Salmo baliki, Turan & Aksu & Oral & Kaya & Bayçelebi, 2021

Turan, Davut, Aksu, Ismail, Oral, Muenevver, Kaya, Cueneyt & Baycelebi, Esra, 2021, Contribution to the trout of Euphrates River, with description of a new species, and range extension of Salmo munzuricus (Salmoniformes, Salmonidae), Zoosystematics and Evolution 97 (2), pp. 471-482 : 471

Salmo baliki sp. nov.

Figures 2 , 3 , 4

Holotype.

FFR 3242, 212 mm SL; Turkey: Ağrı Province: stream Sinek a tributary of Murat River at Taşlıçay, 39.758749°N, 43.464480°E.

Paratypes.

FFR 3234, 6, 132-276 mm SL; same data as holotype. -FFR 3205, 3, 175-267 mm SL; Turkey: Ağrı Province: a tributary of Murat River 39.730705°N, 43.481869°E.

Additional record.

Turkey: Ağrı Province: stream Cuma at Cumaçay, 39.919118°N, 43.192272°E.

Diagnosis.

Salmo baliki differs from the other species of trout recorded from the Euphrates and Tigris River drainages ( S. euphrataeus , S. okumusi , S. munzuricus , S. fahrettini and S. tigridis ) by having large and irregular-shaped red spots on its body (red spots larger than pupil, vs. smaller than pupil). Salmo baliki further differs from S. euphrataeus by the general body color silvery in live (vs. brownish), a shorter head in the male (length 24-27% SL, vs. 27-31), a shorter maxilla in the male (length 8-9% SL, vs. 10-11), and a shorter mouth gape (12-14% SL in male, 11-12 in female, vs.14-17 in male, 12-15 in female). Salmo baliki further differs from S. munzuricus by having fewer black spots in postorbital and suborbital areas (commonly 1, rarely 2, vs. 3-24); fewer black spots on the body (less than 30, vs. more than 80 in adult specimens), whose number does not increase with size (vs. number increasing with size); the black spots circular (vs. irregularly shaped); commonly plain or rarely two roundish red spots on posterior edge of the adipose-fin in male and female (vs. plain or the adipose-fin with a very narrow white margin, then a red submarginal band, then a white band or spots, then a red band again in males, Figures 3 , 5 ), a smaller adipose-fin (8-9% SL in male, 7-8 in female, vs. 9-12 in male, 8-10 in female) a deeper anal-fin in females (16-18% SL, vs. 13-16), a greater anal-fin base (10-12% SL, vs. 8-10), a longer median caudal-fin rays (14-16% SL, vs. 11-14), a greater mouth gape in females (12-13% SL, vs. 10-12), a deeper maxilla in females (maximum maxilla depth 3-4% SL, vs. 2-3), a smaller distance between the adipose and caudal fins in males (15-16% SL, vs. 16-18), and fewer lateral line scales (107-118, vs. 116-123). Salmo baliki further differs from S. okumusi by having one or two pale black spot in postorbital and suborbital area (vs. 1-22), fewer black spots on opercle (3-7, vs. 8-17), fewer black spots on the body in specimens smaller than 210 mm SL (less than 30, vs. more than 90), presence black spot on body in all size (vs. the body with black dots in specimens larger than about 230 mm SL), the shape of the black spots ocellated (vs. irregularly shaped), the black spots scatter on back and upper part of flank (vs. whole flank covered black spots or dots), no black spots on top head (vs. 5-18), one or two dark bands on posterior part of the flank (vs. four dark bands in specimens larger than about 230 mm SL), the parr marks vertically oblong (vs. vertically elongate), the shape of the black spots ocellated (vs. irregularly shaped), a more slender dorsal-fin in males (16-17% SL, vs. 17-19), a shorter pectoral-fin in males (17-19% SL, vs. 19-21), a smaller eye diameter (4-5% SL in males, 4-6 in females; vs. 5-7 in males, 6-8 in females), a shorter maxilla in males (8-9% SL, vs. 9-11) (see Figures 3 , 6 ). Salmo baliki further differs from S. tigridis by having fewer scale rows between the dorsal-fin origin and the lateral line (24-28, vs. 32-35); fewer scale rows between the end of the adipose-fin base and the lateral line (13-15, vs. 19-20), a slenderer caudal peduncle depth (11-12% SL, vs. 12-13). Salmo baliki further differs from S. fahrettini by having fewer black spots on its body (less than 30, vs. more than 80); the black spots scatter on back and upper part of flank (vs. scattered on back, middle and upper part of flank, and anterior part of lower half of flank), their number not increasing with size (vs. increasing with size), fewer red spots on body (fewer than 42 in adult specimens, vs. more than 70 in adult specimens), their number not increasing with size (vs. increasing with size). See Discussion for comparison with other trout in adjacent waters of Anatolia.

