New Laonice species (Polychaeta: Spionidae) from western and northern Australia
Author
Greaves, Elizabeth
Author
Wilson, Robin
text
Zootaxa
2011
2903
1
20
journal article
46772
10.5281/zenodo.207906
d7def72e-32a8-4e01-afdc-bf7662e51694
1175-5326
207906
Laonice
cf.
weddellia
Hartman, 1978
Figures 10–11
Material examined.
Australia
: Indian Ocean, Point Hiller region, L16 400, Stn SS07/2005 166, 35º22.85ʹ S, 117º13.267ʹ E,
8 Jan
2005
, 436 m,
1 specimen
, MV F167421; Indian Ocean, Bald
Island
region, T7 400, Stn SS07/ 2005 199, 35º12.55ʹ S, 118º39.533ʹ E,
10 Jan
2005
, 414 m,
1 specimen
, MV F158703.
Additional material examined.
Laonice weddellia
Hartman, 1978
:
Antarctica
:
Scotia
Sea, cruise ANT 68/1
Walther Herwig
, Stn 149, 61°09.0ʹ S, 56°07.2ʹ W,
24 Feb
1985
, 208 m, box corer,
9 specimens
,
ZMH
P-
20854; Stn 149, 60°57.1ʹ S, 55°55.2ʹ W,
25 Feb
1985
, 246 m, box corer,
20 specimens
,
ZMH
P-
20856; Stn 137, 61°18.5ʹ S, 54°40.3ʹ W,
21 Jan
1985
, 370 m, box corer,
10 specimens
,
ZMH
P-
20850.
Description.
(based on Western Australian specimens of
Laonice
cf.
weddellia
). Two anterior fragments, 36 and 25 chaetigers respectively,
4.3–12 mm
long,
1–1.5 mm
wide.
Prostomium bell-shaped, anteriorly rounded, extending posteriorly to between chaetiger 1–2. Occipital antenna present, short; arising from posterior part of prostomium, well behind eyes. Eyes present, one or three pairs; specimen with three has one anterior pair, close to edge of prostomium and relatively deeply set, second and third pairs more posterior and close together, such that on one side two eyes appear almost as one; specimen with only one pair, eyes at posterior end of prostomium and potentially composed of two closely set pairs. Peristomium separate from prostomium, well developed. Palps lost from both specimens. Nuchal organ present, extending posteriorly until approximately chaetiger 13 (difficult to determine as specimen somewhat damaged) (
Fig. 10
A).
Branchiae from chaetiger 2, continuing until end of fragments; initially short, similar length to notopodial lobe, approximately twice lobe length by about chaetiger 12, by end of longest fragment only just reaching beyond the lobe.
Chaetiger 1 notopodial lobes significantly smaller than those of chaetiger 2. Notopodial lobes initially rounded, gradually increasing in size, by chaetiger 4 pointed dorsally and rounded ventrally, by chaetiger 7 rounded dorsally and ventrally. Neuropodial postchaetal lobes ear-shaped, dorsal margin extending with lateral projection, becoming more triangular (
Fig. 10
B–D). Dorsal crests first present chaetiger 24, continuing to end of fragments; crests less obvious on some chaetigers, appearing as mid-segmental ciliation. Interparapodial pouches present from chaetiger 9, continuing to end of fragment.
Anterior chaetigers with 4–5 dense rows of capillary chaetae, reduced to 1–2 rows by about chaetiger 15; from chaetiger 5 there is a neuropodial inferior fascicle of approximately six capillary chaetae directed ventrally; by chaetiger 13 capillaries stouter and reduced in number (2–4) and probably comparable to sabre chaetae. Neuropodial hooded hooks from chaetiger 22, with paired apical teeth above the main fang (
Fig. 11A–B
).
Pygidium unknown.
Colour.
White (unpigmented) in ethanol.
Distribution.
Southern Western
Australia
,
414–436 m
(
Figs. 1-2
).
Remarks.
The Western Australian material resembles
Laonice weddellia
based on original and subsequent descriptions (
Blake 1983
;
Hartman 1978
;
Radashevsky & Lana 2009
), with some variations noted: the anterior region of the Western Australian specimens has 4–5 rows of capillary chaetae for 11–12 chaetigers, rather than 14– 15; dorsal ciliation appears to be mid-segmental instead of inter-segmental. However these differences were also observed during this study in some specimens identified as
L. weddellia
from
Antarctica
. Specimens of
Laonice weddellia
from the
Scotia
Sea,
Antarctica
include some specimens in which the apical teeth above the main fang of the neuropodial hooks include a smaller tooth above the paired teeth (
Fig. 11
C).
FIGURE 10.
Laonice
cf.
weddellia
(MV F167421). A. Anterior end, dorsal view; branchiae missing chaetigers 5–8. B. Parapodium 6, branchia missing (right). C. Parapodium 13, branchiae missing (right). D. Parapodium 31 (right). Scales: A, C 0.5mm; B, D 0.2 mm.
FIGURE 11.
A–B
Laonice
cf.
weddellia
(MV F167421), chaetiger 25 hooded hooks, hood removed. C.
Laonice weddellia
Hartman, 1978
(ZMH-P20850), chaetiger 25 hooded hooks, hood removed. Scales. A–B 1 µm; C 2 µm.
Laonice weddellia
Hartman, 1978
was originally described from the Weddell Sea and redescribed by
Blake (1983)
, who expanded the distribution into other areas of the
Antarctic
Seas, off southern South
America
and the South
Orkney
and South
Shetland Islands
in depths of
44–3111 m
.
Radashevsky & Lana (2009)
further reported the species from
Brazil
and discussed the need for this species to be reassessed given the unusual distribution. More specimens, including material suitable for genetic analysis, will be required from widespread localities to determine if the specimens identified as
Laonice weddellia
and already encompassing a wide geographic and bathymetric range represent intraspecific variation or separate species in a widely-distributed species complex. Based on the variation noted above and the wide and disjunct distribution of our material, the latter explanation seems most likely to us and we prefer a conservative approach and refer the material from Western
Australia
to
Laonice
cf.
weddellia
.