Two new species of Squalius, S. adanaensis and S. seyhanensis (Teleostei: Cyprinidae), from the Seyhan River in Turkey Author Turan, Davut Author Kottelat, Maurice Author Doğan, Esra text Zootaxa 2013 3637 3 308 324 journal article 10.11646/zootaxa.3637.3.4 69d8d17b-5a6a-4302-8dd1-a611e6155a4d 1175-5326 222361 9D808E86-955E-4CDF-94B5-1BE1F7B7A2F5 Squalius seyhanensis , new species ( Fig. 5 ) Holotype . FFR 1992, 150 mm SL; Turkey : Kayseri Prov.: Sarız Stream, Seyhan River drainage; D. Turan & R. Buyurucu, 3 July 2007 . Paratypes . FFR 1993, 11, 126– 240 mm SL; same data as holotype . – FFR 1994, 15, 88–137 mm SL; CMK 19725, 2, 98–111; Turkey : Kayseri Prov.: Zamantı Stream at Sıradan Köyü, Seyhan River drainage; D. Turan & Z. Bostanci, 12 June 2005 . Additional material (non types ). FFR 0 0 707, 12, 94–232 mm SL; Turkey : Kayseri Prov.: Pınarbaşi county: Zamant Stream at Karagöz Village, Seyhan River drainage; D. Turan, E. Doġan & C. Kaya, 18 September 2007 . Diagnosis. Squalius seyhanensis is distinguished from all the species of Squalius in Turkey and adjacent waters by the combination of the following characters (none unique to the species): a contrasted reticulate pattern on the body, made of densely-set pigments on the exposed scale pockets and a broad band of densely-set melanophores along the posterior margin of each scale ( Fig. 3 b); a deep body (depth 24.4–27.5 % SL); a deep caudal peduncle (depth 12.0–12.9 % SL); a sexually dimorphic head shape (mouth slightly subterminal in males, with a slight chin [ Fig. 6 a]; terminal in females, with a distinct chin [ Fig. 6 b]); snout slightly pointed in males ( Fig. 6 a), rounded in females ( Fig. 6 b); the corner of the mouth not reaching a vertical through the anterior margin of the eye ( Fig. 6 a,b); the upper lip thick, its anterior width approximately 1.6–2.4 times its width at the corner of the mouth; length of the mouth gape shorter than its width; head length 25.4–27.4 % SL, approximately 0.9–1.1 times body depth; a fleshy anal fin; a slightly forked caudal fin (length of middle rays 72–82 % length of lower lobe), lobes slightly rounded; 42–44 + 1–2 lateral line scales; anal and pelvic fins in life with orange pigments on rays. FIGURE 5. Squalius seyhanensis , holotype, FFR 1992, 150 mm SL, Turkey: Kayseri Prov.: Seyhan River drainage. Description. General appearance is shown in Figure 5 ; morphometric and meristic data are given in Tables 1 and 3 . Body deep, slightly compressed laterally. Predorsal profile convex, especially in specimens larger than 200 mm SL, postdorsal profile slightly concave, dorsal profile slightly more convex than ventral profile. Head relatively short, approximately as long as body depth, its dorsal profile slightly convex in interorbital area. Mouth terminal in female, with a distinct chin; slightly subterminal in male, without a distinct chin, its corner not reaching vertical through anterior margin of eye. Width of mouth gape longer than its depth. Upper lip thick, anterior width approximately 1.6–2.4 times width at corner of mouth. Snout slightly pointed in male ( Fig. 6 a), rounded in female ( Fig. 6 b). Dorsal fin with 4 simple and 8½ branched rays; its height approximately equal to pectoral-fin length, outer margin slightly convex; origin markedly behind vertical through pelvic-fin origin. Pectoral fin short, its length 16.1–18.9 % SL, outer margin rounded, with 15–17 branched rays. Pelvic fin rounded, with 1 simple and 8 branched rays. Anal fin with 3 simple and 7½ (4), and 8½ (20) branched rays, fleshy, outer margin convex anteriorly. Caudal fin slightly forked, lobes rounded. Lateral line with 42–44 +1–2 scales; 7–8 scale rows between lateral line and dorsal-fin origin; 3–5 scale rows between lateral line and anal-fin origin. Gill rakers 3 + 6 = 9 on outer side of first gill arch. Pharyngeal teeth 5.2–2.5, distinctly hooked, serrated. Sexual dimorphism. Head shape sexually dimorphic. Mouth terminal in female, with a distinct chin; slightly subterminal, without a distinct chin in male. Snout rounded in female, slightly pointed in male. No tubercles on head, body and fins of either sex. Coloration. Formalin fixed adults and juveniles dark brown on back and flank, yellowish on belly. No or only a slightly distinct black bar behind opercle. Dorsal and caudal fins dark grey; pectoral, pelvic and anal fins yellowish. Scale pockets broad, exposed, densely covered by pigments forming a dark black crescentic blotch; a broad band of densely-set melanophores along posterior margin of each scale, resulting in a contrasted reticulate pattern ( Fig.3 b). A few melanophores on rays in preserved specimens. Anal and pelvic fins with orange pigments on rays in life. Etymology. The species is named for the Seyhan River, an adjective. Distribution and notes on biology. Squalius seyhanensis is presently known only from Sarız and Zamantı streams, tributaries of the upper part of the Seyhan drainage ( Fig. 4 ). It inhabits swift and cold flowing water, with a cobble and pebble bottom. Capoeta angorae was the only fish collected with S. seyhanensis . Its maximum size is 240 mm SL (observed in the field). FIGURE 6. Lateral view of head of: Squalius seyhanensis , a, FFR 1993, 236 mm SL, male; b, FFR 0 0 707, 222 mm SL, female. TABLE 2. Morphometry of Squalius turcicus , S. berak and S. orientalis . Values in parentheses: mean. Values of holotypes included in range.

