Natatolana vieta ( Hale, 1925 )

Keable, Stephen J., 2006, Taxonomic Revision of Natatolana (Crustacea: Isopoda: Cirolanidae), Records of the Australian Museum 58 (2), pp. 133-244 : 231

Natatolana vieta ( Hale, 1925)

Cirolana vieta Hale, 1925: 150 , fig. 11.–1929: 249, fig. 242.– 1940: 288, fig. 1.– Nierstrasz, 1931: 157.

Natatolana vieta .– Bruce 1981: 958.– 1986: 55 figs. 33, 34.–Jones & Morgan, 1993: 142.– Brusca et al., 1995: 82.– Kensley, 2001: 230.– Bruce et al., 2002: 153.

Type material. Holotype: ♀, 13 mm, SAMA C278 (examined). Type locality: Encounter Bay , South Australia, Australia [35°35'S 138°45'E].

Material examined. Queensland: 3, AM P47268, off East Fitzroy Reef , 23°32.53'S 152°16.45'E, 105 m, 16–17 Jun. 1993, SEAS QLD-956 . New South Wales: 2, AM P47267, east of Coffs Harbour , 30°17.49'S 153°13.90'E, 45.4 m, 11–12 Aug. 1993, SEAS NSW-873; series from off Providential Head, c. 34°44'S 150°39'E, baited traps, 25–38 m, S. Keable, A. Parker & J. Lowry on MV Krista, 14–15 Jan. 1991, Australian Museum / The Ecology Lab Pty. Ltd. Pioneer Consultation Project 1991: AM P47247– 47254 . Tasmania: 1, AM P47264, east of Fortescue Bay , 43°06.70'S 148°03.45'E, 100 m, 16–17 April 1993, SEAS TAS- 354 . South Australia: series from Upper Spencer Gulf , 32°42.2'– 33°5'S 137°47.26'–57.44'E, 5–17 m, Fisheries Department Survey, SAMA C5642–5648 . Western Australia: series from North-West Shelf , 19°3.5–5.4'S 118°50.8– 119°3.1'E, 81–84 m, sled, CSIRO 1983; 5, AM P47259–47263 .

Diagnosis. Interocular furrow: absent. Frontal lamina: lateral margins concave but not medially constricted, narrowing toward apex. Antenna: c. 0.8–1.05× as long as body, reaching to between pleonite 4 and just beyond the pleotelson. Coxal plates: furrows strongly developed, on all coxae. Pleonite 4: posterodorsal margin strongly concave proximal to meeting posteroventral margin at apex; apex acute and slightly produced. Pleotelson: narrow, length 0.91× basal width; anterodorsal depression present; anterolateral margins convex; posterolateral margins convex; apex produced into a large point; with 4–8 RS. Pereopod 2: propodus with 6 RS on palm. Pereopod 3: propodus with 5 RS on palm. Pereopod 7: basis narrow, width 0.38× length; distance between anterior margin and medial carina less than between posterior margin and medial carina; posterior margin with sparse setae proximally and distally but not medially. Penes: present. Pleopod 2 appendix masculina: extending beyond tip of endopod; margins moderately curved laterally; apex not at angle to adjacent margins, blunt with a minute spiniform process or bluntly rounded. Uropods: exopod slightly shorter than endopod, 0.85× the length of the endopod.

Variation. Bruce (1986) noted that the scattered furrows, giving a “wrinkled” appearance to the dorsal surfaces of the various body segments that is characteristic of Natatolana vieta , tend to be more developed in larger specimens. This is not the case in the material examined, specimens from Upper Spencer Gulf have clearly developed furrows while specimens of a similar size (or larger) from other localities do not have well-developed furrows. Bruce (1986) illustrated a complete interocular furrow for this species. This appears to be formed from the scattered wrinkle like furrows occurring elsewhere on the body and is not apparent in specimens lacking wrinkles.

The specimens from the North-West Shelf of Western Australia have six to eight robust setae on the pleotelson rather than the usual four found in the other material examined. In material with scattered furrows, the geniculate appearance of the antennular peduncle is more strongly developed. In material examined from Queensland and New South Wales, the spiniform process on the apex of the appendix masculina is not developed.

Sexual dimorphism. Females may have shorter antennae (c. 0.8× body length) than males (c. 1.05× body length) ( Hale, 1940). This is not, however, a constant feature, some males having the antennae only as long as females.

Size. Females to 27.7 mm, mancas to 8.5 mm.

Remarks. Characters that separate Natatolana vieta from all other species, when used in combination, are the long antennae and the presence of a distinct dorsal depression on the pleotelson.

Distribution and ecology. Australia:northwestern Western Australia, south to Rottnest Island; Queensland, north to Gladstone; New South Wales; Victoria; Tasmania; South Australia. At depths of 5– 156 m. Scavenger.