Aulacocerida
Aulacocerida is an order of primitive coleoid cephalopods, possibly derived from michelinoceraitids (Orthocerida) early in the Devonian, which in turn gave rise to the Belemnites. Aulococerids are characterized by a straight, slim, conical shell with a large living chamber, simple aperture. The protoconch (initial, embryonic chamber) is egg-shaped and separated from the phragnocone by a constriction. The siphucle is narrow and ventral, constricted at the septa and expanded in the middle of the chamber; necks are retrochoantiic, project backwards toward the apex. Nacre recovered from aulococerids as well as from belemnites resembles that found in recent Sepia and Spirula but differs from that of recent Nautilus.
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primaryTopic
Aulacocerida
Aulacocerida is an order of primitive coleoid cephalopods, possibly derived from michelinoceraitids (Orthocerida) early in the Devonian, which in turn gave rise to the Belemnites. Aulococerids are characterized by a straight, slim, conical shell with a large living chamber, simple aperture. The protoconch (initial, embryonic chamber) is egg-shaped and separated from the phragnocone by a constriction. The siphucle is narrow and ventral, constricted at the septa and expanded in the middle of the chamber; necks are retrochoantiic, project backwards toward the apex. Nacre recovered from aulococerids as well as from belemnites resembles that found in recent Sepia and Spirula but differs from that of recent Nautilus.
has abstract
Aulacocerida is an order of pr ...... into the long living chamber.
@en
Aulacocerida – rząd wymarłych zwierząt z grupy Belemnoidea.
@pl
Gli Aulacocerida (Stolley 1919 ...... noti solo allo stato fossile.
@it
Wikipage page ID
Wikipage revision ID
728,607,411
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comment
Aulacocerida is an order of pr ...... from that of recent Nautilus.
@en
Aulacocerida – rząd wymarłych zwierząt z grupy Belemnoidea.
@pl
Gli Aulacocerida (Stolley 1919 ...... noti solo allo stato fossile.
@it
label
Aulacocerida
@en
Aulacocerida
@it
Aulacocerida
@pl