Gouania Nardo 1833

3.1.1 | Gouania Nardo, 1833

Gouania Nardo 1833: 548

(type species: Gouania prototypus Nardo 1833 by original designation. Genus appeared first as Covania, name corrected by Canestrini, 1864:181).

Diagnosis. The genus diagnosis is based on the genus description by Briggs (1955) and adjusted to fit the new species: dorsal and anal fins reduced to low ridges with very weak rays, connected to the caudal fin. Ventral adhesive disc of „ double „ type, with no papillae in region A and flattened papillae in regions B and C. Disc small, 5.0 – 9.8 in standard length. Body slender and elongated, posteriorly laterally compressed. Head rounded in dorsal outline; snout not produced. Upper jaw with outer row of medium-sized caniniforms frontally. Behind them irregularly scattered small conical inner teeth. Outer row continues laterally as large caniniforms, followed behind by medium-sized caniniforms. Lower jaw with outer row of medium-sized caniniforms frontally. Behind them irregularly scattered small conical inner teeth. The single row of larger caniniforms continuous laterally. Vertebrae 35 – 40. The first gill arch with hemibranch, the 2nd to 4th gill arches with holobranchs. No fleshy pad present on lower pectoral base. No subopercular spine. Gill membranes attached to isthmus. Six branchiostegals.

Key to the species of Gouania (Figure 2).

1a. Dorsal head profile concave above eye (Figure 2c,d), caudal-fin length 11.1 – 13.0% of standard length, pectoral-fin length 5.4 – 7.5% of standard length, “ slender ” species of Gouania … 2

1b. Dorsal head profile straight above eye (Figure 2a,b,e), caudal-fin length 13.5 – 17.5% of standard length, pectoral-fin length 8.2 – 11.3% of standard length, “ stout ” species of Gouania … 3

2a. Posterior angle of jaws extends to, or close to, a vertical line drawn through the anterior edge of the anterior nostril; longitudinal infralateral and suborbital transversal rows of superficial neuromasts placed in the well-defined deep groove (Figure 2d,f); Adriatic Sea … Gouania pigra

2b. Posterior angle of jaws extends to between a vertical line drawn through posterior edge of anterior nostril and a vertical line drawn through anterior edge of eye; longitudinal infralateral and suborbital transversal rows of superficial neuromasts placed in shallow groove disappearing in posterior part of longitudinal infralateral row (Figure 2c,f); Aegean Sea, rare in the south Adriatic Sea (a single record from Pelješac, Croatia) … Gouania hofrichteri sp. nov.

3a. Posterior opercular edge with pointed upper tip and rounded lower posterior edge (Figure 2a); Adriatic Sea, northern Ionian Sea (Island of Corfu) … Gouania adriatica sp. nov.

3b. Posterior opercular edge with two equally long tips (Figure 2b,e) … 4

4a. Vertebrae 37 – 38; West Mediterranean to Messina … Gouania willdenowi

4b. Vertebrae 35 – 36; southern Ionian Sea and Aegean Sea … Gouania orientalis sp. nov.