Squalius semae, Davut Tura & Maurice Kottelat & Esra Bayçelebi, 2017

Davut Tura, Maurice Kottelat & Esra Bayçelebi, 2017, Squalius semae, a new species of chub from the Euphrates River, Eastern Anatolia (Teleostei: Cyprinidae), Zoology in the Middle East 63 (1), pp. 33-42 : 35-41

Squalius semae , sp. n. ( Figure 1 a-b)

Holotype. FFR 724, 197 mm SL; Turkey: Erzurum Prov.: Serçeme Stream (tributary of Karasu Stream ) (39°56.85’N 40°48.24’E) ; D. Turan, E. Bayçelebi & C. Kaya, 26.v.2013. – Paratypes. FFR 725, 26 , 133– 228 mm SL; same data as holotype. – FFR 669, 9 , 121– 174 mm SL; Turkey: Erzurum: Sırlı Stream (tributary of Karasu Stream ) (40°13.06’N 41°06.03’E) ; D. Turan & R. Buyurucu, 23.iv.2005. – FFR 593, 52 , 50–161 mm SL; Turkey: Erzurum: Toprakkale Stream (tributary of Karasu Stream ), (40°14.51’N 40°59.67’E) ; D. Turan & R. Buyurucu, 15.viii.2009. – FFR 700, 8 , 91–200 mm SL; Turkey: Muş Prov.: Karasu Stream (a tributary of Murat River ) (38°38.94’N 41°46.98’E) ; D. Turan, E. Bayçelebi & C. Kaya, 22.ix.2013. – FFR 703, 4 , 86–123 mm SL; Turkey: Muş Prov.: Murat River (38°51.97’N 41°00.00’E) ; D. Turan, E. Bayçelebi & C. Kaya, 22.ix.2013. – FFR 710, 5 , 86–123 mm SL; Turkey: Ağrı Prov. Doğubeyazıt Dist.: Murat River (39°36.81’N 43°30.98’E) ; D. Turan, E. Bayçelebi & C. Kaya, 16.vii.2012. – FFR 722, 13 , 64–123 mm SL; Turkey: Muş Prov.: Mercimekkale Stream (tributary of Murat River ) (38°04.07’N 41°31.73’E) ; D. Turan, E. Bayçelebi & C. Kaya, 22.ix.2013. – FFR 727, 2 , 165– 190 mm SL; Turkey: Tunceli Prov.: Pülümür Stream (39°08.39’N 39°38.31’E) ; C. Kaya & M. Kocabaş, 27.x.2013. – CMK 26645, 4 , 174– 195 mm SL; Turkey: Erzurum Prov.: Serçeme Stream (tributary of Karasu Stream ) (39°56.85’N 40°48.24’E) ; D. Turan, E. Bayçelebi & C. Kaya, 26.v.2013. All from the Euphrates River drainage.

Diagnosis. Squalius semae sp. n. is distinguished from all other species of Squalius in eastern Anatolia by the combination of the following characters: mouth slightly subterminal to terminal, with a marked chin in males, slightly marked in females; the upper lip thick, slightly projecting beyond lower lip, its anterior width approximately 1.7–2.0 times its width at the corner of the mouth; scale pockets somewhat narrow, with dense dark brown pigments, and almost covered by the posterior margin of preceding scales; a band of densely-set dark brown or blackish pigments along the posterior margin of each flank scale; head length 26.0–32.2% SL, approximately 1.1–1.3 times body depth; anal, pelvic and pectoral fins with numerous black pigments on rays; dorsal fin with numerous black pigments on rays and membranes; dorsal-fin origin behind pelvic-fin base; posteriormost point of anal fin at tip of 3th or 4th branched ray; caudal fin slightly forked, lobes slightly rounded; and 41–46 total lateral line scales.

Comparison with closely related species. Squalius semae is distinguished from S. berak by having numerous black pigments on anal-fin rays in life ([ Figure 3 A], vs.

pigments on rays orange in live specimens, greyish when preserved [ Figure 3 B]); by the absence of a dark stripe on the upper part of the flank, from the head to the end of the caudal peduncle (vs. presence of a faint dark stripe); by having thicker rays in all fins (thick and fleshy, vs. slender and not fleshy) and the tip of the snout rounded (vs. slightly pointed). It also differs from S. berak in the pigmentation pattern on the scales. In S. semae , there is a band of densely-set dark brown or blackish pigments along the posterior margin of each flank scale, resulting in a contrasted reticulate pattern ( Figure 2 a). In S. berak there are a few grey pigments along the posterior margin of each scale (Figure 2b).

