Cyrthoceratites depressus, from Museum Victoria.

Belongs within: Oncoceratidae.

The Nothoceratidae are a group of cephalopods known from the Silurian and Devonian. Nothoceratid shells varied from short and curved to coiled, with the mature aperture being variously constricted.

Characters (from Sweet 1964): Depressed (or primitively compressed), exogastric or endogastric brevicones, nautilicones, and torticones with contracted or visored apertures and ventral, generally concavosiphonate siphuncle occupied by actinosiphonate deposits.

<==Nothoceratidae [Bolloceratidae, Cranoceratidae, Cyrtoceratidae]
    |--Nothoceras Barrande 1856 S64
    |    `--*N. bohemicum Barrande 1856 S64
    |--Blakeoceras Foerste 1926 S64
    |    `--*B. empiricum (Barrande 1877) [=Cyrtoceras empiricum] S64
    |--Bolloceras Foerste 1926 S64
    |    `--*B. rex (Barrande 1865) [=Phragmoceras rex] S64
    |--Cyrthoceratites d’Archiac & de Verneuil 1842 [=Cranoceras Hyatt 1884] S64
    |    |--*C. depressus (Bronn 1835) [=Cyrtocera depressa, *Cranoceras depressum] S64
    |    |--‘Cyrtoceras’ hospitale [=Cranoceras hospitale] H84
    |    `--‘Cyrtoceras’ nigrum [=Cranoceras nigrum] H84
    |--Lorieroceras Foerste 1926 S64
    |    `--*L. lorieri (Barrande 1870) [=Trochoceras lorieri] S64
    |--Metaphragmoceras Flower 1938 S64
    |    `--*M. verneuili (Barrande 1865) [=Phragmoceras verneuili] S64
    |--Paraconradoceras Foerste 1926 S64
    |    `--*P. rigescens (Barrande 1877) [=Phragmoceras rigescens] S64
    |--Perimecoceras Foerste 1926 S64
    |    `--*P. contrastans (Barrande 1877) [=Cyrtoceras contrastans] S64
    |--Turnoceras Foerste 1926 S64
    |    `--*T. turnus (Barrande 1877) S64 [=Cyrtoceras turnus S64, Cranoceras turnus H84]
    `--Conostichoceras Foerste 1926 S64
         |--*C. palinurus (Barrande 1877) [=Cyrtoceras palinurus] S64
         `--C. hardmani (Etheridge 1897) [=Actinoceras hardmani] F71

*Type species of generic name indicated


[F71] Fletcher, H. O. 1971. Catalogue of type specimens of fossils in the Australian Museum, Sydney. Australian Museum Memoir 13: 1-167.

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

[S64] Sweet, W. C. 1964. Nautiloidea—Oncocerida. In Treatise on Invertebrate Paleontology pt. K. Mollusca 3. Cephalopoda—General Features—Endoceratoidea—Actinoceratoidea—Nautiloidea—Bactritoidea (R. C. Moore, ed.) pp. K277-K319. The Geological Society of America and the University of Kansas Press.

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