Salmo brunoi, Turan & Bayçelebi & Aksu & Oral, 2024

Turan, Davut, Baycelebi, Esra, Aksu, Sadi & Oral, Muenevver, 2024, The trouts of the Marmara and Aegean Sea drainages in Tuerkiye, with the description of a new species (Teleostei, Salmonidae), Zoosystematics and Evolution 100 (1), pp. 87-99 : 87

Salmo brunoi sp. nov.

Figs 2 , 3 , 4

Type material.

Holotype: FFR 3243, 175 mm SL; Türkiye, Bursa prov.: stream Aras, a tributary of Nilüfer River, 40.0536°N, 29.1722°E.

Paratypes: FFR 3216, 188-153 mm SL; same data as holotype.-FFR 3213, 7, 142-195 mm SL;-FFR 3215, 7, 142-195 mm SL; Türkiye, Bursa prov.: stream Deliçay at Kestel, 40.1241°N, 29.2737°E.-FFR 3211, 18, 93-180 mm SL; -FFR 3217, 12, 85-153 mm SL; Türkiye, Bursa prov.: stream Ericek at Osmangazi, 40.0426°N, 29.2098°E.

Diagnosis.

Salmo brunoi is distinguished from all the species of Salmo in Türkiye and adjacent areas by the combination of the following characters: a small size (known maximum size 187 mm SL); body brownish in life; one black spot in postorbital and suborbital areas, greater than the pupil; two to four black spots on the opercle, approximately smaller than the pupil; black spots on the body few (fewer than 60), approximately equal to the pupil, ocellated, scattered on the back and the upper part of the flank (missing in the predorsal area); red spots few (fewer than 40), smaller than the pupil, irregularly shaped, surrounded by an irregularly shaped narrow ring, organized in two to four irregular longitudinal rows; number of black and red spots not increasing with size; anal fin short (12-15% SL in males, 12-14 in females), adipose fin large (adipose fin height 8-9% SL in males and females), short distance between adipose fin and caudal fin bases (13-14% SL in males, 12-14% in females).

Description.

The general appearance is shown in Figs 2 , 3 , live images are in Fig. 4 , morphometric data are in Table 1 . Body moderately deep, compressed laterally, its depth smaller than head length. The dorsal profile is slightly arched, and the head is short, upper profile slightly convex on the interorbital area and the snout in males and markedly convex on both interorbital areas and the snout in females. Mouth large in males, small in females, terminal or slightly subterminal in males, subterminal in females. Tip of lower jaw slightly curved upwards, pointed, with a slightly developed process at symphysis in males larger than 160 mm SL. Maxilla somewhat long, with a length of 10-12% SL, reaching beyond the posterior margin of the eye in males larger than 140 mm SL and only reaching the posterior margin of the eye in females. Snout somewhat short, with a pointed tip in males, rounded in females. Adipose fin long, height about 8-9% SL in males and in females. Known maximum size 195 mm SL.

Dorsal fin with 3-4 unbranched and 8-10 branched rays, its distal margin convex. Pectoral fin with 1 unbranched and 11-13 branched rays, its external margin slightly convex. Pelvic fin with 1 unbranched and 7-8 branched rays, its external margin convex. Anal fin with 3 unbranched and 7-9 branched rays, its distal margin convex anteriorly and concave posteriorly. The caudal fin deeply emarginated in specimens less than 120 mm SL, slightly emarginated or truncated in specimens larger than 140 mm SL, lobes slightly pointed. Lateral line with 108-122 scales; 23-32 scale rows between dorsal fin origin and lateral line; 16-23 scale rows between anal fin origin and lateral line; 14-18 scale rows between origin of the adipose fin and lateral line. Gill rakers 15-18 on the first gill arch.

Coloration.

In life: General body color brownish or light brownish. Back and flank brownish and belly yellowish. Red spots conspicuously organized in two to four irregular longitudinal rows on the median part of the body and half of the lower part of the flank. Conspicuously black spots in postorbital and suborbital areas. Black spots roundish, scattered on back and upper part of flank. Pectoral, pelvic and anal fins yellowish, dorsal and anal fins yellowish or light brownish. Adipose fin with reddish margin (see Fig. 4 ).

In formalin: The general coloration of freshly preserved specimens dark brown on the back and upper part of the flank, brownish on the lower part of the flank and yellowish on the belly. One black spot in postorbital and suborbital areas, greater than the pupil; two to four black spots on the opercle, approximately smaller than the pupil. Black spots on the body few (fewer than 60), approximately equal to the pupil, ocellated, commonly scattered on the back and the upper part of the flank (missing in the predorsal area) and rarely median part of the flank; no black spot on top of the head. Red spots few (fewer than 40), small (smaller than the pupil), irregularly shaped, surrounded by an irregularly shaped narrow ring, organized in two to four irregular longitudinal rows on the median part of the body and half of the lower part of the flank. The number of black and red spots on the flanks do not increase with size. Dorsal fin gray, with two or three rows of black spots (smaller than pupil) and one or two rows of red spots (smaller than pupil). Caudal fin dark gray; pectoral, anal and pelvic fins grayish. Adipose fin plain grayish, rarely one or two red spots on its posterior edge (Figs 2 , 3 ). Eleven to thirteen parr marks on the body, distinct in specimens up to about 195 mm SL.