Description.

The general appearance is shown in Figures 2 - 4 , morphometric data are in Table 1. Body deep, compressed laterally, its depth approximately equal to head length. Dorsal profile markedly arched and ventral profile less arched than the dorsal profile. Head short, upper profile straight both on the snout and above the eye in male, straight above the eye and convex on snout in female. Mouth small, terminal or slightly subterminal in male, subterminal in female. Tip of lower jaw slightly curved upwards, pointed, with a slightly-developed process at symphysis in male larger than 200 mm SL. Maxilla short, reaching slightly beyond posterior margin of the eye in males and female larger than about 200 mm SL. Snout somewhat long, with pointed tip in male, rounded in female. Adipose fin somewhat large, its height 7.5-8.7% SL in males and 7.1-8.3 in females. Largest observed specimen 250 mm SL.

Dorsal fin with 3-4 unbranched and 8-10 branched rays, its distal margin slightly convex. Pectoral fin with 1 unbranched and 10-11 branched rays, its external margin slightly convex. Pelvic fin with 1 unbranched and 7-8 branched rays, its external margin slightly convex. Anal fin with 3 unbranched and 7-9 branched rays, its distal margin convex anteriorly and straight or concave posteriorly. Caudal fin deeply emarginated in specimens less than 160 mm SL, slightly emarginated or truncate in specimens larger than about 200 mm SL, lobes slightly pointed. Lateral line with 107-118 scales; 24-28 scale rows between dorsal-fin origin and lateral line; 18-22 scale rows between anal-fin origin and lateral line; 13-15 scale rows between origin of the adipose fin and lateral line. Gill rakers 16-18 on first gill arch.

Coloration.

In formalin: General coloration of freshly preserved specimens silvery on back and flank, yellowish on the belly. One pale black spot in postorbital and suborbital areas, greater than pupil; three to seven black spots on opercle, approximately smaller than pupil. Black spots on body few (fewer than 30), smaller than the pupil, ocellated, scattered on the upper part of flank (missing in back). No black spot on top of the head. Red spots few (fewer than 30), large (greater than pupil), irregularly-shaped, surrounded by an irregularly shaped narrow ring, organized in two to four irregular longitudinal rows on median part of the body, and half of lower part of the flank. The number of black and red spots on flanks does not increase with increasing size. Dorsal fin grey, with three or four rows of black spots (smaller than pupil) and one or two rows of red spots (smaller than pupil). Caudal fin dark gray; pectoral, anal pelvic fins greyish. Adipose-fin plain grayish, rarely one or two red spots on its posterior edge. Eight to nine oblong parr marks on the body, distinct in specimens up to about 190 mm SL. 1-2 vertical bands on posterior half of flank in most specimens.

Distribution and habitat.

Salmo baliki inhabits clear and moderately swift-flowing water, with a substrate of stones and pebbles. The observed material for this species has only been collected from stream Sinek, drainage of Murat River (Figures 1 , 7a ). The species has not been found in adjacent waters except stream Cumaçay (39.919118°N, 43.192272°E) that is located approximately 32 km northwest of Sinek, another drainage of Murat River. However, there was no opportunity to carry out survey in the stream Cumaçay location. Following solid evidences of shape and size of the spots from the video records shown by local people, this location will further be investigated in the near future.

