Ceratothoa carinata ( Bianconi, 1869 )

Martin, Melissa B., Bruce, Niel L. & Nowak, Barbara F., 2015, Review of the fish-parasitic genus Ceratothoa Dana, 1852 (Crustacea: Isopoda: Cymothoidae) from Australia, with description of two new species, Zootaxa 3963 (3), pp. 251-294 : 266-271

Ceratothoa carinata ( Bianconi, 1869)

Cymothoa carinata Bianconi, 1869: 210 , pl. II, figs. 2 (a, b).— Gerstaecker, 1901: 258.

Cymothoa (Ceratothoa) carinata . — Hilgendorf, 1879: 846.

Ceratothoa carinata . —Schioedte & Meinert, 1883: 327, pl. XIII (Cym. XX) figs. 1–2.— Trilles, 1986: 623, tab. 1; 1994: 116; 2008: 23.— Kensley, 2001: 232.— Bruce, 2007: 278.—Trilles 2008: 23.— Martin, Bruce & Nowak, 2013: 397 , figs. 1–3.

Meinertia carinata .— Lanchester, 1902: 378.— Stebbing, 1910: 103.— Trilles, 1973b: 1244, 1256, pl. I, photos 5–7; 1972: 3, photos 1–4.

Codonophilus carinatus . — Nierstrasz, 1931: 132.

Ceratothoa curvicauda Nunomura, 2006: 36 , figs. 12–13.

Ceratothoa sp. — Saito, 2009: 7, photos 1, 2.

Type and type locality. The type, deposited at the Museum für Naturkunde, Germany ( ZMHB) (Schioedte & Meinert 1883) is highly likely to have been destroyed during World War II ( Hadfield 2012; Martin et al. 2013). A neotype was not designated by Martin et al. (2013) as the species is easily recognizable. Should a neotype be designated, it would ideally be from the type locality, Mozambique.

Remarks. Ceratothoa carinata , redescribed by Martin et al. (2013), can be identified by the wider than long pleotelson with a deeply concave posterior margin, a median longitudinal ridge along pereon dorsal surface, the concave dorsal surfaces on either side of pereon and pereopod 7 ischium and basis each with an enlarged carina. Ceratothoa trigonocephala ( Leach, 1818) differs from C. carinata by having a narrow pleonite 1, shorter pleotelson with a broadly convex posterior margin, a smooth and convex dorsum, and lacks an enlarged ischium on pereopod 7 (Martin et al. 2013).

Distribution. Southwest Pacific Ocean ( Lanchester 1902; Bruce 2007; Trilles 1973b, 1972; Martin et al. 2013); western Indian Ocean ( Bianconi 1869; Hilgendorf 1879; Schioedte & Meinert 1883; Stebbing 1910; Trilles 2008); northwest Pacific Ocean ( Nunomura 2006; Saito 2009).

Hosts. Carangidae ( Nunomura 2006; Saito 2009; Martin et al. 2013), Lutjanidae ( Trilles 1973b, 1972).

Ceratothoa globulus sp. nov. Figures 9–11

Material examined. Holotype: ♀ ovig. (24 mm), Lord Howe Island, 3°33.00’S, 159°05.00’E, 1981, host unknown, coll. Raphael (AM P9629).

Paratypes: ♀ ovig. (19 mm, dissected) (AM P92599), ♂ (12 mm) (AM P92598), same data as holotype.

Ovigerous female. Length 24 mm, width 13 mm.

Body ovoid, 1.8 times as long as greatest width, dorsal surface rough, medially dome-shaped, widest at pereonite 4 and pereonite 5, most narrow at pereonite 1, lateral margins convex. Cephalon 0.4 times longer than wide, visible from dorsal view, semi-circular. Frontal margin rounded to form blunt rostrum. Eyes oval with distinct margin, 0.2 times width of head. Pereonite 1 anterior margin slightly produced medially, anterolateral projections broad, reaching past eyes; posterior margins of pereonites 1–5 smooth, pereonites 6–7 concave. Coxae 2–4 posteroventral margins rounded; 5–7 posteroventral margins acute. Pleonite 1 similar length as pleonites 2–5, visible in dorsal view; pleonites posterior margin slightly concave and irregular; posterolateral margins of pleonite 2 forming acute point; pleonites 3–5 similar width. Pleotelson 0.6 times as long as anterior width, anterior margin trisinuate, dorsal surface with scratch-like marks, lateral margin weakly convex, posterior margin emarginate, without median point.

