Cyrtogomphoceratidae

Belongs within: Nautilosiphonata.

The Middle Ordovician to Lower Devonian cyrtogomphoceratid lineage of discosorid cephalopods included the paraphyletic Cyrtogomphoceratidae and the later Phragmoceratidae. The Phragmoceratidae had the shell aperture strongly constricted by encroaching lappets.

Characters (from Teichert 1964): Conchs dominantly medium-sized to large, compressed endogastric cyrtocones; aperture strongly contracted in Phragmoceratidae; siphuncle close to ventral side. Siphuncular segments broadly expanded; connecting rings thick, apical ends expanded into markedly swollen bullettes in early forms, small to vestigial bullettes in Phragmoceratidae.

<==Cyrtogomphoceratidae
    |         Konglungenoceras Sweet 1959T64
    |           `--*K. norvegicum Sweet 1959T64
    |         Parryoceras Sweet & Miller 1957T64
    |           `--*P. euchari Sweet & Miller 1957T64
    |         Lyckholmoceras Teichert 1930KE19, S64
    |           |--*L. estoniae Teichert 1930S64
    |           `--L. graciliforme Lai 1982K93
    |--Ulrichoceras Foerste 1928T64
    |    `--*U. beloitense Foerste 1928T64
    `--+--Strandoceras Flower 1940T64
       |    |--*S. tyriense (Strand 1933) [=Protophragmoceras tyriense]T64
       |    `--S. strandi Sweet 1958K93
       |--Kiaeroceras Strand 1934T64
       |    |--*K. frognoeyense Strand 1934T64
       |    `--K. heroeyenseT64
       |--+--Landeroceras Foerste 1935T64
       |  |    `--*L. prolatum (Miller 1932) [=Diestoceras prolatum]T64
       |  `--Cyrtogomphoceras Foerste 1924T64
       |       |--*C. magnum (Whiteaves 1890) [=Oncoceras magnum]T64
       |       |--C. contractum Foerste 1935P68
       |       |--C. curvatumKE19
       |       |--C. landerense Foerste 1935P68
       |       |--C. minor Foerste 1935P68
       |       |--C. nutatumT64
       |       |--C. perexpansum Foerste 1935P68
       |       |--C. popoagiense Foerste 1935P68
       |       |--C. rotundumP68
       |       |--C. turgidumT64
       |       `--C. vicinum Foerste 1935P68
       `--PhragmoceratidaeT64
            |  i. s.: Talattoceras crenatumKE19
            |--Protophragmoceras Hyatt in Zittel 1900T64
            |    |--*P. murchisoni (Barrande 1866) [=Cyrtoceras murchisoni]T64
            |    `--P. nonnullum Zhuravleva 1972K93
            |--Endoplectoceras Foerste 1924T64
            |    |--*E. secula (Barrande 1865) [=Trochoceras secula]T64
            |    `--E. podolicum Zhuravleva 1972K93
            |--Sthenoceras Flower in Flower & Teichert 1957T64
            |    `--*S. aduncum (Barrande 1866) [=Cyrtoceras aduncum]T64
            `--+--Tubiferoceras Hedström 1917T64
               |    |--*T. proboscideum (Hedström 1917) [=Phragmoceras proboscideum]T64
               |    `--T. prominensT64
               |         |--T. p. prominensT64
               |         `--T. p. minusT64
               |--Phragmocerina Flower 1948T64
               |    |--*P. osculum (Ruedemann 1916) [=Gomphoceras osculum]T64
               |    `--P. litchfieldensisT64
               `--Phragmoceras Broderip in Sowerby in Murchison 1839 (see below for synonymy)T64
                    |--*P. arcuatum Sowerby 1839T64
                    |--P. altidorsatum Foerste 1930P68
                    |--P. altum Foerste 1936P68
                    |--P. broderipi Teichert 1964 (see below for synonymy)T64
                    |--P. colliciare Foerste 1930P68
                    |--P. compressum Sowerby 1839T64
                    |--P. cuneiforme Foerste 1930P68
                    |--P. dubium Hedström 1917TM20
                    |--P. ellipticumP68
                    |--P. eurystomaTM20
                    |    |--P. e. eurystomaTM20
                    |    `--P. e. flexibile Hedström 1917TM20
                    |--P. farcimenT64
                    |--P. hoyi Whitfield 1878P68
                    |    |--P. h. hoyiP68
                    |    `--P. h. ‘compressum’ Whitfield 1878 non Sowerby 1839P68
                    |--P. imbricatum Barrande 1865TM20 [=Rizosceras imbricatumH84]
                    |--P. labiatum Whitfield 1878P68
                    |--P. lamellosumT64
                    |--P. ontarioenseP68
                    |--P. parvumP68
                    |--P. transversaleT64
                    `--P. ventricosum (Steininger 1834) [=Orthoceratites ventricosus]T64

Phragmoceras Broderip in Sowerby in Murchison 1839 [=Phragmocera Braun 1840, Phragmoceratites d’Archiac & de Verneuil 1842, Phragmocerus Bronn 1848]^T64

Phragmoceras broderipi Teichert 1964 [=P. ventricosum Sowerby 1839 non Orthoceratites ventricosus Steininger 1834]^T64

*Type species of generic name indicated

References

[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.

[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.

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

[T64] Teichert, C. 1964. Nautiloidea—Discosorida. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt K. Mollusca 3. Cephalopoda—General Features—Endoceratoidea—Actinoceratoidea—Nautiloidea—Bactritoidea pp. K320–K342. The Geological Society of America and the University of Kansas Press.

[TM20] Turek, V., & Š. Manda. 2020. Discontinuous, asymmetric and irregular colour patterns in Silurian oncocerids (Nautiloidea) with cyrtoconic shells. Bulletin of Geosciences 95 (3): 333–367.