Taxonomic revision of the genus Carasobarbus Karaman, 1971 (Actinopterygii, Cyprinidae)

Abstract Representatives of the fish genus Carasobarbus Karaman, 1971 (Actinopterygii: Cyprinidae) from the Middle East and North Africa were previously placed in 14 different genus-group taxa (Barbellion, Barbus, Barynotus, Capoeta, Carasobarbus, Cyclocheilichthys, Kosswigobarbus, Labeobarbus, Luciobarbus, Pseudotor, Puntius, Systomus, Tor and Varicorhinus). The generic assignment of several species changed frequently, necessitating a re-evaluation of their taxonomic status. In this study, the genus Carasobarbus is revised based on comparative morphological examinations of about 1300 preserved specimens from collections of several museums and freshly collected material. The species Carasobarbus apoensis, Carasobarbus canis, Carasobarbus chantrei, Carasobarbus exulatus, Carasobarbus fritschii, Carasobarbus harterti, Carasobarbus kosswigi, Carasobarbus luteus and Carasobarbus sublimus form a monophyletic group that shares the following combination of characters: medium-sized barbels with a smooth last unbranched dorsal-fin ray, nine or 10 branched dorsal-fin rays and six branched anal fin-rays; scales large, shield-shaped, with many parallel radii; the lateral line containing 25 to 39 scales; the pharyngeal teeth hooked, 2.3.5-5.3.2 or 2.3.4-4.3.2; one or two pairs of barbels. The species are described in detail, their taxonomic status is re-evaluated and an identification key is provided. A lectotype of Systomus luteus Heckel, 1843 is designated. Carasobarbus Karaman, 1971, Kosswigobarbus Karaman, 1971, and Pseudotor Karaman, 1971 are subjective synonyms, and acting as First Reviser we gave precedence to the name Carasobarbus.


Introduction
The species of the cyprinid genus Carasobarbus Karaman, 1971 are distributed across SW Asia and NW Africa. They occur in all major river systems of the Levant, Mesopotamia, southern Iran, the western and south-western Arabian Peninsula and in northern Morocco. Carasobarbus species are an important element of the ichthyofaunas of these areas.
Research about the Mesopotamian and Levantine representatives of Carasobarbus began as early as the middle of the 19 th century. Important ichthyologists of that era, such as A. Valenciennes and J. J. Heckel, were the first to study these fish. One of the most prominent biological collections from the Middle East of this time was made by T. Kotschy from 1836 to 1840. It is stored at the Museum of Natural History of Vienna and encompasses the type specimens of many zoological and botanical taxa (Kähsbauer 1963). The Moroccan ichthyofauna was described towards the end of the 19 th century and the start of the 20 th century by A. Günther and G. A. Boulenger. An expedition lead by C. du Gast in 1912 was one of the first systematic sampling efforts in this area (Pellegrin 1912). The Arabian representatives were reported only about 35 years ago by K. E. Banister and M. A. Clarke. In 1971, M.S. Karaman established the monotypic genus Carasobarbus for Systomus luteus Heckel, 1843 characterised by a laterally compressed and high-backed body, a narrow and high head, a single pair of barbels, pharyngeal bones with three rows of spoon-shaped teeth, a pharyngeal teeth count 2.3.5-5.3.2, a subterminal to terminal mouth, weakly developed lips that run along the jaws as a thin band, no median lobe on the lower lip, infraorbital bones of normal size, a short and broad first infraorbital (lacrimal) bone that is shorter than the eye diameter, a dorsal fin that is moderately long and has 10 branched rays, the origin of the dorsal fin being above the ventral fins, the last unbranched ray of the dorsal fin being well ossified and smooth, the anal fin with six branched rays, and large scales with numerous parallel radii. We revised and expanded Karaman's (1971) diagnosis of the genus that now contains the nine following species: Carasobarbus apoensis (Banister et Clarke, 1977), C. canis (Valenciennes in Cuvier and Valenciennes 1842), C. chantrei (Sauvage, 1882), C. exulatus (Banister & Clarke, 1977), C. fritschii (Günther, 1874), C. harterti (Günther, 1901), C. kosswigi (Ladiges, 1960), C. luteus (Heckel, 1843), and C. sublimus (Coad & Najafpour, 1997). Members of this genus were listed in 14 different genera and subgenera in the past: Barbellion Whitley, 1931, Barbus Cuvier, 1816, Barynotus Günther, 1868, Capoeta Valenciennes in Cuvier and Valenciennes 1842, Carasobarbus Karaman, 1971, Cyclocheilichthys Bleeker, 1859, Kosswigobarbus Karaman, 1971, Labeobarbus Rüppell, 1835, Luciobarbus Heckel, 1843, Pseudotor Karaman, 1971, Puntius Hamilton, 1822, Systomus McClelland, 1839, Tor Gray, 1834, and Varicorhinus Rüppell, 1835 The objectives of the current study are to (1) define a monophyletic genus that is based on synapomorphic characters, (2) provide a conclusive diagnosis of the genus Carasobarbus, (3) give a detailed re-description of all species based on a sample of specimens large enough to show the intraspecific variability, (4) map the range of each species based on records confirmed by voucher specimens, (5) summarise information on biology, habitat and conservation status of each species, (6) discuss the taxonomic history and current status of each species, (7) provide an identification key. This will form a baseline for a molecular phylogenetic and zoogeographic analysis of Carasobarbus and related genera that is currently in preparation and will be published separately by the first author.
Nomenclature of geographic names follows the spelling recommended by the "United States Board on Geographic Names" (http://geonames.usgs.gov/), even though the transcriptions/transliterations of these toponyms are sometimes inconsistent. Wādī or Oued refer to a temporary stream. Nahr, Naẖal, Nehri, Rūdkhāneh or Rūd refer to a permanent river or stream. Buḩayratt, Göl or Daryācheh refer to a lake. 'Ayn or Aïn refer to a spring. Geographical coordinates in parentheses are original coordinates, given by a publication, the collector or a collection database. Coordinates determined ex post are marked by brackets. Most of these are from the National Geospatial-Intelligence Agency gazetteer (http://geonames.nga.mil/ggmagaz/) and as a consequence, do not refer to the actual site of collection, but to the geographic feature itself. For some of the well known waterbodies and cities the conventional name is used: Euphrates (Nahr al Furāt / Fırat Nehri), Jordan River (HaYarden / Nahr al Urdan), Lake Homs (Buḩayratt Qaţţīnah), Lake Tiberias (Yam Kinneret / Buḩhayratt Ţabarīyā), Orontes (Nahr al 'Āşī / Asi Nehri), Tigris (Dicle Nehri / Nahr Dijlah), Aleppo (Ḩalab), Damascus (Dimashq), Mosul (Al Mawşil).
