Chondrostoma smyrnae, Küçük & Çiftci & Güçlü & Turan, 2021

Kuecuek, Fahretti ̇ n, Ciftci, Yilmaz, Gueclue, Salim Serkan & Turan, Davut, 2021, Chondrostoma smyrnae, a new nase from the Tahtali reservoir drainage in the Aegean Sea basin (Teleostei, Leuciscidae), Zoosystematics and Evolution 97 (1), pp. 235-248 : 235

Chondrostoma smyrnae sp. nov. Fig. 3a-c

Holotype.

IFC-ESUF 03-1566, 191 mm SL; Turkey: İzmir prov.: Tahtalı reservoir about 2 km north of Değirmendere, 38°08'19"N, 27°07'10"E.

Paratypes.

IFC-ESUF 03-1567, 22, 152-205 mm SL; IFC-ESUF 03-1568, 22, 181-272 mm SL; same data as holotype. - IFC-ESUF 03-1550, 2, 92.68-109.02 mm SL; Turkey: İzmir prov.: stream Şaşal about 1 km south of Küner, 38°11'57"N, 27°08'09"E. - FFR 2079, 1, 92 mm SL; Turkey: İzmir prov.: stream Balaban at Küner, 38.213950 27.101505.

Material used in molecular genetic analysis.

IFC-ESUF DNA-03-1550, 7, Turkey: İzmir prov.: stream Şaşal about 1 km south of Küner, 38°11'57"N, 27°08'09"E (GenBank accession number: MT387055 - MT387058 ; MW719591 - MW719611 ; MW722822 - MW722824 ) .

Diagnosis.

Chondrostoma smyrnae is distinguished from other species occur to adjacent basin by a cylindrical body (body width at dorsal-fin origin 16.8-19.3% SL, vs. 13.3-15.4 in C. turnai (Fig. 3d ), 14.1-16.6 in C. meandrense , 12.0-16.3 in C. holmwoodii , 12.4-15.7 in C. fahirae , except C. beysehirense ), a wider head (head width at anterior margin of eye 55-65% HL, vs. 42-54), by having less lateral line scales (48-53 vs. 60-67 in C. beysehirense , 60-66 in C. holmwoodii and 56-60 in Chondrostoma meandrense , except C. turnai and C. fahirae ). Chondrostoma smyrnae is further distinguished from C. turnai by the absence keel between pelvic fin-origin and anus (vs. present in specimens larger than 160 mm SL), a straight or slightly arched lower jaw (vs. arched), more total lateral line scales (48-53, vs. 44-51), and fewer gill rakers on first gill arch (19-23, vs. 22-27). Also, C. smyrnae further differs from C. turnai by the shape of jaws, hyomandibular, quadrate and the fifth brachial gill arc. In C. smyrnae , the dentary thick and coronoid process inclined forward (vs. thin and coronoid process nearly vertical); premaxilla very deep and posterior edge short (vs. slender and posterior edge long); hyomandibular long and narrow (vs. short and wide), the fifth brachial gill arc wide angle (vs. narrow angle) and pharyngeal teeth wide (vs. thin); outer margin of quadrate slightly pointed (vs. rounded) (Figs 4 , 5 ).

The new species is also distinguished from C. meandrense by the body colour silvery in life (silvery, vs. brownish). It is further distinguished from C. holmwoodii by having 8-9 scale rows between the lateral line and dorsal-fin origin (vs. 9-11), four scale rows between the lateral line and pelvic-fin origin (vs. 6-7). Chondrostoma smyrnae is further distinguished from C. fahirae by having of 19-23 gill rakers on the first gill arch (vs. 12-14), well keratinised cutting edge present on the lower jaw (vs. slightly) (Fig. 6 ).

Description.

