5-540: Discophyllitidae are discoidal, generally evolute Phylloceratina from the Upper Triassic, derived from the Ussuritidae , in which the principal saddles of the suture have bifurcated or trifurcated endings, described as being di- or triphyllic. Discophyllitid shells are rather similar to those of the ancestral Ussuritidae and are distinguished primarily by the more complex suture. The Discophyllitidae provided
10-802: The Ammonitida , whose range extends from the Lower Triassic to the Upper Cretaceous . Shells of the Phylloceratina are generally smooth with small to large umbilici and complex sutures with leaf-like phylloid saddle endings and lobes with thorn-like projections. The Phylloceratina are most likely derived from the Ceratitid Deineroceratidae, which is thought to have given rise early in the Triassic to
15-619: The Ussuritidae. The Ussuritidae is the ancestral family of the Phylloceratina. The Ussuritidae extend through the Upper Triassic but not into the Jurassic, and gave rise to the Upper Triassic Discophyllitidae. The Discophyllitidae is the probable source for the L Jurassic - U Cretaceous Phylloceratidae and possibly for the L Jurassic Juraphyllitidae. The Phylloceratina gave rise early in the Jurassic through
20-534: The middle Late Triassic, Tragorhacoceras from the Alps and Sicily, Trachyphyllites from the island of Timur. Both result from further, but different, evolutionary developments within the Discophyllitidae. This Ammonitida -related article is a stub . You can help Misplaced Pages by expanding it . Phylloceratina The Phylloceratina comprise a suborder of ammonoid cephalopods, belonging to
25-744: The source for the Jurassic Phylloceratidae and Juraphyllitidae . Four genera are recognized and described. Discophyllites and Rhacophyllites have their beginnings in the early Late Triassic. Both are found in Europe, the Himalayas, and on Timur; Discophyllites in California and Alaska as well. Discophyllites is the more primitive and ancestral genus. Rhacophyllites is slightly more evolved with its more developed suture. Tragorhacoceras and Trachyphyllites are known from
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