A Review of the Genus Eunice - Smithsonian Institution Libraries

56 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY
frequently used and it has a known type locality. Johnston's
name does not appear to have been used separately.
11. Eunice antarctica Baird, 1869
Eunice antarctica Baird, 1869:348.
Eunice pennala.—Hattman
1776].
FIGURE 10; TABLES 19,21
1964:118 [in part, not Eunice pennata Miiller,
MATERIAL EXAMINED.—Three syntypes, BM(NH) ZB
1972.70, Antarctic Seas, Erebus and Terror Southern Seas
Expedition.
COMMENTS ON MATERIAL EXAMINED.—The type material
consists of three syntypes and two posterior fragments. Two of
the three syntypes are incomplete. The third syntype is
complete and is described in detail below.
DESCRIPTION.—Syntype complete, of unknown sex, with
122 setigers; total length 102 mm; maximal width 3.5 mm;
length through setiger 10, 11 mm.
Prostomium (Figure 10a) distinctly shorter than peristomium,
about as wide as peristomium, less than x li as deep as
peristomium. Prostomial lobes frontally rounded, dorsally
inflated; median sulcus shallow. Eyes not observed. Antennae
in a shallow horseshoe, evenly spaced, similar in thickness.
Ceratophores ring-shaped, without articulations. Ceratostylcs
digitiform, with up to 10 irregular, distinct or very indistinct
cylindrical articulations in A-III. A-I to end of peristomium;
A-II to setiger 1 (setiger 3 in another syntype); A-III to setiger
3 (setiger 4 in another syntype). Peristomium cylindrical.
Separation between rings distinct dorsally and ventrally;
anterior ring 4 /s of total peristomial length. Peristomial cirri to
posterior end of prostomium, slender and digitiform, without
articulations.
Jaws not examined.
Branchiae (Figure 10b) present, pectinate, distinctly shorter
than notopodial cirri, not reduced in mid-body region, erect.
Branchiae from setiger 3 to setiger 39-44. Branchiae terminating
well before posterior end, present on less than 55% of total
number of setigers. First 6-7 and last 2 branchiae with single
filaments. Maximum 5 filaments at about setiger 15. Stems
slender, cylindrical, shorter than filaments. Filaments shorter
than notopodial cirri, tapering.
Median acicular lobes distally truncate with aciculae
emerging at midline. Pre- and postsetal lobes follow outline of
acicular lobes closely. First 3 ventral cirri digitiform, about half
as long as notopodial cirri, becoming basally inflated from first
branchial setigers. Inflated bases nearly spherical in most of
branchial region, retaining digitiform, distally truncate tips.
Inflated bases gradually lost in postbranchial region; last
30-40 ventral cirri slender, digitiform, increasing in length
posteriorly, remaining less than half as long as notopodial cirri
in all segments. Anterior notopodial cirri slender, medially
inflated, usually with 1-2 articulations. Median and posterior
notopodial cirri (Figure lOg) increasingly slender, digitiform in
postbranchial region; articulations increasingly poorly marked;
finally represented only by steps in width of cirri.
Limbate setae rather slender, marginally serrated. Shafts of
pectinate setae (Figure lOd) wide, cylindrical. Blades tapering,
flat. One marginal tooth much longer than other teeth, with -10
rather coarse teeth. Shafts of compound falcigcrs (Figure 10c)
barely inflated; marginally smooth; distal beaks distinct.
Appendages thick, bidentatc, with very short teeth. Proximal
teeth much smaller than distal teeth, triangular, directed
laterally. Distal teeth gently curved, directed laterally. Guards
symmetrically bluntly pointed, marginally serrated, without
mucros. Pseudocompound falcigcrs and compound spinigcrs
absent. Aciculae usually paired, yellow, slender, tapering,
gently curved ventrally (Figure 10c); cross-section round.
Subacicular hooks (Figure lOf) yellow, bidentatc. Hooks first
present from setiger 31-44, present in all sctigcrs thereafter,
always single (except for replacements). Hooks slender,
tapering smoothly, with very large heads. Proximal teeth larger
than distal teeth; both teeth directed distally.
UNKNOWN MORPHOLOGICAL FEATURES.—Jaw structure;
pygidium and anal cirri.
EXPECTED STATES OF SELECTED UNKNOWN FEATURES.—
Mx III long, but forming distal arc with left Mx IV.
CHARACTERS USED IN PREPARATION OF KEY NOT
SCORED.—Inappropriate Characters: 56, 58, 59. Unknown
Characters: 4, 6, 13, 14.
ASSUMED STATES FOR PURPOSE OF PREPARING KEY.—
None.
REMARKS.—Eunice antarctica has been considered a synonym
of E. pennata (Hartman, 1964:118). The two species can
be separated on several features. Eunice antarctica has a
maximum of five branchial filaments in branchiae that are
shorter than the notopodial cirri; E. pennata has up to 12
filaments in branchiae that are distinctly longer than notopodial
cirri. In E. antarctica the notopodial cirri have at least one
distinct articulation throughout the body, but lack distinct
cirrophores; in E. pennata the notopodial cirri are articulated in
prebranchial segments; they lack all articulations in the
branchial region and have a distinct basal cirrophore in
postbranchial setigers. Eunice antarctica is listed with similar
species in Tables 19 and 21. It is the only species in Table 21
with branchiae shorter than notopodial cirri and with the
notopodial cirri articulated throughout the body.
Baird (1869) suggested that his new species resembled E.
havaica, one of Kinberg's species; the latter has strongly
moniliform antennal articulations and tridentate subacicular
hooks. Eunice antarctica has cylindrical antennal articulations
and bidentate subacicular hooks.