Endoceratidae

Belongs within: Endoceratoidea.

The Early Ordovician to Silurian Endoceratidae were large straight-shelled cephalopods with simple endocones that may contain bifid or trifid endosiphoblades (Evans & King 2012). Some endoceratids reached immense sizes.

The genus Endoceras is known from the Middle to Upper Ordovician and has a shell with annulations varying from low and closely spaced to well elevated and distinctly apart (Teichert 1964).

Characters (Evans & King 2012): Straight, moderately expanding orthoconic longicones, conchs often robust, large to extremely large; circular to weakly depressed or weakly compressed in section. External shell smooth or transversely annulate, sometimes ornamented with lirae and growth lines. Siphuncle broad, ventral to subcentral in position. Septal necks holochoanitic to macrochoanitic; connecting rings relatively thin, forming a lining on internal surface of septal necks, or thick and weakly convex into lumen of siphuncle. Endosiphuncle simple, endocones typically circular in section, exhibiting regular cone-in-cone structure, occasionally extending further adorad ventrally or dorsally; single endosiphotube central, occasionally slightly eccentric in position apicad; endosiphoblades often forming a bifid or trifid pattern radiating from endosiphotube. Where known, apical end of siphuncle relatively small, not swollen.

Endoceratidae [Cyclendoceroceratidae, Endoceratinae]
    |--Chisiliceras Gortani 1934EK12
    |--Ignoceras Flower 1976EK12
    |--Kiotoceras Flower 1971EK12
    |--Protocyclendoceras Balashov 1968EK12
    |--Schmidtoceras Balashov 1968EK12
    |--‘Trinitoceras’ Flower 1976 non Scott 1940EK12
    |--Ventrolendoceras Balashov 1968EK12
    |--Kawasakiceras Kobayashi 1934EK12
    |    `--*K. densistriatum Kobayashi 1934T64
    |--Kutorgoceras Balashov 1962T64
    |    `--*K. compressum Balashov 1962T64
    |--Triendoceras Flower 1958T64
    |    `--*T. montrealense Flower 1958T64
    |--Vaginoceras Hyatt 1883T64
    |    `--*V. multitubulatum (Hall 1847)T64 [=Endoceras multitubulatumT64, Orthoceras multitubulatumH84]
    |--Foerstellites Kobayashi 1940 [=Foerstella Kobayashi 1937 non Ruedemann 1925]T64
    |    `--*F. faberi (Foerste 1930) [=Cameroceras faberi, *Foerstella faberi]T64
    |--Liskeardia Wilson 1939 [=Hendersonia Wilson 1938 non Wagner 1905]T64
    |    `--*L. sola (Wilson 1938) [=*Hendersonia sola]T64
    |--Vaningenoceras Flower 1958T64
    |    `--*V. styliforme Flower 1958T64
    |--Paracyclendoceras Balashov 1968EK12
    |    `--P. cancellatumEK12
    |--Rossicoceras Balashov 1961EK12
    |    `--R. priguense Balashov 1968K93
    |--Kotoceras Kobayashi 1934EK12 [=Subvaginoceras Shimizu & Obata 1936T64]
    |    |--*K. typicum Kobayashi 1934 [=*Subvaginoceras typicum]T64
    |    `--K. cylindricumT64
    |--Endoceras Hall 1847EK12 [=Andoceras (l. c.)T64; incl. Cyclendoceras Grabau & Schimer 1910T64]
    |    |--*E. annulatum Hall 1847T64
    |    |--E. abundumT64
    |    |--E. baffinense Foerste 1928P68
    |    |--E. baylorense Ulrich, Foerste et al. 1944P68
    |    |--E. centrotubulatum Endo 1932P68
    |    |--E. gouldi Miller, Youngquist & Collinson 1954P68
    |    |--E. incognitumKE19
    |    |--E. indigatorP68
    |    |--E. knighti Ulrich, Foerste et al. 1944P68
    |    |--E. landerense Foerste 1935P68
    |    |--E. lorrainense Ruedemann 1926P68
    |    |--E. paradoxicum Foerste 1935P68
    |    |--E. perannulatum Ruedemann 1935P68
    |    |--E. proteiformeP68
    |    |--E. sansabaense Ulrich, Foerste et al. 1944P68
    |    |--E. trundlesense Ulrich, Foerste et al. 1944P68
    |    `--E. vellvillense Ulrich, Foerste et al. 1944P68
    |--Dideroceras Flower in Flower & Kummel 1950PK22, EK12
    |    |--D. glauconiticum (Heinrichson 1935)K93
    |    |--D. incognitum (Schröder 1882)PK22
    |    |--D. leetsense Balashov 1968K93
    |    |--D. longispiculumPK22
    |    `--D. wennanense Chen & Liu 1976K93
    `--Lobocyclendoceras Balashov 1968EK12

*Type species of generic name indicated

References

[EK12] Evans, D. H., & A. H. King. 2012. Resolving polyphyly within the Endocerida: the Bisonocerida nov., a new order of early Palaeozoic nautiloids. Geobios 45 (1): 19–28.

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

[K93] King, A. H. 1993. Mollusca: Cephalopoda (Nautiloidea). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 169–188. Chapman & Hall: London.

[KE19] King, A. H., & D. H. Evans. 2019. High-level classification of the nautiloid cephalopods: a proposal for the revision of the Treatise Part K. Swiss Journal of Palaeontology 138: 65–85.

[PK22] Pohle, A., B. Kröger, R. C. M. Warnock, A. H. King, D. H. Evans, M. Aubrechtová, M. Cichowolski, X. Fang & C. Klug. 2022. Early cephalopod evolution clarified through Bayesian phylogenetic inference. BMC Biology 20: 88.

[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.

[T64] Teichert, C. 1964. Endoceratoidea. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt K. Mollusca 3. Cephalopoda—General Features—Endoceratoidea—Actinoceratoidea—Nautiloidea—Bactritoidea pp. K160–K189. The Geological Society of America and the University of Kansas Press.