Aega deshaysiana (Milne Edwards, 1840)

Bruce, Niel L., 2004, Reassessment of the isopod crustacean Aega deshaysiana (Milne Edwards, 1840) (Cymothoida: Aegidae): a worldwide complex of 21 species, Zoological Journal of the Linnean Society 142 (2), pp. 135-232 : 189-190

REVIEW OF AEGA DESHAYSIANA , A WORLD-WIDE SPECIES COMPLEX 189

margin weakly convex, with 8 RS; medial margin sinuate, proximally concave, with 4 RS.

Female

Similar to males; ovigerous females not present in the material examined.

Variation

Robust setae: pleotelson apices are all somewhat rubbed, the RS that are present indicate that the pleotelson would have more than 3 + 3. Uropod (n = 8) exopod medial margin with 3–6 RS, with 5 (50%) most frequent; lateral margin 8 or 9 with 9 (75%) most frequent; uropod endopod (n = 7) medial margin with 3– 6, with 4 (twice), 5 (3 times) and 6 (twice), the lateral margin RS are variable with 3 + 3 (once), 4 + 3 (twice), 2 + 4 (once), 4 + 4 (twice), 3 + 5 (twice) and 5 + 4 (once). P1 setation of the merus consistent across its range with 2 + 2 RS (all); P2 with 5 (all); P3 merus with 5 (all except for one which had 9).

Size

Males 33–39 mm, nonovigerous females 32 mm; no ovigerous females present in the material examined.

Remarks

Aega kwazulu sp. nov. may be identified by the medially relatively short but united eyes, anteriorly rounded frontal lamina with a distinctly truncate posterior margin, pleotelson with nearly straight lateral margins, pereopod 1 merus inferior margin usually with 4 robust setae (set as 2 + 2), the merus of pereopods 2 and 3 each with a single row of 5 robust setae and by the uropodal exopod not extending to the endopod apex.

Aega kwazulu is very similar to A. umpara sp. nov. (from the south-western Pacific), from which it can be distinguished by the pleotelson lateral margins being straighter with the apex more strongly produced, the frontal lamina less distinctly rectangular with the lateral margins converging slightly to the posterior, having 2 + 2 robust setae on the pereopod 1 merus, the robust setae of the merus of pereopods 3 and 4 in a single row rather than in two clusters, the distal-most seta of the merus of pereopods 1–3 is less elongate and the uropodal endopod is wider and distally more strongly rounded.

With few specimens it is not possible to be confident about the numbers of robust setae on the uropods, but it would appear the uropodal exopod medial margin will have 4 or 5 compared to consistently 4 for A. umpara and 9 on the lateral margin.

Because the material is limited in quantity, old and fragile, dissection was kept to a minimum and an abbreviated description is given here, with emphasis on the diagnostic and differentiating characters.

Prey

Not known.

Distribution

KwaZulu-Natal coast of South Africa, south-western Indian Ocean. The single depth record is at 237 m.

Etymology

The epithet is taken from KwaZulu-Natal, the regional name for this area of South Africa; noun in apposition.