Antennula comprised of 6 articles; peduncle articles 1 and 2 distinct and articulated; article 2 0.8 times as long as article 1; article 3 0.3 times as long as combined lengths of articles 1 and 2, 0.6 times as long as wide; extending to middle of eye. Antenna comprised of 9 articles, peduncle article 3 1.7 times as long as article 2, 0.8 times as long as wide; article 4 1.2 times as long as wide; article 5 0.6 times as long as article 4, terminal article without setae, extending to posterior of pereonite 1. Labrum lateral margins concave, anterior margin rounded. Mandibular process present, ending with an acute incisor. Maxillula simple, with 4 terminal robust setae. Maxilla mesial lobe partly fused to lateral lobe; 3 recurved robust setae on mesial lobe; and 7 large recurved robust setae on lateral lobe. Maxilliped comprised of 3 articles, weakly segmented, article 3 with 3 recurved robust setae.

Pereopod 1 basis 1.9 times as long as greatest width; ischium 0.6 times as long as basis; merus proximal margin without bulbous protrusion; carpus with straight proximal margin; propodus 0.9 times as long as wide; dactylus stout, 1.7 times as long as propodus, 2.9 times as long as basal width. Pereopod 2 propodus 1.1 times as long as wide; dactylus 1.7 times as long as propodus. Pereopods 3 similar to pereopod 2, gradually increasing in size towards posterior, or all without robust or simple setae. Pereopod 6 basis 1.1 times as long as greatest width, ischium 0.8 times as long as basis, propodus 1.4 times as long as wide, dactylus 1.3 times as long as propodus. Pereopod 7 basis 0.9 times as long as greatest width; ischium 0.9 times as long as basis, with slight bulbous protrusion; merus proximal margin with slight bulbous protrusion, merus 0.3 times as long as ischium, 0.3 times as long as wide; carpus 0.2 times as long as ischium, without bulbous protrusion, 0.4 times as long as wide; propodus 0.7 times as long as ischium, 1.3 times as long as wide; dactylus stout, 1.4 times as long as propodus, 3.0 times as long as basal width.

Pleopods with slight depression on central dorsal surface of each pleopod ramus, exopod larger than endopod. Pleopod 1 exopod 1.1 times as long as wide, lateral margin weakly concave, distally narrowly rounded, medial margin weakly oblique, mesial margin strongly convex; peduncle 2.0 times as wide as long, without retinaculae. Pleopods 3–5 endopods proximal borders extending below exopod to peduncle.

Uropod longer than pleotelson, peduncle 0.7 times longer than rami, peduncle lateral margin without setae; rami extending beyond pleotelson, marginal setae absent, apices broadly rounded, 1.6 times as long as greatest width, lateral margin straight, mesial margin strongly convex. Exopod not extending to end of endopod, 6.5 times as long as greatest width, terminating without setae, mesial margin weakly convex.

Male. Male similar to females except for the following features: body subparallel, pleonites narrower than pereonite seven, pleotelson with convex posterior margin.

Colour. Pale brown in alcohol.

Size. Ovigerous females: 19 mm and 24 mm, male: 12 mm.

Etymology. This species is named for the globular-shaped body.

Remarks. Ceratothoa globulus sp. nov. can be recognised by its broad and ovate body shape (1.8 times as long as greatest width), broad anterolateral projections of pereonite 1 laterally encompassing the cephalon, eyes 0.2 times width of cephalon and 0.6 times longer than wide, pleotelson with a deeply concave posterior margin, scratch-like marks visible on the dorsal surface of the pleotelson and parts of the pleonites, concave mesial margin of pleopod 1 and broad carina on the basis of pereopod 7.

The most similar species to C. globulus is Ceratothoa marisrubri Trilles, Colorni & Golani, 1999 , known only from the Red Sea, with both species having an ovate body, pleonite 1 almost entirely concealed by pereonite 7, anterolateral projections of pereonite 1 extending to the mid-margin of the cephalon and a well-developed carina on pereopod 7 basis. Ceratothoa globulus is readily distinguished from C. marisrubri by the more rounded cephalon anterior margin; pereonite 1 with broad anterolateral projections (minute projections in C. marisrubri ); and uropodal rami extending beyond the pleotelson posterior margin (uropodal rami of C. marisrubri reaching posterior margin of pleotelson).

Distribution. Known only from Lord Howe Island.

Hosts. Not known.

Figures

FIGURE 9. Ceratothoa globulus sp. nov., ovigerous female holotype (24 mm; AM P 92629 A, C, D) and male paratype (12 mm; AM P 92598 B). A, dorsal view of female; B, dorsal view of male; C, dorsal view of female pleotelson; D, lateral view of female.

FIGURE 10. Ceratothoa globulus sp. nov., ovigerous female paratype (19 mm; AM P 92599). A, maxillula tip; B, mandible; C, maxilliped, with magnified view of article 3; D, maxilla, with magnified view of maxilla tip; E, antennula; F, antenna; G, uropod.

FIGURE 11. Ceratothoa globulus sp. nov., ovigerous female (19 mm; AM P 92599). A – D, pereopods 1, 2, 6, 7; E – I, pleopods 1 – 5 respectively.