Chandraniscus negoescuae, George, 2004

George, Robert Y., 2004, Deep-sea asellote isopods (Crustacea, Eumalacostraca) of the north-west Atlantic: the family Haploniscidae, Journal of Natural History 38 (3), pp. 337-373 : 348-351

Chandraniscus negoescuae n. sp.

(figure 7)

Diagnosis. Chandraniscus with cephalon having a convex anterior margin and lacking a median projection. Posterior three pereonites showing a clear decrease in width from pereonites 5–7. Pleotelson shield-like, with the sharp posterolateral angles and the uropods extending beyond the rounded apex of the pleotelson. Antenna 1 with flagellum of five articles, antenna 2 with flagellum of 11 articles.

Material examined. Holotype: intersex, length 2.1 mm, maximum width 0.9 mm. USNM Cat. No. 138675.

Type locality. R / V Eastward Sta. 7810, site Sigma over the continental rise off North Carolina .

Etymology. This new species is named in honour of the Romanian isopodologist Dr Ileana Negoescu with whom I had the pleasure of studying the Antarctic anthurid isopods at the Antipa Museum of Natural History, Bucharest, in the summer of 1979.

Description. Body oval, cephalon broadly rounded anteriorly without a median projection. Cephalon almost twice as long as the first pereonite. Anterior three pereonites subequal in length, pereonite 4 longer than any anterior pereonite. Lateral sutures between anterior five pereonites well-developed. Pereonite 5 significantly longer than either pereonite 6 or 7. Pleotelson shield-like, with posterolateral angles produced, slightly beyond the rounded posterior apex. Pleotelson as long as the posterior three pereonites combined.

Antenna 1 with basal peduncular article partly concealed by the cephalon and second article elongated, with a flagellum of five articles. Antenna 2 with four peduncular articles, basal two articles short, articles 2 and 3 elongated, with a flagellum of 11 articles.

The type specimen is unique, with both male and female secondary sexual appendages and is undoubtedly not a manca since pereonite 7 is well-developed. It is known that asellote isopods, in the early stage of ontogenetic development, seem morphologically more like female than male. It is also known that the intersex phenomenon is rare but still seen in asellote isopods. This species is based on a unique ‘intersex’ specimen. In figure 7E, the female operculum is illustrated, with the male pleopod 1, and underneath the male pleopod 2 showing the stylet.

Remarks. In the shape of the shield-like pleotelson, this new species resembles both C. kussakini from site Alpha-A off Bermuda and also C. costlowi from site Beta on the Carolina lower slope. However, this species has a cephalon with rounded anterior margin, while C. kussakini has a quandrangular cephalon with anterolateral spines. This species is also distinguished from C. costlowi which has a well-defined median cephalic projection. Chandraniscus negoescuae n. sp. is dissimilar to the northern species C. excisus (Richardson, 1908) which lacks the lateral sutures between the anterior pereonites and has a differently shaped pleotelson.