Sturgeon (Acipenseriformes)

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Sturgeon (Acipenseriformes)
Sturgeon (Acipenseriformes)

Video: Sturgeon (Acipenseriformes)

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Representatives of the sturgeon order belong to ray-finned fishes and belong to the subclass of cartilaginous ganoids. They are called ganoid because of the special structure of the scales. The family of sturgeons and copepods (from among the existing ones) are part of the order. Distinctive features of the sturgeon are cartilaginous endoskeleton, intestinal spiral valve, arterial cone and the absence of a vertebral body.

Atlantic sturgeon (Acipenser sturio), photo photograph sturgeon fish
Atlantic sturgeon (Acipenser sturio), photo photograph sturgeon fish

Atlantic sturgeon (Acipenser sturio)

These are ancient fish, fossils of which are found even in the layers of the Jurassic period. The sturgeon order belongs to the lower chordates.

Sturgeons have a somewhat shark-like appearance. Elongated snout. The body is naked or covered with five rows of bony scutes. The upper lobe of the caudal fin is always covered with rhombic scales. Caudal fin with more developed dorsal lobe. The caudal fin in sturgeons is heterocercal. He is unequal-lobed, like sharks. In the upper part of the operculum, many forms retain the rudiment of a squid. The skeleton supporting the dorsal and anal fins is not ossified.

Sterlet (Acipenser ruthenus), photo photography
Sterlet (Acipenser ruthenus), photo photography

Sterlet (Acipenser ruthenus)

The mouth is on the underside of the head, surrounded by soft lips, retractable. An antennae covered with sensory bodies is located near the mouth. The cerebral skull is almost entirely cartilaginous (in the fossil Triassic forms it ossified). The roof of the skull consists of its parietal, frontal and nasal bones; the integumentary bones also form the bottom and sides of the skull. On the body of sturgeon, there are five rows of bone plates. The snout stretched forward is whiter, or less developed (rostrum; it was not present in ancient forms). At the base of their axial skeleton is a chord, dressed in a connecting case with thick walls.

The length of the sturgeon reaches 9 meters (this size is observed in belugas).

Sturgeons are common only in the waters of the Northern Hemisphere, including in the northern seas washing the shores of Russia. Twelve species from the detachment are found in the waters of the Russian Federation.

Black-headed sturgeon male (Acipenser fulvescens), photo photograph commercial fish
Black-headed sturgeon male (Acipenser fulvescens), photo photograph commercial fish

Lake Sturgeon Malek (Acipenser fulvescens)

The sturgeon order refers to fish that live off benthic nutrition, that is, they eat organisms that live in the ground or on the surface of the ground of water bodies. Adult sturgeon fish feed on benthic invertebrates, and large fish feed on fish. Even the Caspian Seal Cubs have been found in belugas' stomachs.

Representatives of the detachment reproduce by external fertilization. Small caviar is spawned in large quantities.

The order includes two families - sturgeon Acipenseridae and copepods Polyodontidae. The first family includes 4 genera and 24 species, the second - 2 genera and 2 species. Such representatives of the sturgeon are widely known as sturgeon proper (Amur, Russian, Siberian), sterlet, beluga (European and Far Eastern), stellate sturgeon. Copepods are not so famous.

Common shovelnose (Scaphirhynchus platorynchus), photo photograph
Common shovelnose (Scaphirhynchus platorynchus), photo photograph

Common shovelnose (Scaphirhynchus platorynchus)

Sturgeons are prized for their delicious meat and caviar. Excessive fishing and pollution of rivers led to the fact that their numbers everywhere sharply decreased; in places they disappeared. Methods for breeding sturgeon fish in reservoirs and ponds are being developed; At the same time, much attention is paid to obtaining stable hybrids (beluga x sterlet, etc.) with a more intensive growth rate.

Systematics of the order Sturgeon fishes

  • Family: Acipenseridae Bonaparte, 1831 = Sturgeon

    • Subfamily: Acipenserinae =

      • Genus: Acipenser Linnaeus, 1857 = Sturgeon

        • Species: Acipenser baerii Brandt, 1869 = Siberian sturgeon

          • Subspecies: Acipenser baeri baicalensis A. Nikolski, 1896 = Baikal sturgeon
          • Subspecies: Acipenser baerii baerii Brandt, 1869 = Ob sturgeon
          • Subspecies: Acipenser baerii stenorhynchus A. Nikolsky, 1896 = Long-snout Siberian sturgeon, or khatys
        • Species: Acipenser brevirostrum Lesueur, 1818 = Blunt sturgeon
        • Species: Acipenser fulvescens Rafinesque, 1817 = Lake sturgeon
        • Species: Acipenser gueldenstaedtii Brandt, 1833 = Russian sturgeon, or Caspian-Black Sea
        • Species: Acipenser medirostris Ayres, 1854 = Pacific, or green sturgeon
        • Species: Acipenser naccarii Bonaparte, 1836 = Adriatic sturgeon
        • Species: Acipenser nudiventris Lovetsky, 1828 = Thorn

          Subspecies: Acipenser nudiventris derjavini Borzenko, 1950 = Kura thorn

        • Species: Acipenser oxyrinchus Mitchell, 1815 = Long-snout sturgeon
        • Species: Acipenser persicus Borodin, 1897 = Persian sturgeon
        • Species: Acipenser ruthenus Linnaeus, 1758 = Sterlet

          Subspecies: Acipenser ruthenus marsiglii Brandt, 1833 = Siberian sterlet

        • Species: Acipenser schrenckii Brandt, 1869 = Amur sturgeon
        • Species: Acipenser stellatus Pallas, 1771 = Sevruga
        • Species: Acipenser sturio Linnaeus, 1758 = Atlantic sturgeon
      • Genus: Huso Brandt, 1869 = Beluga

        • Species: Huso dauricus Georgi, 1775 = Kaluga
        • Species: Huso huso Linnaeus, 1758 = Beluga
    • Subfamily: Priscosturioninae =
    • Subfamily: Propenserinae =
    • Subfamily: Psammorhynchinae =
    • Subfamily: Scaphirhynchinae =

      • Genus: Pseudoscaphirhynchus A. Nikolski, 1900 = False shovelnose

        • Species: Pseudoscaphirhynchus fedtschenkoi Kessler, 1872 = Pseudo-spatula syrdarya
        • Species: Pseudoscaphirhynchus hermanni Kessler, 1877 = Amudarya small pseudo-spatula
        • Species: Pseudoscaphirhynchus kaufmanni Bogdanov, 1874 = Amudarya large pseudopatonos
      • Genus: Scaphirhynchus Heckel, 1835 = Shovelnose

        Species: Scaphirhynchus albus Forbes et Richardson = White Shovelnose

  • Family: Chondrosteidae =
  • Family: Peipiaosteidae =
  • Family: Polyodontidae Bonaparte = Paddlefish, paddlefish

    • Genus: Polyodon Lacepède, 1797 = Paddlefish

      Species: Polyodon spathula Walbaum, 1792 = Paddlefish

    • Genus: Psephurus Günther, 1873 = Chinese paddlefish

      Species: Psephurus gladius Martens, 1862 = Chinese paddlefish, or swordtail sturgeon

Literature:

1. L. S. Berg. Fish of fresh waters of the USSR and neighboring countries. Part 1. Edition 4. Moscow, 1948

2. N. P. Naumov, N. N. Kartashev. Zoology of vertebrates. Inferior chordates, jawless, fish, amphibians. Moscow "High School", 1979

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