Expanathura monile, Shiraki & Shimomura & Kakui, 2021

Shiraki, Shoki, Shimomura, Michitaka & Kakui, Keiichi, 2021, A new species of Expanathura (Crustacea: Isopoda: Anthuroidea) from Iriomote Island, Japan, with a note on male polymorphism, Zootaxa 5047 (3), pp. 377-390 : 378-379

Expanathura monile sp. nov.

[New Japanese name: Kubikazari-uminanafushi]

( Figs 2–8 )

Diagnosis. Head with dorsal V-shaped band of brown pigmentation (in females). Telson oval, 1.56–1.63 (females) or 1.50–1.63 (males) times longer than width, with lateral setae subequal in length, all short. Antennular flagellum with three or four articles in females, seven articles in males. Antennal peduncular article 2 with outer triangular projection; flagellum with three or four articles. Uropodal endopod longer than wide; exopod very broad, with acute-triangular projection (apex angle about 90° in females; about 70° in males).

Etymology. The specific name is a singular noun in the nominative case, from the Latin monile (necklace), referring to the V-shaped band on the head.

Material examined. Holotype: SMBL-V0629 (14 slides and 1 vial), female with fully developed marsupium; coral rubble, 14 m depth, north reef of Sabasaki (24˚21.88′N, 123˚42.79′E), Iriomote Island, Okinawa, southwestern Japan; collected by MS, 10 August 2016 . Allotype: SMBL-V0630 (7 slides and 1 vial), male, collection data as for holotype . Paratypes: SMBL-V0631 (13 slides and 1 vial), one female with fully developed marsupium; SMBL- V0632 (5 slides and 1 vial), one male ; SMBL-V0633 (10 slides and 1 vial) , SMBL-V0634 (10 slides and 1 vial) , SMBL-V0635 (10 slides and 1 vial), and SMBL-V0636 (9 slides and 1 vial), four females lacking oostegites; collection data for all paratypes as for holotype.

Measurements (body length, body width, head length, eye length, eye width; in mm): SMBL-V0629 (2.33, 0.27, 0.26, 0.03, 0.02); SMBL-V0630 (2.15, 0.23, 0.24, 0.12, 0.08); SMBL-V0631 (2.18, 0.24, 0.26, 0.04, 0.02); SMBL-V0632 (2.21, 0.23, 0.23, 0.08, 0.06); SMBL-V0633 (2.20, 0.23, 0.28, 0.03, 0.02); SMBL-V0634 (2.05, 0.24, 0.23, 0.03, 0.02); SMBL-V0635 (1.50, 0.19, 0.20, 0.03, 0.01); SMBL-V0636 (1.66, 0.22, 0.17, 0.03, 0.02).

Figures

FIGURE 2. Expanathura monile sp. nov. Photomicrographs of fixed specimens:A, B, G, paratype (female; SMBL-V0631); C, D, I, allotype (male); E, F, J, paratype (male); H, holotype (female).A, C, E, body, dorsal view; B, D, F, body, lateral view; G–J, head, dorsal view. Scale bars: 1 mm (A–F); 100 µm (G–J).

FIGURE 3. Expanathura monile sp. nov. A–D, I, holotype (female); E–H, J, allotype (male); K–M, paratype (male). A–H, K, dorsal view; I, J, L, M, lateral view. A, E, K, head and pereonite 1 (most appendages in K omitted); B, F, pereonites 2 and 3; C, G, pereonites 4–6; D, H, pereonite 7 and pleon; I, J, body; L, head (appendages omitted); M, pleon. Scales: 500 µm (A–H, K); 1 mm (I, J, L, M).

FIGURE 4. Expanathura monile sp. nov., female. A–C, G, holotype; D–F, paratype (SMBL-V0631). A, left antennula; B, left antenna; C, flagellum of left antenna; D, left mandible; E, right mandible; F, left maxilla; G, left maxilliped. Scale bars: 100 µm (A, B, D–G); 50 µm (C).

FIGURE 5. Expanathura monile sp. nov., holotype female. A, C–G, right pereopods 1 and 3–7; B, left pereopod 2; g1, threepronged spiniform setae on pereopod 7 propodus. Scale bar: 100 µm (A–G); 50 µm (g1).

FIGURE 6. Expanathura monile sp. nov., female.A, C–G, holotype; B, H, I, paratype (SMBL-V0631).A, C, D, right pleopods 1, 3 and 4; B, E, left pleopods 2 and 5; F, right uropodal endopod, ventral view; G, left uropodal endopod, lateral view (setae omitted); H, right uropodal exopod; I, telson. Scale bars: 100 µm.

FIGURE 7. Expanathura monile sp. nov., allotype male.A, right antennula (most aesthetascs omitted); B, right antenna; C, left maxilliped; D–F, right pereopods 1, 2 and 7. Scale bars: 100 µm.

FIGURE 8. Expanathura monile sp. nov. A–D, allotype male; E, F, holotype female.A, B, right pleopods 1 and 2; C, left uropodal exopod; D, telson; E–F, drawing and photomicrograph of right pleopod 2. Arrowheads, appendix-masculina-like projection. Scale bars: 100 µm.