| Tropidodiscidae | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda (?) |
| Order: | † Bellerophontida |
| Superfamily: | † Bellerophontoidea |
| Family: | † Tropidodiscidae Knight, 1956 [1] |
| Genera | |
See text | |
| Synonyms | |
Temnodiscinae Horný, 1963 | |
Tropidodiscidae is an extinct family of Paleozoic fossil molluscs with isostrophically coiled shells. They are of uncertain position taxonomically, in other words it is not known whether they were (Gastropoda (snails) or Monoplacophora)s.
The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005 [2] categorizes Tropidodiscidae in the superfamilia Bellerophontoidea within the Paleozoic molluscs of uncertain systematic position with isostrophically coiled shells (Gastropoda or Monoplacophora). This family has no subfamilies.
Genera in the family Tropidodiscidae include:
Strepsodiscus is an extinct genus of very primitive fossil snail-like molluscs from the early part of the Late Cambrian of North America. The coiled, slightly asymmetrical shells are about 3 cm in height. It is not known whether these are shells of gastropods or monoplacophorans, which are more primitive mollusks.
The Bellerophontida is a taxonomic order of extinct marine mollusks that are found in the fossil record from the Lower Cambrian to the Lower Triassic. They are considered by some experts to be primitive sea snails with primarily symmetrically coiled shells, marine gastropod mollusks.
The Bellerophontidae are an extinct family of specialized globose bellerophontids, Paleozoic and early Triassic mollusks of the class Gastropoda.
Bellerophontoidea, common name "bellerophonts", is a superfamily of extinct planospirally-coiled globose molluscs. This superfamily is generally included within the Gastropoda, but may instead be a group of monoplacophorans. The taxon first appeared late in the Cambrian and continued until late in the Triassic.
Coreospiridae is an extinct family of Paleozoic molluscs of uncertain position taxonomically. They might be snails (Gastropoda), Helcionelloida, or they might be Monoplacophora.
Khairkhaniidae is an extinct family of Paleozoic fossil molluscs of uncertain position. They are thought to belong to either the Gastropoda or Monoplacophora. They possess planispiral coiled shells with a columnar microstructure.
Patelliconidae is an extinct family of Paleozoic fossil molluscs. It is not known whether these were Gastropoda or Monoplacophora.
Protoconchoididae is an extinct family of Paleozoic molluscs of uncertain taxonomic position, i.e. they were either.
†Archaeopragidae is an extinct family of paleozoic molluscs of uncertain position.
Bucanellidae is an extinct family of Paleozoic molluscs of uncertain position, belonging either to Gastropoda (snails) or Monoplacophora. The family lived from the upper Cambrian to middle Permian and the shells are characterized by a relatively small median sinus in the upper margin of the aperture, and collabral (transverse) or spiral (longitudinal) threads covering the shell. The shells are planispirally coiled rather than trochospirally with a spire as is the case with most shelled gastropods.
Tremanotidae is an extinct family of Paleozoic fossil molluscs with isostrophically coiled shells. They occupy an uncertain position taxonomically: it is not known whether they were (gastropods or monoplacophorans.
Bucaniidae is an extinct family of Paleozoic molluscs of uncertain position possibly being either gastropods or monoplacophorans in the superfamily Bellerophontoidea. The family lived from the Lower Ordovician to the Devonian and have shells in which the apertural margins tend to flare. Most genera have a slit and selenizone, others some modification of this feature.
Euphemitidae is an extinct family of Paleozoic fossil molluscs of uncertain position. They have isostrophically coiled shells and may be either Gastropoda sea (snail)s, or Monoplacophora.
Pterothecidae is an extinct family of Paleozoic molluscs of uncertain position, either Gastropoda or Monoplacophora, with isostrophically coiled shells.
Sinuitidae is an extinct family of Paleozoic molluscs of uncertain position. They had isostrophically coiled shells.
Omphalotrochidae is an extinct taxonomic family of Paleozoic molluscs (gastropods?) with anisostrophically coiled shells of uncertain position (Gastropoda?).
Omphalocirridae is an extinct family of Paleozoic molluscs (gastropods?) with anisostrophically coiled shells of uncertain position (Gastropoda?).
Helicotomidae is an extinct family of Paleozoic molluscs (gastropods?) with anisostrophically coiled shells of uncertain position (Gastropoda?).
Lesueurillidae is an extinct family of paleozoic molluscs (gastropods?) with anisostrophically coiled shells of uncertain position (Gastropoda?).
Euomphaloidea, originally Euomphalacea, is an extinct superfamily of marine molluscs that lived from the Early Ordovician to the Late Cretaceous, included in the Gastropoda but speculated as instead perhaps Monoplacophora.
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