''Hyperlioceras'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

cephalopod A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...

included in the ammonitid family

Graphoceratidae Graphoceratidae is an extinct family of ammonites in the order Ammonitida, which lived during the Jurassic. Distribution Fossils are found in the Jurassic marine strata of Canada, France, Germany, Hungary, Italy, Morocco, Saudi Arabia, Spain and ...

that lived during the

Bajocian In the geologic timescale, the Bajocian is an age and stage in the Middle Jurassic. It lasted from approximately 170.3 Ma to around 168.3 Ma (million years ago). The Bajocian Age succeeds the Aalenian Age and precedes the Bathonian Age. Stratig ...

stage of the

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic 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 rare, but geological formations co ...

. The type species is ''Hyperlioceras discites'' (Waagen, 18567)

Morphology

The shell of ''Hyperlioceras'' is very compressed and involute, with a tall persistent keel and a deep umbilicus.

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 stratigra ...

(ICS) has defined the base of the

Stage of the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), 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 J ...

as the lowest occurrence of the genus ''Hyperlioceras'', at 170.3 ± 1.4 million years ago, which defines base of the ''Hyperlioceras discites'' Zone. This point also marks the end of the preceding

Aalenian The Aalenian () is a subdivision of the Middle Jurassic Epoch/Series of the geologic timescale that extends from about 174.1 Ma to about 170.3 Ma (million years ago). It was preceded by the Toarcian and succeeded by the Bajocian. Stratigraphic ...

Stage. The upper boundary of the Bajocian is indicated by the lowest occurrence of the ammonite ''Parkinsonia (G.) convergens'', at about 167.7 Ma, which defines base of '' Zigzagiceras zigzag'' Zone.

Distribution

Luxembourg, Saudi Arabia, Spain and the United Kingdom.

Synonyms

* ''Braunsella'' Buckman, 1904 * ''Braunsina'' Buckman, 1902 * ''Darellia'' * ''Darellina'' Buckman, 1904 * ''Deltoidoceras'' Buckman, 1902 * ''Deltotoceras'' Buckman, 1904 * ''Dissoroceras'' Buckman, 1902 * ''Hugia'' Buckman, 1904 * ''Hyperlioceras (Toxolioceras)'' * ''Lopadoceras'' Buckman, 1904 * ''Reynesella'' * ''Reynesia'' Buckman, 1902 * ''Toxolioceras''

References

* W. Arkell ''et al.'', 1957. Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology, Part L. Geological Society of America and University of Kansas Press. p. L264 Jurassic ammonites Index fossils Ammonites of Europe Bajocian life Hildoceratoidea Ammonitida genera {{jurassic-animal-stub