Genus Petroleuciscus
Bogutskaya, 2002

This genus currently comprises 6 species of which 2 are found in Iran and were formerly placed in the subgenus Squalius of the genus Leuciscus; Squalius is now recognised as a distinct genus too. The genus is distinguished by the small size of adults, the reduced number of vertebrae (modally 34-38 in total, rarely 39 or 40), few sensory cephalic pores (7-10 in the supraorbital canal, 12-19 in the infraorbital canal and 12-17 in the preoperculo-mandibular canal), a relatively small supraethmoid-mesethmoid block, narrow infraorbitals, and a deep neurocranium with a normally developed interorbital septum (Bogutskaya, 2002). The genus is found in the basins of the Aegean, Black, Caspian and Aral seas, the upper Tigris River , Lake Urumiyeh and south-central Iran.

Petroleuciscus persidis
(Coad, 1981)

Common names

'rus mahi persidis.

[Persian chub].

Systematics

Trewavas (1972) has discussed the generic nomenclature of Pseudophoxinus Bleeker, 1859 in which this species was originally described. It is more closely related to the genus Leuciscus according to N. Bogutskaya (pers.comm., 1994; 1996). Bogutskaya (1996) placed this species in her Leuciscus borysthenicus (Kessler, 1859) group which also includes L. ulanus and deserves subgeneric rank, but later erected a new genus.

Saadati (1977) described, but did not name, a new species in the related genus Phoxinellus Heckel, 1843 from the Bid Sorkh River in the Simareh River basin between Sahneh and Kangavar in Kermanshahan (the Bid Sorkh Pass is at 34°26'N, 47°49'E). I was unable to find this species in his collections and no further material has come to light. It had 8-9 dorsal fin branched rays, 8-9 branched anal fin rays, 8 branched pelvic fin rays, 47-56 scales in a complete lateral line, and 20 long and crowded gill rakers.

The type locality of Pseudophoxinus persidis is the "upper Shur River drainage at "Koorsiah" village, near Darab on Darab-Fasa road, 28°45.5'N, 54°24'E, Fars". The holotype is a 54.7 mm standard length male held at the Canadian Museum of Nature, Ottawa under CMNFI 1979-0154A (see figure above). Paratypes comprise 95 fish, 34.7-58.8 mm standard length, from the same locality as the holotype under CMNFI 1979-0154B, and 5 fish, 74.7-92.4 mm standard length, under CMNFI 1979-0499 from an "irrigation ditch at village 32 km west of Kor River bridge on road to Dariush Dam, 30°04.5'N, 52°36'E, Fars". Paratypes were distributed to the following institutions from CMNFI 1979-0154B: BM(NH) (2), ROM (2), UAIC (1), UBC (2) and UMMZ (2).

Key characters

This species is characterised by having a pharyngeal tooth count of 1,5-4,1, modally 7 branched dorsal fin rays, anal fin branched rays 7-9, pelvic fin rays 7-8, pored lateral line scales 35-43 in a complete lateral line, short gill rakers numbering 10-14 on the whole first arch, total vertebrae 34-37, a light coloured peritoneum but with numerous melanophores, and flanks with a lateral stripe evident posteriorly but fading anteriorly and not reaching the head.

Morphology

The mouth is terminal and oblique and the rictus reaches back to a level just anterior to the anterior eye margin. A pelvic axillary scale is present. The subcircular to oval scales bear numerous fine circuli and radii on the anterior and posterior fields (total radii number 23-44). Pharyngeal teeth are strongly hooked, concave below the hook and serrated along the margins of the concave surface, particularly on the anterior edge. In the largest fish, the hook may be much reduced to absent, serrations may be absent, and anterior teeth in the main row are rounded. Gill rakers reach the adjacent raker when appressed. The gut is a short and simple s-shape.

