Cymothoa hermani Hadfield, Bruce & Smit, 2011

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 : 25-28

Cymothoa hermani Hadfield, Bruce & Smit, 2011

Figures 14–15

Cymothoa hermani Hadfield, Bruce & Smit, 2011: 57 , figs. 1–7.— Hadfield, Bruce & Smit, 2013: 163 .

Type material. Holotype: 1 ♀ (ovig. 28 mm; not examined), Miwi Island, Kiwani Bay, Zanzibar, Tanzania, 06°21’S, 39°20’E, 26 April 2008, host marbled parrotfish Leptoscarus vaigiensis (Quoy & Gaimard, 1824) , coll. H. Van der Bank ( SAMC A47890).

Paratypes: 1 ovig. ♀ (23 mm), 2 mature ♂ (14, 15 mm; not examined), same data as holotype ( SAMC A47891).

Material examined. Southeastern Queensland material. 1 ♀ ovig. (37 mm), off Gladstone, March 1979, from parrotfish, coll. A. Kilvert (MTQ W8961). 1 ♂ (18 mm), off Gladstone, March 1971 or 1979, from parrotfish, coll. A. Kilvert (MTQ W34275).

Diagnosis and description. Hadfield et al. (2011, 2013) provided figures and a detailed description of the type material. We include here illustrations and a brief diagnosis of the Australian female specimen (MTQ W8961).

Body ovoid, 1.8 times as long as greatest width, dorsal surface rugose, laterally convex, widest at pereonite 4, most narrow at pereonite 1. Cephalon subtriangular, 1.2 times longer than wide, moderately visible from dorsal view. Frontal margin rounded, ventrally folded. Eyes absent. Pereonite 1 anterolateral margins broad, reaching anterior margin of cephalon; pereonites 1–4 subequal in length, posterior margin moderately linear; pereonites 5–7 subequal in length. Coxae 2–3 posteroventral margins subtruncate; 5 and 6 with broadly acute carinae. Pleonites 1– 5 progressively wider, visible in dorsal view; pleonites posterior margin irregular. Pleotelson 0.6 times as long as anterior width, anterior margin irregular, lateral margin convex, posterior margin rounded, without median point. Antennula comprised of 6 articles. Antenna comprised of 7 articles. Pereopods 1 and 2 dactyli slender; carpus with straight proximal margin; merus proximal margin without bulbous protrusion; basis superior proximal basis smooth, not raised, without acute carinae. Pereopods 3–5 similar to pereopod 2, gradually increasing in size, without robust or simple setae. Pereopods 6 and 7 superior proximal basis without broad and raised carinae; merus proximal margin without bulbous protrusion; dactyli narrow. Uropod half as long as pleotelson length; peduncle 1.1 times as long as exopod; exopod 1.3 times as long as endopod, apices narrowly rounded.

Colour. Ivory white to yellowish-tan.

Size. Ovigerous females: 23–37 mm; adult males 14–18 mm ( Hadfield et al. 2011 and present study).

Remarks. Cymothoa hermani can be identified by the unique bulbous ornamentation on pereonite 1, pereonite 1 anterolateral margins rounded and extending past rostrum, long and slender dactyli and the numerous lobes on pleopods 4 and 5 in the ovigerous female ( Hadfield et al. 2011, 2013).

The Australian specimens and Tanzanian holotype are similar in having a subtriangular cephalon, pereonite 1 anterolateral margins rounded and extending past rostrum and pleonites subparallel. Differences include the Australian specimens having a more ovoid body shape (compared to the subparallel lateral margins), pereonite 1 anterolateral margins reaching rostrum (compared to pereonite 1 producing past rostrum), the more acute posteroventral margins of coxae 4–7 (compared to the straight and smooth margins), pereopods 6 and 7 with a less developed carinae basis, and the rounded pleotelson posterior margin (compared to the subquadrate pleotelson posterior margin). Male specimens from Australia (MTQ W34275) and Hadfield’s et al. (2011) paratype are similar.

Cymothoa borbonica Schioedte & Meinert, 1884 and C. epimerica are the most similar species to C. hermani in the subtriangular cephalon, pereonite 1 anterolateral margins reaching rostrum, and the ovate body shape. Cymothoa borbonica has no bulbous ornamentation on pereonite 1, the lengths of pereonites 6 and 7 are more than half the length of pereonite 4, acute posterior margins on coxae 4–7, sharp carinae basis on pereopods 6 and 7 and the body is dorsomedially flattened (compared to the medial ridge on pereonites 2–4 on C. hermani , visible from the lateral view). Cymothoa epimerica has posterior margins of coxae acute, basis of pereopods 6 and 7 acute and dorsally visible, pleon trisinuate and pleopod margins appearing irregular.

Distribution. Known from southeastern Queensland and the Northern Territory, Australia (present study) and Tanzania, Africa.

Hosts. Known from the host from the family Scaridae ( Hadfield et al. 2011; present study). The host Leptoscarus vaigiensis is known to occur from the northern Red Sea to South Africa and eastwards to Japan and New Zealand ( Hadfield et al. 2011).

Figures

FIGURE 14. Cymothoa hermani ovigerous female (37 mm; MTQ W 8961). A, dorsal view; B, ventral view of mouthpart; C, front view of pereonite 1 and cephalon; D, dorsal view of pleotelson; E, lateral view.

FIGURE 15. Cymothoa hermani ovigerous female (37 mm; MTQ W 8961). A, antennula; B, antenna; C – F, pereopods 1, 2, 6, 7 respectively; G, uropod.