| Yochelcionelloidea | |
|---|---|
 | |
| Yochelcionella cyrano | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | † Helcionelloida |
| Order: | † Helcionelliformes |
| Superfamily: | † Yochelcionelloidea Runnegar & Jell, 1976 |
Yochelcionelloidea is an extinct superfamily of paleozoic molluscs of uncertain position (Gastropoda or Monoplacophora). [1] The earliest yochelcionellids are known from the Middle Tommotian, but they are most diverse from the Botomian through the early Middle Cambrian. [2]
The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005:
Yochelcionelloidea
According to the opinion of P. Yu. Parkhaev is in the class Helcionelloida, subclass Archaeobranchia Parkhaev, 2001, Order Helcionelliformes Golikov & Starobogatov, 1975: [3] [4]
Monoplacophora, meaning "bearing one plate", is a polyphyletic superclass of molluscs with a cap-like shell now living at the bottom of the deep sea. Extant representatives were not recognized as such until 1952; previously they were known only from the fossil record, and were previously thought to have become extinct over 380 million years ago.
Neogastropoda is a clade of sea snails, both freshwater and marine gastropod molluscs.
The Bellerophontidae are an extinct family of specialized globose bellerophontids, Paleozoic and early Triassic mollusks of the class Gastropoda.
Latouchella is an extinct genus of marine invertebrate animal, that is considered to be a mollusk and which may be a sea snail, a gastropod. It is a helcionellid from the Tommotian epoch of what is now Siberia. Its tightly-coiled, spiral shell contains a number of low "walls" running up the front surface of the interior; these would have directed water currents within its shell. Between these walls are a series of furrows, parallel to the shell's aperture, giving casts of the internal structure the appearance of a railway line, with sleepers tying together paired rails that run towards the apex of the shell.
Neritoidea is a taxonomic superfamily of mostly sea snails, nerites and their allies, marine gastropod mollusks in the order Cycloneritida.
Yochelcionella is an extinct genus of basal molluscs which lived during the Tommotian epoch, the first epoch of the Cambrian period. This genus is often reconstructed to resemble snails.
Euconulidae is a taxonomic family of minute, air-breathing land snails, terrestrial pulmonate gastropod mollusks or micromollusks in the superfamily Trochomorphoidea.
Helcionellid or Helcionelliformes is an order of small fossil shells that are universally interpreted as molluscs, though no sources spell out why this taxonomic interpretation is preferred. These animals are first found about 540 to 530 million years ago in the late Nemakit-Daldynian age, which is the earliest part of the Cambrian period. A single species persisted to the Early Ordovician. These fossils are component of the small shelly fossils (SSF) assemblages.
Helcionelloida is an extinct group of ancient molluscs. These are the oldest known conchiferan molluscs, that is, they had a mineralised shell. Some members of this class were mistaken for Monoplacophorans. The class was erected by Peel in 1991.
Scolodontidae is a taxonomic family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Scolodontoidea
Coreospiridae is an extinct family of Paleozoic molluscs of uncertain position taxonomically. They might be snails (Gastropoda), Helcionelloida, or they might be Monoplacophora.
The Cerithioidea is a superfamily of marine, brackish water and freshwater gastropod containing more than 200 genera. The Cerithoidea are included in the clade Sorbeoconcha. The original name of this superfamily was Cerithiacea, in keeping with common superfamily endings at the time.
Olivoidea is a taxonomic superfamily of minute to medium-large predatory sea snails, marine gastropod mollusks in the clade Neogastropoda.
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.
Aldanellidae is an extinct family of paleozoic molluscs that have been assigned to the Gastropod stem group but may also belong to a paraphyletic "Monoplacophora".
Pelagiellidae is an extinct family of Paleozoic fossil marine molluscs.
Carinopelta is a genus within Carinopeltidae, an extinct family of Cambrian molluscs of uncertain position. It is in the superfamily Scenelloidea.
Trenella is the sole genus in the Trenellidae, an extinct family of paleozoic Yochelcionellids.
Stenothecidae is an extinct family of fossil univalved Cambrian molluscs which may be either gastropods or monoplacophorans.
This overview lists proposed changes in the taxonomy of gastropods at the family level and above since 2005, when the taxonomy of the Gastropoda by Bouchet & Rocroi (2005) was published. In other words, these are recent updates in the way various groups of snails and slugs are classified.