Ceratothoa italica Schioedte & Meinert, 1883

Hadfield, Kerry A., Bruce, Niel L. & Smit, Nico J., 2016, Redescription of poorly known species of Ceratothoa Dana, 1852 (Crustacea, Isopoda, Cymothoidae), based on original type material, ZooKeys 592, pp. 39-91 : 57-60

Taxon classification Animalia Isopoda Cymothoidae

Ceratothoa italica Schioedte & Meinert, 1883 Figure 8

Ceratothoa italica Schioedte & Meinert, 1883: 347-350, tab. XV (Cym. XXII), figs 1-4.- Carus 1885: 442.- Trilles 1979: 521; 1986: 624, tab. 1; 1994: 121; 2008: 23.- Rokicki 1984b: 129-131, fig. 32; 1985: 95-119, tab. 1-3, fig. 6.- Trilles, Radujković and Romestand 1989: 289, fig. 8.- Horton 2000: 1047, figs 7 c–e.- Öktener and Trilles 2004: 145-154.- Ramdane, Bensouilah and Trilles 2007: 67-74.

Meinertia italica .- Monod 1924a: 34; 1924b: 432-434.- Montalenti 1948: 42-46, figs 11-14, tab. 5, pl. 3.- Trilles 1964b: 106; 1972a: 1212-1215, figs 156-187, pl. II, figs 10-12; 1972b: 1238-1240.- Dollfus and Trilles 1976: 823.

Ceratothoa italica Identity uncertain: Ceratothoa italica .- Ateş, Trilles, İşmen and Yiğin 2006: 375-380.- Trilles 2008: 23.

Material examined.

Lectotype [here designated]. Zoological Museum, University of Copenhagen (ZMUC CRU-6914) - female specimen (36 mm TL, 17 mm W) collected in Rijeka, Croatia (previously called Fiume), Adriatic Sea by Budde-Lund ( Schioedte and Meinert 1883), host unknown. Also noted: the female has a broken pereonite 1, pleonite 2 and antenna; pereopod 1 missing and other pereopods are damaged and missing dactylii. Paralectotypes. Thirty-seven pullus stage (4-5 mm TL), same data as lectotype (ZMUC CRU-8669); Eighty-two pullus stage (4-5 mm TL), same data as lectotype, label reads "Stor female udt. Som pectotype" (ZMUC CRU-9124).

Description.

Lectotype female. Length 36 mm, width 17 mm.

Body rectangular and elongate, 1.7 times as long as greatest width, dorsal surfaces smooth and polished in appearance, widest at pereonite 5 and pereonite 6, most narrow at pereonite 1, lateral margins subparallel. Cephalon 0.5 times longer than wide, visible from dorsal view, triangular. Eyes irregular in outline, one eye 0.2 times width of cephalon; 0.2 times length of cephalon.

Pereonite 1 with unique bulbous orientation, anterior border anteriorly produced medially, anterolateral angle wide, with inwardly produced point, extend to anterior margin of eyes. Posterior margins of pereonites slightly produced medially. Coxae 4-7 rounded, not extending past pereonite margin. Pereonites 1-4 increasing in length and width; 5-7 decreasing in length and width; 6 and 7 narrower and becoming more progressively rounded posteriorly. Pleon with pleonite 1 same width as other pleonites (except pleonite 5), visible in dorsal view; pleonites posterior margin smooth, mostly concave. Posterolateral angles of pleonite 2 narrowly rounded. Pleonites 3-5 similar in form to pleonite 2; pleonite 5 free, not overlapped by lateral margins of pleonite 4, posterior margin with 2 indented points. Pleotelson 0.5 times as long as anterior width, dorsal surface with medial furrow, lateral margins weakly convex, posterior margin subtruncate.

Pereopod 1 basis 1.5 times as long as greatest width; ischium 0.9 times as long as basis; merus proximal margin with large bulbous protrusion; carpus with straight proximal margin; propodus 1.1 times as long as wide; dactylus slender, 1.2 times as long as propodus, 2.3 times as long as basal width. Pereopod 7 basis 1.2 times as long as greatest width; ischium 0.8 times as long as basis, without protrusions; merus proximal margin with slight bulbous protrusion, merus 0.5 times as long as wide, 0.4 times as long as ischium; carpus 0.5 times as long as wide, 0.3 times as long as ischium, without bulbous protrusion; propodus 1.1 times as long as wide, 0.5 times as long as ischium; dactylus slender, 1.4 times as long as propodus, 2.5 times as long as basal width.

Uropod same length as pleotelson, peduncle 0.5 times longer than rami, peduncle lateral margin without setae; rami extending to pleotelson apex, marginal setae absent, apices narrowly rounded.

Size.

Ovigerous female: 15-30 mm TL; male: 8-15 mm TL; second pullus: 3 mm TL ( Montalenti 1948, Trilles 1972a, Rokicki 1984b).

Distribution.

Mediterranean region and north-western Africa: Adriatic Sea ( Schioedte and Meinert 1883, Carus 1885, Öktener and Trilles 2004); Mauritania ( Monod 1924a, 1924b, Trilles 1972b); Italy ( Montalenti 1948); Galite Islands, Tunisia, France, Morocco ( Trilles 1972b); Montenegro ( Trilles et al. 1989); Aegean Sea ( Ateş et al. 2006); and Algeria ( Ramdane et al. 2007).

Hosts.

In mouth of Spondyliosoma cantharus (previously Cantharus lineatus ) ( Monod 1924b, Trilles 1972b); mouth of Lithognathus mormyrus (previously Pagellus mormyrus ) and other bream ( Montalenti 1948, Trilles 1964b); on Pagellus erythrinus (see Trilles 1964b); on Oblada melanura ; on Mustèle; in mouth of Sargus (see Trilles 1972b); occurs in Sparidae fishes ( Rokicki 1985); in the mouth of Diplodus sargus (see Trilles et al. 1989); in the buccal cavity of Diplodus annularis (see Ramdane et al. 2007).

Remarks.

Ceratothoa italica can be distinguished by the arched body; large bulbous protrusion on the merus of pereopod 1; a pointed rostrum; and uropods that do not extend past the pleotelson. This species also has a prominent projection in the middle of pereonite 1 (hump-like) and a pleon which is usually as wide as the pereon.

Ateş et al. (2006) stated that cymothoid isopods identified as Ceratothoa italica were collected from the eggs of Nephrops norvegicus . As cymothoids are fish parasites, this interaction is an unusual association and is most likely accidental. Similarly, the record of Ceratothoa italica (originally labelled as a Cymothoa sp. [SMF-3515]) from Senckenberg Research Institute, Frankfurt, Germany ( Trilles 2008) seems doubtful as the specimen was collected from Norway and this species has only previously been recorded from the Mediterranean Sea region.

The female ZMUC CRU-6914 is here designated as the lectotype and the pullus stages in the same bottle and the other sample are paralectotypes (ZMUC CRU-8869, 9124).