Natatolana imicola ( Dollfus, 1903 )

Keable, Stephen J., 2006, Taxonomic Revision of Natatolana (Crustacea: Isopoda: Cirolanidae), Records of the Australian Museum 58 (2), pp. 133-244 : 193

Natatolana imicola ( Dollfus, 1903)

Synonymy in Keable & Bruce, 1997: 688, figs. 13–15.

Type material of N. imicola . Syntypes: all IOM; unknown number of specimens, Station 209; 733, 11♀♀, 36 0257, Station 228 (cited as 238); ♀, 36 0252, Station 553; 233 (mature), male (immature), 3♀♀, 36 0256, Station 846. All examined except those from station 209. Type locality of N. imicola: Atlantique , 39°18.08'N 33°32.25'W, 1372 m, [ Campagnes de l’Hirondelle et de la Princesse Alice Station 209]; Atlantique, 38°22.38'N 30°42.78'W, 1924 m, [ Campagnes de l’Hirondelle et de la Princesse Alice Station 228 (cited as 238)]; Atlantique, 37°42.67'N 27°25.5'W, 1385 m, [ Campagnes de l’Hirondelle et de la Princesse Alice Station 553]; Atlantique, 30°01.5'N 27°46'W, 1638 m, [Campagnes de l’Hirondelle et de la Princesse Alice Station 846] .

Type material of N. schmidti . Syntypes: ovigerous ♀ 13.5 mm, male 11 mm, manca 7 mm, ZMUC CRU150, Ingolf stn 25; ♀, 12.5 mm, manca 4.75 mm, ZMUC CRU151, Thor stn 99. All examined. Type locality of N. schmidti: Davis Strait , 63°30'N 54°25'W, 1064 m, [Danish Ingolf Expedition Station 25]; west of the most southern of the Färoe Islands, 61°15'N 9°35'W, 872– 970 m, [ Thor stn 99].

Material examined. Listed by Keable & Bruce (1997).

Diagnosis. Eyes: vestigial, or absent (there is a very slight indication of ommatidia, possibly these become less distinct with preservation). Interocular furrow: moderately developed, distinct but not extending across the cephalon. Frontal lamina: lateral margins straight, narrowing posteriorly. Antenna: c. 0.37× as long as body, reaching to between approximately half way along pereonite 3 and posterior of pereonite 4. Coxal plates: furrows moderately developed, on all coxae. Pleonite 4: apex slightly rounded. Pleotelson: broad, length 0.9× basal width; anterodorsal depression absent (although there is a slight depression it is not equivalent to the distinct and abrupt depression found in species such as N. pellucida ); anterolateral margins convex; posterolateral margins convex; apex not produced, lateral margins converging smoothly to a point; with 8–12 RS. Pereopod 2: propodus with 2 RS on palm. Pereopod 3: ischium anterodistal angle produced, but not as produced as on pereopods 1 and 2, similar to pereopod 4. Propodus with 2 RS on palm. Pereopod 7: basis narrow, width 0.4× length; distance between anterior margin and medial carina less than between posterior margin and medial carina; posterior margin with setae completely absent along entire length. 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, club shaped with a lateral notch. Uropods: exopod slightly shorter than endopod, 0.82× the length of the endopod.

Variation. The development of penes and the appendix masculina varies in male specimens, with the appendix masculina relatively straight and the vasa deferentia opening flush to the surface of the sternite. This variation does not appear to be correlated with size of the individual although it probably represents changes associated with maturity (Keable & Bruce, 1997).

Size. Smallest manca 4.75 mm and largest specimen (ovigerous female) 13.5 mm.

Remarks. Natatolana imicola was originally described as a subspecies of N. neglecta, Keable & Bruce (1997) redescribed it, elevated it to species rank and synonymized N. schmidti with it.

Characters that distinguish N. imicola from similar species are noted in the remarks for N. rekohu .

Distribution. northeastern Atlantic, Davis Strait and Färoe Islands, south to 30°N, westwards to 54°W. At depths of 872–2450 m.