S. turcicus	S. turcicus	S. berak	S. orientalis
Basin	Caspian Sea	Caspian Sea	endorheic basin	Black Sea
Drainage	Aras	Kura	Kueik	Çoruh
Number of specimens	25	14	15	25
Standard length (mm)	126–213	134-237	82–201	125–210
In percent of standard length
Head length	25.7–28.7 (27.3)	25.0–28.4 (27.0)	28.6–30.6 (29.6)	23.9–27.7 (25.6)
Body depth at dorsal-fin origin	18.7–24.2 (21.8)	20.2–23.2 (21.4)	23.0–26.2 (24.2)	21.3–25.2 (22.9)
Predorsal length	53.0–56.5 (54.5)	52.7–55.8 (54.3)	53.0–57.8 (55.9)	52.2–56.0 (53.8)
Prepelvic length	50.3–53.8 (51.8)	49.6–52.8 (51.5)	50.2–53.3 (51.9)	49.6–53.1 (51.3)
Preanal length	70.5–75.1 (72.1)	69.4–74.2 (72.0)	69.4–73.6 (72.2)	70.0–74.5 (71.9)
Pectoral-fin origin to anal fin	45.6–50.5 (48.1)	45.8–50.9 (48.3)	45.5–49.2 (47.2)	45.2–52.5 (49.2)
Pectoral-fin origin to pelvic fin	26.2–29.0 (27.4)	26.1–29.3 (27.5)	24.7–27.7 (26.1)	26.3–29.6 (27.9)
Pelvic-fin origin to anal fin	19.7–22.4 (21.1)	20.0–23.6 (21.4)	19.0–23.7 (21.4)	18.7–23.6 (21.5)
Dorsal-fin height	16.5–20.5 (18.7)	16.2–19.0 (18.5)	16.8–21.3 (19.4)	15.1–19.7 (18.0)
Anal-fin height	14.9–18.4 (16.6)	14.2–17.4 (16.3)	15.7–19.1 (17.3)	14.8–17.7 (16.7)
Pectoral-fin length	17.2–20.0 (18.3)	16.9–18.6 (17.8)	18.2–20.7 (19.5)	16.4–20.3 (18.0)
Pelvic-fin length	14.0–16.6 (15.2)	13.9–15.5 (14.7)	14.7–16.9 (15.7)	13.3–15.7 (14.8)
Length of upper caudal-fin lobe	17.9–21.1 (19.5)	17.3–21.1 (19.5)	19.9–24.7 (22.3)	17.3–21.2 (19.5)
Length of middle caudal-fin rays	11.5–14.1 (12.9)	11.6–14.5 (12.9)	12.2–16.5 (14.2)	11.1–14.5 (12.9)
Length of caudal peduncle	18.8–22.2 (20.8)	19.6–23.6 (21.0)	18.3–22.2 (20.3)	17.6–22.4 (20.4)
Depth of caudal peduncle	10.7–12.1 (11.3)	10.5–11.5 (11.1)	10.7–13.0 (11.8)	10.6–12.1 (11.5)
In percent of head length
Snout length	29–34 (30.7)	29–33 (30.6)	27–32 (29.1)	30–35 (31.8)
Eye diameter	16–24 (18.1)	15–20 (17.9)	16–25 (20.7)	16–21 (18.2)
Interorbital width	34–39 (36.6)	33–39 (36.4)	30–36 (33.5)	34–40 (37.1)
Head width1 at anterior margin of eyes	38–44 (41.0)	39–45 (41.1)	35–42 (37.8)	40–46 (42.7)
Head width2 at posterior margin of eyes	51–61 (54.7)	50–58 (54.6)	47–55 (50.7)	50–60 (54.8)
Head width3 at middle of post opercule	53–65 (58.9)	56–62 (58.7)	51–60 (55.0)	56–65 (60.8)
Head depth1 at interorbital region	42–53 (45.9)	44–48 (46.0)	42–53 (44.9)	44–52 (48.3)
Head depth2 at nape	58–69 (63.1)	62–67 (63.4)	57–64 (61.0)	63–72 (68.1)
Snout width at nostrils	29–42 (37.3)	36–42 (37.5)	31–39 (34.5)	36–42 (39.0)
Snout depth at nostrils	29–34 (31.3)	29–36 (32.9)	26–29 (27.4)	31–36 (33.0)
Width of mouth gape	26–32 (28.7)	26–34 (29.0)	24–32 (26.8)	28–35 (31.1)
Length of mouth gape	31–36 (32.8)	28–36 (32.6)	29–32 (30.4)	31–36 (33.4)
Discussion

In earlier studies, several species of Squalius were described or recorded from Turkey : S. cephaloides , S. cii , S. fellowesii , S. kosswigi , S. pursakensis , S. orientalis , S. turcicus and S. berak (Heckel, 1843; Hanko, 1924; Battalgil, 1942; Berg, 1949; Karaman, 1972). Most of them have later been relegated to the synonymy of S. cephalus , a ‘species’ at some time considered to be distributed throughout Europe (see overview of the western Anatolian species in Stoumboudi et al., 2006; Özuluġ & Freyhof, 2011). More recently, Kottelat & Freyhof (2007) and Özuluġ & Freyhof (2011) revalidated most of these nominal species and described additional ones. The molecular data of Durand et al . (2000) support these morphological observations and show a number of distinct lineages: ‘Western’, ‘Adriatic’ and ‘Aegean’. Durand et al . (2000) reported all three lineages from Anatolia . S. cii , S . fellowesii and S . orpheus belong to the ‘Aegean’ lineage. The Aegean lineage was also found in Seyhan and Kızılırmak rivers. S. kosswigi and an unnamed species from the Euphrates belong to the ‘Western’ lineage, while S. pursakensis , S . recurvirostris and S. turcicus belong to the ‘Eastern’ lineage. Other species in the ‘Eastern’ lineage are S . anatolicus , S . lepidus and S . kottelati . These last three species constitute the S. lepidus group and are morphologically distinguished from the species of the S. cephalus group by their elongate and pointed head and the projecting lower jaw, a greater number of cephalic pores, and the posteriorly expanded lateral portions of the parietals (Bogutskaya, 1994: 617). As we mentioned