Mcqueenoceras
Encyclopedia
Mcqueenoceras is an early endocerid, a nautilus
from the Ordovician period
similar in overall form to Clitendoceras
, from which it may have been derived. It lived during the later stages of the lower Ordovician. McQueenoceras, like Clitendoceras, has ventral siphuncle
but the endocones are thicker on the ventral side and thinner on the dorsal. Also the sutures in McQueenoceras retreat rearward, forming lobes as they cross the venter.
Nautilus
Nautilus is the common name of marine creatures of cephalopod family Nautilidae, the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina. It comprises six living species in two genera, the type of which is the genus Nautilus...
from the Ordovician period
Ordovician
The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian Period and is followed by the Silurian Period...
similar in overall form to Clitendoceras
Clitendoceras
Clitendoceras is a member of the Endocerida from the Lower Ordovician with an elongate shell with a slight downward, endogastric, curvature and a siphuncle that lay along the ventral margin. Common for endocerids, the chambers are short and the septa close spaced with sutures sloping forward...
, from which it may have been derived. It lived during the later stages of the lower Ordovician. McQueenoceras, like Clitendoceras, has ventral siphuncle
Siphuncle
The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and Spirula...
but the endocones are thicker on the ventral side and thinner on the dorsal. Also the sutures in McQueenoceras retreat rearward, forming lobes as they cross the venter.