Oxynoemacheilus euphraticus ( Bănărescu & Nalbant, 1964 ), Banarescu & Nalbant, 1964

Freyhof, Jörg & Özuluğ, Müfit, 2017, Oxynoemacheilus hazarensis, a new species from Lake Hazar in Turkey, with remarks on O. euphraticus (Teleostei: Nemacheilidae), Zootaxa 4247 (4), pp. 378-390: 385-387

publication ID

https://doi.org/10.11646/zootaxa.4247.4.2

publication LSID

lsid:zoobank.org:pub:C6132ED5-A674-493F-9AFA-2FB03EB88E14

DOI

http://doi.org/10.5281/zenodo.5662539

persistent identifier

http://treatment.plazi.org/id/B51F2F36-D866-FFFC-FF63-FF63FD0CE1E8

treatment provided by

Plazi

scientific name

Oxynoemacheilus euphraticus ( Bănărescu & Nalbant, 1964 )
status

 

Oxynoemacheilus euphraticus ( Bănărescu & Nalbant, 1964)  

( Figs. 7–9 View FIGURE 7 View FIGURE 8 View FIGURE 9 )

Noemacheilus insignis euphraticus Bănărescu & Nalbant, 1964:175   , Figs. 11–12

Oxynoemacheilus freyhofi Jouladeh   –Roudbar, Eagderi & Hosseinpour, 2016: 93, Figs. 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5

Material examined. ZMH 1889, holotype of Nemacheilus insignis euphraticus   , 29 mm SL; ZMH 1890, 20 paratypes of N. i. euphraticus   , 24–36 mm SL; Turkey: Malatya.   FSJF 1990, 24, 25–61 mm SL; Turkey: Muş prov.: stream Page at Yaygın , about 30 km west of Muş, 38°55'N 41°16'E. GoogleMaps   FSJF 1996, 5, 36–55 mm SL; Turkey: Elazığ prov.: stream at village Karakocan , at street from Elazığ to Bingöl, 38°57'N 40°01'E. GoogleMaps   FSJF 2636, 20, 35– 60 mm SL; Turkey: Adıyaman prov.: upper River Göksu, 5 km northeast of Gölbaşı , 37° 50.217N 37° 41.088E. GoogleMaps   FSJF 2910, 26, 28–66 mm SL; Turkey: Sivas prov.: stream Kangal under railway bridge at Çetinkaya , 39.2516N 37.6189E. GoogleMaps   FSJF 3376, 31, 34.8–73.6 mm SL; Iraq: Rezan River near Ziraran, a tributary to Greater Zab River , 36°56.60'N 44°11.72'E. GoogleMaps  

Diagnosis. Oxynoemacheilus euphraticus   is distinguished from the other Oxynoemacheilus   species in the Euphrates and Tigris drainage by a combination of characters, none of them unique. Oxynoemacheilus euphraticus   belongs to a group of species ( O. argyrogramma   , O. bergianus   , O. erdali   , O. hanae   , O. karunensis   , O. longipinnis   O. kurdistanicus   O. parvinae   and O. paucilepis   ) having a suborbital groove in males (vs. absent in O. chomanicus   , O. frenatus   , O. gyndes   , O. hazarensis   , O. kaynaki   , O. kiabii   and O. zagrosensis   ) and a deeply emarginate or forked caudal fin (vs. slightly emarginate or truncate in O. chomanicus   , O. frenatus   , O. gyndes   , O. hazarensis   , O. kaynaki   , O. kiabii   and O. zagrosensis   ).

Oxynoemacheilus euphraticus   is distinguished from O. bergianus   , O. erdali   , O. longipinnis   and O. parvinae   by having two prominent black jet-spots at the caudal-fin base (vs. absent), a deeper caudal peduncle (8–11% SL vs. 7–8) and the caudal peduncle usually with regularly shaped bars (vs. caudal peduncle mottled, with irregularly shaped dark-brown bars or large blotches). It should be noted, that in large individuals, especially in clear streams, the flank colour pattern might be very dark and might overlay the two spots at the caudal-fin base in O. euphraticus   . In juvenile fishes, these two spots are always very well visible ( Fig. 7 View FIGURE 7 ).