Meristic values are as follows: dorsal fin branched rays 6(2) or 7(189) after 3 unbranched rays, anal fin branched rays 7(3), 8(37) or 9(10) after 3 unbranched rays, pectoral fin branched rays 13(10), 14(20) or 15(20), pelvic fin branched rays 7(31) or 8(19), lateral line scales 35(2), 36(19), 37(4), 38(10), 39(3), 40(6), 41(5) or 43(1), total gill rakers 10(1), 11(9), 12(32), 13(6) or 14(2), pharyngeal teeth 1,5-4,2(1), 1,5-4,1(13) or 1,5-4,0(1), and total vertebrae 34(1), 35(20), 36(27) or 37(2). Karyotype 2n=50 (Esmaeili and Piravar, 2006a).

Sexual dimorphism

Number of anal fin branched rays is significantly higher in females (mean 8.3 versus 8.0 in males). Pectoral and pelvic fin lengths, longest dorsal and anal fin rays and caudal peduncle length are shorter in females than in males while head length, head width and predorsal length are longer in females than in males.

Colour

The back and upper flanks are dark and the belly cream. The straight lateral stripe extends from a diffuse area on the tail base to a level at or in front of the dorsal fin origin but does not reach the head. The stripe overlaps the lateral line on the caudal peduncle but lies above it on the flank, paralleling the back. Dorsal fin membranes are lightly speckled with melanophores which tend to be concentrated along the fin ray margins. The caudal and anal fin membranes are mostly clear with pigment restricted to fin ray margins. The pectoral fin may be pigmented on the membranes and there is often strong pigment along the posterior edge of the first unbranched ray. The pelvic fin has little or no pigmentation. Large fish are much darker overall than small fish, obscuring the stripe and with more pigment on fin rays and membranes.

Size

Reaches 9.2 cm standard length.

Distribution

This species is found in the Kor River and Hormozgan basins (Coad, 1981e; M. Hafezieh, pers. comm.). Abdoli (2000) reports this species from the Kor and Pulvar rivers, the Hilleh, middle Mand, Shur (tributary of the Dasht-e Palang) and the Kul rivers.

Zoogeography

Durand et al. (2000) place this species in a Leuciscus (= Squalius) cephalus "complex", i.e. descendents of peripheral isolates of a widespread ancestral species, later re-invaded by Danubian S. cephalus.

Habitat

Habitat knowledge is restricted to field data of collections. This species was collected in large rivers, streams, springs, irrigation ditches and qanats, but all these have in common a stream-like environment for much of the year. They are relatively shallow (20 cm to 2 m), variable width (0.5-75 m), medium to slow current, some submergent and emergent aquatic vegetation and a bottom varying from pebbles and gravel to mud. Water temperatures varied from 15 to 23°C from October to January and presumably would be over 30°C in the summer. Conductivity ranged from 0.3 to 1.0 mS. Altitude ranged from 980 to 1940 m. The lower reaches of some of the capture rivers are salty and may not support this species.

Age and growth

Unknown. Esmaeili and Ebrahimi (2006) give a significant length-weight relationship based on 10 fish measuring 4.21-8.33 cm standard length. The a-value was 0.0178 and the b-value 3.229 (a b-value < 3 indicating a fish that becomes less rotund as length increases and a b-value >3 indicating a fish that becomes more rotund as length increases).

Food

Gut contents include insect remains and fragments of large plants. Diet presumably consists mostly of aquatic invertebrates.

Reproduction

Reproduction in this species is unknown but egg development in adult fish collected in winter and young of the year collected in October suggest spring and early summer as the spawning season.

Parasites and predators

Jalalai et al. (2000) record Dactylogyrus sphyrna, a monogenean, from the gills of this species in the Kor River basin. Barzegar and Jalali (2006) report parasites in this species from Kaftar Lake as Lernaea cyprinacea, Trichodina sp., Ichthyophthirius multifilis and Dactylogyrus sphyrna.

Economic importance

None.

Conservation

The distribution of this species in various small habitats probably means that it is not in immediate danger. However water is in short supply in this part of Iran and abstraction may threaten its survival.

Further work

The ecology of this species should be studied and detailed distributional information compiled.

Sources

Based on Coad (1981e).

Type material: See above, Pseudophoxinus persidis (CMNFI 1979-0154A, 1979-0154B, and 1979-0499).

