Haploniscus harrietae George 2004, n. sp.

Haploniscus harrietae n. sp.

(figure 10)

Diagnosis. Haploniscus with anterior margin of cephalon concave, lacking a median projection. Lateral suture well-developed between pereonites 4 and 5. In female pereonites 6 and 7 fused with pleotelson. Posterior margin of pleotelson rounded and extending slightly beyond the small projections of the posterolateral angles. Uropod uniramous and minute. Antenna 1 composed of eight articles. Basal article of antenna 2 completely concealed by cephalon, second article with a prominent conical spine on the outer distal margin.

Material examined. Holotype: female, length 2.9 mm, width 1.2 mm. USNM Cat. No. 138680.

Type locality. R / V Eastward Sta. G-2756, site Beta over the Carolina lower slope.

Etymology. This new species is named in fond memory of the renowned American isopodologist Ms Harriet Richardson who wrote the frequently cited and classical monograph Isopods of North America (1905).

Description. Body oval, about twice as long as wide. Cephalon with anterior margin concave and lacking any median projection. Third pereonite longer than both pereonites 1 and 2. Lateral suture well-developed between pereonites 4 and 5. Pereonites 6 and 7 fused mid-dorsally with the pleotelson in the female. Pleotelson shield-like, the rounded posterior margin reaching slightly beyond the tip of the short, posterolateral projections.

Antenna 1 with basal article less than half the length of article 2, flagellum of six articles, basal article of flagellum as long as the two succeeding articles, terminal three articles each bearing two long distal aesthetascs. Antenna 2 with peduncle of four articles, basal article broader than article 2 and bearing a stout triangular spine at the outer distal angle, its tip reaching as far as half the length of peduncle article 3. Fourth article of peduncle elongated, longer than the first four flagellar articles combined. Flagellum of antenna 2 composed of 11 articles.

Mandible with a palp of three articles; second with two long setae on inner margin, terminal article with a row of 11 spines on the inner margin and a long distal seta. Maxilliped with endite bearing three coupling hooks; palp of five articles, basal article the stoutest and shortest, article 2 the most elongated, longer than articles 3 and 4 combined, fifth article narrow and slightly shorter than article 4. Uropod uniramous, minute, not reaching the level of pleotelson apex, and with four long distal setae.

Remarks. In the type species of the genus, H. bicuspis, known from the Arctic Atlantic (Sars, 1887; Hansen, 1916), north-east Atlantic (Lincoln, 1985b) and south Atlantic (Wolff, 1962), pereonites 6 and 7 are fused with the pleotelson in the male, but in the female only pereonite 7 is fused with the pleotelson. Conversely, in this new species both pereonites 6 and 7 are fused with the pleotelson in the female. Haploniscus harrietae sp. nov. also resembles H. bicuspis in having a minute, uniramous uropod and somewhat shield-like pleotelson, and in lacking a conspicuous median projection on the cephalon. However, the anterior margin of the cephalon in this species is concave while in H. bicuspis it is convex with a slight median triangular elevation.