Oxynoemacheilus euphraticus   is distinguished from O. hanae   and O. karunensis   by having a deep median incision in the upper lip (vs. no or a very short incision), a series of narrow and regularly or irregularly set and shaped bars at least on the flank behind the caudal-fin base (vs. a series of dark-brown roundish or ovoid blotches along the midlateral flank), the midlateral blotches reaching down to ventral side of caudal peduncle (vs. not reaching) and the bars on the flank behind the dorsal-fin-base usually being confluent with the saddles on the back (vs. midlateral blotches usually not confluent with saddles on back, but often overlapping).

Oxynoemacheilus euphraticus   is also distinguished from O. karunensis   by having a well developed pelvic axillary lobe with a free tip (vs. no or only a very rudimentary, shallow and knob-shaped, fully attached to the body), flank without spots, vermiculation or mottling, in some individuals with small, vertically-elongated and transversely-positioned blotches (vs. many minute dark-brown spots on the back, flank above lateral midline and caudal peduncle, with a mottled colour pattern in the interspaces of saddles and large blotches on the back or these interspaces with vermiculated pattern) and flank behind the dorsal-fin base with regularly or irregularly shaped bars usually confluent with the saddles on the back (vs. flank usually with a midlateral row of short, verticallyelongated blotches usually not confluent with the saddles on the back).

We were not able to find characters distinguishing O. kurdistanicus   from O. euphraticus   (see Discussion).

Distribution. Oxynoemacheilus euphraticus   is very widespread in the Euphrates River drainage and records of O. hamwii   from the Euphrates by Krupp & Schneider (1991) might belong to this species. Its presence in the Tigris drainage is confirmed by several findings in the Greater Zab and in streams flowing to the Greater Zab, one very small juvenile individual from the lower Lesser Zab, and from the Karun drainage in Iran. It might be more widespread.

Remarks. Freyhof et al. (2011) treat O. euphraticus   as a synonym of O. argyrogramma   as both species have two prominent black jet-spots on the caudal-fin base and a deeply emarginate caudal fin. Oxynoemacheilus argyrogramma   has been described from the Queiq, an endorheic river west of the Euphrates. Oxynoemacheilus euphraticus   has been described from the upper Euphrates drainage at Malatya in Turkey. Since the study by Freyhof et al. (2011), it turned out that there are two species in the upper Euphrates both distinguished by having two prominent black jet-spots on the caudal-fin base and a deeply emarginate caudal fin. Both species are well distinguished also by their COI sequences and by their colour pattern and the depth of the caudal peduncle, which is slender in one species and deep in the other (adults larger than 50 mm SL: caudal peduncle depth 2.0–2.8 times in the caudal peduncle length vs. 1.4–1.8). The species with the deep caudal peduncle is identified as O. argyrogramma   . The syntypes of O. argyrogramma   (NMW 48541, NMW 59913) from the Queiq have a deep caudal peduncle. Fishes from the Queiq drainage (Sünnep stream) collected by us (FSJF 2926), are superficially identical to the types and also have a deep caudal peduncle. COI sequences of fishes from the Queiq drainage and those from the adjacent Euphrates are almost identical. These are identified as O. argyrogramma   .

The holotype and the paratypes of O. euphraticus   are juveniles (24–36 mm SL) ( Fig. 7 View FIGURE 7 ) and we compared them with juveniles of O. argyrogramma   of about the same size ( FSJF 2892: 26–38 mm SL) and with juveniles of the second species from the Euphrates ( FSJF 2910: 28–35 mm SL). Already in the juveniles, the difference in the caudal peduncle depth is clear (caudal peduncle depth 1.5–1.8 times in the caudal peduncle length in O. argyrogramma   , 2.1–2.8 in types of O. euphraticus   , 2.0– 2.3 in fresh materials from the Euphrates). Therefore, we identify the second species, diagnosed by having two prominent black jet-spots on the caudal-fin base and a deeply emarginate caudal fin, as O. euphraticus   and treat O. euphraticus   as a valid species.

