Neastacilla macilenta (Hale)

King, R. A., 2003, Neastacilla Tattersall, 1921 redefined, with eight new species from Australia (Crustacea: Isopoda: Arcturidae), Memoirs of Museum Victoria 60 (2), pp. 371-416 : 395

Neastacilla macilenta (Hale)

Astacilla macilenta Hale, 1946: 179–182 , figs 11–12.— Monod, 1970: 1139.

Neastacilla macilenta . — Poore et al., 2002: 259.

Diagnosis of female. Eyes small and round. Head without dorsal elevations; lateral margins of head and pereonite 1 not incised, extended anterolaterally; unsutured lateral groove below eye present. Pereonites 2–3 without dorsal elevations. Pereonite 4 7 times as long as pereonite 3, without dorsal elevations, anterolateral margins extended and angular. Pleon length longer than pereonites 5–7 combined, 2 pairs of lateral wings, apex bluntly rounded. 8 mm.

Male. Similar to female except for pereonite 4, which is 15 times as long as pereonite 3.

Pleopod 1 exopod with lateral notch and 2 plumose lateral setae of unequal lengths. Pleopod 2 appendix masculina with ridge on posterior face, curved, not extending past the endopod, apex simple. Penial plate undescribed. 9 mm.

Distribution. Australia: New South Wales. Remarks. This species is diagnosed using the description of Hale (1946). This species is superficially similar to Neastacilla . soelae sp. nov., N. monoseta and N. deducta . However, N. soelae possesses a distinctive long pointed pleotelson and N. monoseta possesses a large, angular lateral wings on the pleotelson. The pleotelson of N. macilenta is rounded and blunt. N. macilenta can be further distinguished from N. monoseta and N. deducta by the absence of an incision in the suture line between the head and pereonite 1.

Hale (1946) illustrated three lateral plumose setae on the exopod of pleopod 1 in males. In all specimens examined here, there were two lateral plumose setae.