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 lemniscata
sp. nov.
Figures 3–4
Material examined.
Holotype
:
Australia
: Indian Ocean, Albany region, T6 200, Stn SS07/2005 183, 35º21.5ʹ S 118º17.4ʹ E,
9 Jan
2005
, 193 m, MV F167370.
Paratypes
:
Indian Ocean, Two Rocks region, T4 200, Stn SS07/ 2005 134, 31º38.9ʹ S, 115º1.267ʹ E,
4 Jan
2005
, 196 m,
1 specimen
, MV F
111057
; Indian Ocean, Bald
Island
region, T7 100, Stn SS07/2005 195, 35º10.65ʹ S, 118º37.917ʹ E,
10 Jan
2005
, 102 m,
1 specimen
, MV F158711; Indian Ocean, Bunbury region, L13 100, Stn SS07/2005 213, 33º2.3ʹ S, 114º48.483ʹ E,
14 Jan
2005
, 102 m,
1 specimen
, MV F
110637
; Indian Ocean, Albany region, T6 200, Stn SS07/2005 183, 35º21.5ʹ S, 118º17.4ʹ E,
9 Jan
2005
, 193 m,
1 specimen
, MV F167372.
FIGURE 3.
Laonice lemniscata
sp. nov.
holotype. A. Anterior end, dorsal view. B. Parapodium 10 (left), branchia lost. C. Parapodium 18 (left). D. Parapodium 25 (left). E. Chaetigers 15–19, anterolateral view. Scales: A–E 0.5 mm.
Description.
All specimens anterior fragments, 18–35 chaetigers except nearly complete
holotype
(MV F167370) with 61 chaetigers,
2.3–15 mm
long (
holotype
15 mm
),
0.3–0.8 mm
wide.
Prostomium blunt, anteriorly rounded, entire or very slightly indented; without frontal or lateral horns. Caruncle present, continuous with prostomium, narrowing at about level of chaetiger 2, then extending back to chaetiger 9 or 10 (difficult to determine due to split dorsum). Long, finger-like occipital antenna present on posterior part of prostomium, behind eyes. Eyes present as one pair, each a dark brown to reddish patch edged anteriorly and laterally by lighter brown crescent. Peristomium separate from prostomium, approximately half the length of prostomium. Palps lost from all specimens. Nuchal organ long, U-shaped, extending posteriorly to about chaetiger 15 or 16 (difficult to determine due to split dorsum) (
Fig. 3
A).
Dorsal branchiae present from chaetiger 2 to near posterior end of body. Branchiae free, separate from notopodial lamellae throughout; all simple, distinctly ciliated on inner margin; longest on anterior third of specimen, first branchiae approximately same length as notopodial lobe, by about chaetiger 7 approximately twice length of notopodial lobe, and in posterior half up to three times length of lobes (due in part to the smaller size of the notopodial lobe).
Notopodial postchaetal lobes reduced to small subtriangular projection on chaetiger 1; then leaf-like and slightly pointed until about chaetiger 4, then becoming more rounded and gradually reduced to small round lobes. Neuropodial postchaetal lobes leaf-like from chaetiger 1; dorsally rounded and ventrally pointed until about chaetiger 15, then rounded and reduced in size; small by about chaetiger 25(
Fig. 3
B–D). Dorsal crests present from chaetiger 10, initially separated by nuchal organ/caruncle, full, ciliated crests from chaetiger 13 and on all remaining chaetigers. Additional transverse ciliation present on segmental margins. Interparapodial pouches on chaetigers 9– 61; starting from chaetiger 9–11 and continuing posteriorly to end of fragment (
Fig. 3
E).
Anterior capillaries in two rows in both noto- and neuropodia, anterior row generally stout and short. Posterior neuropodial capillaries narrower and fewer than anterior. Neuropodial hooded hooks begin from chaetiger 17–22, 4–5 per fascicle, bi- or tridentate (tooth above main fang may or may not have smaller apical tooth) (
Fig. 4
A–B). Neuropodial sabre chaetae first present on chaetiger 10–11, 1–2 per fascicle.
Pygidium unknown.
Colour.
White (unpigmented) in ethanol.
Distribution.
Southwestern
Australia
, shelf,
102–196m
(
Figs. 1–2
).
Remarks.
The prominent dorsal crests distinguish this species from other known
Laonice
species. Of the descriptions that mention dorsal crests, the majority describe them as low or incomplete, not reaching the dorsal midline, except
L. japonicus
(
Moore, 1907
)
and
L. magnacristata
Maciolek, 2000
, which both have large dorsal crests. The crests of
L. japonicus
start around chaetiger 38, much later than those of
L. lemniscata
sp. nov.
.
Laonice magnacristata
has crests starting on chaetiger 11, similar to
L. lemniscata
sp. nov.
, but has a very limited number of branchiae (6 pairs compared to over 50 pairs in
L. lemniscata
sp. nov.
).
Etymology.
Latin for ‘adorned with ribbons’
lemniscata
refers to the appearance of the long, thin branchiae of this species.