Species Accounts - Cyprinidae - Iranocypris

Revised:  05 January 2009

Courtesy of Kiavash Golzarianpour

Iranocypris movie.3gp, courtesy of Kiavash Golzarianpour

Common names

mahi-ye kureghar or mahi-ye kur-e qar (= blind cave fish), kopur mahi kureghar, ماهي كور (= mahi kur).

[Iran cave barb].

Systematics

The holotype is in the Zoological Museum of Copenhagen (ZMUC P 26475) and measures 46.5 mm total length and 38.5 mm standard length (Nielsen, 1974; personal observations). The paratypes number 5 (in Nielsen (1974)), or 6 (in Bruun and Kaiser (1948)) but only 4 were found in ZMUC in December 1999. Paratypes (ZMUC P 26476, 26477, 26478, 26480) measure 19.5-42.0 mm total length and 16.5-34.5 mm standard length according to Bruun and Kaiser (1948). Two fish (P 26476 and P 26480) were used in histological studies and one consists of the body only. The type locality is given below and the fish were collected by E. Kaiser on 6-5-1937 from "lok 80" (= locality 80; but no field notes by E. Kaiser are available in ZMUC).

The date of authorship for this species is variously listed as 1943 on an official reprint, as 1944-49 in one set of Contents and "ready from the press 1944" in another set of contents. Proudlove (2006) states that is did not appear until 1948 because of World War II.

Bruun and Kaiser (1948) believe this species to be related to the genus Barbus, members of which also have two pairs of barbels, although Saadati (1977) considers this unlikely since most Barbus from the Tigris River basin are large fishes.

Key characters

The only eyeless, depigmented cyprinid species in Iran, it is very distinctive.

Morphology

The body is compressed and the head somewhat flattened. There are two pairs of barbels, one pair at the mouth corners and one about half way along the upper lip. The upper lip has a feebly crenulated edge. The mouth is subterminal and horseshoe-shaped. A mental disc is developed in some fish, absent in others. There are significant differences in some morphometric and meristic characters in fish with, and without, a disc (Sargeran et al., 2008). There is no visible trace of eyes in most fish. The skin is naked except for a few rows of scales behind the pectoral fin base, although some individuals may have more flank scales. There are about 32 myomeres  along the flank. A lateral line is present. The dorsal fin has 3 unbranched and 7-8 branched rays, the anal fin 3 unbranched and 4-5 branched rays, the pectoral fin 14-17 branched rays and the pelvic fin 5-7 branched rays. Pharyngeal teeth in 3 rows, 1 to 3 in the outer row, 3 to 4 in the middle row and 3-5 in the inner row. Anterior teeth are very enlarged and conical, appearing as rounded knobs while the posterior teeth in the main row are flattened and slightly hooked. Smaller fish have less conical anterior teeth with a tiny hook at the tip and posterior teeth have a short, flat to slightly concave surface below the tip. Tooth counts are difficult to make with accuracy as it is not always clear to which row a tooth belongs. Smaller fish can be interpreted as 2,3,5-5,3,2 while larger fish may possibly lose a tooth and have a 2,3,4-4,3,2 count. Gill rakers very short, not reaching the adjacent raker when appressed and numbering 10-13 total. Total vertebrae 34-36. Gut s-shaped.

Meristics in specimens examined, including the holotype and 2 paratypes: dorsal fin branched rays 7(30) or 8(29); anal fin branched rays 4(1) or 5(49); pectoral fin branched 12(1), 13(9), 14(8), 15(23) or 16(8); pelvic fin branched rays 6(18), 7(31) or 8(1); total gill rakers 10(2), 12(4) or 13(1); pharyngeal teeth 2,3,5-5,3,2(1), 3,4,5-5,4,2(1), 2,3,4-5,3,2(1) or 2,3,4-4,3,1(1); total vertebrae 34(3), 35(8) or 36(1).

Sexual dimorphism

None reported.

