• Korean Journal of Ichthyology
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• v.11 no.2
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• pp.172-176
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• 1999

Chromosome of cobitid fishes, Iksookimia yongdokensis collected from the 4 streams flowing to the eastsouthern coast of Korea was studied using chromosome of gill and kidney cells prepared by flame drying technique. The results obtained were as follows: the chromosome number was 100 composed of 44 meta-submetacentric and 56 subtelo-telocentric chromosomes, and the fundamental number (FN) was 144. It was remarked that Iksookimia yongdogensis was distinguishable from its congeners in the karyotype. The above evidences may suggest that Iksookimia yongdokensis was one of the tetraploid species of cobitid fishes.

• Animal Systematics, Evolution and Diversity
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• v.33 no.2
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• pp.136-139
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• 2017

The genus Iksookimia (Actinopterygii: Cypriniformes: Cobitidae) is a bottom-dwelling freshwater loaches, which are well-known as their endemism and high geographic variation. However, population genetic relationships among Iksookimia spp. have remained unclear due to a shortage of genetic markers that can be applied generally in the genus. Here, we developed high-resolving microsatellite markers using I. koreensis and I. longicorpa as representatives of Iksookimia species because of their wide distribution range and phylogenetic position. Ten of polymorphic microsatellite loci were isolated from Iksookimia koreensis and were successfully cross-amplified in I. longicorpa. The mean number of observed alleles per locus was about 10.4 (range, 2-17) for I. koreensis and about 13.2 (range, 2-24) for I. longicorpa. The loci, IK03 and IK08, deviated from the Hardy-Weinberg equilibrium in I. koreensis, after applying the Bonferroni correction. The microsatellite markers obtained in the present study will be useful to evaluate population genetic structure and to establish conservation strategies for I. koreensis and related Iksookimia species.

• Korean Journal of Ichthyology
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• v.12 no.1
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• pp.25-32
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• 2000

The structure of skin was studied in Iksookimia longicorpus based on the micro-anatomical investigation of skin fragments taken from four regions. The epidermis was distinguished by two types of skin glands, a small mucous cell and a large club cell. The mucous cell was acid sulfomucins (some sialomueins) but the club cell did not give any histochemical tests for mucosubstances. The presence of a well defined lymphatic system with small lymphocytes was established in the stratum germinativum layer of the epidermis. A large number of blood capillaries run very close to each other just below the basement membrane, and a definite area giving AB and PAS positive was present between the basement membrane and scale.

• Korean Journal of Ichthyology
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• v.22 no.1
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• pp.56-60
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• 2010

The Cobitis hankugensis-Iksookimia longicorpa complex from Korea has been presumed to be a unisexual lineage, originating from C. hankugensis and I. longicorpa and having almost all females. Recently, it was confirmed that the complex consisted of one diploid and two triploid complexes. From observation of their oocyte envelopes, three forms could be classified: a villous projection in I. longicorpa, a granular one in C. hankugensis and two triploid complexes, and a granule with villous one in the diploid complex. Even within the same granular projection, they showed specific features in length and density number from each other. These architectures are first observed in cobitid complexes and may playa role in identification of diploids and triploids.

• Korean Journal of Ichthyology
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• v.13 no.1
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• pp.24-27
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• 2001

The barbel structure of the spined loach Iksookimia longicorpa were investigated histologically. Their barbels consist of epidermis, dermis, and a central rod. The epidermis contains mucous cells, terminal buds, granular cells, and epidermal cells. The mucous cells are thin rims of basophilic cytoplasm and are located at the surface of the epidermis. The terminal bud is basophilic and is situated at the distal portion of the epidermis. The dermis consists of loose connective tissue containing blood vessels, pigment cells, and nerve cells. The central region of cartilage is the innermost region and is enclosed within muscle layers.

• The Korean Journal of Zoology
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• v.39 no.4
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• pp.419-425
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• 1996

The five spedes of genus Iksookimia from Korea were investigated by electron microscopes to clarify the adhesive membranes on zona radiata. In the late vitellogenic stage the adhesive membranes could be classified into three form as follows: 1) villous form of Iksookimia koreensis, I pumila, and I. hugowolfeldi, 2) cotton-shaped form of I. longicorpus, and 3) vine-shaped form of I. choii. And although I. koreensis, I pumila, and I. hugowolfeldi possessed the same villous form, It was evident that fine structure of the zona radiata varied according to spedes. The adhesive membranes and fine structures of zona radiata in Iksookimla showed a species specificity related to closely their habitats and spawning properties.

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.62.1-62
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• 1996

No Abstract, See Full Text

• Korean Journal of Ichthyology
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• v.21 no.sup1
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• pp.7-28
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• 2009

The family Cobitidae of Korea was reviewed as 16 species in 5 genera with the key to species for the identification by the external features. The three genera of Iksookimia, Koreocobitis, and Kichulchoia erected from the genus Cobitis were reclassified based on the presence or absence of Gambetta’s zones on the body sides, their body pigmentation, the shape of lamina circularis in males, the number of unbranched anal fin rays, and some molecular phylogenetic data. By the results of these reexamination, the generic names of the three species were changed as Cobitis choii, Iksookimia pacifica, and Kichulchoia mutifasciata. It was remarked biogeographically that most species of genera Cobitis, Iksookimia, Koreocobitis, and Kichulchoia show the disjunct distributions with bottom-dwelling preferences as endemic to Korean peninsular. Three species of Cobitis choii, Kichulchoia brevifasciata, and Koreocobitis naktongensis are considered to be critically endangered according to the severe habitat destruction and the alteration of river topography.

• Korean Journal of Ichthyology
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• v.17 no.2
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• pp.112-122
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• 2005

Iksookimia longicorpa was investigated in the upper part of the Seomjin River in Korea from 2003 to 2004. It inhabited pebble and cobble bottoms with water-current velocities of 10~30 cm/sec and depths of 30~100 cm. This species is active during daylight hours from March to October but hibernated in the river bottoms in the winter season. The sex ratio of female to male was 1 : 0.65, and the female was 20~40 mm larger than the male. Female length frequencies in this population indicated that the 65~90 mm group is 1+years old, the 90~110 mm group is 2+ years old, and the 110~130 mm group is 3+ years old. The males developed a secondary sexual character, the lamina circularis at the base of their pectoral fin, after 13~14 months. The spawning season was from early to middle June with water temperatures of $20{\sim}24^{\circ}C$ individuals became sexually mature after the age of 2 years. The average number of eggs in the ovaries was $2,402{\pm}944$. Stomach contents were mainly Chironomidae, Ephemeroptera, Arcellidae and Algae. The feeding rate was highest in April and September; they did not fed in the winter.

• Korean Journal of Ichthyology
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• v.20 no.3
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• pp.233-235
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• 2008

A 123.2 mm TL female of Iksookimia longicorpa with a laminar circularis at the base of its pectoral fin was collected in the Hoeya River, Korea, on May 5, 2008. The specimen had full-grown ovaries like those of normal females. Its pectoral fins were larger than those of normal females, but was smaller than those of males. The laminar circularis of the pectoral fin base was more similar to normal males in its shape but was less developed. The ovaries in the individual had about 3,148 mature eggs, with egg sizes approximately $1.26{\pm}0.11mm$.