above, Durand et al .'s (2000) Aegean lineage was also found in the Seyhan River. As these authors did not provide information about the actual localities within the drainage, it is not possible to know which (if any) of our samples might belong to the Aegean lineage. Our surveys in the Seyhan drainage yielded three species of Squalius , all new to science. Among them, S. kottelati (of the S. lepidus group) was already described by Turan et al . (2009). The other two species from the Seyhan drainage ( S. adanaensis and S. seyhanensis ) belong to the S. cephalus group. S. adanaensis was observed in Üçürge, a small stream in the lower part of the Seyhan drainage. S. seyhanensis was observed in two streams, Sarız and Zamantı, in the upper part of the Seyhan drainage. We have not had the opportunity to check the presence of Squalius in the intermediate areas and therefore can not delimit the respective ranges of the two species. Squalius adanaensis is distinguished from S. seyhanensis by having fewer lateral line scales (38–42 + 1–2, vs. 42–44 + 1–2 [ Table 3 ]), a longer head (27.8–31.1 % SL, mean 29.2, vs. 25.4–27.4, mean 26.3), a slenderer body (body depth at dorsal-fin origin 22.6–24.7 % SL, mean 24.0, vs. 24.4–27.5, mean 25.7), without or with very slight chin in both sexes (vs. slightly distinct chin in male; [ Fig.6 a] and distinct chin in female [ Fig.6 b]). Further, in S. adanaensis there is no sexual dimorphism in the shape of the head, while in S. seyhanensis males have the upper head profile straight together with a snout with a slightly pointed tip; in females, the upper head profile is slightly convex and the snout tip rounded. Squalius adanaensis further differs from S. seyhanensis by the pigmentation pattern on the scales and the shape of flank scales. In S. adanaensis , the scale pockets are poorly developed and almost totally covered by the preceding scale; they are covered by melanophores that are not exposed but visible through the preceding scale and superficially appear as a greyish spot at the posterior tip of the preceding scales; there are no or only few melanophores along the posterior margin of the scales ( Fig. 3 a); most flank scales have a somewhat undulating outer margin ( Fig. 3 a). In S. seyhanensis , the scale pockets are broad, exposed and densely covered by pigments forming an intense black crescent-shaped blotch; there is a broad band of densely-set melanophores along the posterior margin of each scale, resulting in a contrasted reticulate pattern ( Fig. 3 b); flank scales have a smooth posterior margin ( Fig. 3 b). The two species are also distinguished by the shape of the mouth. In Squalius adanaensis , the length of the mouth gape is approximately equal to its width, the corner of the mouth approximately reaches a vertical through the anterior margin of the eye, and the upper lip is thin (the width of the upper lip at the tip of the snout is 1.3–1.5 times its width at the corner of the mouth). In S. seyhanensis , the length of mouth gape is smaller than its width, the corner of the mouth does not reach a vertical through the anterior margin of the eye ( Fig. 6 ), and the upper lip is thick (the width of the upper lip at the tip of the snout is 1.6–2.4 times its width at the corner of the mouth). Further, in S. adanaensis , the fin rays are slender and not fleshy, and the anal and pelvic fins have no orange pigments in life; while in S. seyhanensis , fin rays are thick and slightly fleshy, and the anal and pelvic fins have orange pigments in life. Squalius adanaensis and S. seyhanensis are distinguished from S. kottelati by the absence of a broad dark stripe on the upper part of the flank from the head to the end of the caudal peduncle (vs. present). They differ from S. kottelati , S. lepidus and S . anatolicus by the lower jaw not projecting (vs. projecting), fewer branched anal-fin rays (7–8½, vs. 8–10½), and a blunt (vs. pointed) head in males. Further, they have fewer lateral line scales than S. lepidus (38–44 + 1–2, vs. 47–48 + 1–2). TABLE 3. Frequency distribution of meristic features of the species of Squalius from eastern Anatolia. total lateral line scales N 39 40 41 42 43 44 45 46 47 mean S. adanaensis 15 1 3 6 4 1 - - - - 41.1 S . seyhanensis 24 - - - - 8 13 3 - - 43.8 S . berak 16 - - 6 7 3 - - - - 