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Mar 22, 2024 · Ammonoid, any of a group of extinct cephalopods (of the phylum Mollusca), forms related to the modern pearly nautilus (Nautilus), that are frequently found as fossils in marine rocks dating from the Devonian Period (began 419 million years ago) to the Cretaceous Period (ended 66 million years ago).
Ammonoid or Ammonites are an extinct group of marine animals of the subclass Ammonoidea in the class Cephalopoda, phylum Mollusca. Ammonoidea is one of three subclasses of cephalopods, the others being Coleoidea (octopuses, squids, cuttlefishes, extinct belemites), and Nautiloidea (nautilus and extinct relatives).
Ammonoids (Ammonoidea) are an extinct group of marine invertebrates with an external shell. They were cephalopods, and hence closely related to modern cuttlefish, squid, octopuses and the pearly nautilus.
Jul 8, 2023 · The evolution and classification of ammonites reveal a fascinating story of diversification and adaptation over millions of years. Ammonites belong to the subclass Ammonoidea within the class Cephalopoda, which also includes living cephalopods like squid, octopuses, and nautiluses.
The Ammonoidea are ancient cephalopods that are closely related to the modern day chambered Nautilus, cuttlefish (e.g. the Cretaceous Actinosepia canadaensis), octopus, and squid. Their unique, chambered shell shapes have fascinated collectors as well as scientists who use ammonites as index fossils to date the relative age of rocks in which ...
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The Ammonoidea (ammonoids) are an order of the class Cephalopoda (q.v.), phylum Mollusca. The nearest living relative of the ammonoids is the pearly Nautilus of which Oliver Wendell Holmes wrote “ This is the ship of pearl, which, poets feign, /Sails the unshadowed main .”. The hollow shell of most ammonoids is essentially a cone, coiled in ...
Jan 1, 2015 · Ammonoids probably spawned in benthic, demersal or even midwater habitats (Mapes and Nützel 2009) in the neritic to oceanic zone above the shelf areas and upper slopes (Westermann 1996 ). Females are thought to have laid 100–500000 eggs on the sea floor (r- strategy) or spawned egg masses in the water column.