Juveniles of both species have a midlateral row of brown blotches on the flank. Adults of O. euphraticus   ( Fig. 9 View FIGURE 9 ) have bars on caudal peduncle (vs. a marbled colour pattern without bars on the flank in O. argyrogramma   , Fig. 10 View FIGURE 10 ). We found O. euphraticus   in the area of Malatya and the species is widespread in the Euphrates and found also in the Tigris drainage. Oxynoemacheilus argyrogramma   seems to be restricted to the Queiq and the westernmost tributaries of the Euphrates.

Jouladeh-Roudbar et al. (2016) described O. freyhofi   from the Karun drainage in Iran without considering that O. euphraticus   might be an available name for the species they found. Jouladeh-Roudbar et al. (2016) try to balance the lack of correctly identified comparison materials by applying molecular data from NCBI Genbank. That would make sense if all described species would be available from NCBI Genbank, and if the species from which these sequences are derived had been definitively identified, which is not the case. We found O. freyhofi   to be distinguished from other populations of O. euphraticus   only by 0.5% K2P sequence difference in the COI barcode region (own unpublished data). Jouladeh-Roudbar et al. (2016) diagnose O. freyhofi   by having always 10½ branched dorsal-fin rays and lacking a suborbital groove in males. Indeed, O. euphraticus   frequently, but not always has 10½ branched dorsal fin ray (8½–10½). We would be more than surprised if O. freyhofi   lacks the suborbital groove in males. Jouladeh-Roudbar et al. (2016) examined only a single adult individual for their description of O. freyhofi   , the holotype (60.3 mm SL), which might be a female. All 10 paratypes are juveniles (43– 45 mm SL). Juvenile individuals of Oxynoemacheilus   species do not show the sexual dimorphism that is visible in adults. None of the characters provided in the description of O. freyhofi   allows this species to be distinguished from O. euphraticus   . However, in O. argyrogramma   , not all males have a suborbital groove and it cannot be excluded, that some males of O. euphraticus   might also lack a suborbital groove. Freyhof (2016) already treated O. freyhofi   as a synonym of O. euphraticus   without giving reasons and the case is therefore considered here again. It should be noted that it is the responsibility of the authors describing a new species to provide evidence that their species has not in fact yet been described.

When Kamangar et al. (2014) described O. kurdistanicus   , they also followed Freyhof et al. (2011) and considered O. euphraticus   as a synonym of O. argyrogramma   . It is since turned out that this is not the case and that O. euphraticus   represents a valid species (see above). The fishes identified as O. argyrogramma   by Kamangar et al. (2014) were collected in the Iranian part of the Sirvan River, a tributary of the Tigris, and might in fact represent O. hanae   . It was easy to distinguish O. kurdistanicus   from O. hanae   for Kamangar et al. (2014), but to distinguish O. kurdistanicus   from O. euphraticus   is a challenge. Jouladeh-Roudbar et al. (2016) give several morphometric differences between O. euphraticus   (as O. freyhofi   ) and O. kurdistanicus   but all morphometric characters mentioned by Jouladeh-Roudbar et al. (2016) substantially overlap between both species (own data). Even the measurements given by Jouladeh-Roudbar et al. (2016) cannot be used, as no ranges were given for the morphometric characters distinguishing O. euphraticus   from O. kurdistanicus   . We are as a result unable to distinguish O. euphraticus   from O. kurdistanicus   and they might be just one species or two valid but cryptic species without (known) morphological differences.

ZMH

Zoologisches Museum Hamburg

COI

University of Coimbra Botany Department

Kingdom

Animalia

Phylum

Chordata

Class

Actinopterygii

Order

Cypriniformes

Family

Nemacheilidae

Genus

Oxynoemacheilus

Loc

Oxynoemacheilus euphraticus ( Bănărescu & Nalbant, 1964 )

Freyhof, Jörg & Özuluğ, Müfit 2017
2017
Loc

Oxynoemacheilus freyhofi

Eagderi 2016: 93
2016
Loc

Noemacheilus insignis euphraticus Bănărescu & Nalbant, 1964 :175

Banarescu 1964: 175
1964