Twenty morphometric measurements were taken from specimens straightened whenever necessary; severely damaged and bent specimens were not used. There are some differences in the way of taking measurements (e.g. Hubbs and Lagler 1958vs. Banister and Clarke 1977, Krupp 1983a. In this study, seven measurements were done over projections to the body axis. They are as follows: total length (the distance between projections of the tip of the snout and the posterior margin of the longest lobe of the caudal fin, with the caudal fin spread to its natural maximum), standard length (SL) (the distance between projections of the tip of the snout and the end of the hypural plate), preanal length (the distance between projections of the tip of the snout and the origin of the anal fin), predorsal length (the distance between projections of the tip of the snout and the origin of the dorsal fin), preventral length (the distance between projections of the tip of the snout and the origin of the ventral fin), head length (HL) (the distance between projections of the tip of the snout and the posterior margin of the bony opercle), and length of the caudal peduncle (the distance between projections of the insertion of the anal-fin base and the end of the hypural plate). The other measurements were done point-to-point: body depth (BD) as the maximum depth of the body (without dorsal fin) taken orthogonal to body axis; depth (minimum) of the caudal peduncle as the smallest depth of the caudal peduncle; length of the dorsal and anal fins as length of the last unbranched ray in the dorsal and anal fins, respectively; lengths of the pectoral and ventral fins as the distance from the fin base to the tip of the pectoral and ventral fins, respectively; length of the dorsal-fin base and the anal-fin base as a distance between the origin and the insertion of the fin; length of the anterior and posterior barbels as distance from the barbel base to the tip of the barbel when straightened; horizontal diameter of the eye as a distance between the anterior and the posterior bony margins of the eye cavity; width of the mouth as a distance between the two posterior ends of the lower jaw; interorbital distance as a distance between the upper margins of the eye cavities across the head. For comparison between species, all measurements are expressed as percentage of SL.
To attenuate effects of allometric growth, only specimens in the size range between 50 mm SL and 150 mm SL were used for the box-plots and the data given in Table 1.
In addition, seven meristic characters were analysed. The last branched anal-and dorsal-fin rays were counted as one when lying directly adjacent to each other without an interspace. Scales in the lateral line were counted from the first scale with a pore to the last scale on the caudal peduncle (some authors only count to the end of the hypural plate). Scales above the lateral line were counted between the origin of the dorsal fin and the lateral line; the lateral line was not included and a scale on the mid-line of the back was counted as 0.5. Scales below the lateral line were counted between origin of the anal fin to the lateral line; the lateral line was not included and a scale on the mid-line of the belly was counted as 0.5. Scales around the least circumference of the caudal peduncle were counted as one circle of scales around the least circumference of the caudal peduncle. Number of pairs of barbels was counted as two when anterior and posterior pairs are present, counted as one if only posterior pair is present and counted as 1.5 if posterior pair and one single anterior barbel is present.
For counting the number of pharyngeal teeth, the pharyngeal bones were extracted in a subsample of specimens and the pharyngeal teeth counted sometimes only on one side. Lost teeth were counted when the point of insertion was clearly visible. Scales were extracted in the anterior part of the body, above the lateral line.
We did not differentiate between male and female specimens because sex determination was not possible without dissection.
shaped scales with numerous parallel radii; the lateral line with 25 to 39 scales; the pharyngeal teeth hooked at their tips, their count being 2.3.5-5.3.2 or 2.3.4-4.3.2; 1 or 2 pairs of barbels present.
Carasobarbus species are evolutionarily hexaploid (Machordom and Doadrio 2001, Gorshkova et al. 2002, Leggatt and Iwama 2003, Tsigenopoulos et al. 2010. Remarks and discussion. 'Barbus' grypus, Mesopotamichthys sharpeyi and 'Barbus' reinii from the Middle East have five branched rays in the anal fin. The hexaploid species from Africa (Labeobarbus and Varicorhinus), which are the sister group to Carasobarbus and the other species from the Middle East (Tsigenopoulos et al. 2010, KB unpublished), have five branched rays in the anal fin. The Asian species (Tor and Neolissochilus) are sister group to the species from Africa and the Middle East (Tsigenopoulos et al. 2010, KB unpublished) and have five branched rays in the anal fin. By application of the parsimony principle the possession of six branched anal-fin rays is a synapomorphy of the genus Carasobarbus. The possession of nine to 10 branched rays in the dorsal fin is synapomorphic for Carasobarbus, because the closely related Middle-Eastern species 'Barbus' grypus, Mesopotamichthys sharpeyi and 'Barbus' reinii as well as many African hexaploids have the plesiomorphic state of eight branched rays in the dorsal fin. However, in some African species the number of branched dorsal-fin rays is increased convergently. These two synapomorphies establish Carasobarbus as a monophyletic group. Analyses of the mitochondrial cytochrome b gene confirm the monophyly of this genus (Durand et al. 2002, Tsigenopoulos et al. 2010. Colli et al. (2009) found Carasobarbus to be monophyletic in their maximum likelihood analysis but not in their neighbour joining analysis. 'Barbus' grypus Heckel, 1843 is the sister taxon of the genus Carasobarbus (Tsigenopoulos et al. 2010).
Out of the generic names Barbellion, Barbus, Barynotus, Capoeta, Carasobarbus, Cyclocheilichthys, Kosswigobarbus, Labeobarbus, Luciobarbus, Pseudotor, Puntius, Systomus, Tor, and Varicorhinus that were used for this taxon − or its parts − by previous authors, only Carasobarbus, Kosswigobarbus and Pseudotor are available for the genus in question. All other generic names have not been considered, because their type species are not closely related to the species under discussion here (Durand et al. 2002, Tsigenopoulos et al. 2010 or do not share the characters mentioned above. Carasobarbus, Kosswigobarbus and Pseudotor are subjective synonyms. They all were established in the same publication (Karaman 1971) and thus none of them has priority. We, acting as First Reviser, select Carasobarbus to have priority in accordance with article 24.2 of the International Code for Zoological Nomenclature (ICZN 2012). Thus Carasobarbus is the valid name for this genus.
Within the genus, several species share characters that are potentially synapomorph and elucidate sister group relations. Carasobarbus fritschii and C. harterti both have pharyngeal bones with four teeth in the medial row. This character is probably synapomorph, because all other congeners have five teeth in the medial row. This group corresponds to Pseudotor. Carasobarbus kosswigi and C. sublimus share the possession of a spatulate lower jaw and a median lobe on the lower lip. The spatulate lower jaw is synapomorph, because no congener and no other closely related species shares this character. The close phylogenetic relationship between C. kosswigi and C. sublimus is confirmed by genetic analysis ). These two species correspond to Kosswigobarbus.
The dorsal fin and its base are rather short. It usually has four unbranched and 10 branched rays (Table 3). The last unbranched ray is considerably shorter than the head (Fig. 4), weakly ossified, and its distal part is flexible. The anal fin has three unbranched and six branched rays (Table 4). Pectoral and ventral fins are relatively short (Table 1).
Carasobarbus apoensis has 27 to 32 scales in the lateral line (Table 5), usually 4.5 scales above the lateral line (Table 6), 3.5 or 4.5 scales below the lateral line (Table 7) and 12 scales around the least circumference of the caudal peduncle (Table 8). The scales are shown in Fig. 5.
The pharyngeal teeth count is 2.3.5-in 12 specimens, -5.3.2 in two specimens and 1.3.5-in one specimen. The pharyngeal teeth are hooked at their tips (Fig. 6).
Live colouration is golden with olive fins. The upper side is darker than the belly (Fig. 2). In ethanol-preserved specimens the upper side is dark, the belly yellow and the fins are grey or yellow (Fig. 1). Juveniles have a dark lateral spot on the caudal peduncle.
The maximum length observed in the material examined is 288 mm SL.      Carasobarbus apoensis differs from all congeners, except C. luteus, by having one rather than two pairs of barbels. For a comparison with C. luteus populations see below.
Distribution. Carasobarbus apoensis occurs in the Al Ḩijāz mountain range in wadis draining either inland or towards the Red Sea (Fig. 7). It is endemic to Saudi Arabia.
