New species and new records of sea spiders (Arthropoda: Pycnogonida) from deep waters in Western Australia
Author
Arango, Claudia P.
text
Zootaxa
2009
1977
1
20
journal article
10.5281/zenodo.185190
24ca7e3f-75f9-401c-abb1-a914a1c3dc22
1175-5326
185190
Hedgpethia calva
n.sp.
(
Figure 3
,
8A
)
Material examined.
Holotype
:
WAM
T92360,
1 female
.
24 November 2005
, Bald
Island
, Western
Australia
,
CSIRO
station 036-008, collected by beam trawl, from
35.2815°S
18.7090°E
to
35.2810°S
118.7090°E
, soft bottom,
980 m
.
Paratypes
: Details as for
holotype
.
NMV
JM54989,
2 males
.
Diagnosis:
Proboscis almost 1.5 times as long as trunk, spindle-shaped, with short narrow base. Ocular tubercle tall, with pointed apex inclined forward. Palp segments 1 to 5 glabrous, no spines or setae. Legs smooth, only few tiny setae, propodus longer than tarsus, main claw longer than half propodus length.
Description:
Body large for the genus, slender, leg span
27.3 mm
. Trunk completely segmented, posterior rims slightly inflated, lateral processes separated from each other by about their own diameter, glabrous (
Fig. 3
A, 8A). Ocular tubercle tall, height almost twice its basal width, with long, curved apical cone projecting forward; eyes pigmented, equal-sized (
Fig. 3
B). Proboscis 1.36 times as long as trunk, slightly downcurved, narrow base 6% of total proboscis length, then swollen reaching maximum width at midpoint; constriction mark on anterior portion at 40% of total length, tapering distally (
Fig. 3
B; 8A); lips rounded, deep commissures. Abdomen ventrally oriented, not seen in dorsal view, very small, anus apical. Palps longer than proboscis, slender; 10-segmented, third segment longest, glabrous; fifth about half length of third, with sparse setae distally; three distal segments subequal, seventh slightly shorter; long setae ventrally on segments six to ten (
Fig. 3
C). Oviger slender, 10-segmented, fourth segment longest, sixth slightly shorter, with few scattered setae (
Fig. 3
G); strigilis with three rows of simple spines on each segment, distal ones longer; terminal claw very short, leaf-like, about one-fifth as long as terminal segment (
Fig. 3
F). Legs very slender, with sparse tiny setae, third coxae slightly shorter than first, second coxae longest, femur longer than second tibia, thickened distally, with distal seta dorsally; first tibia longest segment; propodus longer than tarsus (
Fig. 3
E); main claw 0.6 times length of propodus (
Fig. 3
D). Genital pores on all pairs of legs, female pores typical, larger and towards centre of coxa, male pores closer to distal margin of the coxa.
Measurements of
holotype
(in mm): trunk length = 3.23, trunk width (across second pair of lateral processes) = 1.32; proboscis = 4.41; palp length = 9.89, segment 1 (p1) = 0.26, p2 = 0.09, p3 = 3.52, p4 = 0.52, p5 = 2.11, p6 = 0.38, p7 = 0.7, p8 = 0.85, p9 = 0.79, p10 = 0.67; oviger length = 7.4, segment 1 (o1) = 0.15, o2 = 0.31, o3 = 0.28, o4 = 1.85, o5 = 0.46, o6 = 2.41, o7 = 0.58, o8 = 0.55, o9 = 0.46, o10 = 0.35; coxa 1 = 0.49, coxa 2 = 0.69, coxa 3 = 0.35, femur = 5.31, tibia 1 = 6.56, tibia 2 = 5, tarsus = 1.17, propodus = 1.47, claw = 0.97.
Etymology:
From
calva
(lat.) meaning bald, bare, referring to the
type
locality, Bald
Island
, WA. It also applies to the glabrous appearance of proximal segments of palps and legs in comparison to
H. dampieri
, also known from WA.
FIGURE 3.
Hedgpethia calva
n. sp.
, holotype female. A. Dorsal view. B. Lateral view. C. Palp. D. Details of distal segments of third leg. E. Third leg. F. Oviger strigilis. G. Oviger. All scale bars = 1 mm except G = 0.1 mm.
Remarks:
These specimens could not be attributed to
Hedgpethia dampieri
(
Child 1975
)
because of 1) different proboscis: body proportion,
1.36 in
the specimens from Bald
Island
,
0.84 in
H. dampieri
(
Child 1975
;
Staples 2007
); 2) the main claw being shorter than the propodus, not subequal as in
H. dampieri
; 3) the lateral processes being closer together than twice their diameter as in
H. dampieri
, and 4) the lack of spines on the third segment of the palp and on the legs of the new species, while spines and setae on these are the main characteristic of
H. dampieri
. Also, the palp segments are longer in the new species.
Hedgpethia dampieri
was described from West Lancelin I., WA, from
120 m
and recorded from other locations in WA (
Child 1975
). The specimens herein occur within that range of geographic distribution but at almost
1000 m
depth. They differ from
H. eleommata
Child 1998
from
New Zealand
in the long, pointed ocular tubercle, not having such noticeable larger, dark-pigmented anterior eyes (
Child 1998
).
Hedgpethia calva
n. sp.
has a larger proboscis not so sharply curved and a longer propodus with a shorter claw; in other aspects the two species are very similar. A species from deep waters in
New Caledonia
,
H. tibialis
(
Stock 1991
)
, shows a similar tarsus: propodus proportion to the species reported here, but the tibiae are extremely long and slender and the ocular tubercle low and blunt.
Hedgpethia dofleini
(
Loman
1911
)
, a species widely distributed in the North Pacific is about 30% larger in body size, the tarsus is longer in relation to propodus and the oviger claw is relatively longer. Another apparently related Pacific species is
Hedgpethia elongata
Takahashi, Dick and Mawatari 2007
from
Japan
, similar in the configuration of trunk, ocular tubercle and strigilis (
Takahashi
et al.
2007
), but the Australian species does not have such a long basal stalk to the proboscis.