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Some Pycnogonida from Cook Strait, New Zealand, with descriptions of two new species

Pallenopsis mauii n.sp. Figs. 9–19

Pallenopsis mauii n.sp. Figs. 9–19

Material: Collection No. VUZ. 96; Stn. BOQ. Off Palliser Bay, 41° 31ʹ S; 174° 55ʹ E; 28/8/57; time, 1330–1530 hrs; bottom depth about 380 fathoms; mud, stones, rock; beam trawl; 1 male (holotype).

VUZ. 75; Stn. KOP. Off Palliser Bay, 40° 45ʹ S; 174° 53ʹ E; 24/11/56; time, 1330–1530 hrs; bottom depth 500–600 fathoms; baited trap; 1 damaged female taken from meshes of trap (paratype).

Description

Trunk slender, smooth, without spines, clearly segmented, lateral processes separated by their own width distally, less proximally; length of cephalon equal to length of last three segments; cephalon with a slight constriction between the bases of the palps and the first lateral processes, and produced anteriorly over the base of the proboscis. Ocular tubercle conical, rounded at tip, height greater than diameter at base; four eyes.

Proboscis long, cylindrical, with a slight median swelling, ventral surface of tip of proboscis covered with fine spines in female, fewer spines in male.

Abdomen fusiform with a slight median constriction, rises from trunk at an angle of 35–40°; reaches beyond the end of the first coxa of the last leg.

Chelifore scape of male distinctly 2-jointed, suture between joints oblique, joints swollen at suture; female scape apparently composed of one segment, with three fine hairs where one would expect to find the suture. Fingers of chelae at right angles to the proboscis; immovable finger slightly longer than dactylus, tips cross when chela is closed. A number of fine irregular denticulations are found on the middle of the cutting edge of the dactylus. Fingers of the chela shorter than the palm. Fingers of male chela not as well developed as in female. A prominent spiny cushion is found at the base of the dactylus in the female but not in the male.

Palp a single, short, bluntly pyramid-like joint, slightly longer in male than in female.

Oviger 10-jointed in both sexes, as is usual in the genus this limb is better developed in the male than in the female. Fourth joint the longest, and in the male this bears a slight lateral swelling, joints 7–9 with lateral setae on their inner margins. The terminal joint of the male bears five spines. The length of joints in mm. in male and female are given below:

Joint 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
Male 0.7 1.95 1.2 2.2 1.95 1.1 0.8 0.6 0.4 0.3
Female 0.6 0.85 0.5 1.1 1.1 0.55 0.4 0.4 0.4 0.25

Third Leg long, slender, sparsely clothed with fine hairs; the first coxa is half as long as the third, which is half as long as the second. Femur and first tibia of equal length; femoral cement glands of male with ducts a little shorter than width of femur, inserted at 5/9ths of femoral length; second tibia is the longest joint, and relatively longer in female than in male. Tarsus very short with a group of stout spines on the ventro distal extremity, propodus small, all basal spines stronger in the male than in the female, where there are four well developed basal spines and a number of smaller spines inserted distally to these; terminal claw half as long as propodus; auxilliary claws well developed.

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Genital apertures are placed on small swellings on the ventral sides of the distal portions of all second coxae in the female, but only on the third and fourth in the male.

Measurements (in mm, holotype first followed by female paratype in brackets).

Length proboscis 4.0 (5.6), width proboscis 1.1 (1.5), length cephalon 3.6 (3.5), width cephalon 3.9 (4.6), length abdomen 2.2 (2.7), total length 11.2 (11.7), width second lateral processes 4.4 (4.1), length chelifore scape 4.4 (4.5).

Third leg of holotype, and fourth leg of paratype (both third legs of paratype damaged): first coxa 1.1 (1.2), second coxa 4.1 (4.9), third coxa 1.95 (2.2), femur 10.0 (15.7), first tibia 11.5 (15.7), second tibia 15.6 (21.3), tarsus 0.55 (0.55), propodus 2.2 (2.2), claw 1.1 (1.1).

Figs. 9–19. Pallenopsis mauii n.sp. 9 and 10—Dorsal and ventral views of female. 11—Male oviger. 12—Female oviger. 13—Female chela. 14—Male chela. 15—Distal joints of fourth leg of female. 16—Distal joints of third leg of male. 17—Female chelifore. 18—Male chelifore. 19—Cement gland of third leg of male. Scale applies to Figs. 9 and 10 only.

Figs. 9–19. Pallenopsis mauii n.sp. 9 and 10—Dorsal and ventral views of female. 11—Male oviger. 12—Female oviger. 13—Female chela. 14—Male chela. 15—Distal joints of fourth leg of female. 16—Distal joints of third leg of male. 17—Female chelifore. 18—Male chelifore. 19—Cement gland of third leg of male. Scale applies to Figs. 9 and 10 only.

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Remarks

I have some slight doubt as to whether the female specimen is in fact of the same species as the male described here or of another very similar and undescribed species. This matter cannot be taken any further on the material at present available. The lateral swelling on the fourth oviger segment of the male is reminiscent of the subgenus Pallenopsodon Stock (1956), but since this species has a tubular duct to the cement gland, and differs in the armature of the 10th oviger joint it is no doubt to be placed in Pallenopsis s. str. I name this fine species after the mythical Maori figure Maui, who is said to have fished up the North Island of New Zealand, and was therefore probably the first man to have fished in Cook Strait.

Figs. 20–21. Pallenopsis sp. 20—Dorsal view. 21—Third leg. 22—Chela. Scale applies to Fig. 20 only.

Figs. 20–21. Pallenopsis sp. 20—Dorsal view. 21—Third leg. 22—Chela. Scale applies to Fig. 20 only.