Eunice mutabilis Gravier 1900

Eunice mutabilis Gravier, 1900

Eunice mutabilis Gravier, 1900:245–248, figs. 105–109, pl. 13: figs. 71–74.

MATERIAL EXAMINED.—Two syntypes, MNHN, Paris, Djibouti, coll. Jousseaume and Coutiére, 1897.

COMMENTS ON MATERIAL EXAMINED.—The description is based on the shorter of the two syntypes.

DESCRIPTION.—Both syntypes complete; one with 196 setigers; total length 95 mm; maximal width 6 mm; length through setiger 10, 8 mm. Other syntype with 313 setigers; length 117 mm; maximal width 7.5 mm; length through setiger 10, 8.5 mm. Anterior body cylindrical, becoming dorsoventrally flattened by setiger 50. Abruptly tapering to pygidium. Anal cirri short, without articulations.

Prostomium (Figure 77d) distinctly shorter and narrower than peristomium, less than as deep as peristomium. Prostomial lobes frontally rounded, dorsally flattened; median sulcus deep. Eyes lateral to bases of A-II, dark. Antennae in a horseshoe, evenly spaced, with A-I thicker than other 3. Ceratophores ring-shaped in all antennae, without articulations. Ceratostyles tapering, without articulations. A-I barely to posterior peristomial ring; A-II to setiger 1; A-III to setiger 2. Peristomium cylindrical; lower lip very muscular, forming distinct ventrolateral pad. Separation between rings distinct dorsally and ventrally only; anterior ring of total peristomial length. Peristomial cirri to front edge of peristomium or posteriormost part of prostomium, basally inflated, tapering to slender tips, without articulations.

Summary maxillary formula 1+1, 4-5+4-5, 6+0, 4-6+6-8, and 1+1. Left Mx IV short; part of distal are with Mx III, with 3 large and varying number of very small, knob-like teeth.

Branchiae (Figure 77a) present, pectinate, distinctly longer than notopodial cirri, not reduced in mid-body region, flexible. Branchiae from setiger 17–18 to setiger 196. Branchiae present to near posterior end; present on more than 65% of total number of setigers. First 2–3 pairs single filaments; all other branchiae with 3 or more filaments. Where best developed, at about setiger 25, branchiae with 12 slender filaments; more usually branchiae with 8 to 9 filaments. Branchial stems slender, flexible. Filaments longer than notopodial cirri in all but first few and last 15–20 setigers.

Anterior neuropodial acicular lobes truncate, becoming rounded by setiger 10 and conical by setiger 30, retaining that shape through rest of body; aciculae emerging above midline. All presetal lobes low, transverse folds. Anterior postsetal lobes higher than acicular lobes, distally rounded, becoming reduced to low, transverse folds by setiger 25. Anterior ventral cirri thick, tapering, becoming basally inflated from setiger 10, retaining inflated condition through rest of body. Inflated bases gradually decreasing in importance posteriorly, forming low transverse ridges in posterior half of body; narrow tips tapering. All notopodial cirri slightly inflated basally, tapering to digitiform tips; those in first 3–4 setigers distinctly longer than those in next following setigers. Notopodial cirri decreasing slowly in length over remainder of body, becoming about half as long in last few setigers as in setiger 10. Notopodial cirri without articulations.

Limbate setae marginally smooth. Pectinate setae (Figure 77b) in distinct fascicles of 15–20 in median and posterior setigers, furled, flared. Both marginal teeth longer than other teeth; 1 marginal tooth distinctly longer than other; ~20 teeth present. Shafts of compound falcigers (Figure 77c) slightly inflated, marginally smooth, with distinct internal striations. Appendages very large, tapering slightly to large heads, bidentate. Proximal teeth slightly larger than distal teeth, triangular, directed laterally. Distal teeth gently curved or nearly erect. Guards symmetrically rounded, marginally smooth; mucros absent. Pseudocompound falcigers and compound spinigers absent. Aciculae projecting, with light to medium brown cores and clear sheaths, tapering, usually straight, slightly curved dorsally in some parapodia; cross sections round. Subacicular hooks (Figure 77e) with light to medium brown cores and clear sheaths, bidentate. Hooks first present from setiger 22–23, present in all setigers thereafter, always single (except for replacements). Hooks tapering strongly to very small heads. Proximal teeth very much larger than distal teeth. Both teeth directed distally.

UNKNOWN MORPHOLOGICAL FEATURES.—Pygidium.

EXPECTED STATES OF UNKNOWN MORPHOLOGICAL FEATURES.—None.

CHARACTERS USED IN PREPARATION OF KEY NOT SCORED.—Inappropriate Characters: 22, 56, 60. Unknown Characters: 4, 6.

ASSUMED STATES FOR PURPOSE OF PREPARING KEY.—None.