Oxynoemacheilus, Mond

Oxynoemacheilus View in CoL

This is the most speciose genus of freshwater fishes in the Western Palaearctic, with 68 known species, and the largest in West Asia, with 64 species. It is distributed throughout West Asia and one species is found in Central Asia ( O. oxianus ). Three species are found in Europe in Albania and Greece ( O. bureschi, O. pindus ), and the northern Caucasus ( O. merga ). Oxynoemacheilus are found virtually everywhere, with one or more species in almost all habitats. They belong to the standard repertoire of nearly every river, stream, and spring. However, this genus is absent in Iran from the Caspian basin, east of the Sefid, and from many of the endorheic basins in southern Iran. It is also absent from the rivers south of the Mond, where mostly loaches of the genus Paraschistura are found, and from all the Arabian Peninsula.

Mature males are typically smaller than females, with upward-curled pectorals that are longer than those of females. These rays are stiffer, wider, and covered by numerous rows of minute tubercles. Outside the spawning season, it can be challenging to distinguish between sexes. In many species, adult males have a suborbital slit or groove below the modified lachrymal bone. However, this slit or groove is absent in many other species. In some species, a small groove may be present in the posterior outline of the lachrymal bone. In other species, the lachrymal bone may be visible but completely covered by skin.

Identifying Oxynoemacheilus species is often challenging, particularly for slender species with a deeply emarginate caudal and a suborbital groove in the male. Such species are usually widely distributed and may exhibit variations in colour patterns within and between populations. Unfortunately, in slender Oxynoemacheilus , several populations without morphological and only small differences in mtDNA had been recognised as separate species, indicating a need for a conceptual framework of boundaries between populations and species. Some of these are not accepted here. Many other species have a stout, massively built body, a slightly emarginate or even truncate caudal, and no suborbital groove in male. These species are often locally endemic. In sympatry, the caudal fin’s shape and the caudal peduncle’s depth can be useful to distinguish between most species. It has been demonstrated that the diversity in body shapes observed in Oxynoemacheilus does not fully correspond to the phylogeny of the different species, as slender and stout species may be closely related. However, nuclear DNA characters may lead to very different phylogenetic patterns if analysed in the future. Some stout species form monophyletic groups in Oxynoemacheilus , but slender species are a highly polyphyletic group. Notably, there are a variety of intermediate morphotypes within this large genus.

We know that the diversity of Oxynoemacheilus presented in this book sometimes not conforms to simplistic, tree-based patterns, as introgressive hybridisation between species has occurred. In several species, isolated populations differ only by small molecular differences without morphological differences, and we do not accept these as species. Of course, we observe the species diversity of Oxynoemacheilus (and other genera) to be streamlined with clusters of minimal COI differences and new species to be described with only ‘invented’ morphological differences. This process has already begun. Here, the concept of “old species” should be applied to avoid false species decriptions.

Further reading. Prokofiev 2009 (genera); Freyhof et al. 2011 (diversity); Kottelat 2012 (diversity).

Keys to species of Oxynoemacheilus View in CoL in West Asia

Caspian basin, including Lake Urmia and Namak basins

Oxynoemacheilus bergi View in CoL is a valid species from the Kura drainage. However, it needs to be better known to be included in the key. It may be a senior synonym of O. bergianus View in CoL , but this hypothesis awaits confirmation. Oxynoemacheilus merga View in CoL from the European Caspian basin in Azerbaijan, north of Baku, is excluded from the coverage of this book. Most Oxynoemacheilus View in CoL species have individuals with a completely or almost complete plain brown colour pattern. The identification of species by colour pattern requires the examination of more than one or a few individuals.

