Ptyctodus
{{Short description|Extinct genus of fishes}}
{{For|the shark of a similar name|Ptychodus}}
{{Automatic taxobox
| fossil_range = late Devonian {{Fossil range|383.7|360.7}}
| image = Ptyctodus compressus.jpg
| image_caption = Ptyctodus
| taxon = Ptyctodus
| authority = Pander, 1858
| subdivision_ranks = Species
| subdivision =
Ptyctodus bradyi
Ptyctodus calceolus
Ptyctodus compressus
Ptyctodus ferox
Ptyctodus molaris
Ptyctodus panderi
}}
Ptyctodus is an extinct armour-plated fish of the late Devonian.{{cite web|title=Ptyctodus Pander 1858|url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=34272|website=Fossil Works|publisher=Gateway to the Paleobiology Database}} 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-plated fish have been found in locations such as in Russia, the Michigan Basis,{{cite book|last1=Holman|first1=Alan|title=Life of the Great Lakes Basin: Precambrian to Pleistocene|date=1995|publisher=University of Michigan Press|page=153}} 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.{{cite journal|last1=Branson|first1=E|title=The Devonian of Missouri|journal=Missouri Bureau of Geology and Mines|date=1922|volume=17|issue=2|pages=127–128}} Through time, an evolutionary morphological trait is that the species within Ptyctodontidae reduce the dermal armour.{{cite journal|last1=Trinajstic|first1=Kate|last2=Long|first2=John|title=A new genus and species of Ptyctodont (Placodermi) from the Late Devonian Gneudna Formation, Western Australia, and an analysis of Ptyctodont phylogeny|journal=Geological Magazine |date=2009|volume=146|issue=5|pages=743–760|doi=10.1017/S001675680900644X |bibcode=2009GeoM..146..743T }} 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.{{cite journal|last1=Eastman|first1=Charles|title=DEVONIAN FISHES OF IOWA|journal=Iowa Geological Survey|page=133}} The {{not a typo|tritors}} 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.{{cite journal|last1=Calvin|first1=Samuel|last2=Leonard|first2=A|title=Iowa Geological Survey|journal=Annual Report|date=1897|volume=7|page=75}} 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.{{cite journal|last1=Miles|first1=Roger|title=Observations on the ptyctodont fish, Rhamphodopsis Watson|journal=Zoological Journal of the Linnean Society|date=October 1967|volume=47|issue=311|pages=99–120|doi=10.1111/j.1096-3642.1967.tb01398.x}}
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.{{failed verification|date=August 2019}}
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.{{cite journal|last1=Johnson|first1=Heidemarie|last2=Elliot|first2=David|title=A New Ptyctodont (Placodermi) from the Upper Devonian Martin Formation of Northern Arizona, and an Analysis of Ptyctodont Phylogeny|journal=Journal of Paleontology|date=November 1996|volume=70|issue=6|pages=994–1003|doi=10.1017/S0022336000038695|bibcode=1996JPal...70..994J |s2cid=132373001 }}
- Ptyctodus calceolus
- Ptyctodus compressus first documentation was in 1870
- Ptyctodus ferox
- Ptyctodus molaris
- Ptyctodus panderi
Gallery
File:Ptyctodus ferox.jpg|Gnathal plates of Ptyctodus ferox showing grinding surfaces; from the Middle Devonian of Wisconsin.
References
{{Reflist}}
{{Portal bar|Animals}}
{{Placodermi|Pt.}}
{{Taxonbar|from=Q30593733}}
{{Authority control}}
Category:Early Devonian first appearances
Category:Late Devonian animals