Revision of the genus Polyeunoa McIntosh, 1885 (Polychaeta, Polynoidae)
Author
Barnich, Ruth
Author
Gambi, Maria Cristina
Author
Fiege, Dieter
text
Zootaxa
2012
3523
25
38
journal article
44230
10.5281/zenodo.214562
4953b549-d530-4cb8-bcc2-617653defc36
1175-5326
214562
158840BF-5C1F-4EBE-9BFE-E18968077548
Polyeunoa laevis
McIntosh, 1885
(
Figs. 1
A–H, 2A–D)
Polyeunoa laevis
McIntosh, 1885
: 76
, pl. 12 fig. 2, pl. 20 fig. 8, pl. 7A figs. 12, 13;
Bergström (1916)
: 288
, pl. 3 fig. 7;
Fauvel (1936)
: 12
;
Monro (1936)
: 102
[part];
Uschakov (1962)
: 177
;
Hartman (1964)
: 42
, pl. 12 figs. 5–7 [part];
Hartman (1967)
: 38
;
Hartman (1978)
: 136
;
Pettibone (1969)
: 46
, fig. 1;
Orensanz (1976)
: 11
;
Hartmann-Schröder (1983)
: 261
;
Knox &
Cameron
(1998)
: 34
, figs. 69–72;
Barnich
et al.
(2012)
: XXX.
Enipo rhombigera
Ehlers, 1908
: 47
, pl. 4 figs. 1–12;
Ehlers (1913)
: 449
.
Polyeunoe
(sic!)
dubia
Hartmann-Schröder, 1965
: 69
, figs. 13–17 [new synonymy].
Polynoe thouarellicola
Hartmann-Schröder, 1989
: 207
, figs. 1–11.
Polynoe antarctica:
Knox &
Cameron
(1998)
: 35, figs. 73–76 [not
P. a n t a rc t i c a
Kinberg, 1858
, see below].
Type
material.
Polyeunoa laevis
:
Syntypes
BMNH
1885.12.1.55 (2 cs, 8 af & numerous fragments), “Challenger“ Exp., St. 145A, off Prince Edward Island,
46°41’S
38°10’E
,
27 December 1873
, 310 fms, volcanic sand.
Enipo rhombigera
:
Lectotype
[designated herein, spm. described and figured in detail in
Ehlers 1908
]
ZMB
10581 (cs), Deutsche Tiefsee-Exp. 1898/1899, St. 131, E of
Bouvet Island
,
54°28’S
3°30’E
,
457 m
, volcanic sand.
Paralectotypes
ZMB
5759 (numerous spms.), Deutsche Südpolar-Exp. 1902/1903, Winterstation,
350–
385 m
.
Polyeunoe dubia
:
Holotype
ZMH
P-
1527 (af) &
paratype
ZMH
P-
15249 (af), Mar
Chile
I Exp., St.
X1
, Gulf of Concorado (S
Chile
),
21 March
1960
, 170 m, fine sand with stones, mud and detritus.
Polynoe thouarellicola
:
Holotype
ZMH
P-
19360 (cs) &
paratype
ZMH
P-
19364 (af), ANT
VI/2
Exp., RV “Polarstern“, St. 12/227, Elephant Island,
61°91.8’S
56°11’W
,
16 December 1987
, 387–
426 m
, bottom trawl, on
Thouarella
sp. (gorgonarian coral).
Additional material.
Off coast of
Argentina
/ S of Falklands: 2 spms.,
SMF
19955, “Walter Herwig” 15, St. 234, E Santa Vitória do Palmar,
35°14’S
52°28’W
,
12 June
1966
,
200 m.
21 spms.,
SMF
19956, “Walther Herwig” 15, St. 245, E Mar de Ajó,
36°49’S
54°02’W
,
14 June
1966
, 600 m, associated with octocorals. 2 spms., MACN-In 39410, “Walther Herwig” 15, St. 245, E Mar de Ajó,
36°49’S
54°02’W
,
14 June
1966
, 600 m, associated with octocorals. 1 spm.,
SMF
20035, “Walther Herwig” 15, St, 246, E Mar de Ajó,
36°48’S
54°03’W
,
14 June
1966
,
500 m.
