IMNRF-UT-1072-9, holotype, 142.6 mm SL. Iran: Mazandaran Prov., Chalus city, Kheyroud River (Figure 8), Caspian Sea basin, 36°36'35"N, 51°33'45"E, S. Eagderi & A. Jouladeh-Roudbar, November 2016.

IMNRF-UT-1072, 14 specimens, 90.7–184.2 mm SL; data same as holotype.

Capoeta razii sp. n. is distinguished from the other species of Capoeta in Iran by a following combination of characters, none of them unique. One pair of barbels; pre-dorsal length equal to postdorsal length; maxillary barbel slightly smaller than eye’s horizontal diameter and reach to posterior margin of orbit; intranasal length slightly shorter than snout length; lateral line with 46–54 scales, 7–9 scales between dorsal-fin origin and lateral line and 6–7 scales between anal-fin origin and lateral line.

See Figure 4 for general appearance and Tables 4–7 for morphometric and meristic data. Body is moderately deepened and compressed laterally. Greatest body depth occurs at the level of dorsal-fin origin. Dorsal profile of the head is convex. Predorsal length is equal to post-dorsal length. Dorsal profile of the body is convex without any keel in the front of dorsal-fin origin. Snout is rounded with a triangular view in ventral. Mouth is almost straight. Upper and lower lips are adnate to jaws. Lower jaw has a strong keratinized edge. Rostral cap is well developed and usually overlaps with upper lip. One set of maxillary barbels that are short, slightly smaller than eye’s horizontal diameter, reaching to posterior margin of orbit. Intranasal length is slightly shorter than snout length. Pelvic axillary scales are triangular, well developed, and pointed. Dorsal fin has 3–4 unbranched and 7–8 branched rays, its outer margin is straight or slightly concave. Last unbranched dorsal-fin ray is thickened and serrated, distally flexible, and with 15–25 serrae on its posterior margin, with serrations along 50–70% of its posterior margin, denticles are long and narrowly spaced but not strongly developed. Last unbranched dorsal-fin ray slightly shorter than first branched ray, and the tip is soft. Pelvic fins are inserted under posterior of the first branched dorsal-fin base. Caudal fin is deeply forked with pointed and equal size of lobes. Pectoral fin has 16–19 branched rays. Pelvic fin has 1 unbranched and 9–10 branched rays. Anal fin has 2–3 unbranched rays, 6 branched rays and its outer margin is usually convex or straight. There are 15–21 gill rakers on the outer side of the first arch. There are 17–18 circum-peduncular scales. Lateral line is complete, with 46–54 scales. There are 7–9 scales between the dorsal-fin origin and lateral line and 6–7 are located between the anal-fin origin and lateral line.

In life, the upper part of the body is golden brown, olive-green, or silver, and the belly is whitish up to the lateral line. The head is dark-brown or olive-green on top and the cheeks are pale brown to white (Figure 4). Anal, pelvic, and pectoral fins are hyaline or light brown, and dorsal and caudal fins have a narrow black line on rays. In specimen smaller than 50 mm SL, minute black spots are present on flanks.

When preserved, the dorsum is dark brown on back and flanks, and yellowish white on belly (Figure 6). Dorsum of the head is dark brown, and the cheeks beige. Fins are often light brown and pelvic and anal fins may be yellowish to hyaline. Dorsal and caudal fins are darker than lower fins. Peritoneum is black.

Capoeta razii is found in many rivers and streams of the southern Caspian Sea basin. It is one of the most abundant species in the Caspian Sea basin along with the members of the genus Alburnoides Jeitteles, 1861. At the Kheyroud River (type locality), the current was medium to fast, river width was between 3–14 m and the maximum depth was around one meter, the stream bed was composed of cobbles and gravel, and the riparian vegetation type was deciduous forests. Following fish species: Poticola iranicus Vasil’eva, Mousavi-Sabet & Vasil’ev 2015, Alburnoides taberstanensis Mousavi-Sabet, Anvarifar & Azizi, 2015, Alburnus chalcoides (Güldenstädt 1772), Barbus cyri De Filippi 1865, Squalius turcicus De Filippi 1865, Luciobarbus capito Güldenstädt 1773, L. mursa Güldenstädt 1773, Cobitis faridpaki Mousavi-Sabet, Vasil’eva, Vatandoust & Vasil’ev 2011, co-exist with C. razii in type locality. Capoeta razii is known from most of rivers and streams between Atrak and Kote komeh (Near Astara city) rivers in southern Caspian Sea basin.