41.8 S . turcicus 24 - - - - 1 6 11 5 1 45.0 S . orientalis 24 - - - - 1 4 9 7 3 45.4 transverse line scales above lateral line below lateral line N 6 7 8 mean 3 4 5 mean S. adanaensis 15 2 8 5 7.2 7 8 - 3.5 S. seyhanensis 24 - 7 17 7.7 5 17 2 3.9 S. berak 16 - - 16 8.0 4 12 - 3.8 S. turcicus 24 - 1 23 8.0 2 22 - 3.9 S. orientalis 24 - - 24 8.0 - 20 4 4.2 branched anal-fin rays branched dorsal-fin rays N 7½ 8½ 9½ mean 7½ 8½ 9½ nean S. adanaensis 15 - 15 - 8.0 - 15 - 8 S. seyhanensis 24 4 20 - 7.8 - 24 - 8 S. berak 16 - 14 2 8.1 - 16 - 8 S. turcicus 24 - 19 5 8.2 3 21 - 7.9 S. orientalis 24 - 6 18 8.8 - 19 5 8.3 Historically, four species of the genus Squalius have been described or reported from eastern Anatolia : S. lepidus , S. berak , S . turcicus and S . orientalis . The type locality of S. lepidus is the Tigris River in Mossul (Heckel, 1843: 1078). Its range has long been considered to include the Tigris, Orontes, Ceyhan and Seyhan drainages, but our studies have shown that the populations from the Orontes, Ceyhan and Seyhan in fact belong to a different species, S. kottelati , discussed above (Turan et al . 2009). Berg (1949: 558) considered that the populations of the Squalius cephalus group from Northern Caucasus, Transcaucasia, the drainages of the Euphrates, of Kuban, Terek, Kuma, Kura and Arax, all rivers of Daghestan, of the Caspian coast of Iran and of western Transcaucasia as far as south as the Çoruh, belong to his S. c. orientalis . The type locality of S. orientalis is Abkhazia on the eastern Black Sea coast (Nordmann, 1840). Our identification of the Çoruh population as S . orientalis is tentative because we do not have access to material from Abkhazia and considering the local political situation we are unlikely to access some in the foreseeable future. The type locality of S. turcicus is the Aras River, a drainage of Kura River, in Erzurum Province ( De Filippi, 1865). This nominal species has long been treated as a synonym of S. orientalis (e.g. Berg,1949: 557). We examined and compared specimens from the upper basins of the Kura and Aras River. They belong to the same species and we identified it as S. turcicus , a valid species. S. turcicus is distinguished from S . orientalis by the absence orange pigments on anal-fin rays in live specimens (a few brownish pigments on anal-fin rays, vs. presence orange pigments on anal-fin rays) and the absence of black pigment in preserved specimens (vs. anal-fin membranes and rays with black pigments), the scale pockets narrow and almost entirely covered by the preceding scales ( Fig. 3 d) (vs. broad scale pockets; Fig. 3 e), black bar behind opercle absent or very slightly distinct (vs. distinct), and the absence of a hump at the nape (vs. a well-developed hump at the nape, especially in specimens larger than 200 mm SL). According to Berg (1949: 557), Barach (1934) created names for three populations of S. orientalis from Turkey , Armenia and Iran ( S. cephalus orientalis natio aralychensis , S. c. o. natio zangensis , S. c. o . natio ardebilicus ). We have not been able to examine this publication. These three names, however, were proposed as infrasubspecific names and are unavailable for nomenclatural purposes and, therefore, not discussed here. Squalius adanaensis is distinguished from S. orientalis and S. turcicus by having fewer lateral-line scales (38–42 + 1–2, vs. 43–45 + 2). In S. adanaensis the length of the mouth gape is approximately equal to its width and the corner of the mouth approximately reaches a vertical through the anterior margin of the eye. In S. turcicus and S. orientalis , the length of mouth gape is usually longer than its width and the corner of the mouth does not reach a vertical through the anterior margin of the eye. S. adanaensis further differs from S. turcicus by having a distinct dark spot on each scale pocket and no or few pigments along the posterior margin of the scales ( Fig. 3 a; vs. melanophores on scale pocket hidden under the broad margin along the posterior margin of the preceding scale; Fig. 3 d). S. adanaensis further differs from S. orientalis by the absence of a black bar behind the opercle (vs. presence) and the absence of orange pigments on anal and pelvic fin rays in life (vs. presence). Squalius seyhanensis is distinguished from