Revision of Sthenelais Kinberg, 1856, Fimbriosthenelais Pettibone, 1971 and Eusthenelais McIntosh, 1876 (Polychaeta, Sigalionidae) in the Northeast Atlantic
Author
Barnich, Ruth
F1E3AEB7-0C77-41BB-8A6C-F8B429F17DA1
Senckenberg, Forschungsinstitut und Naturmuseum Frankfurt, Marine Evertebraten II, Senckenberganlage 25, D- 60325 Frankfurt, Germany. Thomson Environmental Consultants, Compass House, Surrey Research Park, Guildford, GU 2 7 AG, United Kingdom. Eurofins AquaSense, H. J. E., Wenckebachweg 120, 1114 AD, Amsterdam-Duivendrecht, Netherlands.
ruth.barnich@senckenberg.de
Author
Haaren, Ton Van
4913E25D-12EF-4D31-A7D1-39E0A805D4F7
Eurofins AquaSense, H. J. E., Wenckebachweg 120, 1114 AD, Amsterdam-Duivendrecht, Netherlands.
tonvanhaaren@eurofins.com
text
European Journal of Taxonomy
2021
2021-03-29
740
138
171
http://dx.doi.org/10.5852/ejt.2021.740.1287
journal article
7565
10.5852/ejt.2021.740.1287
3678bdb3-f334-4b57-8f9a-b4d5bff857c6
2118-9773
4649646
A1E7F84F-49D0-4DA8-94E6-77E8CA68098F
Eusthenelais hibernica
McIntosh, 1876
(emended)
Fig. 8
Eusthenelais hibernica
McIntosh, 1876b: 407
, pl. 73, figs 4–5.
Sthenelais jeffreysi
McIntosh, 1876b: 406
, pl. 72 fig. 18, pl. 73 figs 1–2 (synonymy according to
Eliason 1962
, confirmed herein).
Sthenelais heterochaeta
McIntosh, 1897b: 176
, pl. 3 figs 6–10 (synonymy acc. to
Eliason 1962
, confirmed herein).
Eusthenelais hibernica
–
McIntosh 1900: 425
, pl. 29 fig. 5, pl. 31 fig. 9, pl. 42 figs 9–10.
—
Gil 2011: 937
. —
Núñez
et al.
2015: 233
, fig. 93.
Sthenelais Jeffreysii
–
McIntosh 1900: 421
, pl. 29 fig. 4, pl. 31 fig. 7, pl. 34 fig. 13, pl. 42 figs 5–8. —
Gil 2011: 947
.
Sthenelais jeffreysi
–
Eliason 1962: 224
fig. 5b–h.
Parasthenelais hibernica
–
Amoureux 1972: 68
, fig. 1. —
Barnich & Fiege 2003: 11
.
Diagnosis
Dorsal cirri present on segment 3. Ventral body surface and parapodial stylodes smooth. Outer elytral margin with several filiform papillae, elytral surface smooth. Neurochaetae spinigers and falcigers.
Type material
(examined)
Eusthenelais hibernica
:
IRELAND
•
syntype
;
NE Atlantic
,
W coast of Ireland
; depth 106 fathoms (
194 m
); “
Porcupine
” expedition leg.; EtOH preserved;
BMNH 1921.5.1.620
.
PORTUGAL
•
syntype
;
off Cape Sagres
; depth 45 fathoms (
82 m
); “Porcupine” expedition leg.; EtOH preserved;
BMNH 1921.5.1.621
.
Sthenelais jeffreysi
:
IRELAND
•
holotype
;
NE Atlantic
,
W coast of Ireland
, station 9;
53°16′ N
,
12°42′ W
; depth 165 fathoms (
302 m
); 1869; “Porcupine” expedition leg.; EtOH preserved;
BMNH 1921.5.1.616
.
The
syntypes
of
Sthenelais heterochaeta
(type locality:
Norway
, Osterfjorden, NE Atlantic) are probably lost.
Other material
(examined)
UNITED KINGDOM
•
1 spec.
;
NW Scotland
, Geikie Slide and Hebridean Slope; stn C05 S41 A1;
58.38° N
,
9.40° W
; depth
650 m
;
23 Jul. 2016
; sandy mud; EtOH preserved; survey code JNCC/MSS 1016S GSH; TUM 65469
•
1 spec.
; same locality as for preceding; stn C11 S15 A1;
58.45° N
,
9.32° W
; depth
868 m
;
21 Jul. 2016
; coarse sandy mud; EtOH preserved; ex TUM 65481; survey code JNCC/MSS 1016S GSH;
NMS.Z. 2020.14.4
•
1 spec.
; same locality as for preceding; stn D03 S83 A1;
58.29° N
,
9.30° W
; depth
438 m
;
29 Jul. 2016
; sandy mud; EtOH preserved; ex TUM 65499; survey code JNCC/MSS 1016S GSH;
NMS.Z.2020.14.1
•
1 spec.
; same locality as for preceding; stn D11 S61 A1;
58.40° N
,
9.17° W
; depth
496 m
;
25 Jul. 2016
; sandy mud; EtOH preserved; ex TUM 65515; survey code JNCC/MSS 1016S GSH;
NMS.Z. 2020.14.3
•
1 spec.
; same locality as for preceding; stn F04 S90 A1;
58.47° N
,
8.78° W
; depth
410 m
;
29 Jul. 2016
; sandy mud; EtOH preserved; ex TUM 65547; survey code JNCC/MSS 1016S GSH;
NMS.Z. 2020.14.2
•
1 spec.