Habitats and biology. This species inhabits the upper courses of wadis, which are characterised by strong seasonal fluctuations in water levels, temperature and other physiochemical parameters.

Conservation status.
Carasobarbus apoensis is rated Least Concern and still occurs in large numbers, but abstraction of large specimens by recreational fishing, water abstraction and habitat loss might become problematic for this species (BCEAW 2002).
Remarks and discussion. Carasobarbus apoensis was originally described from Khamīs Mushayt, Wādī Turabah and Wādī Adamah as a member of the genus Barbus (Banister and Clarke 1977). It was later transferred to the genus Carasobarbus (Ekmekçi and Banarescu 1998). Alkahem and Behnke (1983) reported an unknown Barbus and tentatively considered these specimens to be atypical C. apoensis. We did not find any evidence of an undescribed Carasobarbus species that occurs sympatrically with C. apoensis, thus we agree with their conclusion.
Carasobarbus apoensis is very closely related to C. luteus (KB unpublished data).  Krupp and Schneider 1989). Paralectotype of Barbus canis: MNHN 0000-3944, 1, same data as lectotype. Diagnosis. Two pairs of barbels, 29 to 35 scales in the lateral line and usually 12 scales around the least circumference of the caudal peduncle, last unbranched ray of dorsal fin shorter than head.

Carasobarbus canis (Valenciennes in Cuvier and
Description. The body is low. A nuchal hump is present in adults but absent in juveniles. The largest body depth is at the origin of the dorsal fin. The head is long, rather low and fairly narrow with straight dorsal and convex ventral profile (Figs 8,9). The head length approximately equals the body depth. The mouth is terminal or slightly subterminal. Two pairs of barbels are present ( Table 2). The lips are smooth and thin (Fig. 3). The eyes are at the end of the anterior half of the head. The morphometric characters are summarised in Table 1.
Pectoral, ventral, dorsal and anal fins are comparatively short (Table 1). The dorsal fin usually has four unbranched and 10 branched rays (Table 3). The last unbranched ray is ossified and its distal part is flexible. It is usually markedly shorter than the head (Fig. 4). The anal fin usually has three unbranched and six branched fin rays (Table 4).
There are 29 to 35 scales in the lateral line (Table 5), usually 4.5 or 5.5 scales above the lateral line (Table 6), usually 4.5 scales below the lateral line (Table 7) and usually 12 scales around the least circumference of the caudal peduncle (Table 8). The scales are shown in Fig. 5. The pharyngeal teeth count is 2.3.5-5.3.2 in 23 specimens, 2.3.3-5.3.2 in one specimen, 2.3.5-in one specimen and -5.3.2 in one specimen. The pharyngeal teeth are hooked at their tips ( Fig. 6).
Live specimens are silvery to bronze coloured. The posterior third of the body and the fins are distinctly yellow in many specimens ( Fig. 9). Ethanol-preserved specimens are brownish yellow and the back is only slightly darker than the rest of the body (Fig. 8). The fins are brownish yellow. Juveniles have a dark lateral spot on the caudal peduncle.
Carasobarbus canis differs from C. apoensis and C. luteus in having two pairs of barbels vs. one, from C. kosswigi and C. sublimus in having a crescent-shaped lower lip without median lobe vs. a spatulate lower lip with median lobe, from C. exulatus in modally having 10 branched dorsal-fin rays vs. nine and from C. chantrei, C. fritschii and C. harterti in modally having 10 scales around the least circumference of the caudal peduncle vs. 14 or 16.
Distribution. Carasobarbus canis occurs in the Jordan River system (Fig. 7). There are only few records from coastal rivers of the Mediterranean Sea (Naẖal Na'aman and Naẖal Yarqon). A recent treatment of the inland water fish communities of Israel does not report C. canis from coastal rivers (Goren and Ortal 1999). The population in the Azraq Oasis was introduced by humans ( Krupp and Schneider 1989). Since the year 2000 this species was not found in Azraq (Hamidan 2004) and the population may have disappeared due to drought. Records from the Tigris-Euphrates system (Banister 1980) are based on misidentifications.
Habitats and biology. Carasobarbus canis inhabits a wide range of rivers, lakes and ponds (Goren 1974) with clean as well as polluted water (Mir 1990). Adults reach a length of about 40 cm (max. 66 cm) and are of economic importance locally (annual catch in Israel 1970-85 about 50 t, Fishelson et al. 1996). It feeds on fish, aquatic invertebrates, algae and detritus (Ben-Tuvia 1978, Spataru and Gophen 1985, Krupp and Schneider 1989. The relative proportion of fish in the diet increases with body length and small cyprinids of the genus Mirogrex are their most important prey (Spataru and Gophen 1985). The spawning grounds are (among others) at the shore of Lake Tiberias where the spawn-ing occurs in shallow water over hard bottom in December and January, one month after the start of the rainy season (Fishelson et al. 1996). The sticky eggs attach to the substrate. Winter spawning is seen as evidence for an origin in cooler areas (Fishelson et al. 1996).
Conservation status. Catches in Lake Tiberias are declining (Fishelson et al. 1996). The species is rated Least Concern by the IUCN (Crivelli 2006a). The population in Lake Tiberias does not face serious threats; the riverine populations are declining and threatened by pollution, water extraction, drought and fragmentation due to damming (Crivelli 2006a). Remarks and discussion. Carasobarbus canis was described from the Jordan River as a member of the genus Barbus (Cuvier and Valenciennes 1842). Later it was assigned to Luciobarbus (Heckel 1843), and Labeobarbus (Günther 1864). Subsequently it was transfered back to Barbus (Günther 1868) and then placed in Tor (Karaman 1971, Banarescu 1977, Barbus Clarke 1977, Krupp 1983a), Carasobar-   bus (Ekmekçi and Banarescu 1998) and Barbus subgenus Carasobarbus (Tsigenopoulos et al. 2010). MNHN 0000-1413 was designated as lectotype (Krupp and Schneider 1989). Barbus beddomii is considered to be a junior synonym of C. canis (Berg 1949, Karaman 1971, Krupp and Schneider 1989. (  Diagnosis. Two pairs of barbels, 31 to 38 scales in the lateral line and usually 14 to 16 scales around the least circumference of the caudal peduncle, last unbranched dorsal-fin ray equal to or shorter than head.

Carasobarbus chantrei
Description. The body is comparatively high-backed and laterally compressed in mid-sized specimens but low-backed and almost cylindrical in large specimens. In large specimens a pronounced nuchal hump is present, in smaller specimens it is only weakly developed or absent. The maximum body depth is at the origin of the dorsal fin. The head is short and blunt with a convex ventral profile and a slightly convex to straight dorsal profile (Figs 10, 11). The mouth is terminal or slightly sub-terminal with two pairs of short barbels ( Table 2).The body depth is usually greater than the head length (Fig. 12).The eyes are slightly protuberant and lie at the end of the anterior half of the head. The morphometric characters are summarised in Table 1. The dorsal fin usually has four unbranched and nine to 11 branched rays (Table 3). The last unbranched ray is ossified but not very thick and flexible in its distal part. It is usually shorter than the head (Fig. 4). The anal fin usually has three unbranched and five or six branched rays (Table 4).
There are 31 to 38 scales in the lateral line (Table 5), 4.5 to 6.5 scales above the lateral line (Table 6), four to six scales below the lateral line (Table 7) and 12 to 16 scales around the least circumference of the caudal peduncle (Table 8). The scales are shown in Fig. 5.
