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The popular name "spiny sharks" is because they were superficially shark-shaped, with a streamlined body, paired fins, a strongly upturned tail, and stout, largely immovable bony spines supporting all the fins except the tail—hence, "spiny sharks".
Ischnacanthiformes is a prehistoric order of "acanthodian" stem-chondrichthyans found in Canada, Ukraine and United Kingdom.Members of this order were nektonic carnivores, [1] eating animals that swim rather than plankton.
The Climatiiformes is an order of extinct fish belonging to the class Acanthodii.Like most other "spiny sharks", the Climatiiformes had sharp spines. These animals were often fairly small in size and lived from the Late Silurian to the Early Carboniferous period.
Cheiracanthus (from Greek: χείρ kheír, 'hand' and Greek: ἄκανθα akantha, 'spine') [1] is an extinct genus of a group of fish called Acanthodii (or "spiny sharks"). [2] It was a deep-bodied acanthodian about 12 in. (30 cm) in length. It had a blunt head, upturned tail, and fins protected by spines.
The oldest total-group chondrichthyans, known as acanthodians or "spiny sharks", appeared during the Early Silurian, around 439 million years ago. [13] The oldest confirmed members of Elasmobranchii sensu lato (the group containing all cartilaginous fish more closely related to modern sharks and rays than to chimaeras) appeared during the ...
Acanthodians are often referred to as ‘spiny sharks’, although acanthodians are not true sharks and evolved perhaps 50 million years earlier than sharks. Acanthodians share several features with bony fish and cartilaginous fish; they often have spines supporting their fins. Parexus is recognised by its large anterior dorsal fin spine.
Climatius (from Greek: κλίμα klíma, 'gradation') [1] is an extinct genus of spiny shark. This genus is known from the Early Devonian ( Lochkovian ) of Europe, previously considered Silurian remains actually belong to Nostolepis instead.
Spiny sharks: Spiny sharks, more formally called "Acanthodians" (having spines), constitute the class Acanthodii. They first appeared by the late Silurian ~420 Ma, and were among the first fishes to evolve jaws. They share features with both cartilaginous fish and bony fish, but they are not true sharks, though leading to them. They became ...