Distribution and habitat.

Salmo brunoi sp. nov. inhabits clear and swift-flowing water, with a substrate consisting of gravel and pebbles. The observed material for this species has been collected from streams Aras, Deliçay and Ericek, drainages of Nilüfer River (Fig. 1 ).

Conservation status.

According to the First Author’s (DT) observations, Salmo brunoi sp. nov. is under the influence of overfishing. Besides fresh consumption, trout oil is a widely preferred natural remedy, particularly for the treatment of rheumatism, muscle, and joint pains among local people ( Turan et al. 2006). Therefore, the species is in high demand. Given the highly restricted distribution of S. brunoi sp. nov. to a very limited area (only three streams), and considering the above mentioned socio-economic interest, this species is likely to be under a serious threat. Thus, there is a need for the species to be conserved under international legislation.

Comparison with other Salmo species.

Salmo brunoi sp. nov. differs from the other species of trout recorded from Marmara, Aegean and Black Sea basins ( S. duhani , S. coruhensis , S. abanticus , S. rizeensis and S. labrax ) by having a shorter anal fin in females (12-14% SL, vs. 14-20), a longer adipose fin in females (adipose fin height 8-9% SL, vs. 4-8) and males (8-9% SL, vs. 4-8, except S. coruhensis ), a shorter distance between adipose fin and caudal fin bases in females (12-14% SL, vs. 14-17, except S. duhani ) and males (13-14% SL, vs. 15-17 in S. labrax , 14-16 in S. rizeensis , 14-16 in S. duhani , except S. abanticus and S. coruhensis ). Salmo brunoi further differs from S. abanticus , S. coruhensis and S. labrax by the brownish body color in life (vs. silvery). Salmo brunoi further differs from S. abanticus and S. coruhensis by fewer black spots on the body in adult males (fewer than 60, vs. more than 80), whose number does not increase with size (vs. number increasing with size). Salmo brunoi further differs from S. duhani by having fewer black spots on the back and flank in females (fewer than 60, vs. more than 80). Salmo brunoi is further distinguished from S. abanticus by the presence of red spots on the body in all sizes (vs. absent in specimens larger than about 200 mm SL) and black spots circular (vs. polygonal). Salmo brunoi is further distinguished from S. labrax by having a shorter predorsal distance in males (47-50% SL, vs. 46-47), a slenderer body in males (body depth at anal fin origin 16-19% SL, vs. 19-21) and a slenderer caudal peduncle in females (9-10% SL, vs. 10-11). Salmo brunoi is further distinguished from S. rizeensis by having a slenderer caudal peduncle in females (9-10% SL, vs. 10-11).

The new species, Salmo brunoi , is also distinguished from S. ardahanensis by having fewer gill rakers on the outer side of the first gill arch (15-18, vs. 19-21), no black spots on the top of the head (vs. small black spots). It further differs from S. ardahanensis by having a smaller distance between adipose and caudal fins in females (12-14% SL, vs. 14-17) and a shorter anal fin in males (12-15%SL, vs. 15-18). In males of Salmo brunoi , anal and adipose fins do not reach the caudal fin base (vs. reaching in specimens larger than 200 mm SL) and the interorbital area is convex (vs.flat straight).

Salmo brunoi is further distinguished from Salmo murathani by having fewer black spots on flank and back in adult specimens (fewer than 60, vs. more than 66); one black spot behind eye (larger than pupil); 2-4 spots on preopercle and opercle (vs. 4-15); black spots scattered on back (missing in predorsal area), the upper part of flank, sometimes a few black spots below lateral line behind head (vs. black spots scattered on back, the middle and upper part of the flank and the anterior part of the lower flank in males) black spots few (34-47), restricted to the back and upper part of flank in females smaller than about 210 mm SL). It further differs from S. murathani by having a smaller distance between adipose and caudal fins in females (12-14% SL, vs. 15-17) and a shorter anal fin in females (12-14% SL, vs. 14-18) and a slenderer caudal peduncle depth in females (9-10% SL, vs. 10-12).

Salmo brunoi is distinguished from Salmo araxensis by having a longer maxilla in males (10-12% SL, vs. 9-10), a shorter anal fin (12-15% SL in males, 12-14 in females, vs. 15-18 in males, 14-18 in females), a slenderer caudal peduncle in females (9-10% SL, vs.10-12) and a smaller distance between adipose and caudal fins in females (12-14% SL, vs. 14-17).

Salmo brunoi is distinguished from S. fahrettini by having the general body color brownish in life (vs. silvery); fewer black spots on the body (fewer than 60, vs. more than 80); black spots on the back (missing on the predorsal area) and upper part of flank, sometimes a few below lateral line behind the head (vs. black spots scattered on back, middle and upper part of flank and anterior part of lower half of flank); their number not increasing with size (vs. their number increasing with size); fewer red spots on body (fewer than 40, vs. more than 70 in adult specimens), their number not increasing with size (vs. increasing with size); a longer maxilla in males (length 10-12% SL, vs. 9-10); a longer adipose fin in males (8-9% SL vs. 3-8); a smaller distance between adipose and caudal fins in females (12-14% SL, vs. 15-18) and a shorter anal fin in females (12-14% SL, vs. 15-17).

