Natatolana natalis (Menzies & George, 1972)

Keable, Stephen J., 2006, Taxonomic Revision of Natatolana (Crustacea: Isopoda: Cirolanidae), Records of the Australian Museum 58 (2), pp. 133-244 : 207

Natatolana natalis (Menzies & George, 1972)

Cirolana natalis Menzies & George, 1972: 24 , figs. 14–15. Natatolana natalis .– Bruce, 1981: 958.– 1986: 222.– Brusca et al.,

1995: 82.

Type material. Holotype: 3, 17 mm, USNM 121737 (examined). Type locality: off Peru, Peru-Chile Trench , 08°23'S 80°25'W, 2966– 2945 m, [ANTON BRUUN Sta. 161].

Diagnosis. Eyes: vestigial. Interocular furrow: moderately developed, distinct but not extending across the cephalon. Frontal lamina: lateral margins medially constricted. Antenna: c. 0.39× as long as body, reaching to posterior of pereonite 3. Coxal plates: furrows strongly developed, on all coxae. Pleonite 4: apex slightly rounded. Pleotelson: broad (original description states that the pleotelson is longer than wide but this does not appear to be measured using the basal width), length 0.89× basal width; anterodorsal depression absent; anterolateral margins almost straight and angling posteriorly toward the midline; posterolateral margins convex; apex not produced, lateral margins converging smoothly to a point; RS present (these setae appear to have been rubbed off this margin but there seem to be sockets indicating the presence of at least 10). Pereopod 2: propodus with 6 RS on palm. Pereopod 3: propodus with 4 RS on palm. Pereopod 7: basis narrow, width 0.48× length; distance between anterior margin and medial carina less than between posterior margin and medial carina; posterior margin with sparse setae on distal half. Penes: present. Pleopod 2 appendix masculina: extending subequal with tip of endopod, 1× length of endopod; margins very strongly curved laterally; broad; apex not at angle to adjacent margins, with lateral projection forming a Y shape with acute apex. Uropods: exopod slightly shorter than endopod, 0.86× the length of the endopod; lateral margin RS unknown (originally illustrated as absent, uropod exopods are now missing from the holotype).

Size. Adults to 17 mm.

Remarks. The holotype is the only specimen recorded of Natatolana natalis . The original illustrations and description differ markedly in several respects to the specimen registered as the holotype, although there is no strong reason to doubt that this is the specimen originally described. The original description of the appendix masculina indicates that it has two or three tubercules—this is an artefact, the margins are smooth. The original description of the pleotelson is misleading because it indicates a far more rounded apex and a lack of setae. Plumose setae and sockets are, however, apparent on the margins of the pleotelson, the sockets indicate the former presence of robust setae.

Natatolana natalis is extremely similar to N. imicola and N. rekohu but has a slightly different morphology of the appendix masculina—the apex is more acute and the notch adjacent to the apex is deeper so that an acute projection occurs proximal to the notch. Because the only specimen of N. natalis is in poor condition, further specimens from near the type locality are needed to fully characterize the species and to identify further differences to these species.

Distribution. Off Peru: Peru-Chile Trench. At depths of 2966– 2945 m.