1a - Suborbital groove absent in adult male; flank with 12–17 distinct, regularly shaped, and set bars; caudal slightly emarginate or truncate. ……………… O. cyri

1b - Suborbital groove present in adult male; flank without bars or bars very irregularly shaped, and set; caudal emarginate or furcate. ………………2

2a - Caudal slightly emarginate; flank mottled, with a midlateral series of indistinct blotches, often forming an irregularly shaped midlateral stripe, without distinct bars or large blotches; caudal–peduncle depth 1.3–1.6 times in its length. ……………… O. veyselorum

2b - Caudal deeply emarginate or furcate; flank pattern with distinct bars or large blotches, not forming a midlateral stripe; caudal–peduncle depth 2.0–3.2 times in its length. ………………3

3a - Flank mottled or with large, irregularly shaped, squarish, or vertically elongate blotches, usually as wide or narrower than interspaces; lateral blotches on caudal peduncle usually interrupted in size and/or shape at or above lateral midline; one central or no black, grey or brown blotch or short bar on caudal base, its colour identical to blotches on caudal peduncle. ……………… O. bergianus

3b - Flank with wide, irregularly shaped bars, much wider than interspaces; bars on caudal peduncle not interrupted in size and shape at lateral midline; an upper and a lower bold, black or dark-brown blotch on caudal base, often fused into a bar, its colour distinctly darker than bars on caudal peduncle. ………………4

4a - Caudal emarginate, with many small brown blotches on rays arranged in 3–6, narrow, pale-brown bands; flank usually with irregularly shaped and spaced, dark-brown bars, often split in middle, irregularly shaped and narrower than interspaces, or flank almost plain brown. ……………… O. elsae

4b - Caudal forked, with 1–3 wide and very bold bands; flank with brown bars or vertically elongate blotches, much wider than interspaces, usually regularly set. ……………… O. brandtii

Black and Marmara Sea basins

No external characters are known to distinguish O. banarescui (Devrekani, Filyos) , O. bergianus (Kızılırmak) , O. fatsaensis (Elekçi, Yeşilırmak) , and O. simavicus (Sursuluk, Sakarya, Büyük Melen). These four species are related and can only be distinguished by molecular characters.

1a - Suborbital groove absent in adult males. ……………… O. seyhanensis

1b - Suborbital groove present in adult males. ………………2

2a - Caudal–peduncle depth 6–10 % SL. ……………… O. banarescui , O. bergianus , O. fatsaensis , O. simavicus

2b - Caudal–peduncle depth 10–13 % SL. ………………3

3a - A median incision in upper lip in most individuals. ……………… O. cemali

3b - No median incision in upper lip. ………………4

4a – Caudal with a wide, bold band in middle or posterior half. ……………… O. phasicus

4b – Caudal with 1–3 narrow, pale bands. ………………5

5a - Distance between pectoral and pelvic origins 25–28 % SL; caudal slightly emarginate. ……………… O. angorae

5b - Distance between pectoral and pelvic origins 29–34 % SL; caudal moderately emarginate. ……………… O. marmaraensis

Aegean basin

1a - Belly without scales; caudal slightly emarginate or almost truncate, middle caudal ray 84–98 % of longest upper caudal ray length. ……………… O. anatolicus

1b - Belly with few, small, embedded scales; caudal emarginate, middle caudal ray 71–91 % of longest upper caudal ray length. ………………2

2a - Body depth almost uniform between dorsal and caudal base (i.e., ratio of body depth at posterior of dorsal base to body depth at caudal base is equal or almost equal to 1). ………………3

2b - Body depth decreasing between dorsal and caudal base (i.e., ratio of body depth at posterior of dorsal base to body depth at caudal base is greater than 1). ………………4

3a - Body depth at dorsal origin 17–18 % SL; caudal peduncle 12–13 % SL, length of middle caudal ray 19–23 % SL; dorsal and ventral adipose crests present on caudal peduncle behind vertical of posterior anal base. ……………… O. theophilii

3b - Body depth at dorsal origin 15–17 % SL; caudal peduncle 10–12 % SL; length of middle caudal ray 16–19 % SL; no dorsal and ventral adipose crests on caudal peduncle behind vertical of posterior anal base. ……………… O. fatmae

