Natatolana femina, Keable, 2006

Keable, Stephen J., 2006, Taxonomic Revision of Natatolana (Crustacea: Isopoda: Cirolanidae), Records of the Australian Museum 58 (2), pp. 133-244 : 174-178

Natatolana femina n.sp.

Figs. 17–19

Type material. HOLOTYPE: ♀, 12.5 mm, AM P47232 . PARATYPES: 3, 10 mm, AM P47233, same data as for holotype except off the rocks on the north end of Maurouard Beach , 41°17.3'S 148°21.3'E, 15 m, TAS-124 ; 7 specimens, TM, same data as holotype. Type locality: in the corner off the northern end of Maurouard Beach , St Helens Point, Tasmania, Australia, 41°17.3'S 148°20.9'E, [baited trap], sandy bottom, 5 m, [J. Lowry, S. Keable & C. McCormick, 13–14 April 1991, TAS-125] .

Additional material. Tasmania: 18 mancas, AM P47234, off rocks at the northern end of Maurouard Beach , 41°17.3'S 148°21'E, 10 m, TAS-126; 6 mancas, AM P47235, same data as

holotype except in the cove off Beerbarrel Beach , 41°17.2'S 148°21.3'E, 10 m, TAS-127; 29 mancas, AM P47236, same data as holotype except off Binalong Beach, Binalong Bay, 41°14.7'S 148°17.6'E, 8 m, 14–15 April 1991, TAS-144 .

Diagnosis. Interocular furrow: absent. Frontal lamina: lateral margins concave but not medially constricted, narrowing toward apex. Antenna: c. 0.3× as long as body, reaching to posterior of pereonite 3. Coxal plates: furrows weakly developed, on all coxae. Pleonite 4: posterodorsal margin strongly concave proximal to meeting posteroventral margin at apex; apex forming a broad acute point. Pleotelson: broad, length 0.87× basal width; anterodorsal depression present; anterolateral margins convex; posterolateral margins concave; apex produced into a large point; with 12–15 RS. Pereopods 1–6: males with the RS on the merus of pereopods 1–3, and carpus of pereopods 4–6, shorter than the propodus (but fully mature males not known). Pereopods 2–3: propodus without RS on palm. Pereopod 7: basis broad, width 0.57× length; distance between anterior margin and medial carina less than between posterior margin and medial carina; posterior margin with setae along entire length. Penes: absent, vasa deferentia opening flush to surface of sternite 7 (but fully mature males not known). Pleopod 2 appendix masculina: just shorter than endopod, 0.88× length of endopod; margins very slightly curved laterally; slender; apex not at angle to adjacent margins, bluntly rounded (but fully mature males not known). Uropods: exopod subequal to endopod, 0.98× the length of the endopod.

