Diplodus levantinus (Teleostei: Sparidae), a new species of sea bream from the southeastern Mediterranean Sea of Israel, with a checklist and a key to the species of the Diplodus sargus species group ; Diplodus levantinus (Teleostei: Sparidae), una nueva especie de sargo del Mediterráneo sudeste fr

1 Im Ramstal 76, 97922 Lauda-Königshofen, Germany. E-mail: ronfricke@web.de 2 Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany [temporarily out of office]. 3 National Natural History Collections and Department of Ecology, Evolution and Behavior, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel. E-mail: dani.golani@mail.huji.ac.il 4 Mt. Scopus Library, The Hebrew University of Jerusalem, 91905 Jerusalem, Israel. E-mail: brendag@savion.huji.ac.il


INTRODUCTION
The sparid fish genus Diplodus are distributed in tropical and warm temperate waters of the Atlantic Ocean and the western Indian Ocean including the Red Sea. They are mainly found on shallow water reefs. The genus includes a total of 22 valid subspecies and species (Paz et al. 1974, Paz 1982, Eschmeyer and Fricke 2015. Diplodus was first described by Rafinesque (1810a: 26, 54) for Sparus annularis Linnaeus, 1758. The species of the genus have been known since ancient times; two species now assigned to the genus were described by Linnaeus (1758), namely Diplodus annularis and D. sargus. The latter species has been known since Aristotle, and its description by Linnaeus (1758) was based on multiple sources from localities in the Mediterranean Sea (Greece, France, Italy). Valenciennes in Cuvier and Valenciennes (1830: 14) unnecessarily renamed the species as Sargus rondeletii, a name that was used by many subsequent authors. Diplodus sargus may reach a total length of up to 40 cm (Man-Wai and Quignard 1982: 175), which equals a standard length of approximately 324 mm; Fischer et al. (1987) even give a maximum total length of 45 cm. Cadenat (1964) revised the genus Diplodus from West Africa, and revived the name Diplodus sargus; he described two subspecies, including the description of Diplodus sargus typicus, which included specimens from West Africa as well as the Mediterranean Sea. Partially based on his West African material, Paz et al. (1974) described a new subspecies Diplodus sargus cadenati from West Africa and the Canary Islands.
In his thesis project, Paz (1975) revised the genus Diplodus. He defined the Diplodus sargus species group as having 4-10 vertical bands along the sides of the body, plus sometimes additional smaller bands in the spaces between the main bands, 4 incisors each in the upper and lower jaws, and large molars in 2-4 rows. In the species group, he included the subspecies Diplodus sargus sargus (Linnaeus, 1758) from the Mediterranean, D. s. cadenati Paz, Bauchot and Daget, 1974 from the eastern Atlantic, D. s. capensis (Smith, 1844) from South Africa, and D. s. lineatus (Valenciennes in Cuvier and Valenciennes, 1830) from the Cape Verde Islands. These results were previously summarized in the paper of Paz et al. (1974). In addition, he reported "Diplodus X" from Israel (Paz 1975: 57-61, Fig. 27), which he thought to be a questionable hybrid between D. sargus and D. annulatus. Paz (1982) expanded the Diplodus sargus species group to include two additional subspecies from the South Atlantic, four from the western Atlantic, and two from the Indian Ocean. The suspected hybrid status of the population in Israel was not mentioned again in this paper or in subsequent literature.
When we examined specimens of Diplodus from Israel, our attention was drawn to the identity of specimens previously named Diplodus sargus (non Linnaeus, 1758), which were found to be distinct from "typical" Diplodus sargus from other parts of the Mediterranean Sea. The analysis of these individuals demonstrated that the population from Israel represents a separate species, which is described in the present paper.
Descriptive methods follow Caldwell (1965). Proportional measurements and counts for the holotype of Diplodus levantinus n. sp. are given first, followed by those of the paratypes in parentheses. Following the method of Fricke et al. (2007), subspecies are no longer used: they are either raised to the species level or synonymized. The classification is based on Eschmeyer and Fricke (2015) and references follow Fricke (2015). The museum abbreviations follow Fricke and Eschmeyer (2015).

