Zebrus zebrus (Risso, 1827)

Kovačić, Marcelo, Bonello, Juan Jose & Evans, Julian, 2013, Three new records of Gobiidae from Malta with morphology, colouration and identification of the smallest known juveniles of two small gobiid species, Cybium 37 (4), pp. 233-239 : 237

Zebrus zebrus (Risso, 1827)

Material examined

Juvenile of unidentified sex, PMR VP2878 ( Fig. 4A ), 10.0 + 2.2 mm, Ta’ Xbiex (J3), Malta, 15 Aug. 2011, coll. J.J. Bonello and J. Evans; juvenile of unidentified sex, PMR VP2882 , 9.4 + 2.3 mm, Mistra, Malta, 28 Jul. 2011, coll. J.J. Bonello and J. Evans; ( Figs 1 , 4B ) .

Comparative material of Z. zebrus

One juvenile of unidentified sex, 11.9 + 3.5 mm, PMR VP2778 , Kupari , Dubrovnik, southern Adriatic Sea (42°37’10.7’’N; 18°11’28.8’’E), 14 Sep. 2011, coll. M. Kovačić, M. Kirinčić and D. Zanella ; 1 juvenile of unidentified sex, 10.4 + 2.7 mm, PMR VP2779 , beach between Slano and Trsteno, Dubrovnik, southern Adriatic Sea (42°37’10.7’’N; 18°11’28.8’’E), 15 Sep. 2011, coll. M. Kovačić, M. Kirinčić and D. Zanella.

Diagnosis

(1) Suborbital papillae of lateral-line system without longitudinal row a; (2) predorsal area naked; (3) transverse suborbital rows 7; 4) pelvic fins forming disc; 5) interorbital papillae absent; (6) scales in lateral series 29-30 (the known species range of scales in lateral series is 29-38, Miller, 1986).

Description

Anterior nostril short, tubular, no visible tentacle from inner part of rim. Branchiostegal membrane attached to entire side of isthmus. First dorsal fin VI; second dorsal fin I/11; anal fin I/9; caudal fin with 13 branched rays, 16 segmented rays; pectoral fin 17; pelvic fin I/5+I/5. Uppermost rays of pectoral fin still not free from membrane. Pelvic fins forming disc. Body with ctenoid scales, scales in lateral series 29-30. Head and predorsal area naked. Colour preserved: body yellowish brown, brown melanophores on the body arranged in vertical bands, darker and more intensive on anterior part of body, paler posteriorly ( Fig. 4A ). Vertical bands more visible in the larger PMR VP2878 10.0 + 2.2 mm and less distinguishable in the smaller PMR VP2882 9.4 + 2.3 mm. Breast and belly pigmented. Head pigmented with brown melanophores, underside whitish, but with melanophores. Predorsal area densely pigmented. Dorsal and anal fins pigmented, fin membranes too damaged to determine colouration pattern. Caudal fin lightly pigmented, with brown vertical band present on the origin of caudal fin. Pectoral fin pigmented on upper bases of rays, rest of fin colourless. Pectoral fin base pigmented, more intensive dorsally. Pelvic fins colourless. Head with anterior oculoscapular and preopercular canals, with pores σ, λ, Χ, ω, α, β, ρ, and γ, δ, ε, respectively. Posterior oculoscapular canal still not developed or present only as an open furrow. Rows of sensory papillae: No interorbital rows. No suborbital row a. Seven transverse suborbital rows.

Figures

Figure 1. - Map of the Maltese Islands showing the sixteen sampling locations: (▲) sites with gobiid records; (●) sites from where no gobiid species were identified. Key: A: Wied l-Ghasri; B: Ħondoq Bay; C: Ix-Xatt l-Ahmar; D: Mġarr ix-Xini; E: Mellieha Bay; F: Mistra Bay; G: Qawra; H1-H6: Tigné A – Tigné F; I1-I2: Manoel Island A – Manoel Island B; J1-J4: Ta’ Xbiex A – Ta’ Xbiex D; K: Ħofra ż-Żghira; L: Marsaxlokk; M: Wied ix-Xoqqa; N: Wied iż-Żurrieq; O: Fomm ir-Rih Bay; P: Ġnejna Bay.

Figure 4. - Zebrus zebrus. A: Preserved specimen, PMR VP2878, juvenile of unidentified sex, 10.0 + 2.2 mm, Tigné B, Malta.B: Map of the Mediterranean showing previous records (▲) and new find- ing (●).