Nicidion cariboea (Grube 1856)

Eunice cariboea Grube, 1856

Eunice cariboea Grube, 1856:57.

Eunice gagzoi Augener, 1922b:45 [in part, see also E. gagzoi below].

Nicidion incerta Hansen, 1882:8, pl. 2: figs. 19–21.

Eunice (Nicidion) incerta.—Hartman, 1959:313.

MATERIAL EXAMINED.—Lectotype and 3 paralectotypes, ZMC, and 5 paralectotypes, ZMB 4004, Christiansted, St. Croix, Virgin Islands, coll. A.S. Örsted and H. Kröyer.

Holotype of Nicidion incerta, Leiden no. 1510, Rio de Janeiro, coll. E. v. Beneden.

COMMENTS ON MATERIAL EXAMINED.—Six of the types of E. cariboea are complete. The lectotype consists of 157 setigers and is 30 mm long and 1 mm wide, and the length through setiger 10 is 2 mm. The larger of the two complete paralcctotypes in ZMB is here illustrated and described in detail. The holotype of Nicidion incerta is presently in two parts; it is, however, complete and in good condition. In order to account for minor differences between the two described taxa, the descriptions are presented separately.

DESCRIPTION.—Paralectotype of E. cariboea complete with 127 setigers; total length 24 mm; maximal width 1.2 mm wide at setiger 10. Length through setiger 10, 2.5 mm. Body anteriorly inflated, otherwise cylindrical throughout.

Prostomium (Figure 29g) distinctly shorter and narrower than peristomium, as deep as of the peristomium. Prostomial lobes frontally obliquely truncate; lobes triangular, dorsally flattened; median sulcus shallow. Eyes small, indistinct, posterior to bases of A-I. Antennae in a deep horseshoe; A-I and A-II close together, separated from A-III, similar in thickness. Ceratophores ring-shaped in all antennae, without articulations. Ceratostyles digitiform, stout, nearly sausage-shaped, without articulations. A-I to middle of first peristomial ring; A-II and A-III to middle of second peristomial ring. Peristomium slightly flaring anteriorly; lower lip distinct, muscular. Separation between rings distinct dorsally and ventrally, indistinct only for a short distance laterally; anterior ring of total peristomial length. Peristomial cirri to posterior end of first peristomial ring, nearly ovate, without articulations.

Jaws examined in a ZMC paralectotype. Maxillary formula 1+1, 5+5, 6+0, 4+9, and 1+1. Mx III long; located behind Mx II; Mx VI absent.

Branchiae absent.

Anterior neuropodial lobes (Figure 29k) symmetrically rounded, becoming symmetrically sharply pointed in posterior setigers (Figure 291); aciculae emerging at midline. Presetal lobes low, transverse folds; postsetal lobes following outline of acicular lobes closely. Four or 5 first ventral cirri thick, tapering. Ventral cirri basally inflated from about setiger 5. Inflated bases transversely elongated, welt-like; narrow tips digitiform. Inflated base decreasing in size from about setiger 50. Last 40 ventral cirri without inflated bases, short, nearly tubercular. All notopodial cirri tapering, decreasing in length from anterior to posterior end, without articulations. Anterior notopodial cirri emerging close to parapodial bases; posterior notopodial cirri emerging from dorsum well above parapodial bases.