4a - Caudal–peduncle depth 1.0–1.3 times in caudal–peduncle length; caudal peduncle 13–16 % SL; flank with coarse mottling, without bars or blotches. ……………… O. kottelati

4b - Caudal–peduncle depth 1.3–2.2 times in caudal–peduncle length; caudal peduncle 16–22 % SL; flank with bars and/or blotches, rarely with fine mottling. ………………5

5a - Caudal–peduncle depth 1.3–1.5 times in caudal–peduncle length; scales on belly present from pelvic base to midline between pectoral- and pelvic origins. ……………… O. eliasi

5b - Caudal–peduncle depth 1.5–2.2 times in caudal–peduncle length; scales on belly restricted between pelvic bases, rarely found more anteriorly. ……………… O. germencicus

Central Anatolia and rivers flowing to the Bay of Antalya

1a - Flank without scales, with many roundish blotches or small spots, without bars or elongated blotches. ……………… O. ciceki

1b - Flank with scales, mottled or with bars and / or elongated blotches. ………………2

2a - Caudal–peduncle depth 2.2–2.6 times in caudal–peduncle length. ……………… O. isauricus

2b - Caudal–peduncle depth 1.2–2.1 times in caudal–peduncle length. ………………3

3a - Caudal deeply emarginate, middle caudal ray 65–76 % of longest upper caudal ray length. ……………… O. mediterraneus

3b - Caudal slightly emarginate or almost truncate, middle caudal ray 71–98 % of longest upper caudal ray length. ………………4

4a - Belly with few, small, embedded scales; caudal emarginate, middle caudal ray 76–91 % of longest upper caudal ray length. ……………… O. nasreddini

4b - Belly without scales; caudal slightly emarginate or almost truncate, middle caudal ray 84–98 % of longest upper caudal ray length. ………………5

5a - Flank with a series of dark-brown midlateral blotches usually fused into a wide, irregularly shaped midlateral stripe, rarely a mottled pattern. ……………… O. angorae

5b - Flank with irregularly set and shaped distinct or confluent blotches and spots forming a marbled or mottled pattern, with large, roundish brown blotches in some individuals. ………………6

6a - Pre-dorsal back usually with 3–4 saddles; flank completely covered by scales. ……………… O. anatolicus

6b - Pre-dorsal back with dark-brown fine mottled pattern, without saddles; few isolated scales on flank in front of dorsal origin. ………………7

7a - Dorsal and ventral adipose crests not elevated from dorsal profile, straight, rarely convex, caudal peduncle highest at end of hypural complex; dorsal adipose crest reaching behind vertical of posterior anal base, absent in some individuals; caudal–peduncle depth 1.5–1.9 times in its length; shortest middle caudal ray is 83–91 % of longest ray of upper caudal lobe; usually flank with irregularly set and shaped, distinct, large blotches forming a marbled pattern. ……………… O. eregliensis

7b - Dorsal and ventral adipose crests elevated from dorsal profile, usually with convex margin, caudal peduncle shallower at end of hypural complex and at maximum height of dorsal adipose crest; dorsal adipose crest reaching to or exceeding vertical of anal base; caudal–peduncle depth 1.2–1.6 times in its length; shortest middle caudal ray is 88–98 % of longest ray of upper caudal lobe; usually flank with irregularly set and shaped confluent small blotches and spots forming a mottled pattern, rarely with larger blotches forming a marbled pattern. ……………… O. axylos

Göksu, Seyhan, Ceyhan, and Orontes rivers, plus coastal drainages within their bounds

1a - Suborbital groove absent in male. …………………2

1b - Suborbital groove present in male. …………………6

2a - Caudal slightly emarginate, almost truncate. ………………… O. seyhanensis

2b - Caudal deeply emarginate or forked. …………………3

3a - Lateral line terminating above anal base or on hypural complex; many isolated and embedded scales on back and flank in front of dorsal origin. ………………… O. ceyhanensis

3b - Lateral line terminating anterior to or below dorsal base, rarely above anus or anal base; no or very few ( O. namiri ) isolated and embedded scales on back and flank in front of dorsal origin. …………………4

