''Unipeltoceras'' is an extinct

ammonite Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

genus included in the perisphictacian family,

Aspidoceratidae The Aspidoceratidae comprise a family of middle and upper Jurassic ammonites that make up part of the superfamily Perisphinctoidea, characterized by evolute shells, commonly stocky, that tend to develop tubercles. The Aspidoceratidae are thought ...

, and a member of the subfamily

Peltoceratinae The Peltoceratinae comprise a subfamily in the Aspidoceratidae, (middle and upper Jurassic perisphinctacean ammonites). Genera in the Peltoceratinae have sharply ribbed inner whorls and outer whorls that bear spines or tubercles, or have coarse ...

, that lived during the

Callovian In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 165.3 ± 1.1 Ma (million years ago) and 161.5 ± 1.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the ...

stage, late in the Middle Jurassic. ''Unipeltoceras'' is characterized by its strongly evolute, discoidal shell with sharp ribbing on the inner whorls and differing from ''

Peltoceras ''Peltoceras'' is an extinct ammonite genus from the aspidoceratid subfamily Peltoceratinae that lived during the later part of the Middle Jurassic (U Callovian In the geologic timescale, the Callovian is an age and stage in the Middle Juras ...

'', s.s. by having only an outer row of tubercles on the outer whorls.

References

*Arkell, et al., 1957. Mesozoic Ammonoidea.

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authore ...

, Part L (Ammonoidea). Geol Soc of America and Univ Kansas Press. p. L336 Jurassic ammonites Ammonitida genera Ammonites of Europe Callovian life Aspidoceratidae {{Ammonite-stub