The pharyngeal teeth count is 2.3.5-5.3.2 in two specimens, 2.3.5-in 11 specimens, -5.3.2 in two specimens and 1.3.5-in one specimen. The pharyngeal teeth are hooked at their tips (Fig. 6).
Small live specimens are silvery; larger specimens are silvery or bronze coloured and sometimes have yellow pectoral and ventral fins (Fig. 11). Small ethanol-preserved specimens are silvery with a somewhat darker back and a salmon pink hue. Juveniles have a dark lateral spot on the caudal peduncle. Ethanol-preserved adults are yellowbrown and the back is only slightly darker than the rest of the body (Fig. 10).  The maximum length observed in the material examined is 385 mm SL. Carasobarbus chantrei differs from C. apoensis, C. canis, C. exulatus, C. luteus and C. sublimus in having 31 to 38 scales in the lateral line vs. 27 to 32, 29 to 35, 26 to 32, 25 to 33 and 27 to 29 respectively and modally 14 scales around the least circumference of the caudal peduncle vs. 12. It differs from C. kosswigi and C. sublimus in having a crescent-shaped lower lip without median lobe vs. a spatulate lower lip with median lobe and from C. exulatus, C. fritschii and C. harterti in modally having 10 branched dorsal-fin rays vs. nine.
Distribution. Carasobarbus chantrei occurs in the Orontes river drainage system (Fig. 7). Two juvenile specimens where collected in Nahr Marqīyah, a coastal river in Syria. This species had never before been reported from this location (Krupp 1985a) and it has most likely been introduced by humans. Two potential records from Nahr Quwayq (MNHN A-3861, MGHN 3554) are discussed in Krupp (1985a, c). Locality data for MHNL 3554 are ambiguous (Krupp 1985a). The locality for MNHN A-3861 is given as "Syria, Aleppo" in Krupp (1985a) and considered to be from Nahr Quwayq. The collection database of the MNHN gives "Origine: Syrie, localité: Alep, Milieu: Continent, Bassin hydrologique: Asi, Cours d'eau: Asi" as locality. As these data are contradictory, it is likely that the specimens do not come from the Nahr Quwayq, but from the Orontes (=Asi) and C. chantrei does probably not occur in the Nahr Quwayq. A record from the Ceyhan Nehri (Krupp 1985c) is not backed by specimens. Records from the Tigris-Euphrates basin are misidentified C. luteus (Krupp 1985a, Krupp andSchneider 1991) and the specimen from Balıklıgöl at Şanlıurfa in Turkey (SMF 12966) is probably mislabelled or was introduced there (Krupp 1985a). It is not included in the map.
Habitats and biology. Carasobarbus chantrei occurs in a wide range of habitats stretching from stagnant waters of lakes to rapidly flowing river courses.
Conservation status. Carasobarbus chantrei is utilised as food fish locally but is increasingly replaced by carp (Krupp 1985a). During a field survey in Syria in 2008, the species was still abundant in parts of the Orontes. However, large stretches of this river, especially in the Al Ghāb area, suffer heavily from water abstraction and pollution by sewage and domestic waste and are devoid of fish. The species is rated "Endangered B1ab(ii,iii)" by the IUCN (Crivelli 2006b). The main threat is habitat degradation due to water extraction, pollution and drought (Crivelli 2006b).
Description. The body is not particularly high backed and the maximum body depth is at the origin of the dorsal fin or slightly in front of it (Fig. 13). A nuchal hump is present in adult specimens (Fig. 14) but absent in juveniles (Fig. 15). The caudal peduncle is slender. The head profile is convex ventrally and straight dorsally. The body depth is about the same as the head length (Fig. 12). In specimens below 100 mm SL, the head is rather narrow, in larger specimens it becomes wider. The mouth is subterminal and comparatively narrow. Two pairs of barbels are present (Table 2), the posterior one is rather long. The eyes are at the end of the anterior half of the head and slightly protuberant. The morphometric characters are summarised in Table 1.
The dorsal fin is long and usually has four unbranched and eight to 10 branched rays (Table 3). The last unbranched ray is strongly ossified and only the tip is flexible. Its length is about the same as the head length (Fig. 4). The anal fin is long, usually has three unbranched and five or six branched rays (Table 4).
There are 26 to 32 scales in the lateral line (Table 5), 4 to 5.5 scales above the lateral line (Table 6), 3.5 to five scales below the lateral line (Table 7) and 10 to 12 scales around the least circumference of the caudal peduncle (Table 8). The scales are shown in Fig. 5.
The pharyngeal teeth count is 2.3.5-5.3.2 in one specimen, 2.3.5-in 16 specimens, -5.3.2 in one specimen and 2.3.4-in one specimen. The pharyngeal teeth are hooked at their tips (Fig. 6).
In live specimens and freshly preserved specimens the back and the sides are grey to golden, the belly is yellowish white and the fins are sometimes golden to orange (Fig. 15). Preserved specimens have a dark back and a lighter belly, the fins are whitish or greyish. Juveniles have a dark spot on the sides of the caudal peduncle.
The maximum length observed in the material available is 288 mm SL. Carasobarbus exulatus differs from all congeners, except C. fritschii and C. harterti in modally having nine instead of 10 branched dorsal-fin rays. It differs from C. fritschii and C. harterti in modally having 12 scales around the least circumference of the caudal peduncle vs. 16 and in having 26 to 32 scales the lateral line vs. 30 to 39 and 31 to 38 respectively.   Distribution. This species is endemic to Yemen and occurs in Wādī Ḩaḑramawt / Wādī al Masīlah and its pleistocene tributaries Clarke 1977, Krupp 1983a, Fig. 7). It is also known from Sadd Ma'rib (Al-Safadi 1995), a dam lake at N15°23'46", E45°14'37" and Wādī Ḩajr (N14°02'42", E48°40'27"), where they are "found throughout the whole year and are distributed all over the stream" (Attaala and Rubaia 2005).
Habitats and biology. The biology of this species is mostly unknown. Conservation status. During a field expedition in 2005 one of the authors saw large, continuous water bodies in the Wādī Ḩaḑramawt / Wādī al Masīlah area. The species is rated as "Endangered B1a, b; B2a, b" and water extraction is identified as the main threat (BCEAW 2002).
Discussion. Carasobarbus exulatus was described from Wādī Ḩaḑramawt and Wādī Maran in Yemen and placed in Barbus (Banister and Clarke 1977). Later it was transferred to Carasobarbus (Ekmekçi and Banarescu 1998  Description. The body is of moderate height and sometimes has a small nuchal hump in larger specimens. The head is round with a convex dorsal profile and convex or straight ventral profile (Figs 16, 17). The head length is shorter than the body depth (Fig. 12), the mouth is inferior with two pairs of barbels ( Table 2). The lower lip is crescent shaped and sometimes weakly keratinised. The eyes are in the anterior half of the head. The morphometric characters are summarised in Table 1.
The dorsal fin is short and weakly ossified and more than 15 % of the length of its last unbranched ray is flexible. Its last unbranched ray is about as long as the head (Fig. 4). It usually has four unbranched and seven to 10 branched rays (Table 3). The anal fin usually has three unbranched and five or six branched rays (Table 4). Its length is rather variable in adult specimens. It reaches the base of the caudal fin in some specimens.
Carasobarbus fritschii has 30 to 39 scales in the lateral line (Table 5), usually 5.5 scales above the lateral line (Table 6), usually 4.5 or 5.5 scales below the lateral line (Table 7), and 14 to 20 scales around the least circumference of the caudal peduncle (Table 8). The scales are shown in Fig. 5.
