“Asymptoceras”的意思、由来-开放百科全书

词条

Asymptoceras

释义

References

{{Italic title}}{{Taxobox
| fossil_range = Mississippian
|image=Asymptoceras newloni.png
|image_caption=Asymptoceras newloni
|image_alt=Asymptoceras newloni
|regnum = Animalia
|phylum = Mollusca
|classis = Cephalopoda
| subclassis = Nautiloidea
| ordo = Nautilida
| superfamilia = Aipocerataceae
| familia = Aipoceratidae
| genus = Asymptoceras
| genus_authority = Ryckholt, 1852
|subdivision_ranks=Species
|subdivision=

A. newtoni Hyatt
A. pyxis Shimanskiy, 1967
A. tschernovi Shimanskiy, 1990

}}

Asymptoceras is a genus of aipoceratids (Nautiloidea) similar to Aipoceras but tightly coiled and with only part of the body chamber divergent from the previous whorl. Shell evolute, expanding fairly rapidly; umbilicus open, perforate; whorl section ovoid to subquadrate.

Asymptoceras is known from Mississippian (Lower Carboniferous) sediments in Europe and North America.

References

Bernard Kummel, 1964. Nautiloidea - Nautilida; Treatise on Invertebrate Paleontology, Part K. Geological Society of America.
Asymptoceras in Fossilworks

1 : Prehistoric nautiloid genera

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