Named By: Richard Lund - 1977.
Classification: Chordata, Chondrichthyes, Holocephali, Chimaeriformes.
Species: E. meltoni (type), E. snyderi.
Size: E. meltoni males up to 15 centimetres long, females 7 centimetres. E. snyderi only known from juveniles at the time of writing, but analysis suggests slightly larger than E. meltoni when fully grown.
Known locations: USA, Montana.
Time period: Serpukhovian of the Carboniferous.
Fossil representation: Numerous individuals including juvenile specimens.
only small, Echinochimaera is still a very
interesting fish that is
known to have swum in the waters of what is now Montana during the
Carboniferous. Echinochimaera had a deep round
body that was
propelled by a relatively thin tail which ended in a small caudal fin.
This indicates that Echinochimaera was not a very
fast swimmer, and
as such may have cruised along in slower waters. Sexual dimorphism
seen in the type species is quite extreme with males of E.
growing to just over double the size of the females. At the time of
writing E. snyderi is only known from juveniles,
but comparison to
similarly aged juveniles of E. meltoni suggest
that E. snyderi
would have been the larger species when fully grown.
Strong spines supported the fins, and while these may have provided support for them when brushing past submerged debris, as well as provided some defence against predators, they may have also served a display function. Indeed the males of E. meltoni had a differently shaped dorsal fin to the females, with the main spike being larger and pointing forwards. Males also had four pairs of spines on top of their heads whereas females only had one pair.
- Chondrichthyan life history styles as revealed by the 320 million years old Mississippian of Montana. - Environmental Biology of Fishes (Springer Netherlands) 27 (1): 1–19. - Richard Lund - 1990.