Eulophoceras natalense, from Kennedy & Klinger (2012).

Belongs within: Acanthoceratidae.

The Sphenodiscidae are an Upper Cretaceous (Coniacian to Maastrichtian) lineage of involute, compressed ammonites (Wright et al. 1996).

Characters (from Wright et al. 1996): Involute; compressed; generally with weak lateral and ventrolateral tubercles or smooth; venter sharp or narrowly rounded. A few, less compressed and broader-ventered forms are probably microconchs. Suture with narrow-necked, entire or frilled, and in some cases phylloid saddles; first lateral saddle divided by one or two adventive lobes; many auxiliary elements.

<==Sphenodiscidae [Libycoceratidae]WCH96
    |--Lenticeratinae [Eulophoceratidae, Lenticeratidae]WCH96
    |    |--Lenticeras Gerhardt 1897WCH96
    |    |    `--*L. andii (Gabb 1877) [=Ammonites andii]WCH96
    |    |--Paralenticeras Hyatt 1900WCH96
    |    |    |--*P. sieversi (Gerhardt 1897) [=Amaltheus sieversi]WCH96
    |    |    `--P. spathiWCH96
    |    `--Eulophoceras Hyatt 1903 (see below for synonymy)WCH96
    |         |--*E. natalense Hyatt 1903WCH96
    |         |--*Spheniscoceras’ africanum Spath 1921WCH96
    |         |--E. austriaca (Summesberger 1979) [=*Skoumalia austriaca]WCH96
    |         |--E. jacobiWCH96
    |         |--‘Lenticeras’ jullieni Pervinquière 1910 [=*Praelibycoceras jullieni]WCH96
    |         `--*Pelecodiscus’ umzambiensis Hoepen 1921WCH96
         |--Indoceras Noetling 1897WCH96
         |    `--*I. baluchistanense Noetling 1897WCH96
         |--Daradiceras Sornay & Tessier 1949WCH96
         |    `--*D. gignouxi Sornay & Tessier 1949WCH96
         |--Nubidites Wiedmann & Kullman 1979WCH96
         |    `--*N. omarai Wiedmann & Kullman 1979WCH96
         |--Coahuilites Böse 1928WCH96
         |    |--*C. sheltoni Böse 1928WCH96
         |    `--C. cavinsiWCH96
         |--Libycoceras Hyatt 1900 [incl. Paciceras Olsson 1944]WCH96
         |    |--*L. ismaeli (Zittel 1895) [=Engonoceras ismaeli, Ammonites ismaelis Zittel 1883 (n. n.)]WCH96
         |    `--*Paciceras’ pacificum Olsson 1944WCH96
         |--Sphenodiscus Meek 1871 [incl. Austrosphenodiscus Olsson 1944]WCH96
         |    |--*S. lobatus (Tuomey 1856) [=Ammonites lobatus; incl. A. lenticularis Owen 1852 non Young & Bird 1828]WCH96
         |    |--S. binkhorstiP93
         |    `--S. peruvianus Gerth 1928 [=S. pleurisepta var. peruviana, *Austrosphenodiscus peruvianus]WCH96
         `--Manambolites Hourcq 1949 [incl. Mzezzemceras Basse 1954]WCH96
              |  i. s.: ‘Coahuilites (*Mzezzemceras)’ pervinquieri Basse 1954WCH96
              |--*M. (Manambolites) pivetaui Hourcq 1949WCH96
              `--M. (Praemanambolites Collignon 1969)WCH96
                   `--M. (*P.) hourcqui (Collignon 1969) [=*Praemanambolites hourcqui]WCH96

Eulophoceras Hyatt 1903 [incl. Pelecodiscus Hoepen 1921, Praelibycoceras Douvillé 1912, Skoumalia Summesberger 1979, Spheniscoceras Spath 1921]WCH96

*Type species of generic name indicated


[P93] Page, K. N. 1993. Mollusca: Cephalopoda (Ammonoidea: Phylloceratina, Lytoceratina, Ammonitina and Ancyloceratina). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 213–227. Chapman & Hall: London.

[WCH96] Wright, C. W., J. H. Calloman & M. K. Howarth. 1996. Treatise on Invertebrate Paleontology pt L. Mollusca 4, revised vol. 4. Cretaceous Ammonoidea. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

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