- The
Graciloceratidae is a
family of
nautiloid cephalopods from the
Middle and
Upper Ordovician belonging to the Oncocerida,
characterized by exogastric...
- thick-walled
siphuncles which gave rise to the Tarphycerida, and the
Graciloceratidae,
derived from the former, with thin-walled
siphuncles which gave rise...
-
early in the
Middle Ordovician, and are most
likely derived from the
Graciloceratidae. The
Tripteroceratdae includes five
known genera, as
briefly described...
-
Scientific classification Kingdom:
Animalia Phylum:
Mollusca class:
Cephalopoda Order:
Oncocerida Family:
Graciloceratidae Genus:
Leonardoceras Flower, 1968...
- the
Tarphycerida and by a
thinning of the
connecting rings to the
Graciloceratidae which are
ancestral Oncocerida. Furthermore, they may have
given rise...
- in each
shown in parentheses,
along with the
stratigraphic range.
Graciloceratidae (4) M-U Ord
Tripteroceratidae (5) M-U Ord
Valcouroceratidae (8) M-U...
-
early in the
Middle Ordovician (Sweet 1964)
simultaneously with the
Graciloceratidae, Tripteroceratidae, and Valcouroceratidae,
derived from the Gracilocertidae...
-
Ordovician Kullsberg Limestone Formation Sweden A
member of the
family Graciloceratidae. The type
species is I. niger;
genus also
includes I. consobrinum....
