Trigonoceratidae
Encyclopedia
The Trigonoceratidae is a family
of coiled nautiloid
cephalopods that lived during the period from the Early Carboniferous (Mississippian) to the Early Permian.
in the Treatise,(ibid Kummel) a superfamily. They are also the Triboloceratidae (Flower and Kummel,1950) which form the Tribolocerataceae within the Centroceratina of the Osnovy according to Shimansky. The Trigonocerataceae and Centroceratina are essentially equivalent as are the Trigonoceratidae and Triboloceratidae.
(basis for the name Centroceratina) early in the Mississippian along with the longer lived Grypoceratidae
. Of the five families of the Trigonocerataceae, the Trigonoceratidae was defined first, by Hyatt in 1884, hence the choice of name.
Mississippian Genera from North America and Europe ( L Carb)
Mississippian (L Carb) Genera from Europe
Lower Permian Central Asia
. It is the only genus included that has a subtriangular whorl section consisting of a broad concave venter and narrow dorsum. The remaining can be divided on the basis of shell morphology into those that are smooth, at least on the outer whorl, those with numerous equal longitudinal ribs or lirae, and those with prominent longitudinal ridges separated by wide grooves or sulci.(ibid Kummel)
Those with smooth whorls include Leuroceras and Mesochasmoceras; those with numerous longitudinal ribs or lirie include Chouteauoceras, Discitoceras, and Rineceras; and those with prominent, wide spaced, longitudinal ridges are such as Stroboceras and Vestinautilus.
Trigonoceratid genera can also be grouped on the basis of the suture which may be essentially straight and transverse or slightly sinuous, or may have a well defined ventral lobe, or a ventral saddle. Those with straight or slightly sinuous sutures are Apogonoceras, Diodoroceras, Discitocdras, Rineceras, Stroboceras, and Thrincoceras; with a discernible ventral lobe: Aphelaeceras, Epistroboceras, Lispoceras, Maccoyoceras, Pararineceras, Subclymenia, and Vestinutilus; and with a ventral saddle: Chouteauoceras and Leuroceras.
Ventral saddles are also found in the Centroceratidae
in Carlloceras and Phacoceras, in the Grypoceratidae
in Stenopoceras and Parastenopoceras, and in the Syringonautilidae
.(ibid Kummel)
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of coiled nautiloid
Nautiloid
Nautiloids are a large and diverse group of marine cephalopods belonging to the subclass Nautiloidea that began in the Late Cambrian and are represented today by the living Nautilus. Nautiloids flourished during the early Paleozoic era, where they constituted the main predatory animals, and...
cephalopods that lived during the period from the Early Carboniferous (Mississippian) to the Early Permian.
Diagnosis
Trigonoceratidae comprise members of the order Nautilida characterized by a loosely coiled to evolute shell generally bearing longitudinal ribs or ridges with a whorl section that is oval to subquadrate and varying from compressed (squeezed) to depressed (flattened). (Kummel 1964)Taxonomic position
The Trigonoceratidae along with four other related families are combined in the Superfamily TrigonocerataceaeTrigonocerataceae
The Trigonocerataceae is a superfamily within the Nautilida that ranged from the Devonian to the Triassic that is thought to have contained the source for the Nautilaceae in which Nautilus is found....
in the Treatise,(ibid Kummel) a superfamily. They are also the Triboloceratidae (Flower and Kummel,1950) which form the Tribolocerataceae within the Centroceratina of the Osnovy according to Shimansky. The Trigonocerataceae and Centroceratina are essentially equivalent as are the Trigonoceratidae and Triboloceratidae.
Derivation
The Trigonerceratidae were derived from the core CentroceratidaeCentroceratidae
The Centroceratidae is the ancestral family of the Trigonocerataceae and of the equivalent Centroceratina; extinct shelled cephalopods belonging to the order Nautilida-Diagnosis:...
(basis for the name Centroceratina) early in the Mississippian along with the longer lived 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:...
. Of the five families of the Trigonocerataceae, the Trigonoceratidae was defined first, by Hyatt in 1884, hence the choice of name.
