Haploniscus gnanamuthi George 2004, n. sp.

Haploniscus gnanamuthi n. sp.

(figure 9)

Diagnosis. Haploniscus with cephalon having a median spine-like projection, about two-thirds the length of the cephalon. Pereonite 7 in male fused mid-dorsally with the pleotelson. Pleotelson shield-like and posterolateral angles prominently produced, more than half the length of the pleotelson. Apex of pleon far behind tip of the posterolateral projections and truncated. Antenna 1 with basal article partly concealed by cephalon, flagellum of five articles, second article the shortest. Uropod extending beyond the median pleon apex.

Material examined. Holotype: male, length 2.0 mm, maximum width 0.7 mm. USNM Cat. No. 138672.

Type locality. R / V Eastward Sta. 7786, over site Alpha-A on the western side of the Bermuda Pedestal, north-west Atlantic.

Etymology. This new species is named in honour of the late Prof. C. P. Gnanamuthu of the University of Madras (India), with gratitude for his enthusiastic support of my initial research, in the early 1960s, on the alpha-taxonomy of flabelliferan sphaeromatidid isopods. ‘Gnanum’ in the ancient Sanskrit language means wisdom and ‘muthu’ in the archaic Tamil (Dravidian) language (spoken in India before the Aryan Sanskrit language was introduced to India about 2000 B.C.) means pearl.

Description. Body oval, with lateral suture well-developed between pereonites 4 and 5. Cephalon longer than anterior two pereonites, median projection very produced. Pereonites 3 and 4 subequal. Pereonite 5 slightly longer than pereonite 6. Pereonite 7 in male fused with pleotelson. Posterolateral projections of pleotelson stout and as long as the cephalic median spine. Apex of pleotelson truncated.

Antenna 1 with second peduncular article more than twice as long as the exposed basal article. Flagellum of five articles, basal article twice as long as second article. Terminal three articles subequal. Antenna 2 with third peduncular article very short, less than half length of article 4. Male pleopod 1 with distal lobes fringed with long setae. Second male pleopod with stylet narrow and long, twice as long as sympod. Uropod uniramous, the ramus extending far beyond the pleotelson apex but far behind the tip of the posterolateral projections of the pleotelson.

Remarks. This new species is similar in external morphology to H. unicornis Menzies, 1962, from south of the Azores, north Atlantic in having a prominent median projection on the cephalon, and also in the mid-dorsal fusion of pereonite 7 with the pleotelson. In both species the flagellum of antenna 1 is composed of five articles. However, the frontal projection in H. unicornis is about one-quarter the width of the cephalon, but half the width of the cephalon in H. gnanamuthi. The posterolateral projections are also far stouter and longer in this new species from the north-west Atlantic.