; same locality as for preceding; stn F16 S75 A1;
58.59° N
,
8.45° W
; depth
450 m
;
28 Jul. 2016
; sandy mud; EtOH preserved; ex TUM 65571; survey code JNCC/MSS 1016S GSH;
NMS.Z. 2020.14.5.
(
Fig. 8
)
Description
PROSTOMIUM. Median antenna with long, smooth, tapering style; ceratophore with small auricles. Lateral antennae fused to inner side of tentaculophores, size and shape similar to dorsal tentacular cirri. Eyes indistinct (
Fig. 8A
).
TENTACULOPHORES. Dorsal tentacular cirri long, size and shape similar to median antenna. Ventral tentacular cirri short, not reaching half the length of the dorsal ones (
Fig. 8A
).
ELYTRA. With filiform papillae on outer lateral margin and smooth surface (
Fig. 8B
).
CIRRI. Dorsal cirri present on segment 3, size and shape similar to dorsal tentacular cirri. Ventral cirri without basal knob or long basal papillae (
Fig. 8C–D
).
PARAPODIA. Stylodes without papillae, slender, cirriform, some slightly inflated basally. Parapodia of anterior and middle body with few stylodes present along notopodial bract, on neuropodial acicular lobe and on upper and lower parts of large, bilobed posterior neuropodial bract. Margins of neuropodial anterodorsal and anteroventral bracts smooth. Without long dorsal papillae on notopodia (
Fig. 8C–D
).
CHAETAE. Notochaetae slender, spinous, tapering to simple capillary tip. Upper neurochaetae all slender compound spinigers. Middle neurochaetae slender compound spinigers and stout compound falcigers with short, 1–4 articled blade and bidentate tip. Lower neurochaetae slender compound falcigers with multi-articled blade and minutely bidentate tip (
Fig. 8E–G
).
SIZE. Specimen figured: NMS.Z. 2020.14.5 (
Fig. 8
): anterior fragment, length
45 mm
, width
5 mm
for 98 segments.
Syntypes
of
Eusthenelais hibernica
: BMNH
1921.5.1.620, anterior fragment, length
11 mm
, width
2.5 mm
for about 28 segments; BMNH 1921.5.1.621, anterior and middle fragment, total length about
17 mm
, width
3.5 mm
for 31 segments (total).
Holotype
of
Sthenelais jeffreysi
: BMNH
1921.5.1.616, anterior fragment, length
18 mm
, width
3 mm
for about 39 segments.
Remarks
The description above is emended for the terminology used in describing the parapodial bracts and stylodes and the details regarding the shape and location of the neurochaetae. The recently collected specimens of
Fig. 8.
Eusthenelais hibernica
McIntosh, 1876
. TUM 65571.
A
. Anterior end, left palp not figured, bent downwards.
B
. Left elytron of segment 17.
C
. Left parapodium of segment 19, anterior view.
D
. Same, posterior view.
E–G
. Neurochaetae of same, all distal part.
E
. Upper compound spiniger.
F
. Middle stout compound falciger.
G
. Lower slender compound falciger. Scale bars: A=2 mm; B–D =1 mm; E–G= 100 µm.
E. hibernica
from the Geikie Slide (Northwest Scotland) were in rather good condition and proved very helpful in supplementing the diagnostic characters of the species.
Chambers(1985)
noted that the type material of
Eusthenelais hibernica
is unidentifiable and,consequently,
Read & Fauchald (2020)
list
Eusthenelais
McIntosh, 1876
as a nomen dubium in WoRMS. However, especially the presence of both spinigers and bidentate falcigers as described by
McIntosh (1876b)
is sufficient to distinguish it from other sigalionid species. The other important generic character, i.e., the presence of dorsal cirri on segment 3, was not mentioned in the original description, but later described by
McIntosh (1900)
based on the same material (see respective remark related to generic diagnosis above). We examined the
syntypes
, which are in rather bad condition, but we can confirm the presence of a pair of dorsal cirri on segment
3 in
both specimens.
In both publications (1876b, 1900) McIntosh described
Eusthenelais hibernica
and
Sthenelais jeffreysi
as different species. It is not clear why he did not realise that these are in fact synonymous, as for both species he described the two
types
of neurochaetae and, although he did not mention the dorsal cirri in the text for
S. jeffreysi
, he clearly figured them in his monograph of 1900 (pl. 29 fig. 4).
Eliason (1962)
noted that not only
Sthenelais jeffreysi
, but also
Sthenelais heterochaeta
McIntosh, 1897
could be possible synonyms of
Eusthenelais hibernica
. For
S. heterochaeta
again the dorsal cirri are not mentioned, but the original description of the elytral and chaetal characters leaves no doubt that this is
E. hibernica
.
We checked the
holotype
of
S. jeffreysi
and found it to be unidentifiable; moreover, the type material of
S. heterochaeta
seems to be lost. But, as explained above, the respective original descriptions are sufficient and we confirm Eliason’s view that both
S. jeffreysi
and
S. heterochaeta
are synonyms of
E. hibernica
.
Compared to the other species described herein,
Eusthenelais hibernica
presents a number of remarkable characters: The presence of a pair of dorsal cirri on segment 3 is the main differentiating character (absent in all other species). The auricles are smaller and much less obvious. The lateral antennae are of similar length to the dorsal tentacular cirri (versus distinctly shorter). The neuropodial posterior bract is large and obvious, similar to the one found in
S. limicola
(versus smaller and much less obvious in
S. boa
, or the
Fimbriosthenelais
species).
Distribution and habitat
So far only known from the NE Atlantic: recorded from off
Norway
, along the western coasts of the British Isles and
Ireland
, down to Southwest
Portugal
. Occurring on muddy and sandy substrates from
70 to 870 m
depth (see above).