''Hyperlioceras'' is an extinct
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
cephalopod
A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
included in the
ammonitid family
Graphoceratidae that lived during the
Bajocian stage of the
Middle Jurassic
The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...
. 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 unofficially referred to as the International Stratigraphic Commission, is a daughter or major subcommittee grade scientific organization that concerns itself with stratigraphy, strati ...
(ICS) has defined the base of the
Bajocian 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 143.1 Mya. ...
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 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
Source:
* ''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
{{Taxonbar, from=Q3018611
Jurassic ammonites
Index fossils
Ammonites of Europe
Bajocian life
Hildoceratoidea
Ammonitida genera