Ptyctodus


Ptyctodus is an extinct armour-plated fish of the late Devonian. Ptyctodus belongs to the family Ptyctodontidae and is of the class Placodermi. They share a close resemblance to modern day chimaeras. Fossils of this armour-plated fish have been found in locations such as in Russia, the Michigan Basis, and Arizona, United States.

Description and paleobiology

Ptyctodus species come in a variety of different sizes, measured data shows three specimens being 94 millimeters, 24 millimeters, 22 millimeters in length, 23 millimeters, 6 millimeters, 4 millimeter in height, and 18 millimeters, 7 millimeters, and 4 millimeters in thickness. Through time, an evolutionary morphological trait is that the species within Ptyctodontidae reduce the dermal armour. The dentition of the Ptyctodus has dental elements that are very similarly observed in chimaeroids.
Its dental plates are compressed into a thin cutting edge behind the symphysis and measure 3 inches in thickness and several inches in length. The are expressed as fine punctae in parallel rows. Ptyctodus teeth are very close together in a way that they are like a fish tooth conglomerate. They were also armed with dorsal fin spines closely seen in Hetercanthus and Phlyctaenacanthus.
Just like the other members of the family of Ptyctodontidae, there is a sexual dimorphism between the genders of Ptyctodus in the pelvic region where the characteristics are different; males had claspers, while females had large scale like pelvic fins along with their endoskeleton.
Ptyctodus lived in a nektonic carnivore type-ecology and in carbonate, lagoonal, and shallow subtidal environments. Due to structure and shape of the teeth Ptyctodus would easily be able to crush shellfish like organisms at the bottom of the ocean floors, feeding mainly off of that. They also must seem to have been very agile swimmers, able to escape predators, like arthrodires.

Species

Species of the Ptyctodus:
Timeline of Ptyctodus along with other species within the Ptyctodontidae family

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from: -416 till: -411.2 color:earlydevonian text:Loch.
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color:earlydevonian bar:NAM1 from: -411.2 till: -407 text: Tollodus
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color:middledevonian bar:NAM3 from: -397.5 till: -385.3 text: Desmoporella
color:middledevonian bar:NAM4 from: -397.5 till: -378.1 text: Campbellodus
color:middledevonian bar:NAM5 from: -397.5 till: -374.5 text: Ctenurella
color:middledevonian bar:NAM6 from: -397.5 till: -359.2 text: Denisonodus
color:middledevonian bar:NAM7 from: -397.5 till: -359.2 text: Ptyctodopsis
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Gallery