1 spm. (mf),
SMF
19958, “Walther Herwig” 15, St. 306, E Comodoro Rivadavia,
45°46’S
60°19’W
,
25 June
1966
,
200 m.
1 spm.,
SMF
19957, “Walther Herwig” 15, St. 340, S
Malvinas
Islands (Falklands),
53°47’S
58°46’W
,
1 July
1966
,
165 m.
Weddell Sea (Collection of M.C.
Gambi
): 14 spms.,
EASIZ
I Exped., ANT XIII/3, St. 39/001, NE Kap
Norvegia
,
71°03.10’S
11°25.50’W
,
5 February 1996
, bottom trawl,
462–481 m
, on gorgonarian coral. 7 spms.,
EASIZ
I Exped., ANT XIII/3, St. 39/005, SW Kap
Norvegia
,
71°40.49’S
12°41.70’W
,
6 February 1996
, epibenthic sledge, 254–
239 m
, on gorgonarian coral. 2 spms.,
EASIZ
I Exped., ANT XIII/3, St. 39/011, between Vestkap and Halley,
73°22.60’S
21°10.60’W
,
13 February 1996
, bottom trawl, 338–
333 m
, on gorgonarian coral. 5 spms.,
EASIZ
I Exped., ANT XIII/3, St. 39/012, between Vestkap and Halley,
73°18.10’S
21°10.10’W
,
13 February 1996
, bottom trawl, 459–
457 m
, on gorgonarian coral. 1 spm.,
SMF
21633,
EASIZ
I Exped., ANT XIII/3, St. 39/014, between Vestkap and Halley,
73°36.1’S
22°35.7’W
,
14 February 1996
, small dredge,
850–889 m
, on
Primnoisis
sp., ded. M.C.
Gambi
. 10 spms.,
EASIZ
I Exped., ANT XIII/3, St. 39/015, between Vestkap and Halley,
73°42.00’S
22°30.50’W
,
15 February 1996
, bottom trawl, 446–
428 m
, on gorgonarian coral. 3 spms.,
EASIZ
I Exped., ANT XIII/3, St. 39/016, between Vestkap and Halley,
73°53.40’S
22°26.90’W
,
15 February 1996
, bottom trawl, 246–
242 m
.
3 spms.,
EASIZ
I Exped., ANT XIII/3, St. 39/017, between Vestkap and Halley,
73°18.00’S
21°09.90’W
,
16 February 1996
, bottom trawl, 468–
465 m
, on gorgonarian coral. 3 spms.,
EASIZ
I Exped., ANT XIII/3, St. 39/026, W of Kap
Norvegia
,
71°29.30’S
14°18.6’W
,
24 February 1996
, small dredge,
216–
222 m
. 5 spms.,
EASIZ
I Exped., ANT XIII/3, St. 39/032, NW of Atka,
70°28.90’S
8°15.1’W
,
4 March 1996
, small dredge, 286–
283 m
, on
Primnoisis
sp. and
Dasystenella
sp. 5 spms.,
EASIZ
II Exped., ANT XV/3 St. 48/078, Drescher Inlet,
72°51.1’S
19°15.1’W
,
3 February 1998
, bottom trawl,
391 m
.
Ross Sea (Collection of M.C.
Gambi
): 17 spms., Terra Nova Bay, Road Bay, st. E 2,
24
December 1989 dredge,
100 m
depth.
Diagnosis.
Prostomium with cephalic peaks poorly developed or absent. Antennae and cirri very long, median antenna much longer than lateral antennae. Tip of neuropodial acicular lobe not extended to supra-acicular process. Neurochaetae mainly unidentate, some minutely bidentate. Ventral cirri long, reaching to tip of neuropodia in anterior segments.
Description
(based on additional specimen in good condition, SMF 21633,
Fig. 1
, and
paralectotype
of
Enipo rhombigera
ZMB 5759,
Fig. 2
).
Prostomium bilobed, with indistinct cephalic peaks (
Fig. 1
A); ceratophore of median antenna in anterior notch, style smooth, tapering, very long (reaching back to segment
14 in
paratype
of
E. rhombigera
,
Figs. 2
A,B); lateral antennae inserted ventrally to median antenna, styles smooth, tapering; anterior pair of eyes situated dorsolaterally at widest part of prostomium, posterior pair dorsally near hind margin of prostomium; palps tapering.