Diagnosis.
A species of Diplodus Rafinesque 1810 with 11-12 spines and 10-16 soft rays in the dorsal fin, 3 spines and 11-13 soft rays in the anal fin, 15-17 pectoral fin rays, 6-9 + 8-12 gill rakers on the first gill arch, upper and lower jaws with a single row of 4 incisors on each side, followed by a total of 16-19 molariform teeth in the upper jaw and 12-14 molariform teeth in the lower jaw, with the molariforms of the upper jaw separated from the incisors by a wide gap, and the sides of the body in adults with 8 vertical bars of equal width, which are present even in large adults, followed by a broad bar on caudal peduncle, which usually nearly reaches the ventral margin of the caudal peduncle. Description. Dorsal fin-ray formula XII, 13 (XI to XII, 10 to 16, usually XII, 13 to 14). Anal fin ray formula III, 13 (III, 11 to 13). Pectoral fin ray formula, all elements, 16-16 (15 to 17). Gill rakers 6+9 (6-9+8-12) on first gill arch.
Selected body proportions, included in Table 1, are part of the description.
Body completely scaled; scales ctenoid. Predorsal scales extending to a point above about centre of eye. Cheeks scaled. Snout scaleless. A long ventral axillary scale. Inter-ray membranes of dorsal, anal, pelvic and pectoral fins scaleless. Small scales extending about three-fourths the way out from base of caudal fin. Lateral line a smooth shallow convex curve from its origin to just beyond end of dorsal fin, then nearly straight to fold formed when tail is bent upward. Four scales (two to four) in a line angling upward, extending onto basal portion of caudal fin. Lateral line scales 68 (59-72). Eight (eight or nine) scales above lateral line to origin of dorsal fin, 16 (16-17) below to origin of anal fin, and seven (seven) above highest curve of lateral line to base of dorsal fin. Maximum observed standard length 231 mm.  Dorsal outline a regular curve from tip of snout to end (insertion) of dorsal fin, with only a slight concavity above eye and a slight convexity in front of eye. Snout slightly pointed. Ventral outline slightly convex (nearly straight) from tip of snout to pelvic fin origin, thence nearly straight to anal fin origin, and after angling upward at an angle of about 40°, convex to end (insertion) of anal fin. Dorsal and anal fins low. Pectoral fin long, reaching nearly to or past origin of anal fin, and increasing in relative length with increase in body length. Caudal fin forked. Mouth small, maxillary not reaching anterior margin of orbit in small specimens. Anterior nostril round; posterior nostril an elongate oval, the opening slit-like.
A single outer row of incisor teeth, four on each side both upper and lower, and none notched; upper portion of each tooth essentially rectangular in outline above a narrowed base bearing a posterior buttress on inner surface; teeth protrude and are rather strongly incurved towards cutting edge; anterior corner of each lateral tooth elevated. A mosaic of small molariform teeth in posterior part of mouth, 16 (16-19) in upper jaw, 12 (12-14) in lower jaw; anterior part immediately behind incisor teeth is naked; behind these, in lateral posterior part of mouth, there are three (two or three) rows of molariform teeth above, and three (two or three) rows below. Vertebrae ( Fig. 4): 10 precaudal plus 13 caudal plus one hypural, equalling 10 plus 14 as usually recorded. Three predorsal bones. Two dorsal spines situated on first pterygiophore, thereafter one spine on each pterygiophore (a count of 0-0-0-2 as discussed by Smith and Bailey, 1961).

