Redescription of the monotypic genus Cinusa Schioedte and Meinert, 1884 (Isopoda, Cymothoidae), a buccal-cavity isopod from South Africa Author Hadfield, Kerry A. Author Bruce, Niel L. Author Smit, Nico J. text Zootaxa 2010 2437 51 68 journal article 10.5281/zenodo.194854 745169e6-7022-41cd-92c6-9016863e1baa 1175-5326 194854 Genus Cinusa Schioedte and Meinert, 1884 Cinusa Schioedte and Meinert, 1884 : 312 .– Stebbing, 1910 : 425 .– Nierstrasz, 1931 : 138 .– Barnard, 1940 : 491 .– Kensley, 1978: 78. Diagnosis. Body oval, asymmetrical. Cephalon small deeply immersed into pereonite 1, posterior margin not trilobed. Eyes present, distinct. Pereonite 1 short, lateral margins convex, wider than two thirds the length of pereonite 2; pereonites 4–7 decreasing in width and length posteriorly, widest at pereonites 3 and 4; pereonite 7 posterior margin deeply concave. Pleonite 1 distinctly narrower that pleonite 2 (0.7 as wide as 2; 0.6 as wide as pleonite 5); pleonite lateral margins acute. Antennae bases close-set, almost contiguous; antennule composed of 7 articles, antenna with 10 articles, antennule slightly stouter than antenna. Mandible palp articles not expanded, articles 2 and 3 with setae. Maxilliped palp article 3 with spines. Pereopod 1–7 basis with carina; pereopods 1–3 merus with ventral lobe. Pleopods rami all lamellar, not setose, simple, with slight protrusion on ventral surface of each ramus. Broodpouch without posterior pocket. Uropods more than half the length of pleotelson, rami of similar lengths, apices rounded. Type species: Cinusa tetrodontis Schioedte and Meinert, 1884 , by monotypy. Types held in the Zoological Museum, University of Copenhagen. FIGURE 1. Cinusa tetrodontis , female lectotype (25.5 mm) (ZMUC CRU-20224). A. Full length dorsal view, B. Antennule, C. Antenna, D. Uropod, E. Lateral view of body. Scale bar: 1 mm. FIGURE 2. Cinusa tetrodontis , female lectotype (25.5 mm) (ZMUC CRU-20224). A. Ventral view of cephalon, B. Ventral view of oostegites, C. Dorsal view of cephalosome, D. Ventral view of pleotelson, E. Dorsal view of pleon and pleotelson. Scale bar: 1 mm. FIGURE 3. Cinusa tetrodontis , female lectotype (25.5 mm) (ZMUC CRU-20224). A. Pereopod 1, B. Pereopod 2, C. Pereopod 3, D. Pereopod 4, E. Pereopod 5, F. Pereopod 6, G. Pereopod 7. Scale bar: 2 mm. FIGURE 4. Cinusa tetrodontis , female, fresh material (19 mm) (SAMC A46771). A. Full length dorsal view, B. Ventral view of oostegites, C. Dorsal view of pleotelson, D. Lateral view of body. Scale bar: 2 mm. FIGURE 5. Cinusa tetrodontis , female, fresh material (19 mm) (SAMC A46771). A. Right mandible, B. Right maxillule, C. Antennule, D. Antenna, E. Uropod, F. Right maxilla, G. Right maxilliped. Scale bar: 0.5 mm. FIGURE 6. Cinusa tetrodontis , female, fresh material (19 mm) (SAMC A46771). A. Pereopod 1, B. Pereopod 2, C. Pereopod 3, D. Pereopod 4, E. Pereopod 5, F. Pereopod 6, G. Pereopod 7. Scale bar: 2 mm. FIGURE 7. Cinusa tetrodontis , female, fresh material (19 mm) (SAMC A46771). A. Pleopod 1, dorsal, B. Pleopod 2, dorsal, C. Pleopod 3, dorsal, D. Pleopod 4, dorsal, E. Pleopod 5, dorsal. F. Pleopod 1, ventral, G. Pleopod 2, ventral, H. Pleopod 3, ventral, I. Pleopod 4, ventral, J. Pleopod 5, ventral, Scale bar: 1 mm. FIGURE 8. Cinusa tetrodontis , male paralectotype (17.5 mm) (ZMUC CRU-9140). A. Full length dorsal view, B. Lateral view of body. Scale bar: 2 mm. Remarks. The original Latin diagnosis given by Schioedte and Meinert (1884) , by today’s standards contains little more than family-level characters. A new diagnosis is given here, comparable to that now available for other related genera. Cinusa is best identified by the rounded anterolateral margins of pereonite 1 that does not project anteriorly, maxilliped palp article 3 with spines and pleopod peduncles without retinaculae. The body is widest anteriorly, at pereonite 3. Similar genera are Ceratothoa Dana, 1852 and Cymothoa Fabricius, 1793 which are also found inside the buccal cavity of their fish hosts but can be separated by Cymothoa and Ceratothoa having anterolateral margins of pereonite 1 which are produced around the cephalon while Cinusa has rounded margins and is less produced. Ceratothoa species also have contiguous antennal bases, Cymothoa species have well-separated bases and Cinusa has almost contiguous bases but still separated. Both Ceratothoa and Cymothoa are widest around pereonites 5–6 whereas Cinusa is widest around pereonites 3–4. FIGURE 9. Cinusa tetrodontis , male, fresh material (12 mm) (SAMC A46772). A. Full length dorsal view, B. Dorsal view of uropod, C. Dorsal view of pleotelson, D. Lateral view of body. Scale bar: 1 mm. FIGURE 10. Cinusa tetrodontis , male, fresh material (12 mm) (SAMC A46772). A. Left maxillule, B. Left maxilliped, C. Antennule, D. Antenna, E. Left mandible, F. Left maxilla. Scale bar: 1 mm. FIGURE 11. Cinusa tetrodontis , male, fresh material (12 mm) (SAMC A46772). A. Pereopod 1, B. Pereopod 2, C. Pereopod 3, D. Pereopod 4, E. Pereopod 5, F. Pereopod 6, G. Pereopod 7. Scale bar: 1 mm. FIGURE 12. Cinusa tetrodontis , male, fresh material (12 mm) (SAMC A46772). A. Pleopod 1, dorsal, B. Pleopod 2, dorsal, C. Pleopod 3, dorsal, D. Pleopod 4, dorsal, E. Pleopod 5, dorsal. F. Pleopod 1, ventral, G. Pleopod 2, ventral, H. Pleopod 3, ventral, I. Pleopod 4, ventral, J. Pleopod 5, ventral, Scale bar: 1 mm. Distribution. The genus is known from the Indian Ocean coast of South Africa , from Cape of Good Hope to Port Elizabeth; Schioedte & Meinert (1884) cited the genus as occurring in the eastern Indian Ocean while Nierstrasz (1931) cited the Pacific Ocean; we regard these records as unconfirmed and doubtful.