Colour

This species is almost entirely unpigmented although live fish are pinkish to red from the blood showing through the skin. The gill filament area is bright red and some fish give an overall impression of red like a goldfish. Small, black pigment cells were visible in two small fish over the brain and just behind it and in these two fish and three others a very small, black pigment spot deep in the tissues on the side of the head may indicate a rudimentary but non-functional eye. Gut contents are visible through a semi-transparent body wall. Preserved fish are yellowish-white.

Size

Reaches 55.0 mm total length (Kiavash Golzarian, pers comm., 6 April 2008).

Distribution

Found only at "Kaaje-ru" above the garden "Bagh-e Loveh", "Lowa" or "Levan" (probably Loven at 33°04'N, 48°37'E) which is about 4 km from kilometre 382 on the railway from Bandar Shapur to Tehran and approximately 12 km north of the railway station Tang-e Haft. The stream below the cave locality is the "Ab-e Serum" which runs into the "Ab-e Zezar" which is a tributary of the Dez River, in Lorestan Province. Further locality details are given in Bruun and Kaiser (1948). The locality is at 744 m and 33°04'38.6"N, 48°35'33.1"E according to the Iranian Fisheries Research and Training Organization Newsletter, 21:3, 1998 and Kiavash Golzarian, pers comm., 6 April 2008).

Zoogeography

The relationships of cave species, with their reduced characters, are problematical but the three rows of pharyngeal teeth and mouth structures indicate a possible relationship with Garra.

Habitat

Known only from a well-like but natural outlet of a subterranean system. The outlet overflows to form a small stream from January to May (Smith, 1979) during the snow-melt period in the Zagros Mountains but in April to June this flow ceases (the precise timing of flow and its cessation is estimated from villager's comments and scientific visits and also varies with precipitation). The well area is about 5 by 3 m and gradually decreases as the year progresses. Divers descended to a depth of 60 feet (= 18.3 m) in 1977 in the "well" until the resurgence narrowed (Farr, 1977). A rope was let down by R. Mehrani (pers. comm., 2000) and reached 23 m before the rope ran out and yet it was not at the bottom. Smith (1979) reports divers descending to 60-70 feet (18.3- 21.3 m). The pool shelves deeply under the cliff rearwards but the whole pool surface is exposed to light. There is no vegetation in the pool except for some encrusting algae on the rocky sides. The shale fragments forming the outermost floor of the pool have a thin layer of mud on them which may contain algae.

It seems probable that a complex of flooded but narrow and inaccessible passages is the habitat of this species and the well is merely the surface manifestation of this complex (Bruun and Kaiser, 1948; Smith, 1978; Banister, 1992). There is a smaller pool (about 2 m across narrowing rapidly inside) and flowing exit stream lower down the gorge, about 50 m away from the main locality, where a blind fish was seen but not caught in December 2000 (Smith (1979) also tentatively reports sighting a fish here). This is assumed to be evidence of the interconnectivity of subterranean passages. The main pool was not flowing at this time. The stream from the smaller pool increases in flow downstream, possibly tapping more groundwater, and eventually has a moderate flow. No fish were seen in it. The stream falls over a high waterfall (estimated at 10-15 m high by Smith (1979) which seems about right) so the well localities are isolated from the local fishes in the main river. The main river houses Garra rufa and Nemacheilus species s.l.. The stream shows evidence of recent higher flow which tends to confirm overflow from the main well.

The fish may be seen swimming freely in the well, up to a 20 at a time may be counted. They can be caught with a dip-net.

Sampling in December 2000 recorded a water temperature of 18.5°C, pH 7.5 and a conductivity of 334 µS. Aquarium specimens have been maintained at 5-28°C and were very resistant to changes in oxygen levels (R. Mehrani, (pers. comm., 2000).

Cave locality with R. Mehrani, 4 December 2000

Cave locality showing friable rock surrounds

Age and growth

Unknown although R. Mehrani (per. comm., December 2000) kept fish in aquaria for 18-24 months.