Colour in alcohol.
For pigmentation of body refer to Figures 1-2, which are part of the description.
Head and body silver, scales with horizontal rows of dark pigment. Head dorsally dark grey between the eyes, and a vertical dark streak below the eye. Posterior edge of opercle dark. A dark pectoral axillary blotch. Caudal peduncle with a broad dark grey streak that often reaches to the lower midline. Sides of body with  Rows of molariform teeth in lower jaw 2-3 4-5 4-6 2 3-4

Extent of molariforms towards incisors in upper jaw
Not reaching to base of incisors, leaving a wide gap

Reaching to base of incisors
Not reaching to base of incisors, leaving a wide gap

Extent of molariforms towards incisors in lower jaw
Not reaching to base of incisors, leaving a narrow gap

Reaching to base of incisors
Not reaching to base of incisors, leaving a wide gap about eight narrow vertical bars that extend across the upper three-fourths of the body; the posterior two bars are present but not very well visible on the photograph of the holotype due to light reflections (Fig.  1). Pectoral fins immaculate. Inter-spine and inter-ray membranes of dorsal, anal and caudal fins tinged with dark pigment, which is more intense towards bases of fins. Anterior inter-ray membranes of pelvic fins dark, more so than those of dorsal, anal and caudal fins; the spine and the first membrane are white, however, as are the posterior membranes. Caudal fin distally dark grey.

Reaching to base of incisors
Etymology. The name of the new species, levantinus, refers to the Levant, a historical name for the coasts of the eastern Mediterranean.
Distribution and habitat. Known only from the coast of Israel, eastern Mediterranean Sea, between Haifa and Jaffa (Fig. 5). The species is found from shallow water to 50 m depth, usually on sand bottom near rocks; juveniles are found above sandy substrate near rocks at depths of 0.2-2 m.    Paz (1975: 47), but is corrected and updated; figures A-I and O based on Paz (1975: Fig. 23). Scales indicate 20 mm.
per jaw 16-19, 2-3 rows; lower jaw: 12-14, 2-3 rows), the molariform teeth, which do not extend to the base of the incisors in the upper jaw but leave a wide gap

