Mollusca: Cephalopods

An Illustration by Tyler Ray Fewell of a Silurian Amphicyrtoceras  cephalopod  based on specimens of Amphicyrtoceras and other closely related species from the Chicago area.
An Illustration by Tyler Ray Fewell of a Silurian Amphicyrtoceras cephalopod based on specimens of Amphicyrtoceras and other closely related species from the Chicago area.

CEPHALOPODS of today live only in seawater and include the squid, octopus and pearly nautilus. Cephalopod shells may be coiled, slightly curved, or straight, and all are characterized by internal chambers. The cephalopod body, which included a head with eyes, mouth and tentacles, occupied the final and largest chamber. All modern cephalopods are carnivores that capture and eat other animals. All cephalopods are swimmers, but some, such as the octopus, spend most of their time on the seafloor. | At least 33 species of cephalopods lived as dwellers in the Silurian reefs of Wisconsin. Five of these species, shown above, have been placed in the Silurian reef diorama, and their tentacled heads (figures 2 and 5a) have been reconstructed from the appearance of modern cephalopods. Although the cephalopods in the diorama are shown as active swimmers, the larger forms may have spent most of their time lying on the reef surface.

Kingdom Animalia:
Phylum: Mollusca:

Class: Order: Family: Genus and species

Cepalopoda: Orthocerida: "Cycloceras" niagarense Hall
Cepalopoda: Orthocerida: Geisonocerina wauwatosense (Whitfield)
Cepalopoda: Orthocerida: Leurocycloceras raymondi Foerste
Cepalopoda: Orthocerida: Geisonoceratidae: Harrisoceras orthoceroides Flower
Cepalopoda: Orthocerida: Geisonoceratidae: Protokionoceras medullare (Hall)
Cepalopoda: Orthocerida: Dawsonoceratidae: Dawsonoceras nodocostatum (McChesney)
Cepalopoda: Orthocerida: Dawsonoceratidae: Metaspyroceras ruedemanni Foerste
Cepalopoda: Orthocerida: Kionoceratidae: Kionoceras scammoni (McChesney)
Cepalopoda: Orthocerida: Kionoceratidae: Kionoceras sp. 1
Cepalopoda: Orthocerida: Kionoceratidae: Polygrammoceras sp.
Cepalopoda: Orthocerida: Orthoceratidae: Michelinoceras sp. 1
Cepalopoda: Orthocerida: Orthoceratidae: Michelinoceras sp. 2
Cepalopoda: Orthocerida: Sphaerorthoceratidae:?Plagiostomoceras sp.
Cepalopoda: Orthocerida: Sphooceratidae: Sphooceras sp.
Cepalopoda: Orthoceratoidea: Sactorthoceratidae: Sactorthoceras depressum (Foerste)
Cepalopoda: Ascocerida : Ascoceratidae: Ascoceras croneisi Foerste
Cepalopoda: Oncocerida: Acleistoceratidae: Amphicyrtoceras orcas (Hall)
Cepalopoda: Oncocerida: Acleistoceratidae: Amphycyrtoceras sp. 1
Cepalopoda: Oncocerida: Acleistoceratidae: Crateroceras raymondi Foerste & Savag
Cepalopoda: Oncocerida: Oncoceratidae: Cyrtorizoceras dardanus (Hall)
Cepalopoda: Oncocerida: Oncoceratidae: Cyrtorizoceras fosteri (Hall)
Cepalopoda: Oncocerida: Oncoceratidae: Cyrtorizoceras lucillum (Hall)
Cepalopoda: Oncocerida: Oncoceratidae: Cyrtorizoceras unguicurvatum Foerste
Cepalopoda: Oncocerida: Oncoceratidae: Metarizoceras brevicorne (Hall)
Cepalopoda: Oncocerida: Hemiphragmoceratidae: Hexameroceras septoris (Hall)
Cepalopoda: Oncocerida: Trimeroceratidae: Inversoceras dayi Foerste
Cepalopoda: Discosorida: Phragmoceratidae: Phragmoceras nestor Hall
Cepalopoda: Discosorida: Phragmoceratidae: Phragmoceras parvum Hall & Whifield
Cepalopoda: Discosorida: Phragmoceratidae: Phragmoceras procerum Foerste
Cepalopoda: Barrandeocerida: Uranoceratidae: Uranoceras hercules (Winchell & Marcy)
Cepalopoda: Barrandeocerida: Lechritrochoceratidae: Lechritrochoceras desplainense (McChesney)
Cepalopoda: Tarphycerida: Ophioceras wilmingtonense
Cepalopoda: Nautiloidea : Armenoceratidae: Elrodoceras abnorme (Hall)

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