Iranian material: CMNFI 1979-0025, 11, 19.4-79.6 mm standard length, Fars, Kor River at Marv Dasht (29º51'N, 52º46'30"E); CMNFI 1979-0114, 1, 47.1 mm standard length, Fars, Mand River (29º41'N, 52º06'E); CMNFI 1979-0156, 6, 43.8-64.3 mm standard length, Fars, qanat in Rashidabad (28º47'N, 54º18'E); CMNFI 1979-0163, 8, 31.1-48.3 mm standard length, Fars (no other locality data); CMNFI 1979-0164, 15, 28.8-52.6 mm standard length, Fars (no other locality data); CMNFI 1979-0194, 3, 48.9-58.2 mm standard length, Fars, upper Shur river drainage (28º45'30"N, 54º24'E); CMNFI 1979-0292, 7, 37.0-54.0 mm standard length, Fars, Lapu'i spring near Zarqan (29º48'N, 52º39'E); CMNFI 1979-0305, 2, 23.8-25.5 mm standard length, Fars, Pulvar River at Pasargad (30º12'N, 53º12'E); CMNFI 1979-0342, 33, 23.6-43.2 mm standard length, Fars, Kor River at Band-e Amir (29º46'N, 52º51'E): CMNFI 1979-0503, 4, 32.2-113.5 mm standard length, Fars (no other locality data); USNM 258445, 18, 15.5-44.5 mm standard length, Fars, Chasht Khvar (ca. 29º44'N, ca. 53º12'E).

Petroleuciscus ulanus
(Günther, 1899)

Common names

None.

Systematics

This species was originally described in the genus Leuciscus. Saadati (1977) considers this species to be in the genus Alburnus but did not examine the types. Leuciscus gaderanus Günther, 1899 is a synonym, even Günther (1899) the describer of the two species indicating that this may be the case.

The 2 syntypes of Leuciscus ulanus, 68.0-84.5 mm standard length, are in the Natural History Museum, London and are "from Ula on the Zola Chai", Günther (BM(NH) 1984.10.10:1-2). The 3 syntypes of Leuciscus gaderanus, 44.6-73.0 mm standard length, are "from the Gader Chai" which is near Ocksa (BM(NH) 1899.9.30:113-115). Additionally there are 5 specimens of Leuciscus gaderanus, 11.0-54.5 mm standard length "from near the mouth of the Nazlu Chai at Superghan" (BM(NH) 1899.9.30:108-112). Günther (1899) refers to 3 young specimens from the latter locality as syntypes but of these 5 fish under this catalogue number and locality given as "Superghan" on the label only 2 fish are small (11.0-12.5 mm SL) and the other 3 fish are larger (45.8-54.5 mm SL). Another collection comprising 1 specimen, 27.0 mm standard length, is from the Urmi River according to the label (BM(NH) 1899.9.30:107). Its type status is unclear since the locality is wrong but the size is small and it could be the third of Günther's "three young specimens" since its catalogue number is in sequence.

Key characters

Distribution and meristic characters identify this species.

Morphology

Dorsal fin unbranched rays 3, branched rays 7-9, anal fin unbranched rays 3, branched rays 7-11, pectoral fin branched rays 12-14, and pelvic fin branched rays 7-8. Lateral line scales 36-45. There is a pelvic axillary scale. Scales with a slightly anterior focus and numerous radii on the anterior and posterior fields. Total gill rakers 12-16, reaching the first or second raker below when appressed. Pharyngeal teeth 2,5-4,2, more rarely 2,4-5,2, 2,5-5,2 or 2,4-4,2, hooked at the tip and strongly serrated below on the larger teeth. Total vertebrae 37-38. The mouth is oblique and extends back to just behind the front margin of the eye and the lower jaw protrudes slightly or hardly at all (Günther (1899) has the upper jaw slightly overlapping the lower). The gut is an elongate s-shape and may have an anterior loop to the left.

Meristic values for Iranian specimens are:- dorsal fin branched rays 7(5) or 8(15); anal fin branched rays 7(1), 8(6), 9(11) or 10(2); pectoral fin branched rays 12(5), 13(10), or 14(5); pelvic fin branched rays 7(19) or 8(1); lateral line scales 38(3), 39(6), 40(6), 41(1), 42(1) or 45(2); total gill rakers 12(2), 13(7), 14(6), 15(3) or 16(2); pharyngeal teeth 2,5-4,2(9), 2,4-5,2(2), 2,5-5,2(1) or 2,4-4,2(1); and total vertebrae 37(4) or 38(1).