Additional descriptive characters. Based on holotype. Body: length c. 2.7× width. Colour translucent white to yellow in alcohol. Chromatophores present; both large and small; grey in alcohol; restricted to lateral margins of pereonites, pleonites and coxae, fairly sparse and faint, fading after preservation. Cephalon: submarginal cephalic furrow absent. Eyes: with 5 ommatidia in horizontal diameter; with 9 ommatidia in vertical diameter; ovate; colour red-brown in alcohol. Frontal lamina: length c. 3.85× basal width; apex expanded, anterior margin angled. Antennule: peduncular article 1 and article 2 subequal in length; article 2 with several small penicillate setae on lateral margins and 1 large pappose seta on medial anterolateral margin; article 3 long, larger than article 1 or 2 but shorter than their combined lengths. Flagellum 14-articulate. Antenna: peduncular article 4 with numerous long SS on posterolateral margin, several short SS and 1 penicillate seta at anterodistal angle; article 5 with 2 pappose setae and 4 SS at posterodistal angle, 4 SS at anterodistal angle. Flagellum 27-articulate. Mandible: setal row with 19 RS. Maxillule: medial lobe with 3 large and 1 smaller robust pappose setae and 2 small SS; lateral lobe with 13 RS on distal surface. Maxilla: lateral lobe with 4 SS; medial lobe with 3 SS and 17 PS; middle lobe with 17 long SS on outer row and 4 short SS on inner row. Maxilliped: endite with 2 coupling hooks, 5 PS and 2 SS. Pereon: ornamentation consists of 1 weakly developed furrow on lateral margin of pereonite 1; pereonites 1 and 5–6 subequal in length and longest, 4 and 7 subequal and longer than 2–3 which are subequal. Coxae: pereonite 1, coxae 2–4 with rounded posteroventral corners, coxae 5–6 with sinuate posterior margins developed into small coxal points, coxa 7 with a produced, broad, acute posteroventral corner. Pleonite 2: dorsal posterolateral margin subequal with ventral posterolateral margin. Pereopod 7: basis anterior margin slightly convex; medial carina with PS along entire length; posterior margin convex, SS present. Ischium anterior margin with SS; posterior margin with groups of RS present, PS present. Merus anterior margin with SS; posterior margin with 5 RS (1 proximal and 1 group of 4 medially), SS present. Carpus anterior margin with SS; posterior margin with 6 RS, SS absent. Propodus subequal to carpus; posterior margin with 5 RS, SS absent. 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 triangular; medial margin convex, with 3 RS, PS along entire length; apex with 2 RS; lateral margin straight, with 3 RS, PS along entire length. Exopod medial margin convex, with 4 RS, PS along entire length; apex acute, with 2 RS; lateral margin convex, with 8 RS, PS along entire length.

Supplementary description of male. Based on paratype, 10 mm, AM P47233, not fully mature. Pleopod 2 appendix masculina: arising basally.

Variation. The number of robust setae occurring on the pleotelson is variable, the holotype has 15. Among the seven paratype specimens examined in the Tasmanian Museum, three have 14, two have 13, one has 12 and one is damaged.

Sexual dimorphism. In the material examined there was only one male present, this specimen was not fully mature and sexual dimorphism could not be adequately assessed. In mature males of species that may be closely related, however, conspicuously elongate robust setae develop on the carpus of pereopods 1–3 and on the merus of pereopods 4–6.

Size. Adults to 25 mm.

Etymology. From the Latin “femine” (the female) in reference to the absence of mature males in the material examined.

Remarks. No fully mature males of Natatolana femina are known. Therefore, whether the males develop conspicuously long robust setae on the pereopods as in similar species such as N. corpulenta is unclear. Furthermore, the appendix masculina and penes are probably not fully developed in the specimen described here.

Natatolana femina is most similar to N. natalensis but differs from that species in having the posterolateral margins of the pleotelson concave (not convex) and in lacking robust setae on the propodal palm of pereopods 2–3. Natatolana pellucida , N. sinuosa n.sp., N. debrae n.sp., N. corpulenta and N. pallidocula are also similar. Natatolana pellucida differs from N. femina in having the posterior margins of coxa 3–4 sinuate, forming weak coxal points at the posteroventral corners of these coxae and because the posterolateral margins of the pleotelson are convex. Natatolana sinuosa and N. debrae differ from N. femina because pereonite 1 and coxae 2–7 have sinuate posterior margins that form strong coxal points at their posteroventral corners in these species. Natatolana corpulenta has the anteroventral corner of coxa 2 produced into an acute tooth whereas it is rounded in N. femina . Natatolana pallidocula has rectangular eyes with 14 ommatidia in the horizontal row whereas in N. femina the eyes are rounded with only 5 ommatidia in the horizontal row.

Distribution and ecology. Australia: northeast coast of Tasmania At depths of 5– 15 m. Scavenger.

Figures

Fig. 17. Natatolana femina n.sp., holotype. Scales = 0.5 mm.

Fig. 18. Natatolana femina n.sp., holotype. Scales = 0.5 mm.

Fig. 19. Natatolana femina n.sp., holotype, except; PL2 = paratype male (immature). Scales = 0.5 mm.