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Ctenopleuron
''Ctenopleuron'' is an extinct genus of jawless fish in the class Anaspida Anaspida ("without shield") is an extinct group of primitive jawless vertebrates that lived primarily during the Silurian period, and became extinct soon after the start of the Devonian. They were classically regarded as the ancestors of lampre .... References External links * Birkeniiformes genera Fossil taxa described in 1907 {{paleo-jawless-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaspida
Anaspida ("without shield") is an extinct group of primitive jawless vertebrates that lived primarily during the Silurian period, and became extinct soon after the start of the Devonian. They were classically regarded as the ancestors of lampreys. Anaspids were small marine agnathans that lacked a heavy bony shield and paired fins, but have a striking highly hypocercal tail. They first appeared in the early Silurian, and flourished until the early Devonian, when they disappear from the fossil record. Anatomy Compared to other prehistoric agnathan groups, such as the Heterostraci and Osteostraci, anaspids did not possess a bony shield or armor, hence their name. The anaspid head and body are instead covered in an array of small, weakly mineralized scales, with a row of massive scutes running down the back, and, at least confirmed among the birkeniids, the body was covered in rows of tile-like scales made of aspidine, an acellular bony tissue. Anaspids all had prominent, latera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birkeniiformes
Birkeniiformes (Birkeniida or Birkeniids) is an extinct order of jawless fish belonging to the class Anaspida. Subtaxa A newer taxonomy based on the work of Mikko's Phylogeny Archive, Nelson, Grande and Wilson 2016 and van der Laan 2018. * Genus †''Cowielepis'' Blom 2008 * Genus †'' Hoburgilepis'' Blom, Märss & Miller 2002 * Genus †'' Kerreralepis'' Blom 2012 * Genus †'' Maurylepis'' Blom, Märss & Miller 2002 * Genus †'' Rytidolepis'' Pander 1856 * Genus †'' Schidiosteus'' Pander 1856 * Genus †'' Silmalepis'' Blom, Märss & Miller 2002 * Genus †'' Vesikulepis'' Blom, Märss & Miller 2002 * Family † Pharyngolepididae Kiær 1924 corrig. ** Genus †'' Pharyngolepis'' Kiaer 1911 * Family † Pterygolepididae Obručhev 1964 corrig. ** Genus †'' Pterygolepis'' Cossmann 1920 'Pterolepis'' Kiaer 1911 non Rambur 1838 non De Candolle ex Miquel 1840; ''Pterolepidops'' Fowler 1947 * Family † Rhyncholepididae Kiær 1924 corrig. ** Genus †''Rhyncholepis'' Kiær 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birkeniidae
Birkeniidae is an extinct family of jawless fish belonging to the order Birkeniiformes Birkeniiformes (Birkeniida or Birkeniids) is an extinct order of jawless fish belonging to the class Anaspida. Subtaxa A newer taxonomy based on the work of Mikko's Phylogeny Archive, Nelson, Grande and Wilson 2016 and van der Laan 2018. * Ge .... They were defined in 1899 by Ramsay H. Traquair, and were a successful family among the many jawless fish in the Silurian seas. Morphology Birkeniidae had a large body which was ovular in shape, and a strong, mobile tail. Their eyes were positioned on either side of the head. Their mouth was large for the jawless fish, but contained no teeth. Birkeniidae are distinguished by the crown shaped projection on their back, and the other smaller projections which run down its tail. They also possessed fins which faced downwards, an uncommon trait among the jawless fish. They had typical scaly skin. References External links * Prehistoric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birkeniiformes Genera
Birkeniiformes (Birkeniida or Birkeniids) is an extinct order of jawless fish belonging to the class Anaspida. Subtaxa A newer taxonomy based on the work of Mikko's Phylogeny Archive, Nelson, Grande and Wilson 2016 and van der Laan 2018. * Genus †''Cowielepis'' Blom 2008 * Genus †'' Hoburgilepis'' Blom, Märss & Miller 2002 * Genus †'' Kerreralepis'' Blom 2012 * Genus †'' Maurylepis'' Blom, Märss & Miller 2002 * Genus †'' Rytidolepis'' Pander 1856 * Genus †'' Schidiosteus'' Pander 1856 * Genus †'' Silmalepis'' Blom, Märss & Miller 2002 * Genus †'' Vesikulepis'' Blom, Märss & Miller 2002 * Family † Pharyngolepididae Kiær 1924 corrig. ** Genus †'' Pharyngolepis'' Kiaer 1911 * Family † Pterygolepididae Obručhev 1964 corrig. ** Genus †'' Pterygolepis'' Cossmann 1920 'Pterolepis'' Kiaer 1911 non Rambur 1838 non De Candolle ex Miquel 1840; ''Pterolepidops'' Fowler 1947 * Family † Rhyncholepididae Kiær 1924 corrig. ** Genus †''Rhyncholepis'' Kiær 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motility, able to move, can Sexual reproduction, reproduce sexually, and go through an ontogenetic stage in which their body consists of a hollow sphere of Cell (biology), cells, the blastula, during Embryogenesis, embryonic development. Over 1.5 million Extant taxon, living animal species have been Species description, described—of which around 1 million are Insecta, insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from to . They have Ecology, complex interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology. Most living animal species are in Bilateria, a clade whose members have a Symmetry in biology#Bilate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chordata
A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These five synapomorphies include a notochord, dorsal hollow nerve cord, endostyle or thyroid, pharyngeal slits, and a post-anal tail. The name “chordate” comes from the first of these synapomorphies, the notochord, which plays a significant role in chordate structure and movement. Chordates are also Bilateral symmetry, bilaterally symmetric, have a coelom, possess a circulatory system, and exhibit Metameric, metameric segmentation. In addition to the morphological characteristics used to define chordates, analysis of genome sequences has identified two conserved signature indels (CSIs) in their proteins: cyclophilin-like protein and mitochondrial inner membrane protease ATP23, which are exclusively shared by all vertebrates, tunicates and cep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
