Tainoceratidae
Encyclopedia
The Tainoceratidae is a family of late Paleozoic and Triassic nautiloids that are a part of the order Nautilida
, characterized by large, generally evolute shells with quadrate to rectangular whorl sections. Shells may bear ribs or nodes, or both.
The Tainoceratidae form the larger of the two branches of the Tainocerataceae
derived from the Rutoceratidae around the end of the Devonian or early in the Mississippian (L Carb). The other is of the Koninckioceratidae
which is confined to the Paleozoic. The Tainoceratidae on the other hand extend almost to the end of the Triassic and likely gave rise in the Early Permian to a small family, the Rhiphaeoceratidae
.
The Tainoceratidae are contemporary with the Grypoceratidae
, the dominant trigonoceratacean family, and with the Liroceratidae
which dominate the Clydonautilaceae
, all three of which have the same Carboniferous (L Miss) to Triassic range. Twenty-one genera are ascribed to the Tainoceratidae, of which 10 are confined to the Triassic while four cross into the Triassic from the upper Paleozoic. Seven are limited to the Paleozoic. Thus the Tainoceratidae is essentially a family of Triassic nautiloids, with some Paleozoic predecessors.
Nautilida
The Nautilida constitute a large and diverse order of generally coiled nautiloid cephalopods that began in the mid Paleozoic and continues to the present with a single family, the Nautilidae which includes two genera, Nautilus and Allonautilus, with six species...
, characterized by large, generally evolute shells with quadrate to rectangular whorl sections. Shells may bear ribs or nodes, or both.
The Tainoceratidae form the larger of the two branches of the Tainocerataceae
Tainocerataceae
The Tainocerataceae is a superfamily in the cephalopod order Nautilida characterized by straight to loosely coiled shells, generally with a degressed, such that the width is greater than the height, to quadrate whorl section. Many bore spines, ribs, frills, wings, or nodes...
derived from the Rutoceratidae around the end of the Devonian or early in the Mississippian (L Carb). The other is of the Koninckioceratidae
Koninckioceratidae
The Koninckioceratidae comprise a collection of nautilid genera, typically with more or less evolute shells with depressed whorl sections, that are combined as a family within the Tainocerataceae...
which is confined to the Paleozoic. The Tainoceratidae on the other hand extend almost to the end of the Triassic and likely gave rise in the Early Permian to a small family, the Rhiphaeoceratidae
Rhiphaeoceratidae
The Rhiphaeoceratidae are a small family of nautilids included in the superfamily Tainocerataceae that comprises four very similar genera. These genera are characterized by a perforate umbilicus and little more than a single evolute coil. Whorl sections are oval, subquadrate, or subtrapezoidal...
.
The Tainoceratidae are contemporary with the Grypoceratidae
Grypoceratidae
Grypoceratidae is the longest lived family of the Trigonocerataceae, or of the near equivalent Centroceratina; members of the Nautilida from the Upper Paleozoic and Triassic.-Diagnosis:...
, the dominant trigonoceratacean family, and with the Liroceratidae
Liroceratidae
Liroceratidae is an extinct family of nautilids, shelled marine molluscs, belonging to the Clydonautilaceae, consisting of generally smooth, involute, nautiliconic forms with a small umbilicus...
which dominate the Clydonautilaceae
Clydonautilaceae
The Clydonautilaceae is a superfamily within the nautiloid order Nautilida characterized by smooth, generally globular, shells with nearly straight sutures, in early forms but developing highly differentiated sutures in some later forms...
, all three of which have the same Carboniferous (L Miss) to Triassic range. Twenty-one genera are ascribed to the Tainoceratidae, of which 10 are confined to the Triassic while four cross into the Triassic from the upper Paleozoic. Seven are limited to the Paleozoic. Thus the Tainoceratidae is essentially a family of Triassic nautiloids, with some Paleozoic predecessors.