4-543: Kosmoceras is a moderately evolute ammonite genus from the upper Callovian (Middle Jurassic) of Europe with a simple aperture and irregular ribbing interrupted by an irregular row of lateral tubercles. Strong ventral tubercles are separated by a smooth depression running along the rim. Kosmoceras belongs to the Stephanoceratoidea and is the type genus for the Family Kosmoceratidae and for
8-778: 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
12-699: 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
16-498: The subfamily Kosmoceratinae. Kosmoceras spinosum Waagen is the type species. Lobokosmoceras and Gulielmiceras have been regarded as subgenera of Kosmoceras . Gulielmites is a fine-ribbed variety of Kosmoceras jason This genus includes more than 100 species, including: 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
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