Remigolepis walkeri sp. nov. from the Mandagery
Sandstone (late Devonian) near Canowindra,
New South Wales (NSW), is the second species of Remigolepis to
be described from Australia, the first
being from near Grenfell, NSW. Remigolepis walkeri possesses
unusual paired suborbital plates with a large
oval structure at the anteromesial edge of the plate, representing an attachment
for the autopalatine portion
of the palatoquadrate. Among asterolepidoids, this morphology is most similar
to
Pterichthyodes.
Suborbitals of Remigolepis from East Greenland are said to possess
a transverse ridge on the internal surface,
similar to the bothriolepids Bothriolepis and Nawagiaspis.
However, some specimens from East
Greenland may show a morphology more similar to Remigolepis walkeri.
The internal morphology of the
suborbital plates is constant in the population of Remigolepis
from the Canowindra locality, suggesting the
presence of a single species despite the presence of more than 1000 individuals
in this fauna. The morphology
of the caudal fin of Remigolepis walkeri is similar to Remigolepis
sp. from near Eden, NSW, and
Asterolepis ornata, but differs from Remigolepis sp.
from China. The morphology of the pectoral and caudal
fins of R. walkeri indicate a bottom-dwelling lifestyle,
whereas Bothriolepis from the same fauna may have
been able to generate sufficient lift from the pectoral fins to enter the
water column on a regular basis.
Keraphyton gen. nov., a new Late Devonian fern-like plant from Australia
