A Review of the Genus Eunice - Smithsonian Institution Libraries

NUMBER 523 305
thereafter, always single (except for replacements). Hooks
tapering towards small heads. Proximal teeth nearly twice as
large as distal teeth, directed laterally. Distal teeth nearly erect.
UNKNOWN MORPHOLOGICAL FEATURES.—Pygidium and
anal cirri.
EXPECTED STATES OF UNKNOWN MORPHOLOGICAL FEA-
TURES.—None
CHARACTERS USED IN PREPARATION OF KEY NOT
SCORED.—Inappropriate Characters: 56, 58, 59. Unknown
Characters: 1, 2,47, 50,63.
ASSUMED STATES FOR PURPOSE OF PREPARING KEY.—
None.
REMARKS.—Eunice segregata is listed with similar species
in Tables 19 and 20. Of species in Table 20 with branchiae
starting from setiger 3, two species, E. biannulata and E.
kobiensis, have eight branchial filaments where the branchiae
are best developed; one species, E. caeca has 24 filaments; the
other species have from 11 to 18 filaments. Of the remaining
species, E. mexicana, E. pennata, and E. websteri have distally
drop-shaped to moniliform articulations of the ceratostyles; E.
segregata and E. valens have cylindrical articulations throughout.
The two peristomial rings are distinct on all sides in E.
segregata: the separation are distinct only dorsally and ventrally
in E. valens. The relationship between this species and similar
species was also explored in Fauchald (1969).
180. Eunice semisegregata Fauchald, 1969
FIGURE 104a-d; TABLES 19, 21
Eunice semisegregata Fauchald, 1969:8-10, fig. 4a-e.
Leodice segregata Chamberlin. 1919a:237-240, pi. 54: figs. 1-4 [in part].
MATERIAL EXAMINED.—Paratype, USNM 19398, Albatross
sta 3417, off southwestern Mexico, 16 o 32'00"N, 99°48'(XTW,
11 Apr 1891, 902 m, green mud, small beam trawl.
DESCRIPTION.—Paratype incomplete with 84 setigers; length
55 mm; maximal width 6 mm; length through setiger 10,9 mm.
Body cylindrical, slightly flattened posteriorly, essentially
truncate anteriorly.
Prostomium (Figure 104d) distinctly shorter and narrower
than peristomium, less than 1 /2 as deep as peristomium.
Prostomial lobes frontally rounded, dorsally inflated; median
sulcus deep. Eyes posterior to bases of A-I. Antennae in a
horseshoe, evenly spaced, similar in thickness. Ceratophores
ring-shaped in all antennae, without articulations. Ceratostyles
slender and tapering, with up to 8 cylindrical articulations in
A-III. A-I to middle of anterior peristomial ring; A-I I to setiger
4; A-III to setiger 5. Peristomium inflated, barrel-shaped.
Separation between rings distinct on all sides; anterior ring 2 /3
of total peristomial length. Peristomial cirri to middle of
anterior peristomial ring, slender and digitiform, without
articulations.
Maxillary formula 1+1, 8+9, 10+0, 9+9, and 1+1. Mx III
long, located behind left Mx II. Mx VI absent.
Branchiae (Figure 104a) present, pectinate, distinctly longer
than notopodial cirri, not reduced in mid-body region, erect.
Branchiae from setiger 3 to setiger 65 in paratype and 69 in
holotype. Branchiae terminating well before posterior end,
present on less than 55% of total number of setigers. All
branchiae pectinate; maximum 38 filaments from about setiger
15. Branchial stems slender, tapering, erect. Filaments slender,
nearly filiform.
Neuropodial acicular lobes symmetrically rounded, rather
broadly in anterior setigers, becoming nearly conical in median
and posterior setigers (Figure 104a); aciculae emerging at
midline. Pre- and postsetal lobes low, transverse folds. First 4
ventral cirri thick and tapering. Ventral cirri basally inflated
from about setiger 5 through setiger 40; inflated bases totally
missing by setiger 50. Inflated bases modest, ovate, narrow tips
tapering. Posterior ventral cirri slender and tapering. Anterior
notopodial cirri about as thick as antennae, tapering. In
branchial region notopodial cirri slender and tapering from
slightly inflated bases. Postbranchial notopodial cirri slender,
nearly filiform. Notopodial cirri without articulations.
Limbate setae marginally serrated. Pectinate setae (Figure
104c) tapering, flat. One marginal tooth longer and thicker than
other teeth; 7 teeth present. Shafts of compound falcigers
(Figure 104c) distally inflated, marginally serrated. Appendages
long, tapering towards small heads, bidentate. Proximal
teeth smaller than distal teeth, short, broadly triangular,
directed laterally. Distal teeth gently curved, tapering. Guards
symmetrically sharply pointed, marginally serrated; mucros
absent. Pseudocompound falcigers and compound spinigers
absent. Aciculae paired in most parapodia, yellow, tapering to
blunt tips, distally bent; cross-sections round. Separation
between core and sheath indistinct in both aciculae and
subacicular hooks. Subacicular hooks yellow, bidentate. Hooks
first present from setiger 51 in holotype and from setiger 55 in
paratype, present in all setigers thereafter always single (except
for replacements). Hooks tapering to small heads. Teeth similar
in size and directed distally.
UNKNOWN MORPHOLOGICAL FEATURES.—Features associated
with posterior parapodia; pygidium and anal cirri.
EXPECTED STATES OF UNKNOWN MORPHOLOGICAL FEA-
TURES.—None.
CHARACTERS USED IN PREPARATION OF KEY NOT
SCORED.—Inappropriate Characters: 56, 58, 59. Unknown
Characters: 1,2,4, 6,47, 50, 63, 65-68.
ASSUMED STATES FOR PURPOSE OF PREPARING KEY.—
None.
REMARKS.—Eunice semisegregata was separated from type
material of E. segregata on a series of distributional features
detailed in part in Tables 19 and 21. Eunice semisegregata has
branchiae extending farther back or with many more branchial
filaments, or both, than other species in listed in Table 19, with
the exception of E. megabranchia and E. validobranchiata.
Subacicular hooks are first present from setiger 35 in E.
megabranchia and from setigers 37-40 in E. validobranchiata.