Natatolana brucei, Keable, 2006

Keable, Stephen J., 2006, Taxonomic Revision of Natatolana (Crustacea: Isopoda: Cirolanidae), Records of the Australian Museum 58 (2), pp. 133-244 : 158

Natatolana brucei n.sp.

Figs. 7–8

Type material. HOLOTYPE: 3, 16.0 mm, AM P47185 . PARATYPES: 116, AM P38675 ; 3, ♀ at BMNH, USNM, ZMUC. Type locality: off Grotto Point , Port Jackson, NSW, Australia, 33°49.2'S 151°15.75'E, [baited trap, unknown substrate, probably sediment], 10 m, [S. Keable, J. Lowry & D. Townsend, 16–17 Jul. 1988, Site 37] .

Additional material. New South Wales: 9, AM P47199, off Grotto Point, Port Jackson, 33°49.05'S 151°15.8'E, baited trap on sediment, 15 m, S. Keable & J. Lowry, 8–9 May 1988, site 13; series from south of Sydney, Australian Museum / The Ecology Lab Pty. Ltd. Pioneer Consultation Project 1991, off Providential Head, 34°44'S 150°39'E, baited traps, S. Keable, A. Parker & J. Lowry on MV Krista, 14–15 Jan. 1991: AM P47202–47207; ♀, 25–30 m, PIO-101; 3, 2 mancas, 25–30 m, PI0-103; ♀, 33 m, PIO-116; off Bate Bay / Port Hacking , 34°07.00'S 151°10.00'E: 4, 25– 30 m, S2R1 shallow; 3, ♀, manca, 25–30 m, S2R2 shallow; 3, 35– 40 m, S2R2 medium; series from Twofold Bay , baited trap, J. Lowry & S. Keable, 27–29 Nov. 1988: 9, AM P47200, between Whale Spit and Mungora Point, 37°5.7'S 149°53.1'E, unknown substrate, probably sediment, 8 m, NSW-381; 2, AM P47201, between Lookout Point and Seahorse Shoals, 37°5.6'S 149°56.6'E, unknown substrate—probably sediment, 30 m, NSW-392 .

Diagnosis. Interocular furrow: weakly developed, indistinct and not extending across the cephalon. Frontal lamina: lateral margins straight, parallel. Antenna: c. 0.3× as long as body, reaching to just beyond posterior of pereonite 3. Coxal plates: furrows variously developed, strong and complete on coxae 2–3, 7, indistinct and incomplete on coxae 4–6. Pleonite 4: apex slightly rounded. Pleotelson: narrow, length 1.14× basal width; anterodorsal depression absent; anterolateral margins convex; posterolateral margins concave; apex produced into a large point; with 6 RS. Pereopods 2–3: propodus without RS on palm. Pereopod 7: basis broad, width 0.61× length; distance between anterior margin and medial carina greater than between posterior margin and medial carina; posterior margin with setae on proximal half. Penes: absent. Pleopod 2 appendix masculina: extending beyond tip of endopod, 1.04× length of endopod; margins very slightly curved laterally; slender; apex not at angle to adjacent margins, bluntly rounded. Uropods: exopod slightly shorter than endopod, 0.87× the length of the endopod.

Additional descriptive characters. Based on holotype. Body: length c. 3.3× width. Colour cream in alcohol. Chromatophores absent. Eyes: with 7 ommatidia in horizontal diameter; with 8 ommatidia in vertical diameter; ovate; colour tan in alcohol. Frontal lamina: length c. 6.8× basal width; apex not expanded, anterior margin rounded.

Antennule: peduncular article 1 longer than article 2; article 2 with 1 large pappose seta (broken); article 3 long, larger than article 1 or 2 but shorter than their combined lengths. Flagellum 12-articulate. Antenna: peduncular article 4 with 2 SS and 1 penicillate seta medially on posterolateral margin, 2 SS at posterodistal angle, 2 SS at anterodistal angle; article 5 with 1 pappose and 1 PS at posterodistal angle, 3 SS and 1 penicillate seta at anterodistal angle. Flagellum 22- articulate. Mandible: setal row with 14 RS. Maxillule: medial lobe with 3 large robust pappose setae and 3 SS; lateral lobe with 12 RS on distal surface. Maxilla: lateral lobe with 6 SS; medial lobe with 5 SS and 9 PS; middle lobe with 12 SS. Maxilliped: endite with 2 coupling hooks, 1 SS and 6 PS. Pereon: ornamentation consists of 1 strongly developed furrow on lateral margin of pereonite 1 and 1 short, medial furrow on lateral margins of pereonites 4–6; pereonites 1, 4–6 subequal and longest, 2–3 and 7 subequal. Coxae: pereonite 1 and coxae 2–3 with rounded posteroventral corners, coxae 5–7 with sinuate posterior margins formed into moderately large coxal points. Pleonites: 1–5 visible but 1 almost completely concealed along dorsal margin by pereonite 7. Pleonite 2: dorsal posterolateral margin subequal with ventral posterolateral margin. Pereopod 7: basis anterior margin sinuate; medial carina with PS and SS present (plumose setae on proximal third, slender setae on distal third); posterior margin convex, PS present. Ischium anterior margin with SS; posterior margin with 1 RS (submarginal), PS present. Merus posterior margin with 7 RS (and 4 submarginally), SS present. Carpus posterior margin with 6 RS (2 submarginally), SS absent. Propodus longer than carpus; posterior margin with 7 RS, SS absent. Pleopod 2 appendix masculina: arising sub-basally. Pleopods 1–5: exopod suture strongly developed on pleopods 3–5; endopod PS on most of margins on pleopods 1–4, absent on pleopod 5. Uropods: endopod lanceolate; medial margin convex, with 4 RS, PS along entire length; apex with 2 RS; lateral margin slightly sinuate, with 3 RS and 1 penicillate seta, PS on distal three-quarters. Exopod medial margin convex, with 2 RS, PS along entire length; apex acute, with 2 RS; lateral margin convex, with 7 RS, PS along entire length.

Size. Adults to c. 16 mm.

Etymology. Named after Dr Niel Bruce, in recognition of the help he has given me with this study.

Remarks. Natatolana brucei appears to be very similar to N. pallidocula but differs in having a round eye with fewer ommatidia, a rounded posteroventral margin on coxa 3, a antennal flagellum with more articles, a longer appendix masculina and a broader pereopod 7.

Distribution and ecology. Australia: New South Wales within Port Jackson and off the coast south of Port Jackson; Twofold Bay. At depths of 8– 40 m. Scavenger.

Figures

Fig. 7. Natatolana brucei, n.sp., holotype. Scales for A1, A2, P1, P2 = 0.5 mm. Scales for MD, MP, MX1, MX2 = 0.2 mm.

Fig. 8. Natatolana brucei n.sp., holotype. Scales = 0.5 mm.