Squalius semae sp. n. is distinguished from S. seyhanensis by having black pigments on anal-fin rays in life ([ Figure 3 A] vs. pigments orange in life, greyish when preserved [ Figure 3 B]). Squalius semae sp.n. is further distinguished from S. seyhanensis by the width of the gape of the mouth smaller than its length (vs. width greater than its length). Besides, the two species differ in the pigmentation pattern on the scales. In S. semae sp.n., the scale pockets are somewhat narrow, with faintly dense dark brown or blackish pigments, and almost covered by the posterior margin of preceding scales ( Figure 2 a). In S. seyhanensis , the scale pockets are broad, exposed and densely covered by melanophores forming a black crescent-shaped mark, and approximately one third of the pigments on scale pockets are covered by the posterior margin of preceding scales ( Figure 2 c). Squalius semae sp.n. has a narrower band of densely-set pigments along the posterior margin of each scale than observed in S. seyhanensis .

Kaya, Turan, and Ünlü (2016) identified the Squalius populations of Batman and Silvan streams (Tigris River drainage) as Squalius sp. Squalius semae sp. n. is distinguished from Squalius sp. by having numerous black pigments on anal and pelvic-fin rays in life (vs. anal and pelvic-fin rays with orange pigments). Further the two species differ in the pigmentation pattern of the scales. In S. semae sp. n., the scale pockets are somewhat narrow and almost covered by the posterior margin of preceding scales, and there is a band of densely-set dark brown or blackish pigments along the posterior margin of each scale, resulting in a contrasted reticulate pattern. In Squalius sp., the scale pockets are somewhat large and not covered by the posterior margin of preceding scales, and there are a few melanophores along the posterior margin of the scales.

Squalius semae sp. n. is distinguished from S. adanaensis by having numerous black pigments on anal and pelvic-fin rays (vs. anal and pelvic fins without black or orange pigments) and thicker and fleshy fin rays (vs. slender and not fleshy). Further the two species differ in the pigmentation pattern of the scales and the shape of flank scales. In S. semae sp. n., there is a band of densely-set dark brown or blackish pigments along the posterior margin of each scale, resulting in a contrasted reticulate pattern; flank scales have a smooth posterior margin. In S. adanaensis , there are no or only few melanophores along the posterior margin of the scales; most flank scales have a somewhat undulating posterior margin. The two species are also distinguished by the shape of the mouth. In S. semae sp. n., the width of the gape of the mouth is slightly smaller than its length, the corner of the mouth is in front of a vertical through the anterior margin of the eye, and the upper lip is thick (the width of the upper lip at the tip of the snout is 1.7–2.0 times its width at the corner of the mouth). In S. adanaensis , the length of the mouth gape is approximately equal to its width, the corner of the mouth is about below 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).

Squalius semae sp. n. is distinguished from S. turcicus by the presence of black pigments on anal-fin rays (vs. absence) and the shape of the body in specimens larger than about 160 mm SL (dorsal profile of body convex and ventral profile approximately as convex as dorsal profile, vs. dorsal profile of body straight and ventral profile convex). The two species further differ by the pigmentation pattern of the scales. In S. semae sp. n., there is a band of densely-set dark brown or blackish pigments along the posterior margin of each flank scale, resulting in a contrasted reticulate pattern ( Figure 2 a; vs. a few light brown pigments) and the caudal fin has a greyish margin (vs. with black margin). Squalius semae sp. n. further differs from S. turcicus by having a round- ed snout (vs. pointed), a less rounded outer margin of the anal fin (slightly convex, vs. convex), a distinct chin in males (vs. indistinct), the dorsal fin with slightly convex outer margin (vs. straight or slightly convex), and thicker fin rays (thick or fleshy, vs. thin).

Squalius semae sp. n. is distinguished from S. orientalis by the presence of black pigments on anal- and pelvic-fin rays (vs. anal and pelvic-fin rays with orange pigments). Squalius semae sp. n. has a band of densely-set dark brown or blackish pigments along the posterior margin of each flank scale, resulting in a contrasted reticulate pattern ( Figure 2 a; vs. few melanophores). It further differs from S. orientalis in having fewer branched anal-fin rays (7½ or 8½, mean 7.9, vs. 8½ or 9½, mean 8.8), a somewhat longer and more slender head (head length 26.0–32.2% SL, mean 27.7, vs. 23.9– 27.7, mean 25.6; head depth at nape 58-65% HL, mean 61.3, vs. 63–72, mean 68.1), and by having a very faintly distinct vertical black bar behind the opercle (vs. conspicuous), and denser melanophores along the free margin of each flank scale.

Squalius semae sp. n. is distinguished from S. kottelati and S. lepidus (of the lepidus- group) by the lower jaw not projecting (vs. projecting), by having fewer branched anal-fin rays (7½ or 8½, mean 7.9, vs. 8–10½, mean 9.4), and a blunt (vs. pointed) head in males. Further, it has fewer lateral line scales than S. lepidus (total 41–46, vs. 48–49). Squalius semae sp. n. is further 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. presence).

