- 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...
-
Floian Age of the
Early Ordovician Period, over 470
million years ago. The
Bactritida, a Devonian–Tri****ic
group of orthocones, are
widely held to be paraphyletic...
- have
originated from straight-s****ed (orthocone) "nautiloids"
belong to
Bactritida during the
early Devonian (Emsian), with
transitional fossils showing...
- well as Nautilida,
which includes the
recent Nautilus.
Another order,
Bactritida,
which is
derived from Orthocerida, is
sometimes included with Nautiloidea...
-
first chamber, of some
orthocerids suggests they were
ancestors to the
Bactritida,
small orthoconic forms that gave rise to both the
ammonoids and coleoids...
-
belemnoid order Aulacocerida, which, in turn, is
derived from the
Devonian Bactritida.
Belemnites were
traditionally thought to have
evolved in
northern Europe...
- coleoids, and had
appeared by the Floian. It is
widely held that the
Bactritida, a Silurian–Tri****ic
group of orthocones, are
paraphyletic to the coleoids...
- long-lasting
lineages Goniatite and
ceratite ammonoids Probable coleoid ancestor Bactritida Early coleoids: Jeletzkya?, Gordoniconus,
Syllipsimopodi Earliest belemnoids:...
- 1980
Subgroups Order Orthocerida (in part)†
Order Lituitida†
Order Bactritida†
Subclass Ammonoidea†
Subclass Coleoidea Belemnoidea†
Neocoleoidea Synonyms...
- long-lasting
lineages Goniatite and
ceratite ammonoids Probable coleoid ancestor Bactritida Early coleoids: Jeletzkya?, Gordoniconus,
Syllipsimopodi Earliest belemnoids:...