DISCUSSION
The southeastern Mediterranean (Levantine) populations previously attributed to Diplodus sargus clearly belong to a different species, based on differences in the dentition and colouration. The only junior synonym of D. sargus listed in the Catalogue of Fishes online (Eschmeyer and Fricke 2015) that was described from the eastern Mediterranean, Sargus raucus Geoffroy Saint-Hilaire, 1809, was first considered as the valid name for these; the species was illustrated from Egypt by Geoffroy Saint-Hilaire (1809: pl. 18, Fig. 1), and no type material is available. The material was collected in Alexandria, Egypt in 1798-1799, and when Alexandria was conquered by Britain, Geoffroy Saint-Hilaire refused to hand over the materials and documents to the British general Hutchinson, and later sent the material to Paris (Bauchot et al. 1990: 88). However, Bauchot and Daget ( 1971: 322) found two specimens of Sargus raucus from Alexandria (MNHN 0000-5740), which were used for the description of Geoffroy Saint-Hilaire (1827: 340), and identified them as Diplodus cervinus (Lowe 1838). None of the specimens agrees with the holotype illustrated by Geoffroy Saint-Hilaire (1809: Pl. 38, Fig.  1), which is a smaller specimen and clearly belongs to the Diplodus sargus species group, so the holotype is not included in MNHN 0000-5740. The material collected by E. Geoffroy Saint-Hilaire in Egypt was exclusively sent to Paris, but no other material of the Diplodus sar-gus species group collected during the Egyptian mission is extant in the MNHN collection (see also Bauchot and Daget 1972: 69). We therefore conclude that the holotype is lost. A specimen from Bardawil Lagoon, Egypt (HUJ 6047), very similar in colouration to the one illustrated by Geoffroy Saint-Hilaire (1809), turned out to have the typical dentition of Diplodus sargus with irregularly grouped small molars reaching right to the front teeth, without a naked area in between. The specimen has a dorsal fin count of XII+13, an anal fin count of III+13, pectoral fin rays 16, gill rakers 5+8. In order to avoid nomenclatural confusion, and to fix the classification of southeastern Mediterranean species in the Diplodus sargus group, the specimen (HUJ 6047) is hereby designated as the neotype of Sargus raucus Geoffroy Saint-Hilaire, 1809 (Fig. 11), which is thus a junior synonym of Diplodus sargus (Linnaeus, 1758). The neotype originates from Bardawil Lagoon, northern Sinai, Egypt, which is as close as possible to the original type locality (Egypt). A second specimen from Bardawil Lagoon (HUJ 6057) also agrees in the dentition and general characters with Diplodus sargus. A third specimen, ZMB 1055 (70.5 mm SL) from Alexandria, Egypt, collected during the expedition of Hemprich and Ehrenberg, has likewise a dentition typical of Diplodus sargus.
It can be concluded that Diplodus sargus is found along the Mediterranean coast of Egypt, while the species is replaced by D. levantinus n. sp. in Israel. The difference of the Israeli population from other species of the Diplodus sargus species group were first recognized in the doctoral dissertation of Paz (1975: 57), who provisionally named the specimens from Israel "Diplodus X" and assumed that they were hybrids between D. annularis × D. sargus, due to the dentition, which seemed intermediate between those species. However, the hybrid theory can be ruled out, as no true Diplodus sargus is found in Israel, and genetically they are clearly part of the Diplodus sargus species group, without a component of another species of Diplodus (Yaron Tikochinski, personal communication). Except in the work of Paz (1975), the distinctiveness of Israeli populations previously misidentified as D. sargus was neither mentioned nor discussed again in the literature, including the later paper of Paz (1982).
The body shape and colouration changes during growth in Diplodus spp.; juveniles are more slender, adults more high-bodied, and in some species the number of stripes along the sides of the body increases. Allometric growth in Diplodus sargus compared with Fig. 10. -Diplodus lineatus, HUJ 20368, 4 spec (Upper to lower: 222, 176, 166, 162 mm SL), Boa Vista, Cape Verde Islands, 9 Sept. 2014. Lateral view; photograph of the fresh colouration taken a few hours after collection (Photograph: R. Fricke).
two other species of the genus was analysed by Loy et al. (2001). Allometric growth is also obvious in Diplodus levantinus n. sp., but the number of stripes along the sides of the body does not change from juveniles to adults in this species.
Considering the genetics of species in the Diplodus sargus species group, no genetic differences were found between Diplodus sargus and D. cadenati by Domingues et al. (2007). They agreed with Bargelloni et al. (2005) who considered two hypotheses to explain this lack of differentiation. Either D. sargus is a recent immigrant in the Mediterranean or historical bottlenecks and recolonization processes prevented strong differentiation of Atlantic and Mediterranean basins. In a genetic study of several species of Diplodus, including D. levantinus n. sp., D. sargus and D. lineatus, no significant differences were found among these species (Yaron Tikochinski, personal communication). On the other hand, the Diplodus sargus species group is well distinguished from other species of Diplodus (see Summerer et al. 2001, Casu et al. 2009). However, González-Wangüemert et al. (2006) detected diagnostic alleles differentiating between Diplodus sargus and D. cadenati; additional molecular analyses should be performed for the species group. Apart from potential genetical differences, the species in the Diplodus sargus species group are sufficiently distinguished by their dentition and colouration.
The restricted range of Diplodus levantinus n. sp. appears to represent a relict distribution; its particular dentition recalls that of D. lineatus from the Cape Verde Islands, which is also considered a relict distribution. Species with a stronger dentition (including D. sargus in the Mediterranean) seem to have spread over most of the range of the species group, leaving the species with weaker dentition in such small, restricted areas at the margin. The range of D. levantinus is separated from that of D. sargus by wide stretches of sandy shore without suitable habitat in the south; the situation in the north of its distribution range remains unknown.

CHECKLIST OF SPECIES OF THE GENUS DIPLODUS
Diplodus annularis (Linnaeus,