The pharyngeal teeth count is 2.3.4-4.3.2 in two specimens, 2.3.4-in one specimen and -4.3.2 in eight specimens. Pharyngeal teeth are hooked at their tips (Fig. 6).
Live specimens are silvery and usually have a dark longitudinal band above the lateral line. Fins are hyaline to slightly orange (Fig. 17). Ethanol-preserved specimens are yellow-brown, the back is usually distinctly darker than the belly and flanks.
The maximum length observed in the material available is 180 mm SL. Carasobarbus fritschii differs from all congeners except C. exulatus and C. harterti in having nine instead of 10 branched dorsal-fin rays. It differs from C. exulatus in having 30 to 39 scales in the lateral line vs. 26 to 32 and modally 16 scales around the least circumference of the caudal peduncle vs. 12. It differs from C. harterti in having a convex dorsal head profile and a last unbranched dorsal-fin ray that is weakly ossified and  flexible for more than 15 % of its length vs. a straight dorsal head profile and a strongly ossified last unbranched dorsal-fin ray that is flexible in less than 15 % of its length.
Distribution. Carasobarbus fritschii is widespread and abundant in Northern and Central Morocco (Fig. 18). It occurs in the Oued al Maleh, Oued Bou Regreg, Oued Igrounzar, Oued Moulouya, Oued Oum er Rbia, Oued Sebou and Oued Tennsift drainage systems, and in numerous small coastal rivers. Most records are from Morocco, but one specimen is from the Oued Kiss in Algeria.
Habitats and biology. Carasobarbus fritschii occurs in a wide range of running water courses and dam lakes.
Conservation status. Carasobarbus fritschii is a hardy species and occurs in nearnatural as well as heavily modified habitats. It is tolerant against pollution, damming and the presence of several exotic species (KB pers. obs.). The IUCN rates C. fritschii as "Least Concern" and Barbus paytonii (which is treated as a junior synonym in this study) as "Vulnerable B2ab(iii)" (Crivelli 2006c. According to the latter assessment the population in the lower Oued Oum er Rbia is adversely affected by agricultural pollution (Crivelli 2006e).
Discussion. Carasobarbus fritschii was described from the Oued Ksob as a member of the genus Barbus (Günther 1874). The same author described Barbus rothschildi from the Oued Oum er Rbia (Günther 1901). It is a junior synonym of C. fritschii. One year later Günther (1902) described Barbus riggenbachii from Oued Oum er Rbia and Oued Talmest. It is a junior synonym of C. fritschii. In the same year Capoeta atlantica and Capoeta waldoi were described from Oued Nfis (Boulenger 1902). These two species were placed into Capoeta, based on the keratinised lower lip that occurs in some specimens of C. fritschii. Both are junior synonyms of C. fritschii. Barbus paytonii was described from Oued Oum er Rbia (Boulenger 1911). It is a junior synonym of C. fritschii. In the same publication Boulenger transferred C. waldoi to the genus Barbus. The junior synonyms listed above were described, based on slight differences in mouth and lower lip shape or the degree of ossification of dorsal-fin rays. Sample sizes were usually very small. The examination of a large number of specimens revealed high variability and a continuous distribution of these characters. Boulenger (1919) transferred all species to the genus Barbus subgenus Labeobarbus, based on the possession of scales with parallel radii and an unserrated last unbranched dorsal-fin ray. Pellegrin (1919) listed the species in the genus Barbus but later (Pellegrin 1921(Pellegrin , 1939 accepted the subgenus Labeobarbus. Pellegrin (1939) synonymised B. riggenbachi with B. rothschildi and did not list C. atlantica. Karaman (1971) created the genus Pseudotor and synonymised C. atlantica and C. waldoi with Pseudotor fritschii fritschii. Fowler (1976) accepted all previously described species and transferred C. atlantica and C. waldoi to the genus Varicorhinus. Berrebi (1981) used the genus Barbus subgenus Labeobarbus and found no relevant differences between B. fritschii and B. paytonii in his morphometric and biochemical analysis. El Gharbi et al. (1993) highlighted the African distribution of the subgenus Labeobarbus. Doadrio (1994) and Tsigenopoulos et al. (2010) used Labeobarbus. Subsequent authors used the genus Barbus (Azeroual et al. 2000, Machordom and Doadrio 2001, Leggatt and Iwama 2003, Colli et al. 2009) or the provisional genus 'Barbus' ). We transfer this species to the genus Carasobarbus, based on the possession of a smooth last unbranched dorsalfin ray, modally nine branched dorsal-fin rays, six branched rays in the anal fin and shield-shaped scales with numerous parallel radii. Analysis of molecular genetic characters (Durand et al. 2002, Tsigenopoulos et al. 2010, KB unpublished data) support this decision.
The name of this species is frequently misspelled "Barbus fritschi". The 'Catalog of Fishes' lists SMF 636 and SMF 952 as types for C. fritschii (Eschmeyer 2011). Both lots where collected by K. v. Fritsch and J. Rein in Oued Ksob in 1872, together with the types of 'Barbus' reinii Günther, 1874, Luciobarbus nasus (Günther, 1874) and the syntypes of C. fritschii. SMF 636 contains seven specimens: one Luciobarbus nasus, one Luciobarbus ksibi (Boulenger, 1905), one 'Barbus' reinii and four C. fritschii. SMF 952 contains eight specimens: two 'Barbus' reinii and six C. fritschii. In the original description Günther (1874) did not state the number of type specimens on which he based the description of C. fritschii, but in the same paper he described Luciobarbus nasus (as Barbus nasus), based on two specimens and 'Barbus' reinii, based on three specimens. It is likely that Günther never saw the lots SMF 636 and SMF 952, because all syntypes of Luciobarbus nasus and 'Barbus' reinii are in the BMNH. The collectors, K. v. Fritsch and J. Rein probably deposited these samples immediately in the SMF and we conclude that SMF 636 and SMF 952 are not part of the type series of C. fritschii.  (Günther, 1901) BMNH 1902.7.28:27-33, 7;BMNH 1903.10.29:11-15, 8 -MNHN 1912-0089, 1;MNHN 1912-0090, 1;MNHN 1912-0091, 1;MNHN 1912-0092, 1;MNHN 1912- Diagnosis. Two pairs of long barbels; 31 to 38 scales in the lateral line and 13 to 17 scales around the least circumference of the caudal peduncle; dorsal fin longer than anal fin and less than 15 % of the length of its last unbranched ray is flexible, dorsal profile of the head straight.

Carasobarbus harterti
Description. The body is of moderate height and without a nuchal hump. The head is triangular with almost straight dorsal and ventral profile (Figs 19, 20). The head length is shorter than the body depth (Fig. 12). The mouth is subterminal with two pairs of long barbels ( Table 2). The eyes are in the anterior half of the head and relatively big. The morphometric characters are summarised in Table 1. The dorsal fin is long and strongly ossified and less than 15 % of the length of its last unbranched ray is flexible. Its last unbranched ray is as long as or longer than the head (Fig. 4). It usually has four unbranched and nine branched rays (Table 3). The anal fin usually has three unbranched and six or seven branched rays (Table 4). It does not reach the caudal fin origin.
Carasobarbus harterti has 31 to 38 scales in the lateral line (Table 5), usually 5.5 or 6.5 scales above the lateral line (Table 6), 4.5 to 6.5 scales below the lateral line (Table  7) and 13 to 17 scales around the least circumference of the caudal peduncle (Table 8). The scales are shown in Fig. 5.
