Facts about Placoderms, an extinct prehistoric animal

Dinosaur Jungle

Dinosaur Crosswords

Dinosaur Facts
   Amazing Dinosaurs
   Family Tree
   Life Span
   Living Dinosaurs?
      Triassic Period
      Jurassic Period
      Cretaceous Period
      African Dinosaurs
      Antarctic Dinosaurs
      Asian Dinosaurs
      Australian Dinosaurs
      European Dinosaurs
      Indian Dinosaurs
      N. American Dinosaurs
      S. American Dinosaurs

Dinosaur Jokes

Dinosaur Museums
   Australia Dinosaur Museums
   Canada Dinosaur Museums
   UK Dinosaur Museums
   USA Dinosaur Museums

Dinosaur Names

Dinosaur Pictures

Dinosaur Scientists
   Charles Darwin
   Mary Anning
   Sir Richard Owen
   More Dinosaur Scientists

Dinosaur Types
   Tyrannosaurus Rex
   More Dinosaur Types

Dinosaur Word Search

Other Prehistoric Animals
   Mammal-like Reptiles
   Meganeura Monyi
   Sea Scorpions
   Spiny Sharks
   More Prehistoric Animals

Dinosaur Links
   Dinosaur Coloring
   Dinosaur Hangman
   Dinosaurs News
   Dinosaurs Parks

Education - Math Downloads
   Fun With Figures
   Making Math More Fun
   Math Bingo
   Math Riddle Book
   Download Math eBooks

Education - Reading Downloads
   Child Learning Reading
   Dolch Sight Words
   Phonics Bingo
   Robot Reading Games
   Sight Word Bingo

Education - Science Downloads
   24 Hour Science Projects
   Super Science Fair Projects
   Download Science eBooks


Dinosaur Jungle   >   Other Prehistoric Animals   >   Placoderms




Scientific Classification
  Kingdom Animalia
  Phylum Chordata
  Infraphylum Gnathostomata
  Class Placodermi
Placoderms are a group of extinct armored fish. They are noted for their heavily armored head and thorax, which are covered with armor plates (whereas the rest of the body either has scales or is unarmored depending on the particular species). Additionally, Placoderms are noteworthy for using sharp bony plates as teeth (recent research suggests that Placoderms may have evolved their jaws independently from other jawed vertebrates).

The earliest known fossils date from the mid-Silurian period of the Paleozoic Era (about 430 million years ago) and are found in China. During this time, Placoderms are not believed to have been uncommon, although fossils from rocks of this age seem to be relatively rare - paleontologists attribute this to Placoderms living in environments where fossilization was unlikely.

During the following Devonian period (beginning about 408 million years ago), a diverse array of Placoderms are known to have lived, in both freshwater and saltwater environments. Placoderms however under went a rapid decline during and after the late Devonian mass extinction (about 364 million years ago), and were completely extinct by the end of the Devonian period (about 360 million years ago).

The first scientific descriptions and studies of Placoderms were published by Louis Agassiz in the first half of the 19th century. Since that time, a variety of theories about Placoderms classification have been proposed (in the past, they have been at times described as related to jawless fish, related to cartilaginous fish such as sharks, and even as shelled invertebrates), however today, they are usually classified to fall within the Gnathostomata (the group of animals that includes all jawed fish and other vertebrates), but to be a sister group of all other known Gnathostomata.

Placoderms Timeline:

Placoderms were armored fish that lived between 430 and 360 million years ago

Placoderms were armored fish that lived between 430 and 360 million years ago

Related Information & Resources

See Also

Discuss This Page

Please feel free to post your comments:

Linking to This Page

We do hope that you find this site useful. We welcome people linking to this website or citing us.

The URL of this web page, is:

If you want to link to this web page from your own web site, you can use the following HTML code:

You are also very welcome to tell your friends about us on Facebook:
Making Math More Fun - Math Games Package


DinosaurJungle.com is
Copyright © 2006-2015, Answers 2000 Limited

Disclosure: Our company's websites' content (including this website's content) includes advertisements for our own company's websites, products, and services, and for other organization's websites, products, and services. In the case of links to other organization's websites, our company may receive a payment, (1) if you purchase products or services, or (2) if you sign-up for third party offers, after following links from this website. Unless specifically otherwise stated, information about other organization's products and services, is based on information provided by that organization, the product/service vendor, and/or publicly available information - and should not be taken to mean that we have used the product/service in question. Additionally, our company's websites contain some adverts which we are paid to display, but whose content is not selected by us, such as Google AdSense ads. For more detailed information, please see Advertising/Endorsements Disclosures

Our sites use cookies, some of which may already be set on your computer. Use of our site constitutes consent for this. For details, please see Privacy.

Contact Us   Privacy   Terms Of Use   Advertising/Endorsements Disclosures