- that the
earliest nautiloids had s**** that were
slightly curved. An
orthoconic form
evolved several times among cephalopods, and,
among nautiloid cephalopods...
-
coiled morphologies and
giant straight-s****ed
forms (orthocones). No
orthoconic and only a
handful of
coiled species, the nautiluses,
survive to the present...
- ancestry,
followed by a long,
moderately expanding,
generally straight,
orthoconic adult section with a
subdorsal siphuncle connecting the chambers. The...
- and
related orthoconic nautiloid cephalopods are
often confused with the
superficially similar Baculites and
related Cretaceous orthoconic ammonoids. Both...
- The
Bactritida are a
small order of more or less straight-s****ed (
orthoconic)
cephalopods that
first appeared during the
Emsian stage of the Devonian...
-
Dawsonoceratidae is an
extinct family of
orthoconic nautiloid cephalopods that
lived in what
would be
North America and
Europe from the Late Ordovician...
-
detected in
cephalopod fossils dating as far back as the Silurian;
these orthoconic individuals bore
concentric stripes,
which are
thought to have served...
-
subclass of
nautiloid cephalopods.
Members of this
subclass usually have
orthoconic (straight) to
slightly cyrtoconic (curved) s****, and
central to subcentral...
- Late Silurian.
Their s**** were
variable in form. Some were
straight (
orthoconic),
others curved (cyrtoconic); some were long (longiconic),
others short...
- brachiopods, eurypterids, conodonts, nektaspids, trilobites, a
lobopodian and
orthoconic cephalopods. The
environment of
deposition is
considered to be anoxic...
