Smithsonian National Museum of Natural History

Original Description
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“Cilunculus cactoides n. sp. (Figs. 205, 206)

MATERIAL EXAMINED

Atka Sta. 23, 1 male, holotype, U.S.N.M. Acq. No. 113006; Burton Island Sta. 3, 1 male, allotype, U.S.N.M. Acq. No. 113002.

Eltanin Sta. 436, 1 female.

DESCRIPTION: -- A small, exceedingly spinose species.

PALP: Comparatively large for the size of the animal, slender and spiny.

TRUNK: Oval in outline, lateral processes narrowly separated, trunk somites distinct; cephalic somite produced forward with spiny anterior cephalic spurs; eye tubercle tall, rounded; eyes conspicuous and well developed; on the three anterior trunk somites there are median tubercles flanked by smaller tubercles with large spines; similar complexes of spiny tubercles at the ends of the lateral processes; abdomen long, with spinose tubercles. There are so many spiny tubercles that it is impossible to decide how many there are, or to measure the specimen accurately.

CHELICERAE: Chelicerae 3-segmented, the terminal segment with a spur-like dactly set in a hollow; large spines on the two scape segments.

OVIGER: Terminal segments with rather large spines, which do not appear to be strongly denticulate.

LEGS: Short, heavily spinose; many of the spines arising from elevated tubercles; large genital prominence on the 2^nd coxa of the male, as short, heavy cement gland spigot on the femur at about a third the distance from the distal end; tarsus short, with a few basal spines; propodus with three large basal spines and several smaller ones on the sole; terminal claw approximately two-thirds as long as propodus, curved; accessory claws well developed, about half as long as the terminal claw.

DIMENSIONS OF HOLOTYPE MALE

DISCUSSION: -- This species resembles Cilunculus australiensis Clark, but is more spinose. The dorsal tubercles are lower than the eye tubercle, however, and the cement gland spigot is differently located (in C. australiensis it is at the end of the femur). The ovigeral spines are not strongly denticulate as in Clark’s species.

DISTRIBUTION: -- Specimens have been taken in the Ross Sea and off the South Shetland Islands, at depths of 72-433 m.” (Fry & Hedgpeth 1969, p. 124-126)