Fossil range: Late Devonian
|3D model of Materpiscis|
Long, Trinajstic, Young, and Senden, 2008
Materpiscis (Latin for mother fish) is a genus of ptyctodontid placoderm (a class of extinct, superficially shark-like fishes) from the Late Devonian (about 380 million years ago) located at the Gogo Formation of Western Australia. Known from only one specimen, it is unique in having an unborn embryo present inside Materpiscis, and with remarkable preservation of a mineralised placental feeding structure (umbilical cord). This makes Materpiscis the oldest known vertebrate to show viviparity, or giving birth to live young.
The fossil specimen was found in the Kimberley area of northern Western Australia by Lindsay Hatcher during the 2005 expedition to the Gogo led by John Long of Museum Victoria. 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.
Examination of the tail section of the Materpiscis specimen led to the discovery of the partially ossified skeleton of a juvenile Materpiscis and the mineralised umbilical cord. The team published their findings in 2008.
Materpiscis would have been about 11 inches (28 cm) long and had powerful crushing tooth plates to grind up its prey, possibly hard shelled invertebrates like clams or corals.
The ptyctodontid fishes are the only group of placoderms to display sexual dimorphism, where males have clasping organs and females have smooth pelvic fin bases. It had long been suspected that they reproduced using internal fertilisation, but finding fossilised embryos inside both Materpiscis and in a similar form also from Gogo, Austroptyctodus, proved the deduction was true.
Materpiscis attenboroughi was selected as one of "The Top 10 New Species" described in 2008 by The International Institute for Species Exploration at Arizona State University and an international committee of taxonomists.
Other important fossil fishes from the Devonian period:
Species: Materpiscis attenboroughi
Materpiscis attenboroughi Long et al., 2008