Adamsoceras

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Adamsoceras
Temporal range: M Ordovician
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Nautiloidea
Order: Actinocerida
Family: Wutinoceratidae
Genus: Adamsoceras
Flower, 1957

Adamsoceras is an actinocerid of the family Wutinoceratidae, with spheroidal siphuncle segments like Ormoceras but having a reticular canal system like Wutinoceras. Adamsoceras has a slender, gently expanding, orthoconic shell that is slightly broader than high, i.e. depressed, with close spaced septa that form ventral lobes and a siphuncle that is near the ventral margin.

Adamsoceras is known from rocks of Whiterockian age (early Middle Ordovician) in Nevada, the Baltic, Tasmania, and Manchuria. Adamsoceras may have been derived from Wutinoceras, or from a common ancestor, and give rise to Ormoceras.

The genotype is Adamsoceras isabelae from the upper Pogonip Group in Ikes canyon in the Toquima Range in Nevada, named and described by Rousseau H. Flower in 1957.

References[edit]

  • Flower R.H. 1957. Studies of the Actinoceratida, New Mexico Bureau of Mines and Mineral Resources (NMBMMR) Memoir 2, Socorro NM .
  • ______ 1968, The First Great Expansion of the Actinoceroids, NMBMMR PartI Memoir 19