Cleonardo biscayensis Chevreux, 1908b

Hendrycks, EA & Conlan, KE, 2003, New and unusual abyssal gammaridean Amphipoda from the north-east Pacific, Journal of Natural History 37, pp. 2303-2368 : 2351-2352

Cleonardo biscayensis Chevreux, 1908b Cleonardo biscayensis Chevreux, 1908b: 10 , figure 6; Chevreux, 1935: 109–110, figure 5;

Birstein and Vinogradov, 1964: 178–179, figure 8; Barnard and Karaman, 1991: 315;

Bousfield and Hendrycks, 1995: 15.

Material examined

W, 8.0 mm, (appendages on one slide), CMNC 2002-0007 , Sta. 2305, Cup# 3, 34°53.98∞N, 123°11.10∞W, 3450 m, 23 November 1994 ; X, 11.3 mm, (appendages on one slide), CMNC 2002-0008 , Sta. 621, Cup# 3, 34°50.88∞N, 122°58.68∞W, 4050 m, 17 March 1991 .

Remarks

This is the first record of the species in the Pacific, having been recorded from the north Atlantic (Golfe de Gascogne) and northern part of the Indian Ocean. It is only the third reported collection of the species. The specimens agree fairly closely with the figures of Chevreux (1908b, 1935) and Birstein and Vinogradov (1964). These figures are both incomplete, but are detailed enough to allow comparison with our specimens. The following slight differences were noted in the Pacific material: antenna 1 of the male, proximal flagellar articles are broadened, forming a pseudocallynophore; gnathopod 1, propodus is slightly broader, the spines on the proximal margin of the palm and palmar corner are stronger and the lobes of the telson are acute distally.

The rostrum of the male is broader than the female. Peduncular articles 1 and 2 of antenna 1 in the male are strongly setose and thickened, while the females lack setae and are elongated. Furthermore, the peduncles of antenna 2 in the male are lined with many clusters of thick brush setae, while the female lacks brush setae. The calceoli of the antennae are larger in the male. The third article of the mandibular palp is slightly longer in the male. The few mouthparts figured by Birstein and Vinogradov (1964) match the present specimens. The gills are present on peraeopods 2–7 and are large and slightly pleated. The female has rudimentary, non-setose brood plates.

Distribution

North Atlantic (Golfe de Gascogne), north Indian Ocean and north-east Pacific Ocean, off the coast of California in depths to 4330 m .

Cleonardo macrocephala Birstein and Vinogradov, 1955 Cleonardo macrocephala Birstein and Vinogradov, 1955: 273–275 , figure 31; Birstein and

Vinogradov, 1958: 247; Birstein and Vinogradov, 1962: 53; Barnard and Karaman, 1991:

315; Bousfield and Hendrycks, 1995: 14–15, key, figure 6.

Material examined

W, 6 mm, (appendages on one slide), CMNC 2002-0009 , Sta. 1619, Cup#11, 34°46.48∞N, 123°00.78∞W, 3450 m, 15 June 1993 ; juvenile W, 5.8 mm, (appendages on one slide), CMNC 2002-0010 , Sta. 208, Cup#1, 34°46.59∞N, 123°04.04∞W, 3500 m, 23 October 1989 ; immature, Sta. 2305, Cup# 11, 34°53.98∞N, 123°11.10∞W, 3450 m, 1 February 1995; immature (damaged), Sta. 621, Cup#8, 34°50.88∞N, 122°58.68∞W, 3500 m, 6 May 1991; W (damaged), Sta. 1216, Cup#2, 34°47.94∞N, 123°03.80∞W, 3450 m, 5 July 1992; immature, Sta. 1706, Cup#4, 34°47.20∞N, 123°03.00∞W, 3450 m, 8 November 1993; immature, Sta. 1014, Cup#11, 34°53.22∞N, 123°02.13∞W, 3500 m, 2 February 1992.

Remarks

These specimens agree fairly closely to the figures of Birstein and Vinogradov (1955). However, the following variations were observed in our specimens: the male has five to six clusters of brush setae on peduncular article 1 of antenna 1 (vs none shown), the apical setae on the third article of the mandibular palp are long (vs short), the anteroventral corner of coxa 1 is more pointed (vs rounded), the ventral margin of the carpal lobe of gnathopod 1 has seven to eight setal groups (vs three to four) and the posterior margin of epimeron plate 3 is more convex (vs straight). The figures of Birstein and Vinogradov (1955) are incomplete and crude, so some of these differences may be artificial.

The specimens differ from Cleonardo moirae Bousfield and Hendrycks, 1995 in the stronger anteroventral expansion of coxa 1 (vs slightly expanded) and in the length of the peduncular article 3 of antenna 1, which is about one-third of article 2 (vs one-quarter length of article 2).

All the specimens were collected between 3450 and 3500 m, which supports the bathypelagic nature of this species (J. L. Barnard, 1962; Bousfield and Hendrycks, 1995), and may indicate a preferred depth zone.

Distribution

Antarctica south of 60°, north-west and north-east Pacific , from deep closing net tows in depths of 0–7200 m. These specimens taken at 3450–3500 m are new depth records, as previous confirmed collections are from 1000–1500 m depths (Barnard and Karaman, 1991) .