristomium, as deep as of the peristomium, nearly hidden under large antennae. Prostomial lobes frontally obliquely truncate, dorsally flattened; median sulcus deep. Eyes absent. Ceratophores ring-shaped in all antennae, without articulations. Ceratostyles digitiform, with up to 12 irregular, indistinct cylindrical articulations in A-II. A-I to posterior margin of peristomium; A-II reach setiger 7; A-III incomplete; at least as long as A-II. Peristomium strongly flaring anteriorly; with distinct, muscular lower lip. Separation between rings distinct dorsally, possibly also ventrally, but distorted by overlapping fold; anterior ring of total peristomial length. Peristomial cirri to middle of prostomium, digitiform, without articulations.

Maxillary formula 1+1, 5+6, 6+0, 3+9, and 1+1.

Branchiae (Figure 22e) present, pectinate, distinctly shorter than notopodial cirri, not reduced in mid-body region, flexible. Branchiae from setiger 7, present on all fragments. All branchiae pectinate with up to 18 filaments. Branchial stems curved dorsally and twisted posteriorly in most segments. Filaments short, slender.

Neuropodial acicular lobes broadly rounded; aciculae emerging dorsal to midline. Pre- and postsetal lobes low, transverse folds. First 3 ventral cirri thick, tapering, becoming basally inflated from setiger 4. Inflated bases thick, ovate; narrow tips tapering. Anterior notopodial cirri long, basally inflated, tapering to thick, digitiform tips; in branchial region notopodial cirri shorter, tapering from bases. Notopodial cirri with up to 7 articulations anteriorly; number of articulations decreasing posteriorly; median and posterior notopodial cirri with 3 or 4 articulations.

Limbate setae long, narrow. Pectinate setae (Figure 22c) large, tapering, flat. Marginal teeth no longer than other teeth, about 10 long, distally tapering teeth present. Shafts of pectinate setae distinctly punctate. Shafts of compound falcigers (Figure 22b) tapering. Appendages short, bidentate. Both teeth similar in size. Proximal teeth directed laterally. Distal teeth directed obliquely distally. Guards symmetrically rounded, without mucros. Pseudocompound falcigers and compound spinigers absent. Aciculae paired, dark, superior aciculae bent with irregular knobs (Figure 22d); other aciculae tapering to straight, blunt points; cross-section of aciculae round. Subacicular hooks black, bidentate. Hooks first present from setiger 25, present in all setigers thereafter, always single (except for replacements).

UNKNOWN MORPHOLOGICAL FEATURES.—Relation between Mx III and left Mx IV; features associated with posterior setigers; pygidium and anal cirri.

EXPECTED STATES OF UNKNOWN MORPHOLOGICAL FEATURES.—Branchiae continued to the far posterior end.

CHARACTERS USED IN PREPARATION OF KEY NOT SCORED.—Inappropriate Characters: 14, 56. Unknown Characters: 1, 2, 4, 6, 15–17, 23, 36–38, 40, 42, 57–60, 74, 78.

ASSUMED STATES FOR PURPOSE OF PREPARING KEY.—37,1; 38,1.