4a - Flank pattern, usually with 6–17, very distinct and regularly shaped and set bars, usually all or most flank-bars, at least behind dorsal base, extending to middorsal saddles and usually meeting contralateral. ………………… O. namiri

4b - Flank pattern mottled or with many, very narrow, irregularly shaped and set, pale-brown bars, usually flank- bars separated from middorsal saddles and not meeting contralaterals. …………………5

5a - Lateral line with 23–45 pores; infraorbital canal with 10–13 pores; body depth at dorsal origin 1.2–1.4 times in HL. ……………… O. amanos

5b - Lateral line with 13–23 pores; infraorbital canal with 8–10 pores; body depth at dorsal origin 1.0–1.2 times in HL. ……………… O. cilicicus

6a - Caudal pattern very indistinct, almost or completely absent. ……………… O. seyhanicola

6b - Caudal with dark-brown bands of elongated blotches. ………………7

7a - A bold, black blotch or spot at upper and lower caudal base. ………………8

7b - One central, bold-brown blotch or no blotch on caudal base, often an irregularly shaped black bar at caudal base. ………………10

8a - Flank and caudal peduncle with marbled colour pattern, without series of midlateral blotches or bars. ……………… O. argyrogramma

8b – A series of midlateral blotches on caudal peduncle, in some individuals, flank with bars. ……………… 9

9a - 5–7 flank bars, irregularly shaped and set, extending to middorsal saddles and meeting contralateral; caudal peduncle 1.8–2.4 times longer than deep. …………… O. shehabi

9b - A midlateral series of large blotches, disconnected from saddles on back; caudal peduncle 1.4–1.8 times longer than deep. …………… O. sarus

10a - Caudal–peduncle depth 1.4–1.9 times in its length. ……………11

10b - Caudal–peduncle depth 1.8–3.5 times in its length. ……………13

11a - Middle caudal ray 64–74 % of length of longest ray in upper caudal lobe. …………… O. hamwii

11b - Middle caudal ray 83–92 % of length of longest ray in upper caudal lobe.

12a - Flank with irregularly set and shaped confluent small blotches and spots forming a mottled pattern, rarely with larger blotches forming a marbled pattern; pre-dorsal back with blotches or a dark-brown, fine, mottled pattern, without saddles; few isolated scales on the flank in front of the dorsal origin. …………… O. eregliensis

12b - Flank with a series of dark-brown midlateral blotches usually fused into a wide, irregularly shaped midlateral stripe, rarely a mottled pattern; pre-dorsal back usually with 3–4 saddles; flank completely covered by scales. …………… O. angorae

13a - A yellowish triangle at upper and lower posteriormost portions of caudal peduncle; caudal–peduncle depth 1.8–2.4 times in its length; caudal emarginate, middle caudal ray 80–91 % of length of longest ray in upper caudal lobe. …………… O. evreni

13b - No yellowish triangles at posteriormost portion of caudal peduncle; caudal–peduncle depth usually 2.0–3.0 times in its length; caudal deeply emarginate, middle caudal ray 70–84 % of length of longest ray in upper caudal lobe. …………… O. bergianus

Southern Levant (Damascus basin, Litani, and Jordan drainages)

1a - Suborbital groove absent in adult male; body scaleless or scales restricted to flank behind dorsal base, with few isolated scales on anterior flank in some individuals. ………………2

1b - Suborbital groove present in adult male; back and flank covered by scales. ………………4

2a - Body completely scaleless; 9–11½ branched dorsal rays. ……………… O. galilaeus

2b - Anterior flank scaleless or with few isolated scales, caudal peduncle with densely set scales; 8–9½ branched dorsal rays. ………………3

3a - Lateral line terminating before vertical of dorsal origin; body depth at dorsal origin 20–25 % SL. ……………… O. panthera

3b - Lateral line terminating about at vertical of dorsal origin; body depth at dorsal origin 16–20 % SL. ……………… O. leontinae

