- cephalopods, and,
among nautiloid cephalopods, is
prevalent among the
ellesmerocerids, endocerids, actinocerids, orthoceratoids, and bactritids. Orthocones...
-
Endocerids evolved from the
earlier ellesmerocerids, most
likely from a
genus similar to Pachendoceras. This
ellesmerocerid gave rise to Proendoceras, the...
-
genera (e.g. Paleoceras), the
septa are
uniformly spaced. S**** of
ellesmerocerids are
typically smooth and
compressed and vary in form. They may be breviconic...
-
penetrated by a
narrow tube
which may
contain diaphragms reminiscent of the
Ellesmerocerid ancestor.
Endoceras was
named by Hall in 1847.
Distribution is widespread...
- Ordovician, with two genera,
Ectenolites and Clarkoceras.
Ordovician ellesmerocerids in turn
likely gave rise to
several new
nautiloid superorders: Endoceratoidea...
- ****essment. The recently-named
order Bisonocerida shares traits with
ellesmerocerids and endocerids, and some
studies have
placed it as a
member of Multiceratoidea...
- and the
Plectronocerida have been said to be the
ancestors of the
Ellesmerocerids, the
first "true cephalopods". The
Yochelcionellids have
given rise...
-
meaning "horn", is an
extinct family of
Early Ordovician, (C****inian),
ellesmerocerid cephalopods characterized by short,
essentially straight s****, a fairly...
- but are
smaller and
proportionally narrower. Septa, as
typical for
ellesmerocerids, are
close spaced with
shallow lobes on
either flank. The body chamber...
-
Levisoceras is a
genus of
early Ordovician ellesmerocerid cephalopods.
Levisoceras is a
distinctive ellesmeroceratid that
combines rapid expansion a strong...
