Tasmarcturus lewisi, Poore, 2013

Poore, Gary C. B., 2013, Rectarcturidae Poore, 2001 rediagnosed with descriptions of new Australian genera and species (Isopoda: Valvifera), Memoirs of Museum Victoria 70, pp. 17-36 : 30-33

Tasmarcturus lewisi sp. nov.

Zoobank LSID. http://zoobank.org/ urn:lsid:zoobank.org:act:

F3C16B94-1D11-4CC3-8A87-2FF8BA2B2004

Figures 1c , 9 , 10

Rectarcturus sp. – Poore, 2001: fig 1e.

Material examined. Holotype. Australia, Tas., eastern Bass Strait , 25 km NE of Deal I (39°14.48'S, 147°31.30'E), 57 m, 18 Nov 1981 (stn BSS 174 ), NMV J23745 (male, 6.1 mm).

Paratypes. Collected with holotype, NMV J8768 (9 specimens) .

Vic., eastern Bass Strait, 50 km SE of Port Albert (38°54.18'S, 147°13.24'E), 58 m, 18 Nov 1981 (stn BSS 176), NMV J23445 (female, 7.0 mm) ; NMV J23448 (male, 6.1 mm) ; NMV J23742 (male, 5.1 mm) ; NMV J23743 (ovigerous female, 6.6 mm) ; NMV J8781 (male, 4.3 mm) ; NMV J8780 (manca, 2.9 mm; 7 males, 4.5–6.0 mm; 4 females, 5.9–7.4 mm).

Other material. Tas., Vic. c. 58 specimens from eastern Tas., throughout Bass Strait , 38– 42°S, 143– 148°E, 26–140 m depth (see Museum Victoria database http://collections.museumvictoria.com.au/ for details). (All collected by WHOI epibenthic sled or SM grab by G.C.B. Poore et al., Museum Victoria.)

NSW, S of Worang Point , Twofold Bay (37°03.5'S, 149°56.5'E), 6 m, AM P.36070 (male) .

Description. Ovigerous female. Pereonites 2–4 swollen, taller and broader than more anterior and posterior segments, with highly spinulose transverse ridges and numerous spinules besides, 2.7 times as long as greatest width. Pleotelson 0.3 times total body length.

Head ornamentation rounded anteriorly in lateral view, comprising pair of transverse submedian ridges on anterior margin, followed by pair of larger transverse ridges, spinulose anteriorly and posteriorly, reaching eyes laterally, then another similar thicker pair flattened dorsally; maxillipedal segment with 5 pairs of spinulose tubercles evenly spaced between submedian and sublateral positions; ventrolateral margin smooth, with deep fissure between head and pereonite 1. Pereonite 1 with transverse ridge (doubled laterally) bearing 2 medial tubercles (anterior and posterior) plus 5 pairs of more or less similarly arranged anterior and posterior spinules ranging from submedian to sublateral; pereonite 2 with transverse ridge (doubled laterally) bearing pair of submedian, anteriorly directed, flat, triangular projections decorated with spinules, anterior margin of ridge with 3 pairs of sublateral spines, posterior margin with 5 pairs of spinules, 1 lateral spine at end of ridge; pereonite 3 similar to pereonite 2, submedian decoration larger; pereonite 4 similar to pereonite 3, submedian and sublateral pairs of complex spines more developed; pereonites 5–7 each with transverse ridge bearing median, anteriorly directed spinule plus 4 pairs of anterior and 2 pairs of posterior spinules forming prominent sublateral complexes. Submedian and sublateral tubercles on pereonites 1 and 2 secondarily pustulose; submedian processes on pereonite 3 longitudinally flattened. Pereonites 1–7 + maxillipedal segment with supracoxal rounded plates, larger on 3 and 4, weaker on 5–7, all spinulose (especially on dorsal surfaces), arranged such that a deep lateral groove exists between end of lateral ridge and supracoxal plate. Pereonites 2–4 each with transverse row of tubercles in front of main ridge, most complex on 3. Pleonites 1 and 2 spinulose, developed into submedian plates on pleonite 2; pleonite 3 with submedian plates similar to pleonite 2, without sublateral spinules; posterior pleotelson with spinules arranged into a pair of flat submedian ridges and sublateral clusters, with rounded lateral wings; pleotelson tapering evenly to sharply rounded apex, tapered section 0.7 times as long as wide.

Antennule flagellum article 1 with 3 pairs plus 1 aesthetascs, article 2 with 2 aesthetascs. Antenna, fused articles (1 + 2) short, stout, with ventrolateral flange.

