''Kepplerites'' is a moderately evolute ammonite from the lower

Callovian In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 166.1 ± 4.0 Ma (million years ago) and 163.5 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the ...

(upper

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively ...

) included in the Stephanoceratoidea. Inner whorls are finely ribbed and have a flattened or grooved venter, the outer whorl has a rounded venter with smooth ribs that cross from side to side without interruption. ''Kepplerites'' is assigned to the Kosmoceratidae and to the subfamily Keppleritinae. ''Gulielmina'' and ''Seymourites'' are closely related genera, sometimes regarded as subgenera of ''Kepplerites. ''Kepplerites'' was named by Neumayr and Uhlig in 1892. The type species ''K keppleri'' is from Germany. This genus has also been found in Alaska, British Columbia, Madagascar, and Russia.

Biostratigraphic significance

The

International Commission on Stratigraphy The International Commission on Stratigraphy (ICS), sometimes referred to unofficially as the "International Stratigraphic Commission", is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigr ...

(ICS) has assigned the

First Appearance Datum First appearance datum (FAD) is a term used by geologists and paleontologists to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest fossil discovered, to date, of a particu ...

of the genus ''Kepplerites'' as the defining biological marker for the start of the

Stage of the

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

, 166.1 ± 1.2 million years ago.

References

* Arkell ''et al.'', 1957. Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology, part L, Ammonoidea. Geological Soc. of America and Univ. Kansas Press. * ''Kepplerites'' illustrated in jsdammonite

Jurassic ammonites Index fossils Prehistoric animals of Madagascar Callovian life Ammonitida genera Stephanoceratoidea {{ammonitina-stub