Haploceratoidea, formerly Haplocerataceae, is an extinct superfamily of
ammonoid
Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...
cephalopods belonging to the
Ammonitida
Ammonitida is an order of ammonoid cephalopods that lived from the Jurassic through Paleocene time periods, commonly with intricate ammonitic sutures.
Ammonitida is divided into four suborders, the Phylloceratina, Lytoceratina, Ancyloceratina, a ...
that unites three families,
Strigoceratidae,
Oppeliidae
Oppeliidae are compressed to oxyconic, sculptured Haploceratoidea, either unkeeled, unicarinate, bicarinate, or tricarinate; with sutures in great variety, but ribbing usually more or less falcoid or falcate. The Oppeliidae is the principal famil ...
, and
Haploceratidae, listed below.
Haploceratoidea begins with all three families in the lower
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 ...
,
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 ...
. Strigoceratidae is limited to the Bajocian but Oppeliidae, and Haploceratidae extend through the remaining Jurassic, well into the
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
; the Oppeliidae into the middle
Albian
The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 M ...
, the Haplocertidae only into the
Valanginian
In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 139.8 ± 3.0 Ma and 132.9 ± 2.0 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretaceou ...
.
Diagnosis
Haploceratoidea are typically compressed, discoidal Ammontida that may be keeled or unkeeled, tending to be oxyconic, with usually falcoid or falcate ribbing. The
aptychi are paired and differ between families and have been found ''in situ'' in e.g. ''
Oppelia subrudiata'' and in ''
Pseudolissoceras''.
Taxonomy
The Origin of the Haploceratoidea is undetermined but it is likely all three component families have their beginnings in the
Hammatoceratidae in the middle Bajocian. None of the Haploceratoidea is thought to have given rise to any subsequent group.
Superfamily Haploceratoidea
Zittel, 1884
*Family
Haploceratidae Zittel, 1884
**Genus ''
Lissoceras''
Bayle, 1879
**Genus ''
Glochiceras''
Hyatt, 1900
**Genus ''
Haploceras''
Zittel, 1870
**Genus ''
Neolissoceras''
Spath, 1923
*Family
Oppeliidae
Oppeliidae are compressed to oxyconic, sculptured Haploceratoidea, either unkeeled, unicarinate, bicarinate, or tricarinate; with sutures in great variety, but ribbing usually more or less falcoid or falcate. The Oppeliidae is the principal famil ...
Bonarelli, 1894
**Subfamily
Aconeceratinae (Spath, 1923)
***Genus ''
Aconeceras
''Aconeceras'' is an early Cretaceous ammonite included in the oppeliid subfamily Aconeceratidae, characterized by an involute, high-whorled, flat-sided shell that bears a finely serrate keel along the venter. Sutures have narrower and deeper ele ...
''
Hyatt, 1903
***Genus ''
Gyaloceras''
Whitehouse, 1927
***Genus ''
Koloceras''
Riccardi ''et al.'', 1987
***Genus ''
Sanmartinoceras''
**Subfamily
Hecticoceratinae Spath, 1925
***Genus ''
Hecticoceras
''Hecticoceras'' is an ammonite genus belonging to the haploceratoid family Oppeliidae, that lived during the Middle and Late Jurassic, from the Callovian. ''Hecticoceras'' may be seen as a series of some nine subgenera, beginning with the lo ...
''
Bonarelli, 1893
***Genus ''
Pseudosonninia''
Parent, 2019
**Subfamily
Mazapilitinae Spath, 1928
**Subfamily
Oppeliinae Bonarelli, 1894
***Genus ''
Submazapilites''
Cantu-Chapa, 1962
**Subfamily
Streblitinae Spath, 1925
***Genus ''
Bornhardticeras''
Böhm & Riedel, 1933
***Genus ''
Cyrtosiceras''
Hyatt, 1900
***Genus ''
Substreblites''
Spath, 1925
***Genus ''
Uhligites''
Kilian, 1913
**Subfamily ''
incertae sedis
' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...
''
***Genus ''
Naramoceras''
McNamara, 1985
*Family
Strigoceratidae Buckman, 1924
**Genus ''
Oecoptychius''
**Genus ''
Phlycticeras''
Hyatt, 1900
**Genus ''
Strigoceras''
Quenstedt, 1886
References
* Treatise on Invertebrate Paleontology, Part L Ammonoidea, (L171), Geological Society of America and University of Kansas press, 1964.
Ammonitina
Ammonitida superfamilies
Bajocian first appearances
Early Cretaceous extinctions
{{Ammonitina-stub