Neastacilla marrimarri King, 2003, sp. nov.
Creators: name: King, R. A.
Publisher: name: Zenodo
Year: 2003
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Arcturidae
Neastacilla
Neastacilla marrimarri

description: 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.
description: Published as part of King, R. A., 2003, Neastacilla Tattersall, 1921 redefined, with eight new species from Australia (Crustacea: Isopoda: Arcturidae), pp. 371-416 in Memoirs of Museum Victoria 60 (2) on pages 395-396, DOI: 10.24199/j.mmv.2003.60.29, http://zenodo.org/record/12210258