S. turcicus by having a deeper body (body depth at dorsal-fin origin 24.4–27.5 % SL, mean 25.7, vs. 18.7–24.2, mean 21.6), a deeper caudal peduncle (depth 12.0–12.9 % SL, mean 12.3, vs. 10.5–12.1, mean 11.2), and a lesser (vs. greater) length than width of the mouth gape. In S. seyhanensis , the scale pockets are broad, exposed and densely covered by melanophores forming a black crescent-shaped mark ( Fig. 3 b). In S. turcicus , the scale pockets are narrow and almost entirely covered by the preceding scales so that the melanophores on the pocket are almost completely hidden under the posterior margin of the preceding scale ( Fig. 3 d). Squalius seyhanensis is distinguished from S. orientalis by having a very faintly distinct vertical black bar behind the opercle (vs. conspicuous), denser melanophores along the free margin of each flank scale ( Fig. 3 b; vs. a few melanophores along the free margin of each flank scale; Fig. 3 e), the dorsal profile without a marked discontinuity between head and trunk (vs. with a marked angle), and a sexually dimorphic head shape (snout slightly pointed in male and rounded in female, vs. snout rounded in both sexes). Moreover, S. seyhanensis has a deeper caudal peduncle and body than S. orientalis (caudal peduncle depth 12.0–12.9 % SL, mean 12.3, vs. 10.6– 12.1, mean 11.5; body depth 24.4–27.5 % SL, mean 25.7, vs. 21.3–25.2, mean 22.9). In S. seyhanensis the head length is 0.9–1.1 times body depth, while in S. orientalis it is 1.1–1.2 times body depth. The type locality of Squalius berak is Kueik River in Aleppo province in Syria (Heckel, 1843: 1079). The name of S. berak has sometimes been used for various populations of Squalius from south-western Anatolia (e.g. Kosswig & Battalgil, 1943), which are now recognised by Özuluġ & Freyhof (2011) as S. kosswigi ( type locality: Gümüldür, approximately 40 km south of Izmir) and S. fellowesii ( type locality: Eşen Stream [at Xanthos, approximately 55 km west of Fethiye]). In the same volume, Heckel (1843: 1080) also described S. cephalopsis from the same Kueik River in Aleppo. But, shortly thereafter (1848: 225) he treated S. cephalopsis as a synonym of S. orientalis and listed both S. berak and S. orientalis as occurring in the Kueik (pp. 229, 252). He also commented that local fishermen did not distinguish S. berak from S. 'orientalis' and that both were known under the single vernacular name berak . We examined some Squalius specimens from the upper part of the Kueik River and we identified them as S. berak using the data in Heckel (1843: 1078–1079 ). We could not obtain any specimen identifiable as S . cephalopsis from the upper part of the Kueik. We had no opportunity to sample the lower part of Kueik River (in Syria ) because of the local political situation. We have also examined photographs of the syntypes of S. berak (NMW 48715) provided by J. Freyhof. Heckel (1843: 1078) reported that S. berak has 42–43 total lateral line scales and 7 branched dorsal-fin rays [7½ in our notation], and S. cephalopsis 40–41 total lateral line scales and 8 [8½] branched dorsal-fin rays. The diagnosis of S. cephalopsis was very short, in a footnote. In 1848 (p. 225) Heckel listed S. cephalopsis as a synonym of S. orientalis and described S. orientalis in detail, apparently on the basis of the 1843 material. Heckel (1848) did not explain the synonymy between S. cephalopsis and S. orientalis , or how his S. orientalis is distinguished from S. berak . Our specimens from the Kueik River have 41–42 + 1 lateral line scales and 8½ branched dorsal-fin rays; the mouth is large, its corner almost reaching the vertical through the anterior margin of the eye in both sexes, and the cleft is straight or slightly curved near the angle. Moreover, the general body and mouth shape of our specimens is similar to the figure of S. berak in Heckel (1848: pl. 10 fig. 1). The figure of S . cephalopsis in Heckel (1843: pl. 16 fig. 2) shows a fish with a small mouth, with well developed chin, the corner not reaching the vertical through the anterior margin of the eye, and the mouth cleft strongly curved near the angle. Without more material and a wider sampling in the Kueik we cannot comment further on the validity of S. cephalopsis and tentatively retain it as valid. Squalius adanaensis : comparisons. Squalius