Eunice tenuis (Treadwell 1921)

Eunice tenuis (Treadwell, 1921)

Leodice tenuis Treadwell, 1921:51–52, figs. 154–163, pl. 4: fig. 11.

?Eunice tenuis.—Hartman, 1956:284.

MATERIAL EXAMINED.—Holotype, AMNH 1913–1271, Dry Tortugas, Florida.

COMMENTS ON MATERIAL EXAMINED.—The anterior end of the holotype has been sliced off frontally, so only a remnant of the peristomial rings is present on the dorsal side. The specimen is complete ventrally only from setiger 5–6; thus no illustrations could be made of the anterior end.

DESCRIPTION.—Holotype complete with 695 setigers; total length 460 mm; maximal width 2 mm; length through setiger 10, ∼4.5 mm.

Prostomium according to Treadwell (1921:51) conspicuously bilobed. Ceratophores ring-shaped in all antennae, without articulations. Ceratostyles slender and digitiform, without articulations. Outreaching prostomium, with A-III longest. Peristomial rings distinct on all sides; relative length of rings indeterminable. Peristomial cirri short, ovate, without articulations.

Jaws missing; maxillary formula 1+1, 7+5, 7+0, 3+6, and 1+1 (rewritten after statement in Treadwell, 1921:52).

Branchiae (Figure 107e) present, palmate, distinetly longer than notopodial cirri, not reduced in mid-body region. Branchiae from setiger 81 to posterior end. Branchiae present to near posterior end, present on more than 65% of total number of setigers. First 10 branchiae single filaments; number of filaments increasing to 3 by setiger 150, finally to 4 by setiger 400. Numbers of filaments decreasing to 3 in last 100 segments; last few segments with reduced branchiae.

All neuropodial acicular lobes distally rounded; aciculae emerging at midline. All pre- and postsetal lobes low, transverse folds. First 200 ventral cirri digitiform. Ventral cirri basally inflated in middle 200 segments. Inflated bases ovate; narrow tip tapering. Posterior ventral cirri short, nearly tubercular, without inflated bases. All notopodial cirri digitiform. Notopodial cirri without articulations.

Limbate setae missing in scattered setigers, gently curved, marginally frayed. Pectinate setae (Figure 107g) long and prominent in posterior setigers, narrow, tapering, flat. Marginal teeth no longer than other teeth; less than 10 teeth present. Shafts of compound falcigers (Figure 107f) distally inflated, marginally serrated. Appendages short, stout, bidentate. Proximal teeth very much larger than distal teeth, tapering, directed laterally. Distal teeth tapering, sharply bent. Guards symmetrically rounded, marginally frayed; mucros absent. Pseudocompound falcigers and compound spinigers absent. Aciculae single, light amber-colored, tapering to blunt tips, straight; cross-sections round. Subacicular hooks (Figure 107h) light amber-colored, bidentate. Hooks first present from setiger 124, present in all setigers thereafter, paired in most setigers. Proximal teeth very much larger than distal teeth, directed laterally. Distal teeth directed distally.

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

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

CHARACTERS USED IN PREPARATION OF KEY NOT SCORED.—Inappropriate Characters: 22, 34, 56, 58, 59. Unknown Characters: 4, 6–8, 10–17, 24, 26, 40, 74, 78.

ASSUMED STATES FOR PURPOSE OF PREPARING KEY.—None.