Halice aculeata Chevreux, 1912

Hendrycks, EA & Conlan, KE, 2003, New and unusual abyssal gammaridean Amphipoda from the north-east Pacific, Journal of Natural History 37, pp. 2303-2368 : 2336-2338

Halice aculeata Chevreux, 1912

(figure 14)

Halice aculeata Chevreux, 1912: 1–4 , figures 1, 2; Chevreux, 1935: 88–90, pl. 13, figures 5, 10; Birstein and Vinogradov, 1955: 243–244; Birstein and Vinogradov, 1958: 238; Birstein and Vinogradov, 1960: 210–212, figure 23; Birstein and Vinogradov, 1964: 167; Karaman, 1974: 12–13; Barnard and Karaman, 1991: 576.

Synopioides aculeata: J. L. Barnard, 1959: 38 .

Not Halice aculeata: Shoemaker, 1945: 195 , figures 6, 7 (= H. shoemakeri Birstein and Vinogradov, 1955 ).

? Synopioides secunda: Schellenberg, 1955: 190–191 , figure 4.

? Halice secunda: Dahl, 1959: 231 .

Material examined

X, 8.5 mm, (appendages on one slide), W, 6.2 mm, (appendages on one slide), CMNC 2002-0011 , Sta. 2624, Cup# 6, 34°55.80∞N, 123°09.88∞W, 3500 m, 17 October 1995 .

Remarks

The specimens at hand conform very well to the limited figures of Chevreux (1912, 1935). Additional illustrations are provided to supplement previous ones and add detail. There are some points of interest that warrant mention. The posterodorsal margin of urosomite 1 has a single, long seta that is not shown in the figures of Chevreux. Thurston (1976) and Barnard and Karaman (1991) considered a similar seta occurring on urosomite 2 in Halicoides to have generic significance in the separation of Halice and Halicoides . Thurston (1976) considered that the seta in Halicoides replaced the tooth that is found commonly on urosome 2 in Halice . Birstein and Vinogradov (1960) described a similar species, Halice rotundata , that also has this seta on urosomite 1. This seta is delicate and easily broken off. It may be present in many other Halice species , but may be lost upon collection and therefore never noticed.

The rostrum is well developed, reaching half the length of the first peduncular article of antenna 1. The ventral margin of the upper lip is very slightly indented. The outer plate of maxilla 1 has seven apical spine-teeth and the inner plate is small with a single, apical seta. The outer plate of the maxilliped has two apical spines. Both specimens contain oil droplets in the body.

There is very little sexual dimorphism, even in antenna 1. Both sexes have strong, callynophorate antennae and similar accessory flagella. One difference was noted in peraeopod 4. In the female the posterior margin of the carpus has only one long seta, while in the male this margin is fully lined with setae. Both male and female have this margin fully setose on peraeopod 3. The female specimen has small brood plates which lack setae, indicating that the specimen is not sexually mature.

This is the first record of this widely ranging, pelagic species in the north-east Pacific.

Distribution

Atlantic, northern Indian Ocean, north-west, central, south-west Pacific and north-east Pacific , off Point Conception , California in 0–10 500 m depths .