adanaensis is distinguished from S. berak by having the length of mouth gape approximately equal to its width (vs. length of mouth gape longer than its width) and the absence of orange and black pigments on anal and pelvic-fin rays in life (vs. presence). It is further distinguished by the pigmentation pattern of the scales. In S. adanaensis , the scale pockets are poorly developed and covered by melanophores; there are no or only few melanophores along the posterior margin of the scales. In S . berak , the scale pockets are slightly developed and covered by grey pigments and there are a few grey pigments along the posterior margin of each scale. The following characters, although not totally diagnostic, also show some differences: fewer scale rows around the caudal peduncle (12–13, vs. 14–15), fewer scale rows between the dorsalfin origin and the lateral line [6 (2), 7 (8), 8 (5), vs. 8 (16)], and slenderer fin rays (rays thin, vs. thick or fleshy). S. adanaensis is distinguished from S . cephalopsis by having the corner of mouth almost reaching vertical through the anterior margin of the eye in both sexes (vs. not reaching vertical through anterior margin of; Heckel, 1843: pl. 16 fig. 2) and the mouth straight or slightly curved near the angle (vs. cleft strongly curved near the angle; Heckel, 1848: 225–226). Squalius adanaensis is distinguished from S. fellowesii by having a longer and slenderer head (27.8–31.1 % SL, mean 29.2, vs. 24.1–26.2, mean 24.9; head depth at through eye 43–47 % HL, mean 45.1, vs. 49–55, mean 51.8), the upper lip very slightly projecting beyond lower lip (vs. distinctly projecting beyond lower lip), slenderer fin rays (rays thin, vs. thick), and fewer melanophores along the posterior margin of the scales (no or only few melanophores along posterior margin of each flank scale, vs. a few melanophores along posterior margin). In S. adanaensis , the corner of the mouth approximately reaches a vertical through the anterior margin of the eye. In S . fellowesii , the corner of the mouth does not reach a vertical through the anterior margin of the eye. S. adanaensis is distinguished from S. kosswigi by the absence of an epidermal stripe from the tip of the operculum to the upper part of the caudal peduncle (vs. presence; Özuluġ & Freyhof, 2011). Squalius adanaensis is distinguished from S . cephaloides by having fewer lateral line scales (38–42 + 1–2, vs. 44–45 + 1–2), a longer head (27.8–31.1 % SL, mean 29.2, vs. 24.9–26.1, mean 25.4), the corner of the mouth almost reaching the vertical through the anterior margin of the eye in both sexes (vs. not reaching), and the absence of a black bar from the upper extremity of gill opening to the pectoral-fin base (vs. presence). S. adanaensis is distinguished from S . cii by having fewer lateral line scales (38–42 + 1–2, vs. 42–44 + 1–2), a somewhat longer head (27.8–31.1 % SL, mean 29.2, vs. 25.2–28.4, mean 27.0), the absence of a black bar from upper extremity of gill opening to pectoral-fin base (vs. presence), and the anal-fin membranes hyaline (vs. blackish). It further differs from S . cephaloides and S . cii by the pigmentation pattern on the scales. In S. adanaensis , the scale pockets are poorly developed and covered by melanophores; there are no or only a few melanophores along the posterior margin of the flank scales. In S . cephaloides and S . cii , the scale pockets are slightly developed and covered by melanophores forming a black crescent-shaped mark; there are a few melanophores along the posterior margin of the flank scale. Squalius adanaensis is distinguished from S. pursakensi s by the absence of a black bar from the upper extremity of the gill opening to the pectoral-fin base (vs. presence) and the anal-fin membranes whitish (vs. blackish), having a smaller mouth (length of mouth gape 26–31 % HL, mean 29.3, vs. 32–35, mean 33.7), a less developed scale pocket (poorly developed, vs. well developed) and fewer melanophores along the posterior margin of flank scales (no or only few melanophores along the posterior margin of flank scale, vs. a few melanophores along the posterior margin). Squalius adanaensis is distinguished from S . aristotelis by having fewer lateral line scales (38–42 + 1–2, vs. 41–44 + 1–2), a longer head (27.8–31.1 % SL, mean 29.2, vs. 