''Ptyctodus'' is an extinct armour-plated fish of the late Devonian. ''Ptyctodus'' belongs to the family Ptyctodontidae and is of the class

Placodermi Placoderms (from Ancient Greek πλάξ 'plax'', ''plakos plate' and δέρμα 'dermaskin') are vertebrate animals of the class Placodermi, an extinct group of prehistoric fish known from Paleozoic fossils during the Silurian and the De ...

. They share a close resemblance to modern day

chimaera Chimaeras are Chondrichthyes, cartilaginous fish in the order (biology), order Chimaeriformes (), known informally as ghost sharks, rat fish (not to be confused with rattails), spookfish, or rabbit fish; the last two names are also applied to B ...

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 sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

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 ) is any aquatic organism that can actively and persistently propel itself through a water column (i.e. swimming) without touching the bottom. Nektons generally have powerful tails and appendages (e.g. fins, pleopods ...

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 eco ...

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 ImageSize = width:1000px height:auto barincrement:15px PlotArea = left:10px bottom:50px top:10px right:10px Period = from:-416 till:-299 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:25 start:-416 ScaleMinor = unit:year increment:5 start:-416 TimeAxis = orientation:hor AlignBars = justify Colors = #legends id:CAR value:claret id:ANK value:rgb(0.4,0.3,0.196) id:HER value:teal id:HAD value:green id:OMN value:blue id:black value:black id:white value:white id:paleozoic value:rgb(0.6,0.75,0.55) id:cambrian value:rgb(0.49,0.63,0.33) id:ordovician value:rgb(0,0.57,0.44) id:silurian value:rgb(0.70,0.88,0.71) id:devonian value:rgb(0.8,0.55,0.22) id:earlydevonian value:rgb(0.90,0.71,0.43) id:middledevonian value:rgb(0.96,0.81,0.51) id:latedevonian value:rgb(0.96,0.89,0.71) id:carboniferous value:rgb(0.4,0.65,0.6) id:mississippian value:rgb(0.4,0.56,0.4) id:pennsylvanian value:rgb(0.8,0.77,0.53) id:permian value:rgb(0.94,0.25,0.24) id:mesozoic value:rgb(0.38,0.77,0.79) id:triassic value:rgb(0.51,0.17,0.57) id:jurassic value:rgb(0.2,0.7,0.79) id:cretaceous value:rgb(0.5,0.78,0.31) id:cenozoic value:rgb(0.95,0.98,0.11) id:paleogene value:rgb(0.99,0.6,0.32) id:neogene value:rgb(0.999999,0.9,0.1) id:quaternary value:rgb(0.98,0.98,0.50) BarData= bar:eratop bar:space bar:periodtop bar:space bar:NAM1 bar:NAM2 bar:NAM3 bar:NAM4 bar:NAM5 bar:NAM6 bar:NAM7 bar:NAM8 bar:NAM9 bar:NAM10 bar:NAM11 bar:NAM12 bar:space bar:period bar:space bar:era PlotData= align:center textcolor:black fontsize:M mark:(line,black) width:25 shift:(7,-4) bar:periodtop from: -416 till: -411.2 color:earlydevonian text: Loch. from: -411.2 till: -407 color:earlydevonian text: Prag. from: -407 till: -397.5 color:earlydevonian text: Ems. from: -397.5 till: -391.8 color:middledevonian text: Eif. from: -391.8 till: -385.3 color:middledevonian text:

Givetian 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 ...

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. Major reef-building was under way during ...

from: -374.5 till: -359.2 color:latedevonian text:

Famennian The Famennian is the later of two faunal stages in the Late Devonian epoch. The most recent estimate for its duration is that it lasted from around 371.1 to 359.3 million years ago. An earlier 2012 estimate, still used by the International Commis ...

bar:eratop from: -416 till: -359.2 color:devonian text:

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

PlotData= align:left fontsize:M mark:(line,white) width:5 anchor:till align:left color:earlydevonian bar:NAM1 from: -411.2 till: -407 text: Tollodus color:middledevonian bar:NAM2 from: -397.5 till: -391.8 text:

Goniosteus 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 chim ...

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 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 chim ...

color:latedevonian bar:NAM9 from: -385.3 till: -381.7 text: Eczematolepis color:latedevonian bar:NAM10 from: -385.3 till: -381.7 text:

Palaeomylus ''Palaeomylus'' (meaning 'ancient grinder') is an extinct Devonian ptychodontid placoderm fish. There are seven species accepted in this genus: Etymology The generic name is derived from Greek (''Palaeo'', meaning "ancient") and (''mylos'', ...

color:latedevonian bar:NAM11 from: -385.3 till: -381.7 text: Ptyctodus 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 chim ...

PlotData= align:center textcolor:black fontsize:M mark:(line,black) width:25 bar:period from: -416 till: -411.2 color:earlydevonian text: Loch. from: -411.2 till: -407 color:earlydevonian text: Prag. from: -407 till: -397.5 color:earlydevonian text: Ems. from: -397.5 till: -391.8 color:middledevonian text: Eif. from: -391.8 till: -385.3 color:middledevonian text:

from: -385.3 till: -374.5 color:latedevonian text:

from: -374.5 till: -359.2 color:latedevonian text:

bar:era from: -416 till: -359.2 color:devonian text:

Gallery

File:Ptyctodus ferox.jpg, Gnathal plates of ''Ptyctodus ferox'' showing grinding surfaces; from the Middle Devonian of

Wisconsin Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michig ...

References

{{Authority control * Early Devonian first appearances Late Devonian animals Late Devonian genus extinctions Monotypic vertebrate taxa