from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of various extinct fishes of the Silurian and Devonian periods, characterized by bony plates of armor covering the head and flanks, hinged jaws, and paired fins.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A member of an extinct group of fish with armored heads; the group lived during the Silurian and Devonian periods.
from the GNU version of the Collaborative International Dictionary of English
- n. One of the Placodermi.
from The Century Dictionary and Cyclopedia
- Having the skin covered with broad flat plates, as a fish; belonging to the Placodermi.
- n. A ganoid fish of the group Placodermi.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. fish-like vertebrate with bony plates on head and upper body; dominant in seas and rivers during the Devonian; considered the earliest vertebrate with jaws
Scientists from Australia and Britain studying 380million-year-old fossils of placoderm fish were initially confused when they realized that the two fish were carrying embryos.
Nature that presents this missing piece of the puzzle and completes the picture of placoderm reproduction from mating to birth.
The authors looked for a clasper in their placoderm fossils but couldn't find one, so they were forced to argue that it had been made of soft cartilage and had not been preserved.