25.5–27.5, mean 26.5), a slenderer head (head depth1), 1.0–1.1 times its width at interorbital region, vs. 1.1–1.2 times), the corner of the mouth almost reaching a vertical through the anterior margin of the eye in both sexes (vs. not reaching), the absence of a black bar from upper extremity of the gill opening to pectoral-fin base (vs. presence). Squalius adanaensis is distinguished from S . cappadocicus by having a longer head (27.8–31.1 % SL, mean 29.2, vs. 25.5–27.4, mean 26.3), a more rounded snout (vs. slightly pointed), and the upper jaw slightly projecting beyond the lower jaw (vs. markedly projecting). It further differs from S . cappadocicus by the pigmentation pattern on the scales. In S. adanaensis , the scale pockets are poorly developed and almost totally covered by the preceding scale; covered by melanophores; and there are no or only few melanophores along the posterior margin of the flank scales. In S . cappadocicus , the scale pockets are well developed and covered by melanophores, forming a black crescent-shaped mark; there is a broad band of densely-set melanophores along the posterior margin of the flank scales, resulting in a contrasted reticulate pattern. Squalius adanaensis is distinguished from S . carinus by the shape of the body and the head. In S. adanaensis , the upper profile of the body is straight or slightly convex behind the head and the upper profile of the head is slightly convex. In S . carinus , the upper profile of the body is markedly convex behind the head, and the upper profile of the head is slightly concave in the interorbital area and markedly convex on snout. Moreover, in S. adanaensis , the scale pockets are poorly developed and covered by melanophores, forming a distinct dark spot (vs. well developed and covered by melanophores, forming a black crescent-shaped mark); there is no black bar from upper extremity of the gill opening to the pectoral-fin base (vs. presence); and fin-rays are thin and not fleshy (vs. thick and slightly fleshy). Squalius adanaensis is distinguished from S . recurvirostris by having fewer lateral line scales 38–42 + 1–2, vs. 42–44 + 1–2), a slenderer body (body depth at dorsal-fin origin 22.6–24.7 % SL, mean 24.0, vs. 24.3–26.5, mean 25.1) and less developed scale pockets on flank (vs. well developed). It is further distinguished from S . recurvirostris by the shape of the body, the head and the anal-fin. In S. adanaensis , the upper profile of the body is straight or slightly convex behind the head, the upper profile of the head is slightly convex, and the outer margin of the anal fin markedly convex in the middle. In S . recurvirostris , the upper profile of the body is convex behind the head, the upper profile of the head is straight, and the outer margin of the anal fin is convex posteriorly. Squalius seyhanensis : comparisons. Squalius seyhanensis is distinguished from S. berak by having a shorter head (length 25.4–27.4 % SL, mean 26.3, vs. 28.6–30.6, mean 29.6), a greater interorbital distance (37–41 % HL, mean 38.3, vs. 30–36, mean 33.5), a wider head (width at anterior margin of eye 43–47 % HL, mean 45.4, vs. 35– 42, mean 37.8; at posterior margin of eye 56–60 % HL, mean 58.2, vs. 47–55, mean 50.7; at middle of post opercle 63–67 % HL, mean 65.2, vs. 51–60, mean 55.0), and more lateral line scales (42–44 + 1–2, vs. 41–42 + 2). In S. seyhanensis , the length of mouth gape is shorter than its width, the corner of the mouth does not reach a vertical through the anterior margin of the eye and there is a broad band of dense melanophores along the posterior margin of each flank scale ( Fig. 3 b), while in S. berak , the length of mouth gape is slightly longer than its width, the corner of the mouth approximately reaches a vertical through the anterior margin of the eye and there are only a few melanophores along the posterior margin of each flank scale ( Fig. 3 c). Squalius seyhanensis is distinguished from S . cephalopsis by having a greater number of lateral line scales (42–44 + 1–2, vs. 40–41 total) and a mouth that is straight or slightly curved near the angle (vs. cleft strongly curved near angle; Heckel, 1848: 225–226). Squalius seyhanensis is distinguished from S. fellowesii by having the length of the mouth gape shorter than its width (vs. greater), the upper lip