Definitions for placodermi
This page provides all possible meanings and translations of the word placodermi
Placodermi, class Placodermi(noun)
extinct group of bony-plated fishes with primitive jaws
an extinct group of fishes, supposed to be ganoids. The body and head were covered with large bony plates. See Illust. under Pterichthys, and Coccosteus
Placodermi is an extinct class of armoured prehistoric fish, known from fossils, which lived from the late Silurian to the end of the Devonian Period. Their head and thorax were covered by articulated armoured plates and the rest of the body was scaled or naked, depending on the species. Placoderms were among the first jawed fish; their jaws likely evolved from the first of their gill arches. A 380-million-year-old fossil of one species represents the oldest known example of live birth. The first identifiable placoderms appear in the fossil record during the late Llandovery epoch of the early Silurian; they began a dramatic decline during the Late Devonian extinctions, and the class was entirely extinct by the end of the Devonian.
Find a translation for the placodermi definition in other languages:
Select another language: