Oxynoemacheilus simavicus (Balik & Bănărescu, 1978 )

Freyhof, Jörg, Kaya, Cüneyt & Geiger, Matthias F., 2022, A practical approach to revise the Oxynoemacheilus bergianus species group (Teleostei: Nemacheilidae), Zootaxa 5128 (2), pp. 151-194 : 179-183

Oxynoemacheilus simavicus (Balik & Bănărescu, 1978)

( Fig. 15–18 )

Orthrias brandti simavica Balık & Banarescu , in Banarescu, Nalbant & Balık, 1978: 261, fig. 3 (type locality: Turkey: „ Simav creek , Kütahya “)

Material examined. Simav drainage: FFR 1380, 12, 38–50 mm SL; Turkey: Balıkesir prov: stream Koca at Manyas.— FFR 1505 , 28 , 32–56 mm SL; Turkey: Balıkesir prov: stream Sakar at Manyas , 40.050N 27.962E .— FFR 1512 , 7 , 43–64 mm SL; Turkey: Balıkesir prov: stream Dursunbey 4 km south of Adaören , 39.609N 28.751E .— FFR 1518 , 8 , 44–74 mm SL; Turkey: Balıkesir prov: stream Koca 4 km north of Balya , 39.782N 27.596E .— FFR 1520 , 8 , 47–55 mm SL; Turkey: Balıkesir prov: stream Değirmenboğazı 13 km west of Manyas , 40.000N 27.828E .— FFR 1522 , 4 , 47–51 mm SL; Turkey: Balıkesir prov: stream Koca at Ilıca , 39.878N 27.780E .— FFR 1542 , 4 , 48–49 mm SL; Turkey: Bursa prov: stream Nilüfer at Narlıdere , 40.244N 29.298E .— FFR 1544 , 29 , 39–68 mm SL; Turkey: Bursa prov: stream Nilüfer at Misi , 40.180N 28.974E .— FSJF 1929 , 4 , 46–60 mm SL; Turkey: Balıkesir prov.: stream Çaylak at Susurluk , 39.904N 28.181E .— FSJF 1949 , 1 , 62 mm SL; Turkey: Balıkesir prov.: Simav River east of Susurluk , 39.917N 28.166E .

Büyük Melen drainage: FSJF 3719 , 15 , 50– 6 mm SL; Turkey: Düzce prov.: stream Asar 2.5 km west of Kaynaşlı , 40.7811N 31.2770E .

Material used in molecular genetic analysis. FSJF DNA-2850 ; Turkey: Düzce prov.: stream Asar 2.5 km west of Kaynaşlı , 40.7811N 31.2770E (GenBank accession: OK 316642 , OK 316739 , OK 316651 ) .

Sakarya drainage: FFR 1364, 16, 25–64 mm SL; Turkey: Ankara prov: stream Berçin at Kızılcahamam , 40.483N 32.653E.— FFR 1386 , 13 , 49–62 mm SL; FFR 15515, 1, 62 mm SL; Turkey: Ankara prov: stream Öz at Kızılcahamam , 40.463N 32.653E.— FFR 1387 , 9 , 39–58 mm SL; FFR 1527, 17, 50–62 mm SL; Turkey: Ankara prov: stream İlhanlı 5 km west of Gökçebağ , 40.093N 32.245E.— FFR 1378 , 2 , 45–57 mm SL; Turkey: Kütahya prov: stream Porsuk at Kütahya, 39.467N 30.027E.—FFR 15514, 1 , 59 mm SL; Turkey: Ankara prov: stream Kirmir 3 km north of Güdül , 40.236N 32.261E.— FFR 1525 , 1 , 55 mm SL; Turkey: Kütahya prov: stream Porsuk 6 km south of Ziğra , 39.349N 30.038E. — FSJF 1913 , 5 , 55–66 mm SL; Turkey: Eskişehir prov.: stream Allıkova about 37 km south of Bozüyük at road from Bozüyük to Kütahya, 39.682N 30.154E.— FSJF 1938 , 28 , 26–57 mm SL; Turkey: Eskişehir prov.: stream Pürtek at Mülkköy, a tributary of River Porsuk , 39.555N 31.758E.— FSJF 1965 , 3 , 51–61 mm SL; Turkey: Adapazarı prov.: Sakarya River at Doğançay , 40.596N 30.323E.— FSJF 2499 , 31 , 37–66 mm SL; Turkey: Ankara prov.: stream Bayındır at Kızılcahamam east of Çeltikci , 40.314N 32.467E.— FSJF 3050 , 7 , 51–67 mm SL; Turkey: Bursa prov.: stream Hamamlı between Bozöyük and Bursa, 40.036N 29.606E .

