A Review of the Genus Eunice - Smithsonian Institution Libraries

NUMBER 523 217
EXPECTED STATES OF UNKNOWN MORPHOLOGICAL FEA-
TURES.—None.
CHARACTERS USED IN PREPARATION OF KEY NOT
SCORED.—Inappropriate Characters: 22, 56, 58, 59. Unknown
Characters: 1,2,4, 6,47, 50, 63, 74, 78.
ASSUMED STATES FOR PURPOSE OF PREPARING KEY.—
None.
REMARKS.—Eunice megabranchia is a member of group Al
and was compared to other deep-water species by Fauchald
(1970); it is listed with similar species in Tables 19 and 21; it
is also listed in Tables 24 and 26, because the aciculae and
subacicular hooks may be a rather dark yellow. A detailed
discussion of the relation between this species, E. hawaiensis,
and E. validobranchiata is given as part of the description of
the former.
Eunice megabranchia differs from all species in Table 26 by
having more than five times as many branchial filaments (47
vs. 9) as the species with the next high number listed in that
table.
Eunice megalodus Grubc, 1878
Eunice megalodus Grubc, 1878b:lS6-lS8.pl 9: fig. S.
REMARKS.—The unusual jaw apparatus and the structure of
the anterior end as described by Grube, the setal complement,
and the structure of the notopodial cirri are all features found in
the genus Euniphysa.
121. Eunice mexicana Fauchald, 1970
FIGURE 72; TABLES 8,19,20
Eunice biannulata mexicana Fauchald, 1970:27-28, pi. 1: figs, f, g.
MATERIAL EXAMINED.—Lectotype (AHF Poly 1539) and 10
paralectotypes (AHF Poly 1540), Mexico, Isla Isabel,
21°54 / 1(TN, 1O5°53'O5"W, 18-33 m, corallines, dredge, 2 Apr
1937, Velero sta 747-37.
DESCRIPTION.—Lectotype complete with 106 setigers; total
length 87 mm; maximal width 3.5 mm wide at about setiger 15;
length through setiger 10, 10.5 mm; width at setiger 10, 3.2
mm. Body cylindrical anteriorly, slightly dorsoventrally flattened
posteriorly. Anal cirri short, tapering, possibly articulated.
Prostomium (Figure 72a) distinctly shorter and narrower
than peristomium, as deep as l /2 of peristomium. Prostomial
lobes frontally obliquely truncate, dorsally slightly inflated,
sloping obliquely laterally; median sulcus very shallow. Eyes
posterior to bases of A-I, black. Palpal region marked by
transverse folds on ventral side. Antennae in very open
horseshoe, evenly spaced, similar in thickness. Ceratophores
ring-shaped in all antennae, without articulations. Ceratostyles
slender and slightly tapering; maximum 17 articulations in
A-III; first several articulations cylindrical, becoming increasingly
drop-shaped distally; in some paralectotypes distal
articulations moniliform. A-I to posterior peristomial ring; A-I I
to setiger 5; A-III to setiger 8. Peristomium with distinctly
muscular lower lip. Separation between rings distinct dorsally,
visible ventrally; anterior ring 3 A of total peristomial length.
Peristomial cirri to middle of prostomium, slender and
tapering, with 4 to 5 cylindrical articulations.
Maxillary formula of 5 paralectotypes 1+1, 6-7+7-8,
7-9+0, 6-8+8-11, and 1+1. Mx III relatively short, slightly
curved, located behind left Mx II. Mx VI missing.
Branchiae (Figure 72d,e) present, pectinate, distinctly longer
than notopodial cirri, not reduced in mid-body region, erect
Branchiae from setiger 3 to setiger 40. Branchiae terminating
well before posterior end, present on less than 55% of total
number of setigers. Maximum 18 filaments at about setiger 15;
in lectotype all branchiae with at least 2 filaments; in
paralectotypes up to 3 posterior segments with single branchial
filaments. First 2 and last 3 branchiae shorter than notopodial
cirri; all other branchiae longer. Branchial stems slender,
tapering. Filaments slender, digitiform, shorter than notopodial
cirri in all setigers.
Anterior and median neuropodial acicular lobes asymmetrically
rounded with aciculae emerging dorsal to midline;
posterior acicular lobes increasingly lower, merging into body
wall near posterior end. Pre- and postsetal lobes low, transverse
folds in all setigers. Anterior ventral cirri thick and tapering,
becoming distinctly inflated by setiger 10. Inflated bases ovate,
modest in size; narrow tips digitiform. Inflated bases reduced
from about setiger 25-30. Ventral cirri thick and digitiform
from about setiger 45, retaining that shape in remainder of
body. Anterior and median notopodial cirri thick and tapering,
with up to 5 cylindrical articulations. Posterior notopodial cirri
nearly as long as those in median setigers, digitiform, without
articulations.
Limbate setae thick, marginally finely serrated, longer than
compound hooks in all setigers. All pectinate setae (Figure
72c, f,i) furled, tapering. Both marginal teeth longer than other
teeth; number of teeth increasing from 8 to -12 posteriorly.
Shafts of all compound falcigers (Figure 72b,g,j) tapering,
internally distinctly striated, with distinct beak. All appendages
relatively wide basally, tapering towards small heads, bidentate.
Proximal teeth very short; indistinct low knobs in anterior
and median setigers, distinctly triangular in posterior setigers.
Distal teeth nearly erect in all setigers, increasing in size from
anterior to posterior setigers. Anterior and median guards
asymmetrically bluntly pointed, becoming increasingly symmetrical
and rounded posteriorly, marginally finely serrated;
mucros absent. Pscudocompound falcigers and compound
spinigers absent. Aciculae at least paired, with clear yellow
cores. Anterior aciculae bluntly pointed, distally straight,
medially at least superiormost aciculae distally expanded into
tabs (Figure 72h); posterior aciculae (Figure 72k) tapering,
distinctly bent dorsally; cross-sections round. Separation
between core and sheath distinct in both aciculae and
subacicular hooks. Subacicular hooks (Figure 72k) yellow,