Cymothoa borbonica Schioedte & Meinert, 1884

Hadfield, Kerry A., Bruce, Niel L. & Smit, Nico J., 2013, Review of the fish-parasitic genus Cymothoa Fabricius, 1793 (Isopoda, Cymothoidae, Crustacea) from the southwestern Indian Ocean, including a new species from South Africa, Zootaxa 3640 (2), pp. 152-176 : 154-157

Cymothoa borbonica Schioedte & Meinert, 1884

( Figs 1–2 )

Cymothoa Borbonica Schioedte & Meinert, 1884: 226 , 282–286, tab. X (Cym. XXVIII), figs. 7–10.

Cymothoa borbonica —Thielemann, 1910: 41; Barnard, 1920: 357; 1926: 121; 1940: 491; 1960: 93; Nierstrasz, 1931: 136–137; Brian & Dartevelle, 1949: 182; Trilles, 1975: 989–990, pl. II (14–15); 1979: 260–261; 1986: 627, tab. 1; 1994: 137–138; Kensley, 1978: 79–80, fig. 32i; 2001: 232.

Uncertain identification:

? Cymothoa borbonica .—Stebbing, 1904: 709–710; Chilton, 1924: 887; Monod, 1934: 14, pl. 29–30 (a–c).

Material examined. Lectotype [here designated] ( Figs 1–2 ). Ƥ (32 mm TL; 17 mm W), from Réunion Island (previously Bourbon Island), unknown host (exMNHN-IU-2007-4163).

Paralectotypes. 2 3 (11, 14 mm TL; 5.5, 7 mm W), same data as lectotype (MNHN-IU-2007-5118).

Non-type material. Ƥ (23 mm TL; 11 mm W), from Somalia, 29.03.1904, coll. Gravier, det. J.P. Trilles 1975, in the branchial cavity (MNHN-Is540).

Description. Female, length 32 mm, width 17 mm.

Body oval, 1.4 times as long as greatest width, dorsal surfaces slightly bumpy, widest at pereonite 4, most narrow at pereonite 1, lateral margins slightly convex. Cephalon 0.7 times longer than wide, rounded anterior margin, slightly visible in dorsal view, immersed in pereonite 1. Frontal margin rounded to form blunt rostrum and thickened, ventrally folded. Eyes not visible. Pereonite 1 with unique bulbous orientation, anterior border slightly indented, anterolateral angle wide, with inwardly produced point, posterior margins of pereonites smooth and slightly curved laterally. Coxae 2–3 with posteroventral angles acute, posteriorly produced; 4–7 acute, posteriorly pointed. Pereonites 1–4 increasing in length and width; 5–7 decreasing in length and width; 6 and 7 narrower.

Pleon with pleonite 1 most narrow, visible in dorsal view; pleonites posterior margin not smooth, mostly concave; posterolateral angles of pleonite 2 narrowly rounded, not posteriorly produced. Pleonites 3–5 similar in form to pleonite 2. Pleonite 5 with posterolateral angles free, not overlapped by lateral margins of pleonite 4. Pleotelson 0.5 times as long as anterior width ( Fig. 1 D), dorsal surface with medial furrow, lateral margins convex, posterior margin evenly rounded, without median point. Pereopod 1 basis 1.7 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 1.6 times as long as wide; dactylus slender, 1.3 as long as propodus, 2.5 times as long as basal width. Pereopod 2 propodus 1.4 as long as wide; dactylus 1.3 as long as propodus. Pereopod 3 similar to pereopod 2. Pereopod 6 basis 1.2 times as long as greatest width, ischium 0.7 times as long as basis, propodus 1.3 as long as wide, dactylus 1.8 as long as propodus. Pereopod 7 basis 1.3 times as long as greatest width; ischium 0.8 as long as basis, without protrusions; merus proximal margin with slight bulbous protrusion, merus 0.3 as long as ischium, 0.5 times as long as wide; carpus 1.2 as long as ischium, without bulbous protrusion, 0.8 times as long as wide; propodus 0.6 as long as ischium, 1.5 times as long as wide; dactylus slender, 1.8 as long as propodus, 3 times as long as basal width. Uropod more than half the length of pleotelson, peduncle 2.1 times longer than rami, peduncle lateral margin without setae; rami not extending beyond pleotelson, marginal setae absent, apices broadly rounded.

