Pallenopsis (Bathypallenopsis) scoparia Fage, 1956

Bamber, Roger N., 2002, Bathypelagic pycnogonids (Arthropoda, Pycnogonida) from the Discovery deep-sea cruises, Journal of Natural History 36 (6), pp. 715-727 : 719-720

Pallenopsis (Bathypallenopsis) scoparia Fage, 1956

(®gure 2)

Bamber and Thurston, 1995: 140; ®gure 7C.

Material. One male, sample WS638 (Registration No. NHM.2000.147 3); one female, sample 10105#12; one female?, 10379#9. Depth range (trawl depths) of this material, 500±1000 m. This species has also been recorded from the bathypelagic of the Rockall Trough by Mauchline (1984) and on scyphomedusae oOE the Bahamas ( Child and Harbison, 1986); it is recorded from all the major oceans. The present records are scattered, respectively from the Peru ± Chile Trench, the Porcupine Bank and the Mid-Atlantic Ridge.

The specimen from sample WS638 is the ®rst male to be recorded (albeit collected some 25 years before the original species description). Child (1992) presented comprehensive illustrations of the female, and the present females are consistent with his description. The principal distinctions of the male are in the structure of the oviger and the presence of cement glands.

The male oviger (®gure 2A) is of 10 articles, generally more elongate than those of the female (see Child, 1992, ®gure 31F) and without the inātion of the fourth article shown by the female. Setae are sparse and short, and directed distally.

Recently Bamber (2000, in press) described the male oviger in some other species of Pallenopsis , these being signi®cantly larger than those of the female ( P. (B.) tritonis ) and with larger setae directed proximally (e.g. P. (B.) tritonis ) and hypothesized that these setae were adapted for holding the eggs and/or larvae. The spination of the male oviger of P. (B.) scoparia may imply that the eggs are not retained by the male, but are rapidly transferred to the presumed scyphomedusan host.

Cement gland tubes are evident mid-ventrally on the femora of all eight legs (®gure 2B), of a shape unusual for the genus. They appear as small ¯ask-shaped structures, less than 0.1 times as long as the femur diameter. The cement gland itself is not conspicuous.

The tarsi and propodi of the ®rst three pairs of legs are typical for the species, bearing dense brushes of setae on their`soles’. Those of the fourth legs (®gure 2C) show simple, sparse spination, with six sole spines and three distal spines on the propodus. The sole also bears a few very small curved setules.

The diOEering morphology of the fourth pair of walking legs, without the dense brushes of setae on tarsus and propodus, has been noted before ( Stock, 1987). In fact, no published record speci®cally describes the fourth pair of legs as having dense setal brushes (by convention, it is the third leg which is normally ®gured). Both of the female specimens recorded herein also have setal brushes on the ®rst three pairs of legs, but simple and sparse sole spines on the fourth legs as shown for the male. It seems likely that this is a consistent feature of this species.