Petalichthyida
Encyclopedia
The Petalichthyida was an order of small, flattened placoderm fish
. They were typified by their splayed fins, and numerous tubercles that decorated all of the plates and scales of their armor. They reached a peak in diversity during the Early Devonian
and were found throughout the world, particularly in Europe (especially in Germany), North America, Asia, South America, and Australia. The petalichthids Lunaspis
and Wijdeaspis are among the best known. There was an independent diversification event that occurred in what is now Southern China, producing a handful of unique genera that were once placed in their own order, "Quasipetalichthyida," named after the first discovered species there, Quasipetalichthys haikouensis. Soon after the Petalichthids' diversification, they went into a decline, until the last few species were exterminated along with the rest of the placoderms during the Late Devonian extinction
event.
From what can be garnered from their compressed body forms, it is presumed that the Petalichthids were bottom-dwellers that either chased after, swam after, or ambushed smaller fish. However, their diet is highly speculatory, as none of the fossil specimens found have the mouth or mouth parts preserved.
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
. They were typified by their splayed fins, and numerous tubercles that decorated all of the plates and scales of their armor. They reached a peak in diversity during the Early Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
and were found throughout the world, particularly in Europe (especially in Germany), North America, Asia, South America, and Australia. The petalichthids Lunaspis
Lunaspis
Lunaspis is an extinct genus of petalichthyid fish that lived in shallow marine environments of the Early Devonian period. Fossils have been found in Germany, China and Australia.-Description:...
and Wijdeaspis are among the best known. There was an independent diversification event that occurred in what is now Southern China, producing a handful of unique genera that were once placed in their own order, "Quasipetalichthyida," named after the first discovered species there, Quasipetalichthys haikouensis. Soon after the Petalichthids' diversification, they went into a decline, until the last few species were exterminated along with the rest of the placoderms during the Late Devonian extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
event.
From what can be garnered from their compressed body forms, it is presumed that the Petalichthids were bottom-dwellers that either chased after, swam after, or ambushed smaller fish. However, their diet is highly speculatory, as none of the fossil specimens found have the mouth or mouth parts preserved.