''Monophyllites'' is an extinct cephalopod genus belonging to the family
Ussuritidae
Ussuritidae are ancestral, Triassic, Phylloceratina characterized by generally smooth, discoidal, evolute shells with rounded venters and little or no ornamentation and by sutures with primitive monophyllitic saddles with a single terminal branch ...
that lived during the
Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
period, from
Anisian
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Ep ...
to
Ladinian
The Ladinian is a stage and age in the Middle Triassic series or epoch. It spans the time between Ma and ~237 Ma (million years ago). The Ladinian was preceded by the Anisian and succeeded by the Carnian (part of the Upper or Late Triassic).
...
age.
Description
"Form evolute laterally compressed. Whorl low and increasing slowly in height, little embracing and not deeply indented by the inner volution. Sides somewhat flattened, venter rounded with indistinct abdominal shoulders. Umbilicus wide and shallow exposing the greater part of the inner volutions. Umbilical shoulders abruptly rounded. The height of the whorl is more than one third of the total diameter of the shell and the breadth is about three fourths of the height of the whorl The width of the umbilicus is about one third of the total diameter of the shell. The surface is nearly smooth being ornamented only with the fiexuous striae of growth. The septa are monophyllic, the saddles rounded entire, contracted at the base and the lobes are digitate. The external lobe is divided by a narrow siphonal saddle into two bifid divisions the first lateral is distinctly and symmetrically trifid the second lateral unsymmetrically trifid. The auxiliary consists of three small secondary divisions of the umbilical lobe. Internal septa unknown"
(Original description by Hyatt and Smith, 1905).
Species
The following species are recognized in the genus ''Monophylites''
[Paleobiology Database - Monophyllites](_blank)
28 May 2014
* ''M. agenor''
Muenster, 1834
* ''M. anatolicus''
Toula, 1896
* ''M. aonis''
Mojsisovics, 1882
* ''M. bytschkovi''
Vavilov, 1989
* ''M. caucasius''
Shevyrev, 1995
* ''M. kieperti''
Toula, 1896
* ''M. sphaerophyllus''
(von Hauer) Discover Yale Digital content
/ref>
* ''M. wengensis'' Klipstein, 1843
* ''M. wetsoni'' Oppel, 1862
Distribution
Fossils of species within this genus have been found in the Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
of Afghanistan, Albania, Canada, Hungary, Italy, Japan, New Zealand, Oman, Pakistan, Russia, Switzerland, Turkey, United States.
References
GBIF
{{Taxonbar, from=Q16985938
Ammonites of Europe
Triassic ammonites
Ammonites of Australia
Ammonites of North America
Anisian life
Ammonitida genera