The pharyngeal teeth count is -4.3.2 in four specimens examined. The pharyngeal teeth are hooked at their tips (Fig. 6).
Live specimens are silvery with an olive tinge and orange fins (Fig. 20). Ethanolpreserved specimens are yellow-brown, the back is darker than the belly and flanks.
The maximum length observed in the material examined is 250 mm SL. Carasobarbus harterti differs from all congeners except C. exulatus and C. fritschii in having nine rather than 10 branched dorsal-fin rays. It differs from C. exulatus in having 31 to 38 scales in the lateral line vs 26 to 32 and modally 16 scales around the least circumference of the caudal peduncle vs. 12. It differs from C. fritschii in having a straight dorsal head profile and a last unbranched dorsal-fin ray that is strongly ossified and flexible for less than 15 % of its length vs. a convex dorsal head profile and a last unbranched dorsal-fin ray that is weakly ossified and flexible for more than 15 % of its length.
Distribution. Carasobarbus harterti occurs in the rivers of the Oued Oum er Rbia and Tennsift drainage systems in Morocco (Fig. 18).
Habitats and biology. Carasobarbus harterti is less common than C. fritschii and inhabits only the lower and middle course of big rivers.
Conservation status. The IUCN rates this species as "Vulnerable A2ace" (Crivelli 2006d). The population has declined more than 30 % in the time from 1996 to 2006 due to urban, agricultural and industrial pollution (Crivelli 2006d).
Discussion. Carasobarbus harterti was described from Oued Oum er Rbia as Barbus harterti (Günther 1901). Some authors placed this species in the genus Barbus subgenus Labeobarbus (Boulenger 1919, Pellegrin 1921 while others continued using the  genus Barbus (Pellegrin 1919(Pellegrin , 1939. Karaman (1971) synonymised it with C. fritschii, but regarded it as a distinct subspecies. He incorrectly synonymised B. rothschildi, B. riggenbachi and B. paytonii with this subspecies and placed it in his newly erected genus Pseudotor. Subsequent authors did not accept Karaman's proposal and continued using Barbus (Fowler 1976, El Gharbi et al. 1993, Azeroual et al. 2000, Leggatt and Iwama 2003, Colli et al. 2009 or proposed using Labeobarbus (Doadrio 1994, Tsigenopoulos et al. 2010). We transfer this species to the genus Carasobarbus, based on the possession of a smooth last unbranched dorsal-fin ray, nine branched dorsal-fin rays, six branched rays in the anal fin and shield-shaped scales with numerous parallel radii. Analysis of molecular genetic characters (Durand et al. 2002, Tsigenopoulos et al. 2010, KB unpublished data) support this decision. (Ladiges, 1960) http://species-id.net/wiki/Carasobarbus_kosswigi Diagnosis. Two pairs of barbels; 32 to 38 scales in the lateral line, usually 14 to 16 scales around the least circumference of the caudal peduncle; last unbranched dorsal-fin ray markedly longer than head; mouth narrow, lower lip spatulate and median lobe present.

Carasobarbus kosswigi
Description. Body moderately high, laterally compressed and without a nuchal hump. The greatest body depth is at the point of the origin of the dorsal fin. The ventral profile of the head is straight, its dorsal profile has a slight to pronounced hump near the nostrils (Figs 21, 22). The head is short and narrow. The mouth is inferior. The maximum body depth is bigger than the head length (Fig. 12). The lips are comparatively thick and the lower jaw is narrow with a sharp horny sheath and a median lobe. The two pairs of barbels (Table 2) are stout and the anterior pair is quite long. The eyes are rather high in the middle of the head and rather small. The morphometric characters are summarised in Table 1.
The dorsal fin is long and usually has four unbranched and nine or 10 branched rays (Table 3). The last unbranched ray is long and well ossified; only the tip is flexible. It is considerably longer than the head (Fig. 4). The anal fin usually has three unbranched rays and six branched rays (Table 4). Its base is long. The bases of the dorsal and anal fin have a sheath of scales.
There are 32 to 38 scales in the lateral line (Table 5), 5.5 to seven scales above the lateral line (Table 6), 4.5 to 6.5 scales below the lateral line (Table 7) and (12) 14 to 16 scales around the least circumference of the caudal peduncle (Table 8). The scales are shown in Fig. 5.  The pharyngeal teeth count is 2.3.5-5.3.2 in seven specimens, 2.3.5-in one specimen and -4.3.2 in one specimen. The pharyngeal teeth are hooked at their tips (Fig. 6).
Live specimens are silvery. The back is darker than the belly, which is almost white (Fig. 22). Fixed specimens are yellow-brown and some have a darker back.
Carasobarbus kosswigi differs from all congeners, except C. sublimus, by having a spatulate lower jaw with a median lobe on the lower lip vs. a crescent-shaped lower jaw and a lower lip without median lobe. It differs from C. sublimus by having 32 to 38 scales in the lateral line vs. 27 to 29 and modally 14 scales around the least circumference of the caudal peduncle vs. 12 and by having a longer and more ossified last unbranched ray in the dorsal fin.
Distribution. Carasobarbus kosswigi occurs in the Euphrates-Tigris system (Fig. 7). Habitats and biology. Carasobarbus kosswigi is rare, inhabits fast-flowing reaches of rivers and feeds on small animals . The maximum length is about 150 mm SL and this species has no economic importance .
Conservation status. Little information is available, but because this species is dependent on fast-flowing water, it is probably impacted by the construction of dams.
Discussion. Carasobarbus kosswigi was described from the Batman Çayı and placed in the genus Cyclocheilichthys (Ladiges 1960). Karaman erected the new genus Kosswigobarbus for this species (Karaman 1971). Coad gave a detailed re-description of this species and transferred it to the genus Barbus (Coad 1982). Kosswigobarbus was revalidated (Ekmekçi and Banarescu 1998) and sometimes used as a subgenus of Barbus (Tsigenopoulos et al. 2010). Later the species was placed in Carasobarbus .
Carasobarbus kosswigi is paraphyletic with respect to C. sublimus . (Heckel, 1843) http://species-id.net/wiki/Carasobarbus_luteus The lectotype (NMW 54253:2) is a specimen of 211 mm SL, collected in the Tigris near Mosul on 10 Apr 1843 by T. Kotschy (Fig. 23). It has four unbranched and 10 branched rays in the dorsal fin, three unbranched and six branched rays in the anal fin, 27 scales in the lateral line and one pair of barbels. A bigger specimen (216 mm SL) from the same lot (NMW 54253:1) was not selected as lectotype, because it is atypical in having 11 branched rays in the dorsal fin and two pairs of barbels. The designation of a lectotype became necessary to fix the type locality of S. luteus (see Discussion).

Carasobarbus luteus
Diagnosis. One pair of barbels; 25 to 33 scales in the lateral line, and typically 12 scales around the least circumference of the caudal peduncle; last unbranched ray of the dorsal fin about as long as the head or slightly shorter.
Description. Specimens from Rūdkhāneh-ye Naband basin were excluded from this species description (see below).
The dorsal profile is convex up to the origin of the dorsal fin and a nuchal hump is present in specimens longer than about 100 mm SL. This species has a high back and caudal peduncle (Figs 23, 24). The ventral profile of the head is convex, its dorsal pro-file is almost straight to convex and has a hump near the nostrils in juvenile specimens. The mouth is sub-terminal. The barbels are short and stout. The maximum body depth is usually greater than the head length (Fig. 12). Usually one pair of barbels is present, but about 10 % of the specimens have two pairs of barbels ( Table 2). The eyes are at the back of the anterior half of the head. They are big and slightly protuberant. The morphometric characters are summarised in Table 1.
