Acanthodii


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Acanthodii

[ə‚kan′thō·dē‚ī]
(paleontology)
A class of extinct fusiform fishes, the first jaw-bearing vertebrates in the fossil record.
References in periodicals archive ?
The little fish, measuring just over 11 centimetres in length, belongs to an extinct group called the Acanthodii (colloquially, the "spiny sharks").
The discovery of this new species, which we call Machaeracanthus goujeti and belongs to the Acanthodii group -of which very little is known-, expands our knowledge of the biodiversity that existed on the peninsula 480 million years ago, when the modern-day region of Teruel was covered by the sea," Hector Botella, professor in the palaeontology unit in the University of Valencia and the study's lead author, explained to SINC.
The Acanthodii group of fish are also known as 'spiny sharks' owing to their appearance and, from what we know to date, they only lived during the Palaeozoic Era and reached their maximum level of diversity in the Devonic period.
Some other fossil fishes also have a nodular ultrasculpture on their scales but it differs strongly in measurements (the nodes being very fine: 1-2 [micro]m in Acanthodii, see Beznosov 2001; 2.