Natatolana debrae, Keable, 2006

Keable, Stephen J., 2006, Taxonomic Revision of Natatolana (Crustacea: Isopoda: Cirolanidae), Records of the Australian Museum 58 (2), pp. 133-244 : 170-173

Natatolana debrae n.sp.

Figs. 14–16

Cirolana corpulenta .– Hale, 1925: 134 fig. 3 (part) [misidentification, not Natatolana corpulenta ( Hale, 1925) ].

Type material. HOLOTYPE: 3, 9 mm, AM P31604 . PARATYPES: ♀, 16 mm, ♀, 6.5 mm, manca, 6 mm, AM P47245. Type locality: Henley Beach , Adelaide, South Australia, Australia, 38°56'S 138°31'E, low tide sand bar 20 m off shore, fine sand and shell, [J.K. Lowry, 29 Dec. 1976] .

Additional material. South Australia, paratype female of Natatolana corpulenta, SAMA C 277, Brighton [presumably Gulf St Vincent, 35°01'S 138°31'E], from body cavity of Heterodontus phillipi, H. Collyer .

Diagnosis. Interocular furrow: absent. Frontal lamina: lateral margins medially constricted. Antenna: c. 0.46× as long as body, reaching to posterior of pereonite 4. Coxal plates: furrows moderately developed, on all coxae. Pereonite 1, coxa 2 posterior margins sinuate, posteroventral corners developed into weak coxal points. Pleonite 4: posterodorsal margin strongly concave proximal to meeting posteroventral margin at apex; apex forming a broad acute point. Pleotelson: broad, length 0.9× basal width; anterodorsal depression present; anterolateral margins convex; posterolateral margins concave; apex produced into a large point; with 10 RS. Pereopods 1–6: males with conspicuous elongated RS subequal to propodus on the merus of pereopods 1–3 and extending from the carpus to dactylus of pereopods 4–6. Pereopods 2–3: propodus without RS on palm. Pereopod 7: basis narrow, width 0.42× length; distance between anterior margin and medial carina less than between posterior margin and medial carina; posterior margin with setae along entire length. Penes: present. Pleopod 2 appendix masculina: extending beyond tip of endopod, 1.05× length of endopod; margins sinuate; slender; apex not at angle to adjacent margins, bluntly rounded. Uropods: exopod subequal to endopod, 0.93× the length of the endopod; lateral margin with RS.

Additional descriptive characters. Based on holotype. Body: length c. 2.11× width. Colour cream-yellow in alcohol. Chromatophores absent. Eyes: with 5 ommatidia in horizontal diameter; with 8 ommatidia in vertical diameter; ovate; colour brown in alcohol. Frontal lamina: length c. 3.8× basal width; apex expanded, anterior margin angled. Antennule: peduncular article 1 longer than article 2; article 2 with 1 large pappose seta; article 3 short, subequal to article 1. Flagellum 10-articulate. Antenna: peduncular article 4 with 5 SS medially on posterolateral margin, 4 SS on distal margin, 3 SS and 1 penicillate seta at anterodistal angle; article 5 with 2 conspicuous pappose setae and 1 SS at posterodistal angle, 3 SS on distal margin and 2 SS at anterodistal angle. Flagellum 20-articulate. Mandible: setal row with 16 RS. Maxillule: medial lobe with 3 large robust pappose setae and 2 SS; lateral lobe with 12 RS on distal surface. Maxilla: lateral lobe with 4 SS; medial lobe with 6 SS and 9 PS; middle lobe with 11 SS. Maxilliped: endite with 2 coupling hooks, and 7 PS. Pereon: ornamentation consists of 1 strongly developed furrow on lateral margin of pereonite 1; pereonite 1 longest, 4–6 subequal and longer than 2–3 and 7 which are subequal. Coxae: coxal points weakly developed on posteroventral corners of pereonite 1 and all coxae. Pleonite 2: dorsal posterolateral margin subequal with ventral posterolateral margin. Pereopod 7: basis anterior margin slightly convex; medial carina with PS along entire length; posterior margin convex, SS present. Ischium anterior margin with SS; posterior margin with 1 RS (and 2 submarginally), PS present. Merus anterior margin with SS; posterior margin with 1 RS (submarginal), SS present. Carpus anterior margin with 1 SS; posterior margin with 3 RS (and 1 submarginally), SS absent. Propodus subequal to carpus; posterior margin with 3 RS, SS absent. Penes: forming well separated flattened lobes. Pleopod 2 appendix masculina: arising basally. Pleopods 1–5: exopod suture strongly developed on pleopods 3–5; endopod PS on most of margins of pleopods 1–4, only a few setae on pleopod 5. Uropods: endopod triangular; medial margin slightly convex and obtusely angled proximal to peduncle, with 5 RS, PS along entire length; apex with 2 RS; lateral margin slightly convex, with 4 RS and 1 penicillate seta, PS along entire length. Exopod medial margin convex, with 3 RS, PS along entire length; apex acute, with 2 RS; lateral margin convex, with 8 RS, PS along entire length.

Variation. The right uropod endopod of the holotype has two robust seta on the apex and four robust setae on the medial margin.

Sexual dimorphism. Females lack the conspicuously elongated robust setae present on the merus of pereopods 1–3 and the carpus of pereopods 4–6 of adult males.

Size. Adults to c. 16 mm.

Etymology. Named after my wife Debra, in recognition of the help she has given me during this and other projects.

Remarks. The specimen of Natatolana corpulenta recorded by Hale (1925) from the body cavity of a Port Jackson shark collected by H. Collyer at Brighton is registered in SAMA collections (C277) as a paratype of N. corpulenta but is actually a specimen of N. debrae .

Natatolana debrae is most similar to N. corpulenta , N. femina n.sp. and N. sinuosa n.sp. Natatolana debrae differs from N. corpulenta in lacking an acute produced tooth on the anteroventral corner of coxa 2; in having sinuate posterior margins developed into weak coxal points on the posteroventral corners of pereonite 1 and coxae 2–3; and in having longer antennae. Natatolana sinuosa and N. femina can be readily distinguished from N. debrae by the development of coxal points on the posteroventral corners of pereonite 1 and coxa 2–3 (much stronger in N. sinuosa and rounded in N. femina ).

Distribution and ecology. Australia: known only from Gulf St Vincent, South Australia. Apparently intertidal and subtidal. Scavenger (specimens have been recorded from the body cavity of a Port Jackson shark).

Figures

Fig. 14. Natatolana debrae n.sp., holotype. Scales = 0.5 mm, except MX1, MX2 = 0.2 mm.

Fig. 15. Natatolana debrae n.sp., holotype, except; female = paratype female, AM P47245. Scales = 0.5 mm.

Fig. 16. Natatolana debrae n.sp., holotype. Scales = 0.5 mm, except MX1, MX2 = 0.2 mm.