The dorsal fin usually has four unbranched and eight to 11 branched rays (Table 3). In specimens from the Tigris-Euphrates drainage system the last unbranched ray of the dorsal fin is strong with only the tip being flexible and it is about as long as the head. It is shorter and less ossified in Iranian populations (Fig. 4). The anal fin usually has three unbranched rays and five to seven branched rays (Table 4).
There are 25 to 33 scales in the lateral line (Table 5), 3.5 to 6 scales above the lateral line (Table 6), 3 to 5.5 scales below the lateral line (Table 7) and 10 to 13  scales around the least circumference of the caudal peduncle (Table 8). The scales are shown in Fig. 5.
Live specimens are silvery to olive and sometimes have yellowish fins (Fig. 24). Ethanol-preserved specimens are light yellowish brown to grey. In most cases the back is darker than the rest of the body. Some of the lighter coloured specimens have a salmon hue, others are silvery. The fins are yellowish brown to grey. Juveniles have a dark spot on the sides of the caudal peduncle.
Carasobarbus luteus from Ḩelleh, Kol, Mahārlū and Mand populations: The last unbranched ray of the dorsal fin is shorter and less well ossified. It is pronouncedly shorter than the head (Fig. 4). The mouth is wider and the body is not as high-backed as in specimens from the Tigris-Euphrates system (Fig. 12).
Carasobarbus luteus from Rūdkhāneh-ye Naband basin: In this population all specimens examined had two pairs of barbels ( Table 2). The anterior pair is longer than in specimens from Tigris-Euphrates system with two pairs. The last unbranched ray in the dorsal fin is considerably shorter than the head (Fig. 4) and comparatively weak. Compared with specimens from Tigris-Euphrates system, the dorsal and ventral fins tend to be slightly further away from the head. The head is longer and the body not as high backed as in specimens from Tigris-Euphrates system (Fig. 12). The general body shape (Fig. 25) resembles that of C. apoensis and C. canis. Some of the gill rakers are y-shaped in the largest specimen examined.
Carasobarbus luteus, except the population from Rūdkhāneh-ye Naband, differs from all congeners, except C. apoensis, in having one instead of two pairs of barbels. It differs from C. apoensis, C. canis, C. chantrei, C. fritschii, C. harterti and C. kosswigi in modally having 28 scales in the lateral line vs. 30, 32, 34, 34, 34 and 33 respectively. It differs from C. kosswigi and C. sublimus in having a crescent-shaped lower lip without median lobe vs. a spatulate lower lip with median lobe and from C. exulatus, C. fritschii and C. harterti in modally having 10 rather than nine branched dorsal-fin rays. All populations, except the one from Rūdkhāneh-ye Naband differ from C. apoensis in having a shorter head and a higher back. The population from Rūdkhāneh-ye Naband is very similar to C. apoensis in body shape, but differs in having two as compared to one pair of barbels.
Distribution. Carasobarbus luteus has a much greater range than any of its congeners and its distribution area is fragmented, resulting in several isolated populations. It is widespread all over the Tigris-Euphrates drainage system, and occurs in the rivers of south-western Iran (Fig. 7). The Nahr al Quwayq population, from one of the sites of the type locality, is probably extirpated due to drought and pollution (Krupp 1980, Krupp 1983b). There are only few, mostly older, records from the Orontes (Krupp 1985c, Krupp 1987. During recent fieldwork C. luteus was not found there. Because C. chantrei is still widespread and abundant in many parts of the Orontes, it is unlikely that C. luteus disappeared due to habitat degradation. It might have been driven out by competition with C. chantrei or records were based on misidentifications or mislabelled specimens. One specimen (NMW 10827) is reported from Damascus. Because C. luteus does not occur in the Damascus basin and it is highly unlikely that it ever occurred there, the origin of this specimen is unclear.
Habitats and biology. Carasobarbus luteus is mainly herbivorous. It feeds on algae, aquatic plants, detritus and small invertebrates, the main feeding period is at noon, but food is also taken at night (Naama and Muhsen 1986). The intestine is long (Ali 1986). The maximum size is 38 cm total length and 750 g, but normally they are smaller than 35 cm and weight less than 500 g (Ahmed 1982). They reach maturity at the age of one or two years and at a size of about 14 cm; the spawning period is June and July in the Tigris-Euphrates system, the eggs are spawned among reeds, roots or other aquatic vegetation and fecundity is high (Al Hazzaa and Hussein 2003a).
This species can tolerate saline waters to some degree (Al-Hassan and Muhsin 1986, Mohamed et al. 1993) and is of commercial importance due to its size and abundance (Ahmed 1982, Barak and Mohamed 1983. There are attempts on aquaculture of this species. The stickiness of the eggs can be lowered by several chemical treatments for this purpose (Al Hazzaa and Hussein 2003b). During spawning males get reddish brown in the anterior part of the body and greenish at the caudal peduncle while females are less colourful (Al Hazzaa and Hussein 2003a). Males can produce series of sharp clicking noises which do not seem to be associated with aggressive behaviour (Al Hazzaa and Hussein 2003a).
Larvae hatch at 64 degree-days in well oxygenated water and the eyes are still without pigments at this stage. The development is similar to that of other cyprinids (Al Hazzaa and Hussein 2003a). Ahmed et al. (1984) studied the reproductive biology of C. luteus.
Conservation status. Carasobarbus luteus is widespread and abundant in the Tigris-Euphrates system. Peripheral populations, like those in smaller Iranian rivers and the Nahr al Quwayq in Syria are more threatened or have already been extirpated (see above). Discussion. Carasobarbus luteus was described as Systomus luteus by Heckel (1843). Heckel (1843) listed Orontes, Tigris, Aleppo and Mosul as type localities. As all but one of the type specimens are either from the Tigris-Euphrates system or from the Nahr al Quwayq and Aleppo is located on the Nahr al Quwayq and not on the Orontes, Heckel may have confused these two rivers. One of the type specimens (NMW 10827) is from "Damascus" and can not be attributed to any of the relevant drainage systems. By designating NMW 54253:2 as lectotype we fix the Tigris near Mosul as type locality for S. luteus. The same confusion exists for the type localities of Systomus albus, which was also described from Tigris and Orontes in the same publication. A few years later Systomus albus var. alpina was described from the Daryācheh-ye Parīshān (Heckel 1847). These three taxa where later synomymised and placed in the genus Barbus (Günther 1868). Sauvage (1882Sauvage ( , 1884 accepted C. luteus and C. albus as valid species and transferred them to the genus Barynotus. Later, both species where synonymised again and transferred to the genus Barbus, subgenus Puntius (Misra 1947) or the genus Puntius (Menon 1956). Ladiges (1960) synonymised both species under the name Barynotus albus. Because Günther (1868) had previously selected luteus as the valid species name, he is to be considered the first revising author and Ladiges' action is not valid. Kähsbauer (1963) lists the species under two different generic names: Barbus (as B. luteus) and Systomus (as S. albus var. alpina). Karaman (1971) erected the new genus Carasobarbus for this species. This met mixed acceptance. While some authors accepted the new taxonomic position (e.g. Wossughi 1978, Bianco and Banarescu 1982, Ahmed et al. 1984, Naama and Muhsen 1986, others did not embrace it (e.g. Banister and Clarke 1977, Krupp 1985a, c, Coad 1995, Coad 1996 until the revision by Ekmekçi and Banarescu (1998). Fowler (1976) placed C. luteus in the genus Barbellion. Tsigenopoulos et al. (2010) used Barbus subgenus Carasobarbus. Barbus parieschanica was described from Daryācheh-ye Parīshān (Wossughi et al. 1983). In the same publication the species name is also spelled B. parschanica, but B. parieschanica is probably the intended spelling .  as the first revising author fixed B. parieschanica as the correct original spelling. Barbus parieschanica is a synonym of C. luteus. The 'Catalog of Fishes' lists RMNH 2463 as possible syntype of S. luteus and RMNH 2464 of S. albus var. alpina (Eschmeyer 2011). We did not examine these specimens.