not projecting beyond lower lip in females (vs. markedly projecting beyond lower lip in both sexes), a slenderer caudal peduncle (depth 12.0–12.9 % SL, mean 12.3, vs. 10.7–12.0, mean 11.4), denser melanophores along the free margin of the flank scales ( Fig. 3 b; vs. a few melanophores along the free margin of the scales). Squalius seyhanensis is distinguished from S. kosswigi by having a greater number of lateral line scales (42–44 + 1–2, vs. 38–40 + 2–3), and the absence of an epidermal stripe from the tip of the operculum to the upper part of the caudal peduncle (vs. present; Özuluġ & Feryhof, 2011). Squalius seyhanensis is distinguished from S . cephaloides by having a deeper body (body depth at dorsal-fin origin 24.4–27.5 % SL, mean 25.7, vs. 22.3–25.0, mean 23.6), a deeper caudal peduncle (12.0–12.9 % SL, mean 12.3, vs. 10.3–11.7, mean 11.1), a wider mouth (width of mouth 31–35 % HL, mean 33.6, vs. 26–29, mean 27.5), a slenderer head (head depth at through eye 1.0–1.1 times its width, vs. 1.1–1.2), and the anal-fin membranes yellowish (vs. blackish). Squalius seyhanensis is distinguished from S . cii by having a deeper caudal peduncle (12.0–12.9 % SL, mean 12.3, vs. 10.5–11.6, mean 11.2), a wider head (head width at posterior margin of eye 56–60 % HL, mean 58.2, vs. 49–53, mean 51.2), the length of the mouth gape approximately equal to its width (vs. greater than its width), the mouth terminal in female (vs. slightly subterminal) and the anal-fin membranes yellowish (vs. blackish). S.seyhanensis further differs from S . cephaloides and S . cii by having more developed scale pockets on the flank ( Fig. 3 b; vs. slightly developed) and denser melanophores along the posterior margin of flank scales ( Fig. 3 b; vs. a few melanophores along the free margin of each scale). Squalius seyhanensis is distinguished from S . pursakensis by having a shorter, wider head (25.4–27.4 % SL, mean 26.3, vs. 27.2–30.0, mean 28.6; head width at posterior margin of eye 56–60 % HL, mean 58.2, vs. 49–55, mean 51.9), a shorter mouth gape (length of gape 27–31 % HL, mean 29.2, vs. 32–35, mean 33.7), the length of the length of mouth gape approximately equal to its width (vs. longer than its width) and denser melanophores along the posterior margin of flank scales ( Fig. 3 b; vs. a few melanophores along the free margin of each scale). Squalius seyhanensis is distinguished from S . aristotelis by having a deeper body (body depth at dorsal-fin origin 24.4–27.4 % SL, mean 25.7, vs. 21.7–24.8, mean 23.0), a slenderer head (head depth at through eye 1.0–1.1 times its width, vs. 1.1–1.2), a terminal mouth in females (vs. subterminal), the outer margin of the anal-fin convex posteriorly (vs. convex in the middle), more developed scale pockets on flank (vs. slightly developed) and denser melanophores along the free margin of flank scales ( Fig. 3 b; vs. a few melanophores along the posterior margin of each scale). Squalius seyhanensis is distinguished from S . cappadocicus by having a deeper body (24.4–27.5 % SL, mean 25.7, vs. 23.2–24.7, mean 23.7), a narrower mouth (mouth width 31–35 % HL, mean 33.6, vs. 26–31, mean 28.8), a very faintly marked vertical black bar behind the opercle (vs. conspicuous) and the upper jaw not projecting beyond the lower jaw in females (vs. distinctly projecting in both sexes). Squalius seyhanensis is distinguished from S . carinus by having a smaller head (25.4–27.4 % SL, mean 26.3, vs. 27.3–29.8, mean 28.4), a somewhat deeper body (24.4–27.5 % SL, mean 25.7, vs. 23.3–25.2, mean 24.5), the upper profile of the head slightly convex (vs. the upper profile of the head slightly concave in interorbital area and distinctly convex on snout), and denser melanophores along the posterior margin of flank scales (vs. a few melanophores along posterior margin of each scale). Squalius seyhanensis is distinguished from S . recurvirostris by having a deeper caudal peduncle (12.0–12.9 % SL, mean 12.3, vs. 10.3–11.6, mean 11.1), the length of mouth gape shorter than its width (vs. approximately equal), the upper profile of the head slightly convex in female (vs. straight or slightly concave in interorbital area in both sexes), and denser melanophores along the posterior margin of flank scales (vs. a few melanophores along the posterior margin of each scale).