First or tentacular segment with a pair of tentaculophores inserted laterally to prostomium, without notochaetae, but with a dorsal and a ventral tentacular cirrus, styles smooth, very long, tapering (
Fig. 2
B). Second or buccal segment with first pair of elytra, biramous parapodia and long tapering ventral or buccal cirri. Following segments with ventral cirri rather long, reaching to tip of neuropodium in anterior segments, getting shorter more posteriorly (
Fig. 1
C).
Fifteen pairs of elytra, on segments 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 26, 29 and 32 (in other specimens additional, sporadically and irregularly arranged pairs of elytra present after segment 32); elytra nearly covering dorsum in anterior body region, becoming smaller more posteriorly; usually smooth, occasionally anterior elytra with few scattered marginal papillae near anterior margin (
Figs. 1
B, 2B,C). Cirrigerous segments with small, rather indistinct dorsal tubercles in anterior segments, tending to disappear more posteriorly; dorsal cirri with cylindrical cirrophore, styles smooth, very long and tapering (
Fig. 2
A–D).
Parapodia biramous; notopodia and neuropodia with prominent acicular lobe, tip of neuropodial acicular lobe not extended to supra-acicular process; tips of noto- and neuroacicula penetrating epidermis (
Fig. 1
C). Notochaetae few, about as stout as neurochaetae, with faint rows of spines and blunt tip (
Fig. 1
D,E); neurochaetae more numerous, with distinct rows of spines distally, and mostly with unidentate tip, occasionally bidentate, with minute secondary tooth (often abraded) (
Fig. 1
F–H).
Dorsal side of segments with or without transverse or longitudinal pigmentation (in ethanol).
Measurements.
Specimens figured here: cs in two fragments, L
55 mm
, W
6 mm
for 64 segments (
Fig. 1
, SMF 21633); cs, L
60 mm
, W
7 mm
for 62 segments (
Fig. 2
, ZMB 5759,
paratype
of
E. rhombigera
). Largest complete
syntype
of
P. l a e v i s
(BMNH 1885.12.1.55): L
38 mm
, W
7 mm
for 68 segments.
Remarks.
As noted already by several authors, like
Bergström (1916)
,
Pettibone (1969)
, and
Stiller (1996)
,
Polyeunoa laevis
shows a number of variable characters. Examination of several specimens from the same station (ANT XIII/3 St. 0019) confirmed that not only the number and insertion of elytra and the expression of the cephalic peaks are variable characters, but also the presence and extent of pigmentation on the dorsum and the presence or absence of dorsal tubercles are subject to individual variability. However, characters which are constant and clearly allow the identification of
P. la ev i s
are the presence of neuropodia with tip of acicular lobe not extended to supraacicular process and neurochaetae all unidentate or mostly unidentate and some minutely bidentate. Additional molecular characters might be helpful, but such a study is beyond the scope of this paper (see also remark related to the genus
Polyeunoa
above).
If specimens of
P. laevis
show only 15 pairs of elytra, differentiation from
Neopolynoe antarctica
(
Kinberg, 1858
)
n. comb.
(see below) might be difficult. However, in the latter species the anterior pair of eyes is situated slightly in front of the widest part of the prostomium, the cephalic peaks are well developed, and the tip of the acicular neuropodial lobe, is extended to a thick, stout supra-acicular process (
Table 2
).
Polyeunoa laevis
and
Parapolyeunoa flynni
(
Benham, 1921
)
n. comb.
have often been confused in the past. As we demonstrate below, differentation of both species is rather easy, since
Parapolyeunoa flynni
is mainly characterised by the presence of distinct cephalic peaks, a short, digitiform supra-acicular process, short ventral cirri and distinctly bidentate neurochaetae (
Table 2
).
Distribution.
Widely distributed in the SW Atlantic (northwards up to Buenos Aires) and the Magellan, Sub-
Antarctic
and
Antarctic
regions, in
35–2450 m
depth, often associated with gorgonarian corals, e.g., with
Thouarella
sp.,
Primnoisis
sp. or
Dasystenella
sp. (see also
Stiller 1996
,
Barnich
et al.
2012
)