We do not think that the population at Rūdkhāneh-ye Naband should be elevated to specific rank, because the number of specimens available is too low. We provisionally consider it an atypical population of C. luteus that might have been affected by bottleneck effects and accelerated morphological change, due to the restricted size and extreme conditions (high salinity and temperature) of its habitat. It would be very interesting to collect more samples for morphological studies and molecular sequence analysis.
In spite of some morphometric differences, C. luteus populations of Tigris-Euphrates system and Iran belong to the same species ); specimens from Rūdkhāneh-ye Naband were not included in that study.
Carasobarbus luteus and C. apoensis are closely related to each other (KB, unpublished data) and C. apoensis might be the ecologically specialised sister species of C. luteus, that is adapted to the environmental conditions of the wadi ecosystems of the Al Ḩijāz mountains. Diagnosis. Two pairs of barbels; 27 to 29 scales in the lateral line, 12 scales around the least circumference of the caudal peduncle; last unbranched dorsal-fin ray about as long as the head; mouth narrow, lower jaw spatulate and median lobe present on lower lip. Description. A nuchal hump is not developed. The maximum body depth is at the anterior end of the dorsal fin base. The ventral profile of the head is almost straight; the dorsal profile is convex and evenly curved (Figs 26,27). The maximum body depth is greater than the head length (Fig. 12). The mouth is inferior, narrow, the lips are thick and the lower jaw is spatulate with a horny sheath and a median lobe on the lower lip. The two pairs of barbels (Table 2) are well developed. The eyes are at the posterior end of the anterior half of the head. Some morphometric characters are summarised in Table 1.
The dorsal fin usually has four unbranched and nine or 10 branched rays (Table 3). The last unbranched ray of the dorsal fin is weakly ossified and about as long as the head (Fig. 4). The anal fin usually has three unbranched and six branched rays (Table 4) and its base is surrounded by a sheath of scales. Pectoral, ventral and anal fins are longer than in all other Carasobarbus species (Table 1).
There are 27 to 29 scales in the lateral line (Table 5), 4.5 or 5.5 scales above the lateral line (Table 6), 3.5 to 5.5 scales below the lateral line (Table 7) and 12 scales around the least circumference of the caudal peduncle (Table 8). The scales are shown in Fig. 5.
The pharyngeal teeth count is 2.3.4-5.3.2, 2.3.4-5.3.1 or 3.3.4-4.3.3 (Coad and Najafpour 1997). The pharyngeal bones available were too small for photography but are very similar to those of C. kosswigi (Fig. 6).
Live specimens from Rūdkhāneh-ye Fahlīān are silvery with hyaline fins (Fig. 27). Live specimens from Rūdkhāneh-ye A'lā are silvery with a slightly darker back, the scales have dark pigments on their hind margin; pectoral, ventral and anal fins have a yellow to orange hue, which is most obvious with fins folded back; dorsal and caudal fins are grey or hyaline (Coad and Najafpour 1997). Ethanol-preserved specimens are yellowish brown with a somewhat darker back and juveniles have a dark spot on the sides of the caudal peduncle.
Carasobarbus sublimus differs from all congeners, except C. kosswigi, by having a spatulate lower jaw with a median lobe on the lower lip vs. a crescent shaped lower jaw and a lower lip without median lobe. It differs from C. kosswigi by having 27 to 29 scales in the lateral line vs. 32 to 38 and modally 12 scales around the least circumference of the caudal peduncle vs. 14 and by having a shorter and less ossified unbranched last dorsal-fin ray.
Distribution. This species is known from Rūdkhāneh-ye A'lā, Rūdkhāneh-ye Fahlīān and possibly Rūdkhāneh-ye Kashgān (see discussion) in south-western Iran (Fig. 7).  Habitats and biology. Carasobarbus sublimus is adapted to streams with fast currents with water flowing over hard substrate (Coad and Najafpour 1997). The biggest specimen known has a SL of 115 mm (Coad and Najafpour 1997).

Conservation status.
Little is known about the conservation status of C. sublimus, but because this species is dependent on fast-flowing water, it is probably impacted by the construction of dams.
Discussion. Carasobarbus sublimus was described in the genus Barbus and aligned with C. apoensis, C. canis, C. chantrei, C. exulatus, C. kosswigi and C. luteus in the original description (Coad and Najafpour 1997). Coad recommends the use of the genus Kosswigobarbus for this species (Coad 2011). It was transferred to Carasobarbus, based on morphological characters and close genetic relationship .
Locality data for CMNFI 79-0277 is not beyond doubt, because this lot was mentioned as C. kosswigi in the original description of C. sublimus (Coad and Najafpour 1997). According to morphometric and meristic characters (scales in lateral line, above lateral line and around the least circumference of the caudal peduncle; length of dorsal, pectoral, ventral and anal fin) this specimen is within the range of C. sublimus and outside the range of C. kosswigi. It might be an aberrant specimen or it might have been accidentally swaped with CMNFI 1995-0010 (a specimen of similar size from the same locality as the types of C. sublimus). We had no opportunity to examine CMNFI 1995-0010. Though we think it is unlikely that C. kosswigi and C. sublimus occur sympatrically, for the time being we consider it to be a possible record of C. sublimus from the Rūdkhāneh-ye Kashgān.

Hybrids
Two putative intergeneric hybrids of C. canis with other cyprinids are known, one with Capoeta damascina (Valenciennes in Cuvier and Valenciennes 1842) and one with Luciobarbus longiceps (Valenciennes in Cuvier and Valenciennes 1842).

Carasobarbus canis × Capoeta damascina
The hybrids are intermediate in many morphometric and meristic characters (Mir et al. 1988). The head resembles that of Capoeta damascina, the mouth is more inferior than in C. canis and the lips are thicker. The scales are larger than in Capoeta damascina and smaller than in C. canis (Mir et al. 1988, Fig. 28). Oogonia and spermatogonia coexist in the gonads of both sexes and the development of the gametes is disturbed, thus the hybrids are sterile (Fishelson et al. 1996).

Carasobarbus canis × Luciobarbus longiceps
These hybrids are intermediate in many morphometric and meristic characters (Krupp 1985b , Fig. 29). The lateral line scale count matches that of C. canis. Heterologous cells are present in the gonads of this hybrid but the gametes mature normally (Fishelson et al. 1996). This hybrid was described as Barbus continii Vinciguerra, 1926 from a single specimen (Krupp 1985b).

Authors contribution
KB and FK developed the concept for this study and conducted field research independent of each other. KB collected, analysed and interpreted the data presented in this study and prepared the manuscript. FK reviewed the manuscript.