Food

Unknown but the aquarium specimens referred to above were fed Artemia, dried and fine-ground Gammarus, zooplankton and phytoplankton. Faecal contents were phytoplankton and one fish was observed to scrape the aquarium wall. Occasionally aquarium fish will swim upside down with the snout at the water surface and may be feeding on an algal film. Fish with a disc can attach to and graze on the substrate; a significantly longer intestine in such fish may be indicative of a detrital feeding habit (Sargeran et al., 2008).

Reproduction

Unknown.

Parasites and predators

None reported from Iran.

Economic importance

Robins et al. (1991) list this species as important to North Americans. Importance is based on its use in textbooks and its status as a cave fish.

Conservation

A fine of 10,000 rials (U.S.$139.94, 15 March 1978) was imposed specifically for illegal fishing of this species (Anonymous, 1977-1978), now 100,000 rials (U.S.$11.04, 7 April 2008). It is on the 1994 IUCN Red List of Threatened Animals as one of two rare fish species from Iran (see also Paracobitis smithi) and is on the 2000 IUCN Red List and subsequent ones as VU D2 (Vulnerable, acute restriction in its area of occupancy; see also Proudlove (2001)). The habitat is of unusual importance for studies on evolution in unique environments. Coad (2000a), using 18 criteria, found this species to be one of the top 4 threatened species of freshwater fishes in Iran.

B. Sandford (in litt., 1979) considered this fish to be endangered. The cave appeared to be a recently collapsed system and the network of fissures could be quite small. The main pool is at the end of a narrow cleft, overhung by a cliff of friable shale. Shale fragments fall spontaneously and the nearer end of the pool has a floor of shale fragments. Coupled with recent collecting the number of extant specimens may be quite low but this is impossible to confirm.

Local informants in December 2000 estimated that 5-6 parties visit the site each year. The number of specimens taken is unknown but an estimated 66+, possibly more than 100, have been collected in recent years (from 2000 to 2008). Eight specimens are referred to in the literature, 4 specimens were caught in 1998 (R. Mehrani, pers. comm., 2000), in the two years 1999-2000 13 specimens were collected by one party, 18 by another in December 2000 (R. Mehrani and IFRO staff, N. Najafpour, IFRO, F. Razi, Darabad Museum, Tehran and B. W. Coad), 10 specimens by Ali Ebrahimi (pers. comm, 25 January 2006), 11 by Kiavash Golzarian (pers comm., 6 April 2008), and more than 10 by others.

Four fish collected in 1998 survived 2 years in an aquarium (R. Mehrani, pers. comm., December 2000). They were fed on Artemia, zooplankton, phytoplankton and fine-ground Gammarus. Water temperature ranged from 5 to 28°C and resistance to changes in oxygen levels was high. Fish were sometimes observed to swim upside down at the water surface.

The establishment of a small park or reserve around the site and education of the local people to maintain a watch on the cave would be most useful to protect this species, and the other cave species at this site, from unauthorised collectors. A survey of the local people and the Department of the Environment files should be made to determine the numbers of visitors to this remote site.

Further work This is a small species of fish of unusual appearance and provenance and could be bred and sold as an aquarium and experimental species, providing that numbers at the site warrant removal of breeding stock. If successful, this would ensure survival of the species. Captures at present appear to be fortuitous and give no real picture of the population size; removal of more specimens would have to be carefully planned and monitored. Surveys of groundwater recharge in the area and a more thorough investigation of the cave system should be undertaken to assess the status of the habitat.

Sources

Movaghar (1973) is an additional reference, in Farsi, on this species.

Type material: See above (ZMUC P 26475, P 26476, 26477, 26478, 26480).

Iranian material: CMNFI 2007-0124, 8, 27.3-42.2 mm standard length, Lorestan, type locality as above.

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© Brian W. Coad (www.briancoad.com)