Conservation status.

There is serious pressure on the populations of Salmo baliki due to overfishing. The species is taken for curative purposes, hence demand is very high. Within the first fieldwork in the area which was carried out in 2006, in total 3 specimens were found in the middle of the stream (39.730705°N, 43.481869°E), however no specimens were detected in the same location during the recent survey, only a small population observed about 4 km upstream (a restricted area, far from the villages, and the only transportation is provided through a rough and muddy road). Taking all these factors into account, endemic S. baliki is stuck in a very limited area, thought to be under a serious threat. Therefore, there is a need for the species to be conserved under international legislation.

Sexual dimorphism.

The snout of the male is more pointed than that of the female. The depth of the adipose-fin and the length of the mouth gape in male are greater than those of the female.

Etymology.

The species is named after Dr. Süleyman Balık (Turkey), taxonomist, in appreciation of his contributions to the freshwater fish fauna of Turkey.

Phylogenetic placement of Salmo baliki .

We analyzed a total of 65 sequences (22 new sequences in this study and 43 sequences from GenBank; Table 2) to assess if the phylogenetic relationship among Salmo sp. Salmo baliki new species is genetically different from the other Salmo species. The nodes separating the species in the phylogenetic tree topology of the Cyt b gene were supported by high posterior probability and bootstrap values. (Figure 8 ). The bootstrap values in ML analysis are relatively low compared to the posterior probability values in BI analysis. However, the two tree topologies do not contradict each other. According to the result of phylogenetic analysis, Salmo baliki is a sister taxon to S. munzuricus (Figure 8 ). For Salmo species, phylogenetic tree topology corresponds exactly with the fiction formed as a result of morphological data.

Range extension of Salmo munzuricus .

Within the aim of the present study a geographic range extension for Salmo munzuricus was also recorded. This species was previously only described from Munzur River, north western Euphrates ( Turan et al. 2017). Here, two new localities have been identified for S. munzuricus (Figure 7b, c ). These new localities in the Murat River, located 140 and 340 km east of the previously known distribution range of the species, reveal the scarce bio-geographic knowledge of the species in the Euphrates basin.

Figures

Figure 1. Distribution of Salmo species in the Euphrates River basin.

Figure 2. Salmo baliki, FFR 3242, holotype, 212 mm SL, male; Turkey: stream Sinek, a tributary of Murat River.

Figure 3. Salmo baliki, FFR 3234, paratypes, a. 216 mm SL, male; b. 170 mm SL, male; c. 164 mm SL, female; Turkey: stream Sinek, a tributary of Murat River.

Figure 4. Salmo baliki, FFR 3205, paratypes, a. 250 mm SL, male; b. 267 mm SL, female; Turkey: stream Sinek, a tributary of Murat River.

Figure 5. Salmo munzuricus: a. FFR 3226, 211 mm SL, male; Turkey: Tunceli Prov., stream Kalan; b. FFR 3241, 205, male; Turkey: Mus Prov., stream Mengel; c. FFR 3226, 240, male; Turkey: Agri Prov., stream Alakoclu.

Figure 6. Salmo okumusi, FFR 3157, 260 mm SL, male; Turkey: stream Goekpinar, a tributary of Tohma River.

Figure 7. a. Stream Sinek, Murat River, Turkey; type locality of Salmo baliki: b. Stream Alakoclu; c. Stream Mengel, Murat River Turkey, two new localities of S. munzuricus.

Figure 8. Bayesian inference (BI) phylogenetic tree based on Cyt b sequences of Salmo species. ML and BI methods generated the similar topologies and therefore only the BI tree is shown. The bootstrap values of ML and posterior probability values of BI are indicated on nodes (ML / BI).