4a - Lateral line incomplete, terminating between vertical or dorsal and anal base, usually to anal base. ……………… O. pantheroides

4b - Lateral line complete, terminating at or almost at caudal base. ……………… O. insignis

Euphrates, Qweiq drainages, and Lake Van basin

1a - Lateral line incomplete, terminating anterior to dorsal origin or above anal base. ………………2

1b - Lateral line complete, reaching to caudal base. ………………5

2a - Flank with distinct bars; an upper and a lower black spot at caudal base; caudal peduncle with a long, high dorsal adipose crest; crest with yellowish or whitish margin, reaching beyond vertical through anal origin, usually below last dorsal rays when folded down; flank with isolated and deeply embedded scales. ……………… O. tigris

2b - Flank with a mottled, marbled, or marmorated pattern, often with narrow, indistinct bars on caudal peduncle or a series of dark-brown blotches; colour pattern on caudal base not differentiated from flank pattern, with or without a black bar, never with two black spots; caudal peduncle without or with a short dorsal adipose crest, crest without white margin, reaching to middle of caudal peduncle or to vertical through anal base; flank without scales. ………………3

3a - A central pore in supratemporal canal; a bold bar on caudal base, usually M-shaped, fused with a roundish or vertically elongate, dark-brown blotch at vertical midline; caudal usually with wide, bold, dark-brown bands. ……………… O. arsaniasus

3b - No central pore in supratemporal canal; a mottled or marmorated pattern on caudal base, without bold bar; caudal with narrow, indistinct, pale-brown bands. ………………4

4a - Caudal–peduncle length 1.0–1.3 times its depth; body width at dorsal origin 13–17 % SL; dorsal adipose crest on caudal peduncle high, not reaching to vertical through last anal ray base in individuals larger than 50 mm SL. ……………… O. ercisianus

4b - Caudal–peduncle length 1.3–1.6 times its depth; body width at dorsal origin 11–13 % SL; dorsal adipose crest on caudal peduncle shallow, reaching to vertical through last anal ray base in individuals larger than 50 mm SL. ……………… O. muefiti

5a - Suborbital groove or flap absent in male. ………………6

5b - Suborbital groove present in male. ………………7

6a - Caudal peduncle without adipose crest or ridge; flank with a distinct midlateral series of large, roundish, or horizontally elongated brown blotches and a row of small brown blotches between upper pelvic base and lowermost caudal base. ……………… O. paucilepis

6b - Caudal peduncle with a shallow, wide, often long adipose ridge; flank with a brown mottled or marmorated pattern, with irregularly shaped brown bars, especially on flank behind dorsal origin in some individuals. ……………… O. kaynaki

7a - Caudal slightly emarginate. ……………… O. araxensis

7b - Caudal deeply emarginate or slightly forked. ………………8

8a - One central or no black, grey or brown blotch or short bar on caudal base, its colour identical to blotches on caudal peduncle; upper lip without median incision. ……………… O. bergianus

8b - A bold upper and a lower black blotch or spot on caudal base, often overlaid by a dark-brown or black chevron-shaped bar; upper lip with a median incision. ………………9

9a - Flank and caudal peduncle with marbled colour pattern, without bars; caudal–peduncle depth 1.4–1.8 times in caudal–peduncle length. ……………… O. argyrogramma

9b - Caudal peduncle, and in some individuals also flank, with bars; caudal–peduncle depth 2.0–2.8 times in caudal– peduncle length. ……………… O. euphraticus

Kor basin

1a - Caudal deeply emarginate; no dorsal crest on caudal peduncle. ……………… O. persa

1b - Caudal slightly emarginate or truncate; shallow dorsal crest on caudal peduncle. ……………… O. tongiorgii

Tigris drainage

The Tigris is the biodiversity hotspot for Oxynoemacheilus , but not all species have been described, especially from Iraq and Iran. Many species have small ranges, and their distribution might help identify them.

