Natatolana intermedia ( Vanhöffen, 1914 )

Keable, Stephen J., 2006, Taxonomic Revision of Natatolana (Crustacea: Isopoda: Cirolanidae), Records of the Australian Museum 58 (2), pp. 133-244 : 194

Natatolana intermedia ( Vanhöffen, 1914)

Cirolana intermedia Vanhöffen, 1914: 500 , fig. 37.– Tattersall, 1921: 205.– Hale, 1937: 17.– 1952: 27.– Kussakin, 1967: 224.

Natatolana intermedia .– Bruce, 1981: 958.– 1986: 222.– Brandt, 1988: 113, figs. 51–55.– Brusca et al., 1995: 80.

Type material. Lectotype designated by Brandt (1988): 3, 15.5 mm, originally ZMG but now in SIF ZMG 260 (not examined) . Paralectotypes: 3, 17 mm, 4♀♀, 13 mm, 14 mm, 15 mm, 16 mm, SIF ZMG 261 (not examined). Also , 233, ZMUC CRU158 ; 2♀♀, ZMUC CRU159 ; apparently part of original syntype series from the type locality donated by the ZMB in 1926 (examined). Other possible paralectotypes are ZMB 17618 (male and 2♀♀) ZMB 17620 (male and 6♀♀); all from type locality ( Brandt, 1988) (not examined). Type locality: off Gauss Station, Posadowsky Bay, Antarctica, 66°2.9'S 89°38.5'E, 385 m, [Deutsche Sudpolarexpedition 1901–1903] .

Diagnosis. Eyes: well developed; elongate, length c. 2× height. Interocular furrow: weakly developed, indistinct and not extending across the cephalon. Frontal lamina: lateral margins straight, narrowing anteriorly. Antenna: c. 0.33– 0.4× as long as body, reaching to between the posterior of pereonite 3 and 4. Coxal plates: furrows strongly developed, on all coxae. Pleonite 4: posterodorsal margin strongly concave proximal to meeting posteroventral margin at apex; apex forming a narrow acute point. Pleotelson: broad, length 0.92× basal width; anterodorsal depression absent (there is an indistinct depression but this is not as distinct and abrupt as in species such as N. pellucida ); anterolateral margins convex; posterolateral margins convex; apex produced into a small point; with 10–16 RS. Pereopod 2: propodus with 3–4 RS on palm. Pereopod 3: propodus with 3–6 RS on palm. Pereopod 7: basis narrow, width 0.45× length; distance between anterior margin and medial carina less than between posterior margin and medial carina; posterior margin with setae along entire length. Penes: present. Pleopod 2 appendix masculina: extending subequal with tip of endopod, 1× length of endopod; margins very strongly curved laterally; slender; apex not at angle to adjacent margins, bluntly rounded. Uropods: exopod slightly shorter than endopod, 0.81× the length of the endopod.

Size. Females to 23 mm, males to 24 mm.

Remarks. Natatolana intermedia is most similar to N. nitida but has a rounded anteroventral corner on coxa 2, a pleotelson with convex posterolateral margins and a slender and strongly curved appendix masculina. Natatolana obtusata is also similar but has pleonite 4 with a sinuate posterodorsal margin.

Distribution. Antarctica: Gauss Station; McMurdo Sound; Banzare Coast; Kemp Coast; Davis Sea; Enderby Land; Lars Christensen Coast; Antarctic Peninsula; Weddell Sea ( Brandt, 1988). At depths of 163–560 m ( Kussakin, 1967).