Materpiscis Temporal range: late Devonian
A female Materpiscis giving live birth
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Placodermi
Order:	Ptyctodontida
Family:	Ptyctodontidae
Genus:	Materpiscis
Binomial name
M. attenboroughi Long et al 2008

Materpiscis (Latin for "mother fish") is a genus of ptyctodontid placoderm from the late Devonian period, about 380 million years ago. A fossil of this armored placoderm shows an embryo and umbilical cord inside its body. So Materpiscis is the oldest known vertebrate to show viviparity (giving birth to live young). Viviparity of one kind or another is quite common in certain kinds of fish, for example sharks.

The holotype was found in the Kimberley area of northern Western Australia. Fossils from the Gogo Formation are preserved in limestone nodules, so dilute acetic acid is used to dissolve the surrounding limestone and reveal the fossil. These fossils are often preserved in three dimensions with minimal distortion.