Carasobarbus kosswigi (Ladiges, 1960)

Borkenhagen, Kai & Krupp, Friedhelm, 2013, Taxonomic revision of the genus Carasobarbus Karaman, 1971 (Actinopterygii, Cyprinidae), ZooKeys 339, pp. 1-53 : 27-29

Carasobarbus kosswigi (Ladiges, 1960)

Cyclocheilichthys kosswigi Ladiges 1960: 135.

Material.

Type material. Holotype of Cyclocheilichthys kosswigi : ZMH H 1148, Turkey, Batman Çayı [37°47'16"N, 41°0'51"E], C. Kosswig, IV.1939.

Non-type material. Tigris-Euphrates system. NMW 90369, 1, Turkey, Batman Çayı near Baschkaja [37°53'15"N, 41°7'56"E], V. Pietschmann, 15 Jul 1914. - NMW 90805, 1, Turkey, Gökçesu Çayı (37°45'N, 41°45'E), 26 Sep 1985. - ZMH 9548, 2, Turkey, Ceylanpınar [36°50'50"N, 40°3'0"E]. - SMF 33119, 1, Syria, Nahr al Khābūr at Al Ḩasakah [36°30'9"N, 40°44'52"E], F. Krupp. - SMF 30172, 1, Syria, Nahr al Khābūr near Tall Budayrī (36°24'N, 40°52'E), F. Krupp, 2-4 Nov 1986. - SMF 30173, 1, Syria, Nahr al Khābūr near Nahāb (36°23'N, 40°50'E), F. Krupp, 23-27 May 1989. - SMF 30174, 1, Syria, Nahr al Khābūr near Nahāb (36°23'N, 40°50'E), F. Krupp, 28 Sep– 8 Oct 1988. - CMNFI 79-0290, 2, Iran, Qaşr-e Shīrīn (34°31'N, 45°35'E). - CMNFI 79-0289, 1, Iran, 25-30 km from Qaşr-e Shīrīn (34°28'N, 45°52'E). - BMNH 1974.2.22:1292-1296, 4; BMNH 1974.2.22:1281, 1, Iraq, Euphrates at Ḩadīthah [34°8'23"N, 42°22'41"E], 19 Oct 1953. - CMNFI 79-0275, 1, Iran, Rūdkhāneh-ye Kashgān, 2 km from Ma‘mūlān (33°25'N, 47°58'E). - SMF 33129, 3, Iran, Rūdkhāneh-ye Karkheh at Pol-e Dokhtar (33°9'36"N, 47°43'12"E), N. Alwan et al., 3 Mar 2008. - ZM-CBSU 4153, 1; ZM-CBSU 4154, 1, Iran, Rūdkhāneh-ye Dez at Dezfūl [32°22'57"N, 48°24'7"E], F. Bossaghzadeh, 8 Jun 2005.

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.

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 Carasobarbus 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 Carasobarbus 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 ( Krupp and Schneider 2008). The maximum length is about 150 mm SL and this species has no economic importance ( Krupp and Schneider 2008).

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 ( Borkenhagen et al. 2011).

Carasobarbus kosswigi is paraphyletic with respect to Carasobarbus sublimus ( Borkenhagen et al. 2011).