Generic composition
Seventeen trigonoceratid genera are listed in the Treatise. All but one are found in the Lower Carboniferous of Europe and equivalent Mississippian of North America.(ibid Kummel)Geographic Distribution
Mississippian Genera from North America alone- ChouteauocerasChouteauocerasChouteauceras is an openly coiled, gyroconic, nautiloid cephalopod from the Mississippian of North America belonging to the Nautilid family Trigonoceratidae, and superfamily Trigonocerataceae....
- Diodoceras
- Imonautilus
Mississippian Genera from North America and Europe ( L Carb)
- AphelaecerasAphelaecerasAphelaeceras is an extinct genus from the nautilid family Trigonoceratidae which is part of the Trigonocerataceae, that lived during the Mississippian Period in the late Paleozoic—a nautiloid cephalopod...
- Maccoyoceras
- RinecerasRinecerasRhineceras is an extinct genus from the nautilid family Trigonoceratidae which is part of the Trigonocerataceae, that lived during the Mississippian Period in the late Paleozoic....
- StrobocerasStrobocerasStroboceras is an extinct nautiloid named by Hyatt in 1884 that's included in the nautilid family Trigonoceratidae; the group that have rise to the Nautilidae which includes the living Nautilus....
- Thrincoceras -- -- extends to Lower Permian
- Vestinautilus
Mississippian (L Carb) Genera from Europe
- TrigonocerasTrigonocerasTrigonoceras is an extinct prehistoric nautiloid genus from the nautilid family Trigonoceratidae that lived during the Early Carboniferous in what is now western Europe....
- DiscitocerasDiscitocerasDiscitoceras is an extinct genus of nautiloid from the Lower Carboniferous....
- Epistroboceras
- Leuroceras
- Lispoceras
- Mesochasmoceras
- Pararineceras
- Subclymenia
Lower Permian Central Asia
- Apogonoceras -- see Thrincoceras
Morphological variations
Trigonoceras, type genus, named by Hyatt, 1844, is unique among the Trigonoceratidae in the TreatiseTreatise on Invertebrate Paleontology
The Treatise on Invertebrate Paleontology published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and covering every phylum, class, order, family, and genus of fossil and...
. It is the only genus included that has a subtriangular whorl section consisting of a broad concave venter and narrow dorsum. The remaining can be divided on the basis of shell morphology into those that are smooth, at least on the outer whorl, those with numerous equal longitudinal ribs or lirae, and those with prominent longitudinal ridges separated by wide grooves or sulci.(ibid Kummel)
Those with smooth whorls include Leuroceras and Mesochasmoceras; those with numerous longitudinal ribs or lirie include Chouteauoceras, Discitoceras, and Rineceras; and those with prominent, wide spaced, longitudinal ridges are such as Stroboceras and Vestinautilus.
Trigonoceratid genera can also be grouped on the basis of the suture which may be essentially straight and transverse or slightly sinuous, or may have a well defined ventral lobe, or a ventral saddle. Those with straight or slightly sinuous sutures are Apogonoceras, Diodoroceras, Discitocdras, Rineceras, Stroboceras, and Thrincoceras; with a discernible ventral lobe: Aphelaeceras, Epistroboceras, Lispoceras, Maccoyoceras, Pararineceras, Subclymenia, and Vestinutilus; and with a ventral saddle: Chouteauoceras and Leuroceras.
Ventral saddles are also found in the Centroceratidae
Centroceratidae
The Centroceratidae is the ancestral family of the Trigonocerataceae and of the equivalent Centroceratina; extinct shelled cephalopods belonging to the order Nautilida-Diagnosis:...
in Carlloceras and Phacoceras, in 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:...
in Stenopoceras and Parastenopoceras, and in the Syringonautilidae
Syringonautilidae
The Syringonautilidae comprise the last of the Trigonocerataceae and are the source for the Nautilaceae which continued the Nautiloidea through the Mesozoic and into the Cenozoic right down to the recent. The Syringonautilidae, itself, is a strictly Triassic family, derived early in the Triassic...
.(ibid Kummel)
See also
- Flower, R.H and Kummel, B. 1950; A Classification of the Naulioidea; Journal of Paleontology, V 24, no 5. pp604-616, Sept 1950
- Flower, R.H. 1988; Progress and Changing Concepts in Cephalopod and Particularly Nautiloid Phylogeny and Distributuion, in Cephalopods, Present and Past, pp 17-24, Wiedmann, J, & Kullmann, J (Eds).