The new species is named in honour of Abū Bakr Muhammad ibn Zakariyyā al-Rāzī, a Persian polymath, physician, alchemist, and philosopher, for his important contributions in the history of medicine. He also discovered numerous compounds including Ethanol.

Capoeta razii sp. n. is distinguished from C. aculeata and C. alborzensis by a smaller scale size and a higher number of total lateral line scales (46–54 vs. 39–44).

Capoeta razii sp. n. is distinguished from C. fusca, by a smaller caudal peduncle width (2.8–4.1 vs. 5.5–7.0 %SL), a smaller head length (20.5–24.0 vs. 25.0–28.6 %SL), and the presence of numerous minute scales on the caudal fin base extending distally onto the fin membranes for more than half the fin ray length (vs. absence of minute scales on the caudal fin base) (Figure 10).

Capoeta razii sp. n. is distinguished from C. anamisensis, C. barroisi, C. buhsei, C. Capoeta, C. coadi, C. damascina, C. heratensis, C. mandica, C. saadi and C. umbla by a larger scale size, a fewer number of total lateral line scales (46–54 vs. 55–102).

– Capoeta aculeata: IMNRF-UT-1058, 9. 53–116 mm SL, Iran: Fars prov.: Tange Boragh village, Kor River, Kor basin, 37°14'46"N, 58°08'01"E, Aug 2014, S. Eagderi & H. Mossavi-Sabet. – Capoeta alborzensis.: IMNRF-1063, 7. 50–153mm SL, Iran: Tehran prov.: Nam River, tributary of Hableh River, near Arjomand village, 35°48'00"N, 52°30'57"E; IMNRF-UT-2063, 23, 46–163mm SL, Iran: Tehran prov.: Nam River, tributary of Hableh River, Kavir basin, near Harandeh village, 35°42'41"N, 52°40'19"E, S. Eagderi & A. Jouladeh-Roudbar, September 2014. – Capoeta buhsei: IMNRF-UT-1075, 12. 103.9–211.8 mm SL, Iran: Markazi prov.: Tafresh town, at Khalife kandy village, Mazlaghan Chay River, Namak basin, 34°45'34"N, 49°56'50"E, Nov 2016, A. Rahmani, M. A. Jahazi, R. Rahbar-zare, A. Jouladeh-Roudbar. – Capoeta capoeta: IMNRF-UT-1067, 15. 66–157 mm SL, Iran: Tabriz prov.: Near Ajab shir city, Ghale Chay River, Urmia Lake basin, 37°29'25"N, 45°59'57"E, Nov 2016, T. Hosseinpour, M. Ahmadian & A. Jouladeh-Roudbar. – Capoeta coadi: IMNRF-UT- 1074, 15. 125.7–194.7 mm SL, Iran: Chaharmahal and Bakhtiari prov.: Near Joneghan town, at Darkesh varkesh village, Behesht Abad River, Tigris basin, 32°05'22"N, 50°39'54"E, Aug 2016, T. Hosseinpour, A. Soleymani & A. Jouladeh-Roudbar. – Capoeta fusca: IMNRF-UT-1065, 8. 46–121 mm SL, Iran: North Khorasan prov.: Near Farooj town, at segonbadan village, Qanat-e Segonbadan, Hari basin, 37°14'46"N, 58°08'01"E, Jun 2016, S. Eagderi & A. Jouladeh-Roudbar. – Capoeta heratensis: IMNRF-UT-1064, 15. 116–161 mm SL, Iran: Khorasan-e Razavi prov.: Near Sarakhs, at Pole-e Khaton, Hari River, Hari basin, 35°56'51"N, 61°08'51"E, Jun 2016, S. Eagderi & A. Jouladeh-Roudbar. – Capoeta trutta: IMNRF-UT- 1073, 15. 54.1–165.2 mm SL, Iran: Kermanshah prov.: Songhor to Satar road, Tape Esmail village, Gavehroud River, Tigris basin, 34°56'01"N, 47°12'49"E, Aug 2016, T. Hosseinpour, A. Soleymani & A. Jouladeh-Roudbar. – Capoeta umbla: IMNRF-UT-1077, 15. 107.3–175.9 mm SL, Iran: Kurdistan prov.: Near Sardasht town, Barisu village, Little Zab River, Tigris, 36°08'48"N, 45°32'17"E, May 2016, S. Eagderi, H. Porbagher, P. Jalili & A. Jouladeh-Roudbar.