- agnathans. The
psammosteids had broad,
flattened bodies,
suggesting a
predominantly benthic habit. The
earliest unequivocal psammosteid is Drepanaspis...
-
specific sized plankton from the
water column. If
Weigeltaspis is not a
psammosteid pteraspidid, then the
Anchipteraspidids are the oldest-most
known pteraspidid...
- to
other Ostracoderms,
reaching a
width of 1.5 m (4.9 ft). Like
other Psammosteid Heterostracans,
Tartuosteus had a
broad and
flattened body
which was...
- and
pteraspidid species were
applied to
Psammosteids, but
proved not to be useful. At the time,
Psammosteids were not well
characterized morphologically...
-
besides the tail or
caudal fin. In some pteraspids,
especially in the
psammosteids, the ends of the
branchial plates (the
plates that
covered the gills)...
- Frasnian-Famennian boundary),
about 372.2 Ma. Many
fossil agnathan fish, save for the
psammosteid heterostracans, make
their last
appearance shortly before this event...
- loose . "Pteraspidomorphi:
Psammosteida (2): Guerichosteids, Pycnosteids,
Psammosteids & Psammolepis".
Palaeos Vertebrates.
Fishes of the
World by
Joseph S...
- (and best)
known genus,
Drepanaspis from the Hunsrück lagerstätte. The
Psammosteids were the only
heterostracans that
survived the
Upper Frasnian extinction...
-
suggest the
living animals were, at
least superficially,
similar to
psammosteids, some authorities, such as Tarlo,
place them
within Psammosteida. Because...
- Pteraspididae,
Gigantaspis and Protaspididae), and the
anchipteraspidids and the
Psammosteids.
Protopteraspids are
found in
Lower Devonian marine strata of the Western...
