Subterranean Fishes of the World

5367

2008

Scientific Research Iranian Veterinary Journal

60-69

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The Iranian blind cave fish (Iranocypris typhlops) is a unique taxon which only lives within a cave in Lorestan province in southwest of Iran. Despite the fact that this taxon is very valuable regarding genetically resources, as a result of receiving little attention it is highly threatened by extinction. In this investigation we studied morphology and histology of digestive tract in this interesting fish. To perform this task, 10 specimen of this taxon were captured from natural habitat and transferred to the laboratory where they were then sacrificed. Afterwards, we scrutinized their morphological characteristics by the aid of a stereomicroscope and later we processed them for histological observations. Subsequently, 7 micrometer sections were prepared which-were then stained by Hematoxylin & Eosin technique. Detailed examinations of the fishes showed that the mouth is horseshoe-shaped and located in an inferior situation (ventral side) of the head. Within it, there are three rows of pharyngeal teeth including inner, medial and outer rows, which bear 5, 3 and 3 teeth respectively. The esophagus is very short and lined with an epithelium containing numerous mucous folds. The stomach is not present. The anterior segment of the intestine is S-shaped which comprises about one half the guts. In this part, there are mucosal folds which show different sizes and mucous layer is thicker than other layers (submucosa, muscle layer and serosa). The distal portion of the intestine is straight (rectal) and terminates to the anal region. In general, the ratio of intestine length is 1.2, as compared to the body length. This study showed that the liver in this taxon is composed of two lobes, the right lobe being two-parts and bigger than the left one. The gall bladder is clear and spherical in appearance. The pancreas is red or orange and observed as scattered masses of cells on the mesentery of the digestive system. Keyword(s): BLIND CAVE FISH, DIGESTIVE SYSTEM, MORPHOLOGY, HISTOLOGY

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