• Title/Summary/Keyword: Cenozoic fish

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The description of the Flat fish (Pleuronectiformes) Fossils from the Miocene Duho Formation, Pohang Yeonam-dong in Korea and its Implication (포항시 여남동 마이오세 두호층에서 산출된 가자미목 화석의 기재와 의의)

  • Ko, Ju Yeong
    • Journal of the Korean earth science society
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    • v.37 no.1
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    • pp.1-10
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    • 2016
  • Four entities of the Cenozoic fish fossils were discovered in the Miocene Duho Formation, Pohang, Korea. these fossils were identified as the first Pleuronectiformes in Korea based on the following-the presence of postcleithrum, the elongation of the first proximal pterygiophore of the anal fin ray, almost consistent presence of two proximal pterygiophore of the anal fin rays between the two adjacent hemal spines, the fusion of the first and second hypurals, the fusion of the third and fourth hypurals and the first preural centrum, the presence of well-developed anteriormost plate-like neural spine, the presence of the urohyal like fish-hook and its elongated sciatic part, and the division of the parahypural from the first preural centrum. On the other hand, geological studies about the Duho Formation consistently claimed that shallow-sea creatures were washed away by meteorological events such as a great flood and deposited at the bottom of deep-sea by the turbidity current. However, in Duho Formation, only shallow-sea ones have been discovered thus far. This study reported that Flat fish, deep-sea creature, was discovered in Duho Formation for the first time in Korea.

Pleuronichthys sp. Fossils (Pleuronectidae) from the Duho Formation, Pohang Uhyeon-dong in Korea (포항시 우현동 두호층에서 산출된 Pleuronichthys sp. 화석)

  • Ko, Ju-Yeong;Nam, Kye-Soo
    • Journal of the Korean earth science society
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    • v.37 no.3
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    • pp.133-142
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    • 2016
  • Two specimens of the Cenozoic fish fossils were discovered from the Miocene Duho Formation of Uhyeon-dong, Pohang, Korea. These fossils are identified as Pleuronichthys sp. based on the following- firstly, front dorsal fin rays elongated to the upper part of neurocranium, Secondly, right sided orbit of neurocranium, Thirdly, presence of urohyal like fish-hook, Fourthly, curved sciatic part of the urohyal, Fifthly, presence of postcleithrum, Sixthly, over 27 centrum, Seventhly, elongated first pterygiophore of the anal fin rays, Eightly, c-shaped inner side of urohyal, Ninthly, small or few cardiac apophysis, and Tenthly, presence of many spots on body. These fossils of Pleuronichthys represent the first record in East-Asia. Two specimens are anatomically different in the extent of the asymmetry and the flatness of skull. This represents the unique ontogeny stage of the Pleuronectidae, because they accompany the above anatomical difference when they transform from pelagic lifestyle to benthic lifestyle.

Origin of the Korean Mandarin Fish, Siniperca scherzeri and Its Molecular Phylogenetic Relationships to Other Siniperca Fishes (한국산 쏘가리의 기원과 분자계통진화적 위치)

  • Kim, Maeng-Jin;Song, Choon-Bok
    • Korean Journal of Ichthyology
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    • v.23 no.2
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    • pp.95-105
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    • 2011
  • To explain the origin of the Korean mandarin fish (Siniperca scherzeri), phylogenetic relationships and DNA polymorphism among Siniperca fishes have been investigated based on mitochondrial cytochrome b DNA sequences. As a result, S. roulei were firstly differentiated early in the evolution of Siniperca fishes and the other six species (S. schezeri, S. undulata, S. fortis, S. obscura, S. knerii and S. chuatsi) were evolved slightly later. However, the order of species differentiation among six species was not clear because the nodes of their phylogeny were poorly resolved. The constructed molecular phylogeny revealed three genetically distinct groups of local populations of S. scherzeri. The first group (group 1) is the local populations of Korean peninsula and northern China including Lioaning and Henan. The second one (group 2) is the local populations of Anhui, Fujian and Guangxi. The third one (group 3) is the local population of Zhejiang. The number of nucleotide differences in base pairs were 31~43 between group 1 and 2; 37~44 between group 2 and 3; 27~29 between group 1 and 3; and 1~5 within group 1. Thus, the Korean mandarin fish was likely to be originated from the northern China local population which was isolated from the middle or southern China local populations during the Cenozoic Pliocene. Low level of sequence divergence between Korean mandarin fish populations and northern China population indicated a recent expansion of distribution ranges from northern China to Korean peninsula.