Limbate setae short, stout, geniculate, marginally serrated. Two to 3 short pectinate setae (Figure 29h) in fascicle anteriorly; shafts coarse, cylindrical; blades tapering; flat. One marginal tooth longer than other teeth;~10 teeth present in a seta. In far posterior setigers up to 10 long pectinate setae (Figure 29n) in a fascicle; shafts slender, cylindrical; blades flaring, flat. One marginal tooth longer than other teeth; up to 15 teeth in a seta. Shafts of compound falcigers (Figure 29j) distally inflated, marginally serrated; beak indistinct. Appendages very small, delicate; head small, bidentate. Proximal teeth curved, tapering, directed obliquely distally; distal teeth longer than proximal teeth, blunt, erect. Guards symmetrically bluntly pointed, marginally serrated, without mucros. Pseudocompound falcigers and compound spinigers absent. Aciculae single; cross-sections round. Anterior aciculae tapering to sharp tips, light brown to dark yellow. Aciculae mucronate (Figure 29i), bluntly pointed, dark brown or black from about setiger 30. Subacicular hooks (Figure 29m) dark brown or black, bidentate. Hooks first present from setiger 24–31, present in all setigers thereafter, always single (except for replacements). Hooks subdistally curved; head large; both teeth strongly curved, directed laterally. Proximal teeth about twice as large as distal teeth. Guards truncate.

DESCRIPTION OF Nicidion incerta.—Holotype complete, of unknown sex, with 158 setigers; total length 38 mm; maximal width 1.5 mm at setiger 20; length through setiger 10,2.75 mm; width at setiger 10, 1.25 mm. Body ventrally flattened anteriorly, becoming cylindrical medially and retaining that shape for the rest of body. Truncate anteriorly, slowly tapering posteriorly. Pygidium is dorsally smooth; only the short anal cirri are present.

Prostomial lobes (Figure 29q) frontally rounded, dorsally slightly inflated; median sulcus shallow. Eyes not observed (illustrated as being behind and between A-I and A-II in Hansen, 1882). Antennae in shallow horseshoe, evenly spaced and similar in thickness. Ceratophores short, ring-shaped. Ceratostyles thick, digitiform, without articulations. A-I to middle of anterior peristomial ring; A-II to middle of posterior peristomial ring; A-III to middle of posterior peristomial ring, slightly outreaching A-II. Nuchal fold with lateral notch; lower lip entire. Peristomium tapering anteriorly. Separation between rings distinctly dorsally and ventrally; anterior ring ~ of total peristomial length. Peristomial cirri barely outreaching posterior peristomial ring, thick, ovate, without articulations.

Jaws not examined.

Branchiae absent.

Neuropodial acicular lobes symmetrically rounded. Pre- and postsetal lobes low, transverse folds. Ventral cirri tapering through first 9 setigers, distinctly inflated from about setiger 10. Inflated bases large, spherical; distal tips digitiform. Inflated bases decreasing in size from about setiger 60 and totally missing posterior to setiger 100. Posterior ventral cirri short, thick, tapering; distinctly shorter than notopodial cirri. Notopodial cirri well separated from neuropodial acicular lobes, thick, without articulations. Anterior neuropodial cirri digitiform. Median and posterior neuropodial cirri tapering.

Limbate setae medially thick, marginally serrated, slightly longer than other setae. Pectinate setae not seen. Shafts of posterior compound falcigers (Figure 29p) distally inflated, without distinct beaks, marginally serrated, without internal striations. Appendages short, tapering, with distinct heads. Proximal teeth about as large as distal teeth, narrowly tapering, directed slightly to distinctly distally. Distal teeth tapering, directed obliquely distally, slender. Guards of posterior compound hooks symmetrically rounded, without mucros or marginal serrations. Posterior aciculae single, about as thick as subacicular hooks, brown, without distinct separation between sheath and core, tapering to blunt tips, straight. Subacicular hooks (Figure 29o) single, brown, without separation into sheath and core, bidentate. Hooks abruptly tapering to distinct, bent necks. Proximal teeth longer than distal teeth, erect, straight or slightly tilted distally, erect. Distal teeth short, thick, blunt, erect.

UKNOWN MORPHOLOGICAL FEATURES.—Pygidium and anal cirri.

EXPECTED STATE OF UNKNOWN MORPHOLOGICAL FEATURES.—None.

CHARACTERS USED IN PREPARATION OF KEY NOT SCORED.—Inappropriate Characters: 22, 31–42, 56, 58, 59. Unknown Characters: 74, 78.

ASSUMED STATES FOR PURPOSE OF PREPARING KEY.—None.