Natatolana tenuistylis ( Miers, 1884 )

Keable, Stephen J., 2006, Taxonomic Revision of Natatolana (Crustacea: Isopoda: Cirolanidae), Records of the Australian Museum 58 (2), pp. 133-244 : 228-229

Natatolana tenuistylis ( Miers, 1884)

Cirolana tenuistylis Miers, 1884: 303 , pl. 33B.– Hansen, 1890: 356.– Hale, 1925: 136, fig. 4.– Nierstrasz, 1931: 157.– Holdich et al., 1981: 572, fig. 7.– Ellis, 1981: 123.

Natatolana tenuistylis .– Bruce, 1981: 958.– 1986: 103, figs. 70, 71.– Keable, 1995: 43.– Brusca et al., 1995: 82.– Bruce et al., 2002: 152.

Type material. Lectotype designated by Holdich et al. (1981): 13.9 mm, BMNH 1882:7 ( Bruce (1986) has 1882:1). Paralectotypes: 2, BMNH 1882:53 ( Ellis (1981) has 1856:33 for the syntypes). Holdich et al. (1981) question the conspecific status of these specimens with the lectotype. Bruce (1986) regards one paralectotype as Natatolana vieta and the other as too badly damaged to be identified but most likely to be N. matong . None examined. Type locality: Prince of Wales Channel, Queensland, Australia [10°32'S 142°10'E].

Material examined. Listed by Keable (1997).

Diagnosis. Interocular furrow: well developed, extending across the cephalon (not illustrated by Holdich et al. (1981) but present according to Bruce (1986) and in material examined); smoothly convex. Frontal lamina: lateral margins medially constricted. Antenna: c. 0.6× as long as body, reaching to posterior of pereonite 5. Coxal plates: furrows moderately developed, on all coxae. Pleonite 2: ventral posterolateral margin acute, formed into long curved process. Pleonite 4: apex broadly rounded dorsally, but meeting convex ventral margin at a point. Pleotelson: broad, length 0.94× basal width; anterodorsal depression absent; anterolateral margins convex; posterolateral margins convex; apex not produced, lateral margins converging smoothly to a point; with 8–12 RS. Pereopods 2–3: propodus without RS on palm. Pereopod 7: basis broad, width 0.6× length; distance between anterior margin and medial carina greater than between posterior margin and medial carina; posterior margin with setae on proximal half. Penes: absent. Pleopod 2 appendix masculina: just shorter than endopod; margins very slightly curved laterally; slender; apex not at angle to adjacent margins, with a distinct acute projection. Uropods: exopod slightly shorter than endopod, 0.88× the length of the endopod.

Variation. The lectotype is damaged and has only four robust setae present on one side of the pleotelson apex, Keable (1997) discusses the variation in the total number of robust setae occurring on the pleotelson.

Size. Adults to c. 17.5 mm.

Remarks. Characters that are particularly useful for identifying Natatolana tenuistylis are: the complete interocular furrow; the ventral posterolateral margin of pleonite 2 (produced and formed into an acute process); the acute projection on the apex of the appendix masculina; the long antennae, reaching to the posterior of pereonite 5 (c. 0.6× the length of the body); and the unusual shape of the posterolateral margin of pleonite 4 (rounded dorsally and meeting the ventral margin at a point) ( Bruce, 1986; Keable, 1997).

Distribution and ecology. Australia: northern Western Australia, Northern Territory, northern Queensland. Papua New Guinea: Daru. At depths of 3– 62 m. Scavenger.