Pereopod 1 propodus twice as long as wide. Pereopod 2 tuberculate, especially basis and flexor margin of carpus; dactylus unguis as long as dactylus body. Pereopod 4 and extensor margin of basis; dactylus body 1.2 times as long as propodus, unguis setiform, 0.4 times length of dactylus body. Pereopods 5–7 with 2 to several tubercles on extensor margin of basis and ischium, 1 each on carpus and propodus. Pereopod 7 dactylus body 0.6 times as long as propodus, unguis stout, 0.5 times length of dactylus body.

Oostegites 1–4 supported by oval coxal plates; oostegites 5 a pair of adjacent oval discs.

Uropodal exopod 0.7 times length of endopod.

Male. Of even dimensions throughout length, with highly spinulose, transverse ridges and numerous spinules besides. Head ornamentation rounded anteriorly in lateral view, comprising high suprantennal forehead, frontal margin ornamented with 3 pairs of ridge-like tubercles, with pair of anterior transverse ridges separated by medial notch, almost occluded dorsally, followed by pair of submedian flattened ridges, all microtuberculate; maxillipedal segment with 5 pairs of spinulose tubercles evenly spaced between submedian and sublateral positions; ventrolateral margin smooth, with deep fissure between head and pereonite 1. Pereonite 1 with transverse ridge (doubled laterally) bearing 2 medial tubercles (anterior and posterior) plus 4 pairs of more or less similarly arranged anterior and posterior spinules ranging from submedian to sublateral; pereonite 2 with transverse ridge (doubled laterally) bearing 4 pairs of anterior and 4 pairs of posterior tubercles, irregularly spaced; pereonites 3 and 4 similar to pereonite 2; pereonites 5–7 each with a transverse ridge bearing a median, anteriorly directed spinule plus 5 pairs of anterior and 2 pairs of posterior spinules; submedian and sublateral tubercles on pereonites 1 and 2 secondarily pustulose; pereonites 1–7 + maxillipedal segment with supracoxal rounded plates, larger on 3 and 4, weaker on 5–7, all spinulose especially on dorsal surfaces, arranged such that a deep lateral groove exists between end of lateral ridge and supracoxal plate; pereonites 2–4 each with a transverse row of tubercles in front of main ridge, most complex on 3. Pleonites 1 and 2 with paired flat ridges divided into 1 medial and 2 sublateral plates on pleonite 1, and a pair each of flat submedian tubercles and sublateral tubercles; pleonite 3 with submedian plates similar to pleonite 2, without sublateral spinules; posterior pleotelson with spinules arranged into a pair of flat submedian ridges and sublateral clusters, with rounded lateral wings; pleotelson tapering evenly to a sharply rounded apex, tapered section 0.7 times as long as wide.

Antenna, article 5 twice as long as article 4; flagellum of 3 articles, 0.7 times length of peduncle article 5.

Male pleopod 1 exopod little more than 3 times basal width; posterior face without erect lobes along groove; lateral margin bearing row of 6 multifid setae proximally, 9 stout setae distally; distomesial seta-bearing lamina well separated from apex by deep triangular notch and well exceeding it in length.

Etymology. For my grandson, Lewis Poore.

Distribution. Southeastern Australia, 37– 40°S, 26–140 m depth.

Remarks. The head of Tasmarcturus lewisi has a rounded lateral profile, distinguishing it from the squarish profile of T. erinae and the conical tubercles of T. simplicissimus . This species is distributed within the latitudinal range of T. erinae but occurs over a wider depth range.

Figures

Figure 1. Dorsal and lateral views of four species of Rectarcturidae, males on top, females below. (a) Nowrarcturus jamesi sp. nov. (with ventral view of oostegites 3–5), male, NMV J19187; female, NMV J23734. (b) Tasmarcturus erinae sp. nov., male, NMV J16686; female, NMV J62082. (c) Tasmarcturus lewisi sp. nov., male and female, NMV J23743. (d) Tasmarcturus simplicissimus (Whitelegge, 1904), male and female, NMV J8758. Scale bars = 1 mm.

Figure 9. Tasmarcturus lewisi sp. nov. Female paratype, NMV J23743: habitus; P3–P5, oostegites and coxal plates of pereonites 3–5. Male holotype, NMV J23745: a1, antennule with detail of flagellum; a2, antenna; ur, uropodal rami.

Figure 10. Tasmarcturus lewisi sp. nov. Male holotype, NMV J23745: p1, p2, p4, p7, pereopods 1, 2, 4 and 7 with details of distal articles; pl1, pleopod 1.