Natatolana meridionalis ( Hodgson, 1910 )

Keable, Stephen J., 2006, Taxonomic Revision of Natatolana (Crustacea: Isopoda: Cirolanidae), Records of the Australian Museum 58 (2), pp. 133-244 : 201-202

Natatolana meridionalis ( Hodgson, 1910)

Cirolana meridionalis Hodgson, 1910: 20 , pl. 3.–? Stephensen, 1947: 24, fig. 7.

Natatolana meridionalis .– Bruce 1981: 958.– 1986: 218, 222.– Brandt 1988: 102.– Brusca et al., 1995: 80.– Castelló, 1999: 278.– Takeuchi et al., 2001: 624.

Cirolana albinota Vanhöffen, 1914: 497 , fig. 35.– Monod, 1931: 22.– Hale, 1952: 26.–? Menzies 1962: 126, fig. 41, F–G.– Kussakin, 1967: 223.– Carvacho 1977: 40.

Natatolana albinota .– Bruce, 1981: 958.– 1986: 218, 222.– Brandt, 1988: 105, figs. 45–50.

Type material of N. meridionalis . Holotype: ♀, 35 mm, BMNH 1910.3.18:39-40 (examined). Type locality of N. meridionalis: Winter Quarters , National Antarctic Expedition

1901–1904, Antarctica, [78°S 165°E, fide Stephensen (1947), 29 Aug. 1903, trap], 25 fathoms. Hodgson (1910) mentions another mutilated specimen found in a seal’s stomach. The description, however, appears to have been based entirely on the intact specimen taken in the trap. There are two specimens in the type lot, the larger female specimen is the holotype. The smaller female specimen appears to be the specimen from the seal’s stomach. A note with the smaller specimen reads “The damaged specimen, with eyes, is probably C. [ Natatolana ] intermedia, Vanhöffen (note by W.M. Tattersall)”; this identification by Tattersall appears to be correct.

Type material of N. albinota . Lectotype designated by Brandt (1988): 3, 40.5 mm, originally ZMG but now in SIF, ZMG 259 . Paralectotypes: 333, 37 mm, 40 mm, 42 mm, 3♀♀, 35 mm, 35 mm (ovigerous), 43 mm (ovigerous), SIF, ZMG 258 . None examined. Also , 233, ZMUC CRU153 ; 2♀♀, ZMUC CRU154 ; apparently part of original syntype series from the type locality donated by the ZMB in 1926 (examined). Type locality of N. albinota: Gauss Station, Posadowsky Bay, Antarctica, 66°2.9'S 89°38.5'E, 385 m, [Deutsche Sudpolarexpedition 1901–1903] .

Diagnosis. Eyes: well developed or vestigial (apparently fading with preservation). Interocular furrow: moderately developed, distinct but not extending across the cephalon. Frontal lamina: lateral margins straight, parallel. Antenna: c. 0.33× as long as body, reaching to posterior of pereonite 3 or half way along pereonite 4. Coxal plates: furrows moderately developed or strongly developed, on all coxae. Pereonite 1, coxa 2 posterior margins straight or slightly convex, or sinuate. Pleonite 4: posterodorsal margin strongly concave proximal to meeting posteroventral margin at apex; apex forming a narrow acute point. Pleotelson: broad, length 0.9× basal width; anterodorsal depression absent; anterolateral margins convex; posterolateral margins convex; apex produced into a small point; with 12–18 RS. Pereopod 2: propodus with 4 RS on palm. Pereopod 3: propodus with 5 RS on palm. Pereopod 7: basis narrow, width 0.44× 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, or completely absent. Penes: present. Pleopod 2 appendix masculina: extending beyond tip of endopod, 1.16–1.27× length of endopod; margins very slightly curved laterally; slender; apex not at angle to adjacent margins, bluntly rounded. Uropods: exopod subequal to endopod, 0.91× the length of the endopod.

Size. Males to 42 mm, females to 43 mm ( Brandt, 1988).

Remarks. Bruce (1986, p. 222) regarded Natatolana albinota to be a junior synonym of N. meridionalis . This synonymy was overlooked by Brandt (1988) as noted by Brusca et al. (1995, p. 80). Comparison of type specimens, of the two nominal taxa, supports the synonymy of Bruce (1986). Brandt (1988) used the absence of well-developed eyes in N. meridionalis to separate it from other Antarctic species of Natatolana , including N. albinota which was described as having small, light red eyes. Although the eyes of the holotype of N. meridionalis were described as absent ( Hodgson, 1910), they are actually present with indistinct ommatidia that lack pigment. In other characters N. meridionalis resembles N. albinota , the difference in the appearance of the eyes is probably due to initial and subsequent preservation of the material examined by Brandt (1988) because the type material of N. albinota examined in this study also has indistinct weakly pigmented eyes.

Brandt (1988) discussed the records by Schultz (1977) of Natatolana oculata from southern Argentina, intimating that they were of N. meridionalis (= N. albinota ). His illustrations, however, showing the posterior margins of the pleotelson and a relatively short appendix masculina, with a tapered apex, indicate he may have been describing another species, possibly N. pastorei . Schultz (1977, 1978) indicated that the record of N. meridionalis by Menzies (1962) from Chile may be N. oculata . Both of these records require verification by examination of the specimens.

Distribution and ecology. Antarctica: Discovery Bay, Davis Sea ( Vanhöffen, 1914); Enderby Land and Pzydz Bay ( Hale, 1952; Takeuchi et al., 2001); Banzare Coast; Lars Christensen Coast; Ross Sea ( Monod, 1931); Antarctic Peninsula; Weddell Sea; Scotia Sea. At depths of 35–670 m ( Brandt, 1988). The records of Menzies (1962) from southern Chile require verification. Scavenger.