See Figures (3) for general appearance, Table 3 , 4 for morphometric and Table 5 , 6 for meristic data. A small-sized individual of Chondrostoma symrnae with a cylindrical body shape is shown on Figure 7 . Dorsal and ventral body profiles markedly convex. Interorbital area slightly convex. Mouth inferior, arched, with a keratinized cutting edge on lower jaw. The lower jaw slightly arched. Snout long, length 31-35% HL, with slightly rounded tip. Rostral cap almost covers upper jaw. Lower jaw relatively long, lower jaw-quadrate junction on vertical through eye pupil margin. Eye diameter about equal to interorbital distance. Caudal peduncle depth fits 10-12 times in its length. Dorsal-fin outer margin markedly concave. Anal-fin outer margin concave. Caudal-fin deeply forked, lobes with pointed tips. Outer margins of pectoral and pelvic-fins slightly convex. Pharyngeal teeth in two rows, 5-6, 5-5, sharp, serrated, hooked at tip (Fig. 5 ). Dentary thick and coronoid process inclined forward. Premaxilla very deep and its posterior edge short. Hyomandibular long and narrow. Fifth branchial gill arc wide angle and pharyngeal teeth wide. Outer margin of quadrate slightly pointed.

The number of lateral line scales, scale rows between the lateral line and dorsal-fin origin, scale rows between the lateral line and pelvic-fin origin, branched dorsal-fin rays, branched anal-fin rays and rakers on the outer side of the first gill arch are shown in Tables 5 - 6 .

Colouration.

In life: fins pinkish with hyaline margins; back brown; flank silvery with pinkish hue. After fixation: back and upper portion of flank dark greyish; mid-lateral portion of flank and belly yellowish. Dorsal and caudal fins dark grey, pelvic and anal fins yellowish. Peritoneal membrane black.

Distribution.

Chondrostoma smyrnae is known from the Tahtalı reservoir basin (Fig. 8 ). It is also expected to be native to the Küçük Menderes River drainage but attempts to find it there have thus far proven unsuccessful and it may have been extirpated.

Etymology.

The species is named for Smyrna, the historic name of the city known today as Izmir. A noun in genitive, indeclinable.

Figures

Figure 3. a. Chondrostoma smyrnae, IFC-ESUF 03 - 1567, just after fixation form, 167 mm SL, Turkey: Tahtali reservoir; b. IFC-ESUF 03 - 1566, holotype, 191 mm SL, Turkey: Tahtali reservoir; c. IFC-ESUF 03 - 1567, paratype 205 mm SL, Turkey: Tahtali reservoir; d. Chondrostoma turnai, IFC-ESUF 03 - 1557, 197 mm SL, Turkey: Cine stream.

Figure 4. Jaws bones of C. smyrnae (a.) and C. turnai (b.) (Dn: dentary, Pmx: premaxilla, Mx: maxilla, Crp: Coronoid process).

Figure 5. Hyomandibular, quadrate and pharyngeal teeth of C. smyrnae (a.) and C. turnai (b.) (Hym: hyomandibulare, qu: quadrate, Pht: Pharyngeal teeth).

Figure 6. Ventral view of head: a. C. smyrnae, IFC-ESUF 03 - 1567, paratype, 189 mm SL, Turkey: Tahtali reservoir; b. C. turnai, IFC-ESUF 03 - 1524, 174 mm SL, Turkey: Cine Stream; c. C. meandrense, IFC-ESUF 03 - 1519, 183 mm SL, Turkey: Isikli Spring; d. C. holmwoodii, IFC-ESUF 03 - 1513, 156 mm SL, Turkey: Gediz River; e. C. angorense, IFC-ESUF 03 - 1502, 152 mm SL, Turkey: Sakarya River; f. C. fahirae, IFC-ESUF 03 - 1512, 109 mm SL, Turkey: Dalaman River; g. C. beysehirense, IFC-ESUF 03 - 1505, 288 mm SL, Turkey: Beysehir Lake.

Figure 7. Top view of Chondrostoma smyrnae (a.) IFC-ESUF 03 - 1567, 194.2 mm SL; (b.) 190.0 mm SL, Tahtali Reservoir; and C. turnai (c.) IFC-ESUF 03 - 1524,195.1 mm SL; (d.) 181.3 mm SL, Stream Cine.

Figure 8. Distribution of Chondrostoma species in western Anatolia.