The three species of the S. cephalus group present in the Euphrates River drainage ( S. seyhanensis , S. semae sp. n. and S. berak ) were compared using principal component analysis (PCA). The PCA was performed on 28 morphometric characters. The PCA shows that the new species almost separated from S. seyhanensis and S. berak as well as from each other ( Figure 5 ). The most important loadings on PC II are for the body depth, distance between pelvic-fin origin and anal fin origin, the height of the dorsal and anal fins, the length of the upper caudal lobe, the length and width of the snout, and the head width.

Description. Body shape as in Figure 1 a–b; morphometric and meristic data are given in Tables 1–2 . Body moderately deep, slightly compressed laterally. Dorsal profile of body convex, ventral profile approximately equal to dorsal profile. Head long (length 26.0–32.2% SL), approximately 1.1–1.3 times body depth, its dorsal profile slightly convex above eye and convex on snout. Mouth slightly subterminal to terminal, its corner not reaching vertical through anterior margin of eye. Length of mouth gape approximately slightly greater than its width. Upper lip thick, anterior width approximately 1.7–2.0 times width at corner of mouth. Snout with rounded tip.

Dorsal fin with 4 simple and 7½ (1) or 8½* (29) branched rays, its height approximately equal to pectoral-fin length, outer margin slightly convex. Pectoral fin short, its length 16.4–20.0% 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 (1), 8½* (28) or 9½ (9) branched rays, fleshy, outer margin convex posteriorly. Caudal fin slightly forked, lobes slightly rounded. Total number of lateral line scales 41 (2), 42 (2), 43 (10), 44* (13), 45 (1) or 46 (1); 7* (5) or 8 (25) scale rows between lateral line and dorsal-fin origin; 3 (6) or 4* (24) scale rows between lateral line and anal-fin origin. Gill rakers 3 + 8–9 = 11–12 on outer side of first gill arch. Pharyngeal teeth 5.2–2.5, distinctly hooked, serrated.

Sexual dimorphism. There are small tubercles on the head in the males, which are absent in the females.

Colouration. In life, general body colour silvery, pelvic, anal and pectoral fins yellowish, and dorsal and caudal fins light greyish. Numerous black pigments on anal, pelvic and pectoral fin rays. Dorsal fin with numerous black pigments on rays and membranes. A faint narrow black bar behind opercle. Formalin-fixed adults and juveniles dark brown on back and upper part of flank, yellowish on belly. Faint black bar behind opercle. Dorsal and caudal fins dark grey; pectoral, pelvic and anal fins light greyish. Scale pockets with dense dark brown or blackish pigments, and almost covered by posterior margin of preceding scales. A band of densely-set dark brown or blackish pigments along posterior margin of each flank scale, resulting in a contrasted reticulate pattern ( Figure 2 a). Anal, pelvic and pectoral fins with black pigments on rays ( Figure 3 A). Dorsal fin with numerous black pigments on rays and membranes.

Etymology. The species is named for Sema Turan, the beloved wife of the first author. Distribution and Notes on Biology. Squalius semae sp. n. is presently known from Sırlı, Toprakkale and Serçeme streams (tributaries of Karasu Stream), Pülümür Stream and Murat River (northeastern drainage of Euphrates) ( Figure 4 ). It inhabits cool, swift flowing water, with a cobble and pebble bottom. Salmo euphrataeus , Oxynoemacheilus sp., Alburnoides velioglui , Alburnus mossulensis and Capoeta umbla were collected with S. semae sp. n. The maximum size observed in the field was about 600 mm SL.

Figures

Figure 1. Squalius semae sp. n., Turkey: Erzurum Prov.: Serçeme Stream (tributary of Karasu Stream), Euphrates River drainage. Above: FFR 724, holotype, 197 mm SL, female; Below: FFR 669, paratype, 174 mm SL, male.

Figure 2. Pigments on flank scales: (a) Squalius semae sp. n., FFR 669, 174 mm SL; (b) S. berak, FFR 775, 164 mm SL; (c) S. seyhanensis, FFR 729, 228 mm SL.

Figure 3. Pigments on rays and membranes of anal-fin of Squalius species from Euphrates River: A: S. semae sp. n., FFR 725, 187 mm SL; B: S. berak, FFR 775, 164 mm SL; C: S. seyhanensis, FFR 729, 228 mm SL.

Figure 4. Distribution of the species of Squalius in Anatolia: S. adanaensis (), S. anatolicus (), S. aristotelis (), S. berak (), S. cappadocicus (), S. carinus (), S. cephaloides (), S. cii (n), S. fellowesii (), S. kosswigi (), S. kottelati (), S. lepidus (▲), S. orientalis (), S. pursakensis (), S. recurvirostris (), S. semae sp. n. (©), S. seyhanensis (), S. turcicus (*) and Squalius sp. (¢).

Figure 5. Scatterplot of the scores of the first two principal components (PC I against PC II) on 28 morphometric characters for 63 specimens of three species of Squalius: S. berak (Ǫ), S. semae sp. n. (∆) and S. seyhanensis (+).