Cymothoa curta Schioedte & Meinert, 1884

Martin, Melissa B., Bruce, Niel L. & Nowak, Barbara F., 2016, Review of the fish-parasitic genus Cymothoa Fabricius, 1793 (Crustacea: Isopoda: Cymothoidae) from Australia, Zootaxa 4119 (1), pp. 1-72 : 57-63

Cymothoa curta Schioedte & Meinert, 1884

Figures 39–43

Cymothoa curta Schioedte & Meinert, 1884: 228 , tab. VI (Cym. XXIV) figs. 3–6.— Trilles, 1994: 139.— Trilles & Bariche, 2006: 228.

Excluded

Cymothoa curta .— Avdeev, 1978b: 282; 1982a: 65. — Bruce, Lew Ton & Poore, 2002: 175 [= Cymothoa sp.].

Material examined. Lectotype (here designated): 1 ovig. ♀ (14 mm), locality unknown, from largescale foureyes Anableps anableps ( Linnaeus, 1758) (previously Anableps tetrophthalmi ), ( NHMW 6142).

Paralectotype (here designated): 1 immature ♂ (7 mm), same data as lectotype ( NHMW 25653).

Brazilian material: 3 ovig. ♀ [14 mm (MTQ W34285), 15 mm (MTQ W34286), 19 mm (MTQ W34288)], 1 immature ♂ [7 mm (MTQ W34288)], lagoon, Ajuruteua, Bragança, Pará, 0.806782°S, 46.632843°W, 8 December 2012, from four-eyed fish Anableps microlepis Müller & Troschel, 1844 , coll. Han Xiao and Jeferson Carneiro.

1 ovig. ♀ (17 mm), 1 immature ♂ (9 mm), Raposa Beach, São Luiz, Maranhão, 2.454693°S, 44.080582°W, 27 October 2012, from four-eyed fish Anableps microlepis , coll. Han Xiao and Jeferson Carneiro (MTQ W34284).

1 ovig. ♀ (17 mm), 1 immature ♂ (7 mm), Salinópolis, Pará, 0.6059535°S, 47.366180°W, 20 October 2012, from four-eyed fish Anableps microlepis coll. Han Xiao and Jeferson Carneiro (MTQ W34283).

Ovigerous female Length 14 mm width 7 mm (lectotype).

Body ovoid, 1.8 times as long as greatest width, dorsal surface smooth, widest at pereonite 5, most narrow at pereonite 1, lateral margins moderately convex. Cephalon 0.2 times longer than wide, visible from dorsal view, semi-circular. Frontal margin rounded to form blunt rostrum. Eyes partially visible. Pereonite 1 anterior margin linear, anterolateral margins minute; pereonites 1–5 posterior margins smooth and linear, progressively wider; pereonites 2–6 subequal in length. Coxae 2–4 posteroventral margins rounded, 4–7 narrowly produced points. Pleonites 1–4 subequal in length and width, visible in dorsal view; pleonites 2–4 posterior margin bisinuate; pleonite 5 trisinuate. Pleotelson 0.4 times as long as anterior width, lateral margin weakly convex, posterior margin rounded.

Antennula comprised of 8 articles; peduncle articles 1 and 2 distinct; article 2 0.9 times as long as article 1; article 3 0.3 times as long as combined lengths of articles 1 and 2, 1.0 times as long as wide; extending to middle of eye. Antenna comprised of 9 articles, peduncle article 3 0.8 times as long as article 2, 1.0 times as long as wide; article 4 1.1 times as long as wide; article 5 1.0 times as long as article 4, terminal article without setae, extending to posterior of pereonite 1. Labrum lateral margins convex, anterior margin rounded.

Pereopod 1 basis 1.7 times as long as greatest width, superior proximal margin smooth, without raised carina; ischium 0.7 times as long as basis; merus proximal margin without bulbous protrusion; carpus with straight proximal margin; propodus 1.1 times as long as wide; dactylus slender, 1.7 times as long as propodus, 2.4 times as long as basal width. Pereopod 2 basis 1.7 times as long as greatest width, superior proximal margin smooth, without raised carina; propodus 1.2 times as long as wide; dactylus 1.5 times as long as propodus. Pereopods 3–5 similar to pereopod 2, gradually increasing in size, without robust or simple setae. Pereopod 6 basis 1.0 times as long as greatest width, superior proximal margin smooth, with moderately raised carina; ischium 1.3 times as long as basis, propodus 1.0 times as long as wide, dactylus 1.8 times as long as propodus. Pereopod 7 basis 1.1 times as long as greatest width, superior proximal margin smooth, with raised carina; ischium 0.7 times as long as basis, with bulbous protrusion; merus proximal margin without bulbous protrusion, merus 0.3 times as long as ischium, 0.4 times as long as wide; carpus 0.2 times as long as ischium, without bulbous protrusion, 0.4 times as long as wide; propodus 0.5 times as long as ischium, 1.2 times as long as wide; dactylus slender, 1.7 times as long as propodus, 2.4 times as long as basal width.

Uropod not reaching posterior margin of pleotelson, peduncle 0.8 times as long as exopod, peduncle lateral margin without setae; marginal setae absent, apices broadly rounded, 1.6 times as long as greatest width, lateral margin straight, mesial margin strongly convex. Exopod extending past endopod, 7.0 times as long as greatest width, mesial margin weakly convex.

Male. Length 7 mm, width 3 mm (paralectotype).