Sexual dimorphism

Males bear tubercles on the pectoral fins mostly in a single file, occasionally two together, branching with the rays. Small tubercles are also found thickly on the top and sides of the head but no pattern was discernible in the specimens examined (types of L. ulanus).

Colour

There is a narrow, straight black stripe running from the upper half of the eye to the end of the lateral line separating the bluish back from the silvery flanks (Günther, 1899), best developed in preserved specimens posteriorly. Live fish have a grey-silver flank with some spots, a brown-green back and a light silver abdomen. Lower fins are pale to light yellow and the dorsal and caudal fins are light grey (Abbasi and Sabkara, 2004a; 2004b). The lower half of the operculum below the mid-eye level has few or no spots while the upper half is heavily pigmented. There is also no pigment below the eye or it is restricted to a thin line around this lower margin. The flanks are dotted with minute pigment spots. The back mid-line has a black stripe, most obvious predorsally. The rays and membranes of the dorsal fin, caudal fin and anterior pectoral fin bear melanophores; melanophores weak to absent on the anal and pelvic fins. The peritoneum is silvery brown with scattered melanophores.

Size

Reaches 14.2 cm for length (Abbasi and Sabkara, 2004b).

Distribution

This species is endemic to the Lake Orumiyeh basin (Günther, 1899). This species was found only in the Gadarchai and Mahabad River and was not caught in the Zolachai, Nazluchai, Baranduzchai and sampled areas of the Siminerud and Zarrinerud in recent collections by Abbasi and Sabkara (2004a; 2004b).

Zoogeography

Petroleuciscus kurui (Bogutskaya, 1995) from the upper Tigris River system of Turkey is the closest relative of this species (Bogutskaya, 1995) although other members of the Orumiyeh ichthyofauna are related to fishes from the Caspian Sea basin.

Habitat

Essentially unknown, found in stream or river habitats.

Age and growth

Fish caught by Abbasi and Sabkara (2004b) in the Gadarchai and Mahabad River were 34-142 cm in fork length and 1.4 years old. Males comprised 28.8% and females 71.2% of the total population. Maturity was attained at 2 years.

Food

Generally unknown but traces of insects and large quantities of filamentous algae were found in the gut contents of a few specimens. The algae may be an accidental inclusion as the gut is short and probably cannot digest plant material. Fish caught by Abbasi and Sabkara (2004a; 2004b) however contained a wide range of phytoplankton (19 genera) and zooplankton (7 groups), as well as benthic organisms (4 groups). Daphnia, Chydrus and chironomids were dominant gut contents. It was considered to be an omnivorous fish preferring to feed on zooplankton and other mid-water animals.

Reproduction

Spawning of fish in caught by Abbasi and Sabkara (2004b) took place from 1 April until 1 July with absolute fecundity estimated at 1810-16,115, average 6437 eggs.

Parasites and predators

Jalali et al. (2005) summarise the occurrence of Gyrodactylus species in Iran and record G. sp. in fish from the Baranduz and Halaj rivers.

Economic importance

None.

Conservation

This species is known only from the type series and a few other collections. This suggests that it is quite rare or has a restricted habitat preference.

Further work

The biology, distribution and abundance of this poorly known species should be investigated to see if it requires protection.

Sources

Type material: See above for L. ulanus (BM(NH) 1984.10.10:1-2) and L. gaderanus (BM(NH) 1899.9.30:113-115 and BM(NH) 1899.9.30:108-112).

Iranian material: CMNFI 1970-0560, 35,11.4-48.8 mm standard length, Azarbayjan-e Bakhtari, Mamiyand Chay (ca. 36º59'N, ca. 45º39'E); CMNFI 2007-0096, 6, 38.8-68.5 mm standard length, Azarbayjan-e Bakhtari, Baranduz Chay basin (ca. 37º25'N, ca. 45º10'E); BM(NH) 1899.9.30:107, 1, 27.0 mm standard length, Azarbayjan-e Bakhtari, Urmi River (no other locality data).

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