1a - Suborbital groove absent in male. ………………2

1b - Suborbital groove present in male. ………………8

2a - Lateral line incomplete, terminating in front of or above anal base. ………………3

2b - Lateral line complete, terminating behind vertical of anal base or at caudal base. ………………5

3a - Scales present on back and flank in front of anus; central pore in supratemporal canal present. ……………… O. frenatus

3b - Scales absent on back and flank in front of anus; central pore in supratemporal canal absent. ………………4

4a - Lateral line very short, terminating slightly behind pectoral base, not reaching vertical through dorsal origin; a midlateral series of small, horizontally elongated, dark-brown blotches often fused into an irregularly shaped midlateral stripe, one additional stripe above and below midlateral stripe in many individuals. ……………… O. gyndes

4b - Lateral line long, terminating under dorsal base or above anal base; flank with vertically elongated, irregularly shaped blotches or narrow bars. ……………… O. kiabii

5a - Posterior process of bony air-bladder capsule directed posteriorly. ……………… O. zagrosensis

5b - Posterior process of bony air-bladder capsule directed laterally. ………………6

6a - 8+8 branched caudal rays; caudal–peduncle depth 1.0–1.2 times in caudal–peduncle length; interorbital distance 1.1–1.4 times in snout length; colour pattern on flank behind dorsal base mottled or marmorated. ……………… O. zarzianus

6b - 10+9, 9+9, or 9+8 branched caudal rays; caudal–peduncle depth 1.3–1.8 times in caudal–peduncle length; interorbital distance 1.4–1.9 times in snout length; colour pattern on flank behind dorsal base with bars or vertically elongated blotches. ………………7

7a - Very indistinct, fuzzy bars or vertically elongated blotches on caudal peduncle; maxillary barbel reaching to anterior eye margin or middle of eye; interorbital distance 1.4–1.5 times in snout length; caudal–peduncle depth 1.3–1.4 times in caudal–peduncle length. ……………… O. chomanicus

7b - Distinct bars or vertically elongated blotches on flank behind dorsal origin; maxillary barbel reaching beyond middle of eye, usually to posterior eye margin; interorbital distance 1.6–1.9 times in snout length; caudal–peduncle depth 1.2–1.3 times in caudal–peduncle length. ……………… O. kentritensis

8a - Flank naked, only caudal peduncle behind anus with scales; lateral line incomplete; caudal slightly emarginate. ……………… O. hazarensis

8b - Flank completely covered by scales; lateral line complete; caudal deeply emarginate or forked. ………………9

9a - Flank with a distinct series of midlateral blotches, fused to each other or fused into a stripe, isolated patches of blotches, or a row of small dark-brown spots below lateral series of blotches. ……………… O. hanae

9b - Flank mottled or marmorated, lower flank without colour pattern or colour pattern of midlateral flank reaching down to lower flank. ………………10

10a - Upper lip without or with very short median incision. ………………11

10b - Upper lip with well-developed median incision. ………………13

11a - One central or no black, grey or brown blotch or short bar on caudal base, its colour identical to blotches on caudal peduncle. ……………… O. bergianus

11b - Two bold, black blotches or spots at caudal base, distinctly darker than flank pattern, usually prominent in life and preserved fish, in some individuals overlaid by a chevron-shaped, dark-brown or black bar. ………………12

12a – Flank with very dense mottling between blotches on flank; caudal–peduncle depth 1.7–3.1 times in its length. ……………… O. karunensis

12b – No dense mottling in interspaces between blotches on flank; caudal–peduncle depth 1.4–1.7 times in its length. ……………… O. chaboras

13a – Last bars on caudal peduncle narrower than interspaces. ……………… O. kurdistanicus

13b – Last bars on caudal peduncle as wide or wider than interspaces. ………………14

14a – Juveniles larger than 20 but smaller than 45 mm SL with intense mottled pattern between midlateral blotches on flank. ……………… O. marunensis

14b – Juveniles larger than 20 but smaller than 45 mm SL with poorly developed mottling between midlateral blotches on flank. ……………… O. euphraticus