Body subtriangular, 2.1 times as long as greatest width, dorsal surface smooth, widest at pereonite 6. Cephalon 0.6 times longer than wide, visible from dorsal view, subtruncate, not deeply immersed in pereonite 1. Eyes partially visible. Pereonite 1 anterolateral minute, posterior margins of pereonites 6 and 7 not deeply arched. Coxae 2–4 anteroventral and posteroventral margins rounded. Pleon not overlapped by pereonite 7; pleonites subequal in width, posterior margin not trisinuate. Pleotelson subtruncate. Antennula comprised of 8 articles.

Pereopod 1 basis 1.5 times as long as greatest width; ischium 0.5 times as long as basis; merus proximal margin without bulbous protrusion; carpus with straight proximal margin; propodus 1.3 times as long as wide; dactylus 2.3 times as long as propodus. Pereopods 2–7 similar to pereopod 1, moderately bigger in size, pereopods 6 and 7 basis superior proximal margin without raised carinae. Uropod exopod and endopod apices broadly rounded.

Colour. Female and male type appearing yellow–tan. Brazilian female and male specimens with blackish grey colouration.

Size. Ovigerous females: 14–17 mm; males: 7–9 mm.

Remarks. Cymothoa curta has a stout body (1.8 times longer than wide); cephalon rounded; pereonite 1 anterolateral margin minute, and not extending anteriorly beyond half of cephalon length; pereonites 1–4 subequal in length; pleonites 2–4 posterior margin bisinuate; pleonite 5 trisinuate; pereopod 7 basis with raised carina and uropods which do not extend past the pleotelson posterior margin. The male paralectotype differs from the lectotype in having a subtriangular body morphology, cephalon dorsally more visible, pleon not overlapped by pereonite 7, anterolateral and posterolateral margins of coxae 2–7 smooth and linear, and pereopod 7 basis without a sharp carina.

The Brazilian female specimens are similar to the lectotype in the rounded cephalon, pereonites 1–4 subequal in length; pleonites 2–4 posterior margin bisinuate; and uropods which do not extend past the pleotelson posterior margin. The Brazilian specimens differ from the lectotype in the moderately subtruncate pleotelson posterior margin, and the pleon partially overlapped by pereonite 7. Pleopods of the Brazilian female specimens have the exopods 1–5 similar size to endopod, depression on the central dorsal surface of pleopods 2–4; pleopod 5 endopod has large fleshy folds present; endopods 2–5 lateral margin strongly convex, distally broadly round, medial margin oblique, mesial margin strongly convex; and peduncle lobes from pleopods 1–5 present and becoming progressively larger. The Brazilian males differ from the paralectotype male in the more subparallel body morphology.

Schioedte & Meinert (1884) identified the type host, Anableps anableps , without mention of the type locality. Anableps anableps is a South American fish that does not occur in the Indo-Pacific ( Froese & Pauly 2015). The present material of C. curta from Brazilian Anableps microlepis verifies that the host species does not occur in Australia. Avdeev (1978b) apparently found C. curta in the buccal cavity of sailfin velifer Velifer hypselopterus Bleeker, 1879 (family Veliferidae ) from the Arafura Sea. Velifer hypselopterus is known to occur in the Indo- Pacific region ( Froese & Pauly 2015). It is highly unlikely, given the host and geographic difference, that Schioedte & Meinert’s (1884) C. curta from Brazil and Avdeev’s (1978b) record are of the same species, and as Avdeev (1978b) did not indicate where the material was deposited, we exclude the species from the Australian fauna.

Cymothoa epimerica is similar to C. curta from the ovoid body shape (1.8 and 1.9 times longer than wide respectively), pleonites posterior margins trisinuate and uropods which do not extend past the pleotelson posterior margin. Cymothoa epimerica differs from C. curta by the more developed anterolateral margins of pereonite 1 that reaches the anterior margin of cephalon; posterolateral margin of pereonite 1 with minute projection; dorsally visible coxae, with acute posterolateral margins; acute carinae of pereopods 6 and 7 basis (compared to the highly raised carina in C. curta ), long and narrow uropods (compared to the more stout uropodal rami), and the irregular margins of all pleopods.

Distribution. South America: Brazil (present material).

Hosts. Anablepidae : Anableps anableps (see Schioedte & Meinert 1884) and Anableps microlepis (present study).

Figures

FIGURE 39. Cymothoa curta, ovigerous female holotype (14 mm; NHMW 6142). A, dorsal view; B, ventral view of mouthpart; C – F, pereopods 1, 2, 6, 7 respectively; G, lateral view.

FIGURE 40. Cymothoa curta, ovigerous male paratype (7 mm; NHMW 6142). A, dorsal view; B, ventral view of mouthpart and pereopod 1 (dactylus and propodus); C – F, pereopods 1, 2, 6, 7 respectively; G, uropod; H, lateral view.

FIGURE 41. Cymothoa curta, ovigerous female Brazilian (17 mm; MTQ W 34283). A, dorsal view; B, front view of cephalon; C, antennula; D, antenna; E, uropod; F, dorsal view of pleotelson; G, lateral view.

FIGURE 42. Cymothoa curta, ovigerous female Brazilian (17 mm; MTQ W 34283). A – D, pereopods 1, 2, 6, 7 respectively; E – H, pleopods (dorsal view) 1 – 4 respectively; I – L, pleopods (ventral view) 2 – 5 respectively.

FIGURE 43. Cymothoa curta, male Brazilian (7 mm; MTQ W 34283). A, dorsal view; B, antennula; C, antenna; D – G, pereopods 1, 2, 6, 7 respectively; H, lateral view; I, uropod.