- from the
Middle Silurian to Late Devonian.
Anatomically speaking, the
osteostracans,
especially the
Devonian species, were
among the most
advanced of all...
-
Cephalaspidomorphs are a
group of
jawless fishes named for
Cephalaspis of the
osteostracans. Most
biologists regard this
taxon as extinct, but the name is sometimes...
-
Cephalaspis sensu stricto was the sister-taxon of
cornuate osteostracans, i.e., all
osteostracans that
either have, or have
ancestors that had
defined corners...
- most do have a
dorsal or a
caudal fin. Some
fossil agnathans, such as
osteostracans and pituriaspids, did have
paired fins, a
trait inherited in
their jawed...
- displacement, and sound. The
presence of
these extrinsic grains in
osteostracans, chondrichthyans, and
acanthodians indicates a
common inner ear physiology...
- ostracoderms. Most
fossil agnathans, such as galeaspids, thelodonts, and
osteostracans, are more
closely related to
vertebrates with jaws (called gnathostomes)...
-
chronological order from
oldest to most
recent include heterostracans,
osteostracans,
coelolepid agnathans, acanthodians,
osteichthyan fishes, chondrichthyan...
-
Zenaspidida is an
extinct order of
osteostracans, a
group of
jawless stem-gnathostomes. They
possessed a
distinct headshield,
which varied in
width to...
- Keating,
Joseph N.; Sansom,
Robert S.; Purnell, Mark A. (2012). "A new
osteostracan fauna from the
Devonian of the
Welsh Borderlands and
observations on...
-
point of
their evolution. Most of the ostracoderms, such as thelodonts,
osteostracans and galeaspids, were more
closely related to the
gnathostomes than to...