Material used in molecular genetic analysis. FSJF DNA-47 ; Turkey: Adapazarı prov.: Sakarya River at Doğançay , 40.596N 30.323E (GenBank accession: OK 316688 ) .— FSJF DNA-49 ; Turkey: Eskişehir prov.: stream Allıkova about 37 km south of Bozüyük at road from Bozüyük to Kütahya, 39.682N 30.154E (GenBank accession: OK316620 , OK316798 ) .— FSJF DNA-890 ; Turkey: Ankara prov.: stream Bayındır at Kızılcahamam east of Çeltikci , 40.3143N 32.467E (GenBank accession: OK316743 , OK316622 , OK316635 , OK316616 , OK316796 , OK316735 ) .

Distribution. Turkey: Simav drainage in the Marmara Sea basin as well as in Büyük Melen and Sakarya drainages in the Anatolian Black Sea basin. See Fig. 2 for the distribution of this species.

Remarks. Based on DNA barcoding, O. simavicus is separated from all other species of the O. bergianus group by a minimum K2P distance of 3.7%, also supported as PTP, mPTP and ASAP entity/entities.

Oxynoemacheilus simavicus is separated into three population groups, one in the Simav (Marmara basin; Fig. 15 ) and two in the Sakarya ( Fig. 16–18 ), one of these also found in the Büyük Melen drainage, a small river flowing to the Black Sea east of the Sakarya. Oxynoemacheilus simavicus from the Simav is distinguished by a minimum 2.2% K2P distance from the first and 2.5% from the second group and both groups are distinguished by 1.7% from each other. We found no confident morphological differences between both groups in the Sakarya and understand very little about their distribution or whether they are allopatric. We found one group in the upper Porsuk (FSJF 1913), the middle Sakarya River (FSJF 1965) and in the Büyük Melen drainage (FSJF 3719). The second group is so far only confirmed from one stream north of Ankara (FSJF 2499). As we would expect two such groups to hybridise in sympatry, the analysis of mtDNA alone, as the COI studies here, is of little help in distinguishing the two groups. Indeed, the two mtDNA groups might not be supported by nuclear, recombining DNA markers and both lineages might belong to just one population. We might speculate that fish from two different refuges, from which both or one expanded their range, have widely hybridised, now forming a single population.

We find no consistent morphological difference between individuals from the Simav and those of both molecular groups from the Sakarya. Interestingly, in the molecular group found in the Sakarya and the Büyük Melen (FSJF 1913, FSJF 1965, FSJF 3719), the sole population studied from the Büyük Melen drainage (FSJF 3719, n=10) is differentiated from two Sakarya populations (FSJF 1913, n=5; FSJF 1965, n=3) by having a deeper caudal peduncle (caudal peduncle depth 1.7–2.2 times in its length vs. 2.4–3.3 in Sakarya). However, the variability in this character is much larger in individuals of O. simavicus from the Simav (1.8–2.7, n=20) and in the only studied population of the other molecular group from the Sakarya (1.9–2.8, FSJF 2499, n=20). As discussed under O. bergianus above, single populations might be slightly differentiated from others especially when only a few individuals are examined. But if larger series are studied, ideally several populations with the same or very similar molecular characters, these small differences are diluted and no consistent morphological differences remain to distinguish the three molecular clades within O. simavicus and to distinguish this species from O. bergianus and O. fatsaensis .

Similar to O. fatsaensis , O. simavicus is well separated based on COI data from O. bergianus , from which it is distinguished by a K2P distance of 3.7% (3.8% to O. fatsaensis ). We treat O. simavicus as a valid species indistinguishable from the other species of the same group by the morphological characters studied so far.

Figures

FIGURE 2. Records of species of the O. bergianus group. Different colours indicate different molecular groups within species. Grey circles indicate records of O. simavicus without assignment to a molecular group.

FIGURE 15. Oxynoemacheilus simavicus, FSJF 1929; 65 mm SL, 70 mm SL; stream Çaylak, Simav drainage.

FIGURE 16. Oxynoemacheilus simavicus, first molecular cluster, from top: FSJF 2499, 54 mm SL; 56 mm SL; 59 mm SL; 56 mm SL; Turkey: stream Bayındır, Sakarya drainage.

FIGURE 17. Oxynoemacheilus simavicus, first molecular cluster in Sakarya, FSJF 2499, 64 mm SL; Turkey: stream Bayındır.

FIGURE 18. Oxynoemacheilus simavicus, second molecular cluster in Sakarya, from top: FSJF 1965, 65 mm SL, not preserved, same locality as FSJF 1965, about 55 mm SL; Turkey: Sakarya River; FSJF 3719, 54 mm SL; 55 mm SL; Turkey: stream Asar, Büyük Melen drainage.