Uddenitinae
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The Uddenitinae a subfamily of the
Medlicottiidae Medlicottiidae is a family of ammonoid cephalopods belonging to the Prolecanitida, known from the Upper Carboniferous ( Pennsylvanian) to the Early Triassic. Characteristics Medlicottidae are characterized by discoidal to thinly lenticular shell ...
, a family of ammonoid cephalopods included in the Prolecanitida. The Uddenitinae, proposed by Miller and Furnish, and known from the Pennsylvanian (U
Carb The California Air Resources Board (CARB or ARB) is the "clean air agency" of the government of California. Established in 1967 when then-governor Ronald Reagan signed the Mulford-Carrell Act, combining the Bureau of Air Sanitation and the Motor ...
) and Lower
Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...
, are transitional between the ancestral Pronoritidae and the more traditional medlicottiids


Morphology

Genera of the Uddenitinae have narrow discoidal shells with narrow flat or sometimes grooved venters. Sutures are goniatitic to ceratitic with rounded saddles and slightly pointed to digitate lobes which form a declining series going toward the umbilicus. The ventral lobe is commonly long and narrow, and trifurcated with sharp, simple prongs.


Genera

The Uddenitinae includes ''Prouddenites'', (ancestral form), ''Uddenites'',(type genus), ''Daixites'', ''Neouddenites'', and ''Uddenoceras''. ''Prouddenites'', named by Miller, 1930, which is found in the Pennsylvanian of the south-central United States and the Urals, has a discoidal shell with a flattened venter and a suture with an unequally trifid first lateral lobe. It is intermediate between '' Pronorites'' and ''Uddenites''. ''Uddenites'', named by Böse, 1919, known from the Upper Pennsylvanian of Texas and the Urals, has a discoidal shell with a retuse (grooved) venter. The ventral portion of the first lateral lobe is intermediate in depth. ''Diaxites'', Ruzhentsev 1941, has the characteristic discoidal form but the ventral lobe is quite wide, still trifid. ''Diaxites'' is Upper Pennsylvanian and Lower Permian in age. ''Neouddenites'', Ruzhentsev 1961, is similar to ''Uddenites'', but later, coming from the Lower Permian. ''Uddenoceras'', named by Miller and Furnish, 1954, from the Upper Pennsylvanian of Texas and the Urals has a discoidal shell like ''Uddenites'', but the ventro-lateral portion of the suture forms a broad saddle.


Generic phylogeny

''Prouddenties'' has its origin in the (Pronoritidae), probably in ''Uralopronorites'' from the Upper Mississippian, and giving rise to ''Uddenites'' and ''Daixites''. ''Uddenites'' in turn gave rise to ''Uddenoceras'' and ''Neouddenties''. ''Daixites'' left no known descendants.


References

* Miller, Furnish, and Schindewolf, 1957. Paleozoic Ammonoidea (Prolecantina); Treatise on Invertebrate Paleontology, Part L, (Ammonoidea). Geol Soc of America and Univ Kansas Press. p. L72-L73.
Uddenitinae-Paleobio db
* Sunders, et al., 1999. Evolution of Complexity in Paleozoic Ammonoid Sutures. Supplementary material.
List of ammonites This list of ammonites is a comprehensive listing of Genus, genera that are included in the subclass †Ammonoidea, excluding purely vernacular terms. The list includes genera that are commonly accepted as valid, as well those that may be invalid ...
Prolecanitida Permian ammonites Ammonites of North America Prehistoric animal subfamilies Pennsylvanian first appearances Cisuralian extinctions {{Prolecanitida-stub