Search results
Results from the WOW.Com Content Network
Despite being called "spiny sharks", acanthodians predate sharks. Scales that have been tentatively identified as belonging to acanthodians, or "shark-like fishes" have been found in various Ordovician strata, though, they are ambiguous, and may actually belong to jawless fishes such as thelodonts .
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. They had slender builds, light armor, deeply inserted spines, shark-like teeth, and two dorsal fins. [1]
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 common name "spiny sharks" is really a misnomer for these early jawed fishes. The name was coined because they were superficially shark-shaped, with a streamlined body, paired fins, and a strongly upturned tail; stout bony spines supported all the fins except the tail – hence, "spiny sharks".
Parexus is an extinct genus of acanthodian fish. 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.
Unless you are visiting a zoo, you will only find kangaroos roaming the wild in Australia, Tasmania, and nearby islands. They can live in many different habitats including forests and grasslands.
Spiny creature with fins like a bird wing found swimming off Fiji. See the new species. Irene Wright. March 21, 2024 at 4:06 PM. In the blue island waves surrounding Fiji, a small fish moves ...
The origins of the teleostomes are obscure. They are traditionally assumed to be descendants of the Acanthodians ("spiny sharks") from the Early Silurian Period; however, more recent discoveries show that the "spiny sharks" are actually a paraphyletic assemblage leading to Chondrichthyes, and that placoderms like Entelognathus are more closely related to true bony fish. [1]