Salmo brunoi is distinguished from S. euphrataeus by having a smaller distance between adipose and caudal fins in males (13-14% SL, vs. 14-16), a slenderer caudal peduncle in females (9-10% SL, vs.10-12), a shorter anal fin in females (12-14% SL, vs. 16-19), and the adipose fins do not reach the caudal fin base (vs. reaching in specimens larger than 200 mm SL).

Salmo brunoi is distinguished from S. platycephalus , S. chilo , S. labecula , S. kottelati , S. opimus , all from streams draining to the Mediterranean and S. okumusi , S. munzuricus and S. baliki from Euphrates River, by having a smaller distance between adipose and caudal fins in males (12-14% SL, vs. 14-19), a slenderer caudal peduncle in females (9-10% SL, vs.10-13), a shorter anal fin (12-15% SL, vs.15-21, except S. labecula and S. munzuricus ) and fewer gill rakers on first gill arch (15-18, vs. 18-25, except S. munzuricus and S. balıki). Salmo brunoi is further differs from S. platycephalus , S. chilo , S. labecula , S. kottelati and S. opimus , by the absence of four dark bands on the flank (vs. presence). It further differs from S. munzuricus by having a smaller adipose in males (8-9% SL, vs. 9-12) and a longer maxilla in males (10-12% SL, vs. 8-10). It further differs from S. platycephalus by the presence of red spots on flank (vs. absent in specimens larger than about 70 mm SL) also differs from S. labecula by the presence of red spots on flank in all size (vs. absent in specimens larger than about 70 mm SL).

Salmo brunoi differs from S. tigridis by having fewer scale rows between the dorsal fin origin and the lateral line (23-32, vs. 32-35); fewer scale rows between the end of the adipose fin base and the lateral line (14-18, vs. 19-20), a slenderer caudal peduncle depth 9-11% SL, vs. 12-13).

Sexual dimorphism.

The maxillary length in males is longer than that of females (10-12% SL in males, 9-10 in females). The length of mouth gape in males is longer than that of females (12-17% SL, 12-13). The snout of the male is more pointed than that of the female.

Etymology.

The species is named after Dr. Bruno Guinand (University of Montpellier, ISEM, France) for his valuable contribution to Salmo population genomics research.

ddRAD loci and SNP calling

In total, an average of thirteen million raw reads were generated per individual with a mean sequence depth of 30. Sequences with a missingness index higher than 20% were removed from the dataset. Once filtered according to sequencing depth, missing data, frequency and number of alleles, a total of 215k SNPs were retrieved. More than 187k unlinked SNPs within the 50 bp window were used for downstream population analysis.

Interference of ADMIXTURE and PCA analysis

The ADMIXTURE program identified 9 separate clusters. In the reference lineages, the Danubian (DA) cluster was placed in two groups of which DA-1 ( S. labrax ) separated from DA-2 and DA-3 ( S. ischchan ) corresponding to the origin and the geographic basin. The rest of the reference Salmo species including S. obtusirostris and S. marmaratus clustered separately, as expected. Similarly, S. brunoi sp. nov., generated a separate cluster from the rest of the Marmara and Aegean trout of Anatolia. The only exception was observed in Salmo duhani , which individuals clustered together (K=9; Fig. 5 ; see Discussion for detailed explanation).

The 187,385 unrelated SNPs for each of the 12 individuals from the Marmara Aegean basin were used for PCA. The analysis results indicated 3 clusters of which the first cluster included DA reference samples originated from Armenia as S. ischchan , the second cluster included S. brunoi and S. coruhensis clustered with S. labrax from Russia and the third cluster included S. duhani and that of S. pelagonicus (see discussion). The first two components of PCA represented 29.31% and 21.39% of the variance among individuals.

Figures

Figure 1. Distributions of Salmo in Marmara and Aegean Sea basins.

Figure 2. Salmo brunoi, FFR 3243, holotype, 175 mm SL, male; Tuerkiye: stream Aras, a tributary of Niluefer River.

Figure 3. Salmo brunoi, from top: FFR 3216, paratypes, 137 mm SL, male; 105 mm SL, female; Tuerkiye: stream Aras, a tributary of Niluefer River.

Figure 4. Salmo brunoi, from top: not preserved, ~ 145 mm SL, male; not preserved, ~ 150 mm SL, female; Tuerkiye: stream Aras, a tributary of Niluefer River.

Figure 5. Bar plots of the individuals ancestry generated by ADMIXTURE v. 1.3.0 using 187,385 unlinked SNPs. Vertical lines represent each individual and color-code defines the ancestry origin with k = 9 groups. Reference trout specimens are: Adriatic (AD), Atlantic (AT) and Danubian (DA) lineage (originates from two different locations), Salmo marmaratus and S. obtusirostris.