Distribution. Western Indian Ocean: Réunion Island (Schioedte & Meinert 1884; Trilles 1975); South Africa (Barnard 1920; 1940); Mozambique (Barnard 1926); “Sainte-Marie Galande” (Monod 1934; Trilles 1975); Madagascar (Barnard 1960; Trilles 1975; 1979); and Djibouti (Trilles 1975).

We could not find the location “Sainte-Marie Galande”; possibilities are Marie Galante Island, Gaudeloupe, or Sainte Marie Island, Madagascar. We accept that Sainte Marie Island, Madagascar is the logical location. Stebbing (1904) suggested that this species may be located in Maldives but this is unconfirmed.

Hosts. Unidentified Scaridae (see Stebbing 1904); Epinephelus tauvina (Forsskål, 1775) (see Barnard 1960); Ptychochromis oligacanthus (Bleeker, 1868) (see Trilles 1975); and Mugil cephalus Linnaeus, 1758 (see Trilles 1979).

Remarks. Schioedte and Meinert (1884) described Cymothoa borbonica from three specimens collected from Réunion Island (as Bourbon Island) and gave descriptions and figures of the non-ovigerous female and the adult male. Cymothoa borbonica can be identified by a greatly indented anterior margin of pereonite 1; unique bulbous ornamentation on pereonite 1; wide anterolateral projections of pereonite 1 extending more than half the length of the cephalon; blunt rostrum; large carinae on pereopod 7 and a wide pleotelson, wider than the pleon.

Monod (1934) gave two drawings of C. borbonica in comparing that species to C. eremita and C. eximia . The C. borbonica specimen drawn was, according to Monod (1934), labelled as “ type ” material from Sainte-Marie Galande (Type specimen—“Coll. Museum 6-1862, Coquerel legit ”). Trilles (1975) also mentioned that this nonovigerous female of Monod (1934) from Sainte-Marie Galande represents the type of the species. Along with the Sainte-Marie Galande specimen, Trilles (1975) also examined the three specimens that Schioedte and Meinert (1884) used in their original description (Sample No 230 in Trilles 1975), which have corresponding data to that of Schioedte and Meinert’s original description, thus these specimens are recognised as the syntypes for the species. As the Sainte-Marie Galande specimen (MNHN-Is540) was not mentioned by Schioedte and Meinert (1884), nor collected from the type locality, it cannot be a type specimen. A lectotype and paralectotypes (from Schioedte and Meinert’s examined material) are here designated and described.

The specimen identified as the female specimen C. borbonica from Sainte-Marie Galande (MNHN-Is365) did not agree with the type material redescribed here and is excluded from the species synonymy, remaining at present as Cymothoa sp.

Trilles (1975) reported C. borbonica from freshwater in Madagascar. As C. borbonica has only been found in marine environments, this record does require further confirmation. Trilles (1975) stated that the specimens were collected from the mouth of the freshwater fish Ptychochromis oligacanthus , a species that is known to occur in estuaries so this record could be valid.

Figures

FIGURE 1. Cymothoa borbonica Schioedte & Meinert, 1884 female lectotype (32 mm) (MNHN-IU- 2007 - 4163). A, dorsal view; B, anterior view of pereonite 1 and cephalon; C, ventral view of cephalon; D, dorsal view of pleotelson; E, lateral view.

FIGURE 2. Cymothoa borbonica Schioedte & Meinert, 1884 female lectotype (32 mm) (MNHN-IU- 2007 - 4163). A, pereopod 1; B, pereopod 2; C, pereopod 6; D, pereopod 7.