Gastrioceras specimen, photographed by Linda Spashett.

Belongs within: Gastriocerataceae.

Gastrioceras is an Lower to Middle Pennsylvanian (Upper Carboniferous) genus of ammonoid.

Characters (from Gordon 1964): Conch subglobose to subdiscoidal at maturity, more or less barrel-shaped in immaturity, planorbital when young. Venter well-rounded; umbilicus moderately involute to evolute; umbilical shoulder ornamented by generally transversely elongate nodes. Transverse sculpture may or may not include strong ribs or sinuous lirae; longitudinal lirae present in some species confined to nodes or generally over ventral region and flanks. Suture with eight lobes and saddles; ventral lobe deeply divided into two narrow asymmetrical prongs, first lateral lobe fairly symmetrical, long and pointed.

Gastrioceras Hyatt 1884H84
`--G. (Lissogastrioceras)P68
|--G. (L.) adaenseP68
`--G. (L.) fittsiP68

Gastrioceras incertae sedis:
G. angulatum Girty 1911P68
G. caneyanum Girty 1909P68
G. excelsumP68
G. glenisteri Nassichuk 1975HK93
G. globulosumP68 [=Goniatites globulosusH84]
G. hyattianum Girty 1911P68
G. jossae [=Goniatites jossae]H84
G. kingii (Hall & Whitfield 1877)H84, P68 [=Goniatites kingiiH84]
G. listeri [=Goniatites listeri]H84
G. liuiG31
G. marianumG31 [=Goniatites marianusH84]
G. richardsonianum Girty 1909P68
G. richthofeniG31
G. roemeriG31
G. serratum Girty 1908P68
G. sigma Wright 1926HK93
G. simulator Girty 1910P68
G. sosienseG31
G. subcrenatumC81
G. suessiG31
G. venatum Girty 1911P68
G. welleriP68
G. wongiG31
G. zitteli [=Girtyites zitteli]G31

*Type species of generic name indicated


[C81] Chamberlain, J. A., Jr. 1981. Hydromechanical design of fossil cephalopods. In: House, M. R., & J. R. Senior (eds) The Ammonoidea: The evolution, classification, mode of life and geological usefulness of a major fossil group pp. 289–336. Academic Press.

Gordon, M., Jr. 1964. Carboniferous cephalopods of Arkansas. Geological Survey Professional Paper 460.

[G31] Grabau, A. W. 1931. The Permian of Mongolia: A report on the Permian fauna of the Jisu Honguer limestone of Mongolia and its relations to the Permian of other parts of the world. American Museum of Natural History: New York.

[HK93] Hewitt, R. A., J. Kullmann, M. R. House, B. F. Glenister & Wang Y.-G. 1993. Mollusca: Cephalopoda (pre-Jurassic Ammonoidea). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 189–211. Chapman & Hall: London.

[H84] Hyatt, A. 1883–1884. Genera of fossil cephalopods. Boston Soc. Nat. History, Proc. 22: 253–338.

[P68] Purnell, L. R. 1968. Catalog of the type specimens of invertebrate fossils. Part I: Paleozoic Cephalopoda. United States National Museum Bulletin 262: 1–198.

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