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The class Osteostraci (meaning "bony shells") is an extinct taxon of bony-armored jawless fish, termed "ostracoderms", that lived in what is now North America, Europe and Russia from the Middle Silurian to Late Devonian. Anatomically speaking, the osteostracans, especially the Devonian species, were among the most advanced of all known ...
Thelodonti ('feeble-teeth') are a group of small, extinct jawless fishes with distinctive scales instead of large plates of armour. There is much debate over whether the group of Palaeozoic fish known as the Thelodonti (formerly coelolepids [11]) represent a monophyletic grouping, or disparate stem groups to the major lines of jawless and jawed ...
Furcacaudiformes is an extinct order of jawless fish in the class Thelodonti. [1]Because the paucity of intact fossils, especially since some families are known entirely from scale fossils, taxonomy of thelodonts is based primarily on scale morphology.
A newfound fossil of a jawless fish is the oldest known vertebrate cranium preserved in 3D. The 455 million-year-old find could illuminate how vertebrate heads evolved.
Astraspis ('star shield') is an extinct, monotypic genus of primitive jawless fish from the Ordovician of Central North America including the Harding Sandstone of Colorado and Bighorn Mountains of Wyoming. It is also known from Bolivia. [2] It is related to other Ordovician fishes, such as the South American Sacabambaspis, and the Australian ...
Thelodonti (from Greek: "nipple teeth") [4] is a class of extinct Palaeozoic jawless fishes with distinctive scales instead of large plates of armor.. There is much debate over whether the group represents a monophyletic grouping, or disparate stem groups to the major lines of jawless and jawed fish.
A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as well as possible hydrodynamic advantages.
Lepidaspis serrata ("serrated scaly shield") is an extinct heterostracan jawless fish from Early Devonian Canada. Its scientific name refers to the fact that the armor is composed of hundreds of tiny scales with serrated edges. Lepidaspis serrata cast. Mackenzie Mountains, Northwest Territories . At the Royal Tyrrell Museum of Palaeontology.