''Ptyctodus'' is an extinct armour-plated fish of the late Devonian.
''Ptyctodus'' belongs to the family
Ptyctodontidae and is of the class
Placodermi
Placodermi (from Greek πλάξ 'plate' and δέρμα 'skin', literally 'Plate (animal anatomy), plate-skinned') is a Class (biology), class of armoured prehistoric fish, known from fossils, which lived from the Silurian to the end of the Devoni ...
. They share a close resemblance to modern day
chimaera
Chimaeras are cartilaginous fish in the order Chimaeriformes , known informally as ghost sharks, rat fish, spookfish, or rabbit fish; the last three names are not to be confused with rattails, Opisthoproctidae, or Siganidae, respectively.
At ...
s (Holocephali). 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
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
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
Nekton or necton (from the ) refers to the actively swimming aquatic organisms in a body of water. The term was proposed by German biologist Ernst Haeckel to differentiate between the active swimmers in a body of water, and the passive organisms ...
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
Arthrodira (Greek for "jointed neck") is an order of extinct armored, jawed fishes of the class Placodermi that flourished in the Devonian period before their sudden extinction, surviving for about 50 million years and penetrating most marine ec ...
.
Species
Species of the ''Ptyctodus'':
*''Ptyctodus bradyi'' was discovered by the basis of two tooth plates in 1942 by Hussakof on Mt. Elden in Arizona.
*''Ptyctodus calceolus''
*''Ptyctodus compressus'' first documentation was in 1870
*''Ptyctodus ferox''
*''Ptyctodus molaris''
*''Ptyctodus panderi''
Timeline
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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from: -407 till: -397.5 color:earlydevonian text: Ems.
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The Givetian is one of two faunal stages in the Middle Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Eifelian Stage and followed by the Frasnian Stage. It is named after the town of Givet in Fra ...
from: -385.3 till: -374.5 color:latedevonian text:Frasnian
The Frasnian is one of two faunal stages in the Late Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Givetian Stage and followed by the Famennian Stage.
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from: -374.5 till: -359.2 color:latedevonian text:Famennian
The Famennian is the latter of two faunal stages in the Late Devonian Epoch. The most recent estimate for its duration estimates that it lasted from around 371.1 million years ago to 359.3 million years ago. An earlier 2012 estimate, still used b ...
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The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...
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The ptyctodontids ("folded-teeth") are placoderms of the order Ptyctodontida, containing the family Ptyctodontidae. With their big heads, big eyes, reduced armor and long bodies, the ptyctodontids bore a superficial resemblance to modern day ch ...
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
''Ctenurella'' (from el, κτείς , 'comb' and el, ουρά , 'tail') is an extinct genus of ptyctodont placoderm from the Late Devonian of Germany. The first fossils were found in the Strunde valley in the Paffrather Kalkmulde.
Descriptio ...
color:middledevonian bar:NAM6 from: -397.5 till: -359.2 text: Denisonodus
color:middledevonian bar:NAM7 from: -397.5 till: -359.2 text: Ptyctodopsis
color:latedevonian bar:NAM8 from: -385.3 till: -381.7 text: Chelyophorus
The ptyctodontids ("folded-teeth") are placoderms of the order Ptyctodontida, containing the family Ptyctodontidae. With their big heads, big eyes, reduced armor and long bodies, the ptyctodontids bore a superficial resemblance to modern day ch ...
color:latedevonian bar:NAM9 from: -385.3 till: -381.7 text: Eczematolepis
''Eczematolepis'' is an extinct genus of ptyctodontidan from the Milwaukee Formation of Wisconsin
Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most popul ...
color:latedevonian bar:NAM10 from: -385.3 till: -381.7 text: Palaeomylus
The ptyctodontids ("folded-teeth") are placoderms of the order Ptyctodontida, containing the family Ptyctodontidae. With their big heads, big eyes, reduced armor and long bodies, the ptyctodontids bore a superficial resemblance to modern day ch ...
color:latedevonian bar:NAM11 from: -385.3 till: -381.7 text: 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 (Holocephali). Fossils of this armour- ...
color:latedevonian bar:NAM12 from: -385.3 till: -359.2 text: Rhynchodus
The ptyctodontids ("folded-teeth") are placoderms of the order Ptyctodontida, containing the family Ptyctodontidae. With their big heads, big eyes, reduced armor and long bodies, the ptyctodontids bore a superficial resemblance to modern day ch ...
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File:Ptyctodus ferox.jpg, Gnathal plates of ''Ptyctodus ferox'' showing grinding surfaces; from the Middle Devonian of Wisconsin
Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...
.
References
{{Authority control
*
Early Devonian first appearances
Late Devonian animals
Late Devonian genus extinctions
Monotypic vertebrate taxa