4-420: The Vascoceratidae is a family of Upper Cretaceous ammonites in the superfamily Acanthoceratoidea characterized by shells that are either smooth or bluntly tuberculate, or have sparse, coarse ribs. Sutural elements are shallow, irregular, and slightly indented, or deep and very indented. Whorl section and degree of involution vary, even within species. The Vascoceratidae is a short lived family restricted to
8-744: The Jurassic through Paleocene time periods, commonly with intricate ammonitic sutures . Ammonitida is divided into four suborders, the Phylloceratina , Lytoceratina , Ancyloceratina , and Ammonitina . The Phylloceratina is the ancestral stock, derived from the Ceratitida near the end of the Triassic . The Phylloceratina gave rise to the Lytoceratina near the beginning of the Jurassic which in turn gave rise to
12-714: The early and middle Turonian stage. Its duration, no more than a few million years. They are derived from the Acanthoceratidae and are the predecessors of the Tissotiidae , which in turn gave rise to the Coilopoceratidae ; all taking place in a short time span in the Turonian. This Ammonitina -related article is a stub . You can help Misplaced Pages by expanding it . Ammonitida Ammonitida or "True ammonites" are an order of ammonoid cephalopods that lived from
16-673: The highly specialized Ancyloceratina near the end of the Jurassic. Both the Phylloceratina and Lytoceratina gave rise to various stocks combined in the Ammonitina. These four suborders are further divided into different stocks, comprising various families combined into superfamilies. Some like the Hildoceratoidea and Stephanoceratoidea are restricted to the Jurassic. Others like the Hoplitoidea and Acanthoceratoidea are known only from
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