Natatolana caeca

Natatolana caeca (Dollfus, 1903)

Synonymy in Keable & Bruce, 1997: 671, figs. 5–7.

Type material. Syntypes: all IOM; 138 specimens, 36 0188, Station 318; 2 specimens, 36 0189, Station 506; 5 specimens, 36 0184, Station 769; 5 specimens, 36 0185, Station 1048; 2 specimens, 36 0186, Station 1.100. All examined. Type locality: all Méditerranée, (Campagnes de l’Hirondelle et de la Princesse Alice, 38°37'N 13°5'E, 1210 m, [Station 318]; 43°36'N 5°17'E, 1503 m, [Station 506]; 43°28'N 5°25'E, 2368 m, [Station 769]; 41°47'N 4°54'E, 2276 m, [Station 1048]; 43°02'N 6°22'E, 2500 m, [Station 1.100]).

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

Diagnosis. Eyes: absent. Interocular furrow: well developed, forming a ridge that extends across the cephalon; smoothly convex. Frontal lamina: lateral margins straight, narrowing anteriorly. Antenna: c. 0.25× as long as body, reaching to posterior of pereonite 2. Coxal plates: furrows completely absent on all coxae. Pleonite 4: apex rounded. Pleotelson: broad, length 0.98× basal width; anterodorsal depression absent; anterolateral margins convex; posterolateral margins convex; apex not produced, lateral margins converging smoothly to a point; with 8 RS. Pereopods 1–6: males with RS on the merus of pereopods 1–3, and carpus of pereopods 4–6, shorter than the propodus. 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 0.46× 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: absent. Pleopod 2 appendix masculina: extending beyond tip of endopod, 1.07× length of endopod; margins very slightly 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. Adults to 15 mm.

Remarks. Keable & Bruce (1997) redescribe Natatolana caeca and discuss its identification and character variation. The reduced anterodistal angle of the ischium of pereopod 3 and absence of eyes are particularly useful characters for identifying this species.

Distribution. Material recorded by Keable & Bruce (1997) and the records of Hansen (1890) and Monod (1930) are from the northeast Atlantic between c. 18° to 50°N and 6° to 17°W. Only the type material has been recorded from the Mediterranean Sea. Most records are from the vicinity of about 1000 m depth, but the type specimens come from a maximum depth of 2500 m and a reliable minimum depth of 486 m is recorded by Keable & Bruce (1997).