Neastacilla marrimarri, King, 2003

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 : 395-396

Neastacilla marrimarri sp. nov.

Figures 16–17

Material examined. Holotype. Australia: WA, King George Sound , 35º00.7'S, 118º10.1'E, 25 m, 15 Apr 1984, NMV J16641 (1 female, 6.4 mm).

Description of female. Head with 2 dorsal elevations between eyes, anterolateral margins angular, rostral point absent; lateral margin of head and pereonite 1 not incised. Pereonite 1 with large dorsal elevation and small dorsolateral elevations. Pereonites 2 and 3 with dorsal and dorsolateral elevations, with lateral margins extended. Pereonite 4 about 5 times as long as pereonite 3; with 2 dorsal elevations midlength each with 2 apices, small dorsolateral elevations at midlength, anterior dorsolateral elevations, 2 posterodorsal elevations and 2 posterior dorsolateral elevations, anterolateral margins rounded and extended. Pereonites 5–7 progressively shorter posteriorly, with dorsal and dorsolateral elevations. Pleon similar length to the combined lengths of pereonites 5–7, with 2 sets of lateral wings, apex subacute.

Eyes small and round. Antenna 1 reaching past the second peduncular article of antenna 2; aesthetascs present distally and laterally on flagellum. Antenna 2 slender, more than half as long as body; flagellum of 3 articles ending with claw; with 2 rows of scales along full length.

Maxilla 1mesial lobe with 3 terminal setae; lateral lobe with 9 distal robust setae. Maxilla 2 mesial lobe with 15 plumose setae, middle lobe with 3 setae, lateral lobe with 3 setae. Maxillipedal endite with 8 mesial setae; 1 coupling hook; palp article 2 with mesial setal rows, articles 3 and 4 with mesial and lateral setal rows, article 5 with distal setae.

Pereopod 1 propodus and carpus of a similar length; dactylus longer than wide; without unguis. Pereopods 2–4 with small dactylus. Pereopods 5–7 dactylus denticulate, with unguis and secondary unguis; secondary unguis half size of primary unguis. Uropodal exopod with 2 setae of equal length. Oostegite 4 with a sutured small posterior lobe.

6.4 mm.

Male. Unknown

Distribution. Australia: Western Australia; subtidal.

Etymology. "Marrimarri " is an Australian Aboriginal word in the Nyungar dialect from south-western Australia where this specimen was found. It means “crustacean” or “crab”.

Remarks. Even though this species is known only from a single female specimen, it is sufficiently distinct to warrant a new species. Superficially this species resembles Neastacilla tuberculata from New Zealand and N. sheardi from southern Australia. However, in N. marrimarri sp. nov. the dorsal elevation of pereonite 4 is not as pronounced and the lateral margins not expanded to as great an extent as they are in N. tuberculata . The ornamentation of pereonite 4 is also arranged differently. Neastacilla sheardi has less ornamentation than N. marrimarri . Further, the pleotelson of N. marrimarri is more narrow, than in N. tuberculata and more angular than that of N. sheardi .

Figures

Figure 16. Neastacilla marrimarri sp. nov., female holotype (NMV J16641):A, lateral view; B, dorsal view; C, ventral view with oostegites, Scale = 1.0 mm.

Figure 17. Neastacilla marrimarri sp. nov., female holotype (NMV J16641): A1, A2, left MXP, MX1, MX2, MD; P1, P3, P5. Scales: a (A1, A2) = 0.5 mm; b (MP, MX1, MX2, MD, P1) = 0.5 mm; c (P1, P3) = 0.5 mm; d (P5) = 0.5 mm.