First record of the Goldstripe sardinella-Sardinella gibbosa ( Bleeker , 1849 ) in the Mediterranean Sea and confirmation for its presence in the Red Sea

This report updates the geographical distribution of Sardinella gibbosa (Bleeker, 1849): confirming its presence in the Red Sea and documenting its introduction into the Eastern Mediterranean Sea. Both updates are based on overlooked museum voucher specimens, some of which were collected 86 years ago. In addition, a simplified morphological key is provided for identifying the clupeids currently found in the Eastern Mediterranean Basin.


Introduction
The goldstripe sardinella Sardinella gibbosa (Bleeker, 1849) is a commercially important marine sardine (Clupeidae) with average annual landings of 227,000 t during 2008-2012(FAO yearbook 2012)).It is a coastal pelagic species that inhabits the Indo West-Pacific region from north Australia in the east to the western borders of the Indian Ocean including the Persian Gulf (Whitehead 1985) and the Red Sea (Dor 1984).However, due to several questionable identifications, the Red Sea was later omitted from its geographic distribution (Whitehead 1985;Golani and Bogorodsky 2010).
In this study, we confirm the existence of S. gibbosa in the Red Sea, based on the examination of type specimens archived at the Muséum National d'Histoire Naturelle, Paris, France (MNHN) and specimens from the fish collection of the Hebrew University of Jerusalem, Israel (HUJ).
In addition, we have discovered the occurrence of S. gibbosa from the Israeli Mediterranean coast from specimens collected during bottom trawl surveys conducted in 2011-2012.Re-examination of the clupeid collection at the Steinhardt Natural History Museum and National Research Centre at Tel Aviv University, Israel (TAU) revealed 60 specimens of S. gibbosa previously collected from the Eastern Mediterranean Sea with the earliest specimen during April 2008 (voucher specimen TAU P.13954).All of these specimens had been erroneously identified and vouchered as the Mediterranean indigenous species Sardinella maderensis (Lowe, 1839).
This report elevates the number of nonindigenous clupeid at the Mediterranean to five and the total number of clupeids in the Eastern Mediterranean to nine.In order to minimize future taxonomic difficulties, an updated morphological key to the clupeids of the Eastern Mediterranean is provided.

Material and methods
Morphological characters were measured using digital calipers with 0.01 mm accuracy.Length of specimens is given as standard length (L S ), instead of total length, due to the occasional disfigurement at the tip of the caudal fin.Body height was measured at the dorsal fin origin.Predorsal, pre-pelvic, and pre-anal lengths were measured from the tip of the snout to the origin of the corresponding fin.Scales from the anterior, middle, and posterior parts of the body were sampled and examined under a light stereoscope.The first gill arch was gently removed from the left side of each specimen and examined under a light stereoscope.The morphological key was based on the catalogued species of Whitehead (1985) and from the fish collection at TAU.

Diagnosis
Sardinella gibbosa is morphologically distinguished from its congeneric by the combination of four characters: (1) slender body, its height ranges 21.4-28.2% of its L S ; (2) 33 ventral scutes; (3) 46-61 gill rakers on the lower arm of the first arch, increasing with size of fish; and (4) interrupted longitudinal striae formation in lateral scales (Figure 2B).Differentiating S. gibbosa from the Mediterranean con-sub-generic S. maderensis is mainly based on the significant gap in lower gill rakers counts; 77-166 in S. maderensis vs. 46-61 in S. gibbosa and in the deeper bifurcated caudal fin of S. maderensis where the length of the forked caudal fin lobes constitutes an average of 70.5% of total length vs. 53.13% in S. gibbosa.

Brief description
Based on selected meristic and morphometric measurements (Table I): slender species of Sardinella with elongated and compressed body shape.Mouth terminal with minute teeth on lower jaw and tongue.Two triangular formations are present on top of head, each composing 9-13 fronto-parietal striae (Figure 2A).Dorsal fin rays average count 18; pectoral fin with 14-16 rays, tightly embedded in a triangular groove.Pelvic fin with eight rays; triangular axillary scale above the origin of the pelvic fin is equal in length to the longest pelvic ray.Anal fin with 18-20 rays, averaging 19.3; last two anal rays enlarged, thickened and branched.Lateral scales deciduous; scales with one continuous vertical striae followed by 5-9 discontinuous striae,  2B).Prepelvic and post-pelvic ventral scutes count 18+14, respectively, 32 in total.Gill rakers on lower arm of the first gill arch count less than 50 in juveniles under 100 mm L S , gradually increasing up to 61 at the size of 150 mm L S .Adult specimens present a distinct golden blotch (darkens after preservation) at the margins of the operculum, approximately the size of the pupil.Dark spot also present at the base of the dorsal fin, tinting the membrane of the anterior four dorsal rays.Faint shades are present at the tip of the snout and at the tips of the dorsal and caudal fins.A pale thin horizontal golden line along the flank can be occasionally observed in fresh specimens.

Remarks
The present research at MNHN has revealed that the two paratypes of Harnegula dollfusi (Chabanaud, 1933), MNHN 1966-0343 and1966-0344, that were previously identified by Whitehead (1985) as a S. albella were in fact S. gibbosa, in accordance with Dor (1984).In addition, one of the paratypes of Dussumieria productissima (Chabanaud, 1933), MNHN 1966-0261, previously identified by Whitehead (1985) as S. fimbriata was also found as S. gibbosa.D. productissima was synonymized with D. elopsoides by Whitehead and Bauchot (1985); this particular specimen was likely erroneously vouchered by Chabanaud and was later misidentified by Whitehead.The similar morphological appearances of S. albella, S. gibbosa, and S. fimbriata as well as the insufficient taxonomic knowledge often led to misidentifications in natural history fish collections (unpublished data).Reliable identification of these specimens can be achieved based on (1) the number of ventral scutes -32 in S. gibbosa versus 30-31 in S. albella and S. fimbriata; (2) the number of anal fin rays -18-19 in S. gibbosa versus 20-23 in S. albella and S. fimbriata and (3) body height -less than 28% of its L S in S. gibbosa vs. higher body with 29-35% of its L S for S. albella and S. fimbriata.

Table 1 .
Meristic and morphometric characters for Sardinella gibbosa from the Res Sea and the Eastern Mediterranean.SD -standard deviation.