Pardaliscopsis tenuipalpa Chevreux, 1911

Hendrycks, EA & Conlan, KE, 2003, New and unusual abyssal gammaridean Amphipoda from the north-east Pacific, Journal of Natural History 37, pp. 2303-2368 : 2343-2345

Pardaliscopsis tenuipalpa Chevreux, 1911

(figure 17) Pardaliscopsis tenuipalpa Chevreux, 1911: 7 , figures 4, 5; Chevreux, 1935: 86–88, pl. 12,

figure 12, pl. 13, figure 6; J. L. Barnard, 1959: 39; Karaman, 1974: 31; Barnard and

Karaman, 1991: 580–581.

Material examined.

W, 12 mm, (appendages on one slide), CMNC 2002-0033, Sta. 2624, Cup# 7, 34°55.80∞N, 123°09.88∞W, 4050 m, 17 October 1995; X, 9 mm, (appendages on one slide), CMNC 2002-0034, Sta. 1706, Cup# 10, 34°47.20∞N, 123°03.00∞W, 4050 m, 8 November 1993.

Type material

Pardaliscopsis tenuipalpa Chevreux, 1911 . H, ovigerous X, 14 mm, eight slides, (MOM), Cat. No. 37 0749, Sta. 2964, Golfe de Gascogne , 46°17.30∞N, 5°42∞W, 4380 m, 20 July 1910.

Remarks

This is the first male specimen of this rarely collected species to be reported, the first record in the Pacific, and only the second published record of the species. Some drawings are provided to supplement previous figures, especially where dimorphism occurs. Both specimens agree very well with the figures of Chevreux (1911, 1935). The holotype female was borrowed and examined. The type material consists of eight slides that are variously dried out and in poor condition. Even though the type is in very poor condition, the following discrepancies were noted between Chevreux’s type material and his figures: the maxilla 1 palp is drawn wider distally than it appears and the maxilla 2 outer plate is angled and therefore drawn much narrower than it really is.

The mandibles of the study material are nearly identical with the type specimen of Chevreux (1911). The incisors are strongly dissimilar, with the right having four large, distinct teeth and the left having much finer teeth. The left lacinia is very broad, with a finely serrated margin. The inner plate of maxilla 2 is slightly shorter and distinctly broader than the outer plate, not equal as stated by Barnard and Karaman (1991:581). The inner plate of maxilla 1 is present as a long narrow lobe with a single, apical seta, and the outer plate has eight spine teeth (vs seven in Chevreux’s figure). Prior to this study, the inner plate of maxilla 1 had never been described or figured (Karaman, 1974; Barnard and Karaman, 1991). The second article of the outer ramus of uropod 3 is longer and the prominent ventral lobe of the upper lip is not as rounded as shown in Chevreux (1935). The lateral cephalic lobe is broadly rounded.

The male possesses a large callynophore on antenna 1, which is about equal to peduncular articles 1–3 combined. The accessory flagellum of the male is longer than the combined lengths of peduncles 1–3 and composed of one very long, proximal article and four small, distal ones. Peduncular article 4 of antenna 2 is equal to peduncular article 5, while in the female article 4 is longer than 5. The posterodorsal teeth on urosomites 1 and 2 are both stronger in the male and urosomite 3 is elevated into a dorsal hump. The female specimen has small, non-setose brood plates.

Distribution

North-east Atlantic (Gulf of Gascogne) and the north-east Pacific off Point Conception, California in 4050–4380 m depth.