Cyrtogomphoceratidae

Reconstructed model of Phragmoceras by Klaus Leitl.

Belongs within: Discosorida.

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
    |  i. s.: Konglungenoceras Sweet 1959 T64
    |           `--*K. norvegicum Sweet 1959 T64
    |         Parryoceras Sweet & Miller 1957 T64
    |           `--*P. euchari Sweet & Miller 1957 T64
    |--Ulrichoceras Foerste 1928 T64
    |    `--*U. beloitense Foerste 1928 T64
    `--+--Strandoceras Flower 1940 T64
       |    `--*S. tyriense (Strand 1933) [=Protophragmoceras tyriense] T64
       |--Kiaeroceras Strand 1934 T64
       |    |--*K. frognoeyense Strand 1934 T64
       |    `--K. heroeyense T64
       |--+--Landeroceras Foerste 1935 T64
       |  |    `--*L. prolatum (Miller 1932) [=Diestoceras prolatum] T64
       |  `--Cyrtogomphoceras Foerste 1924 T64
       |       |--*C. magnum (Whiteaves 1890) [=Oncoceras magnum] T64
       |       |--C. contractum Foerste 1935 P68
       |       |--C. landerense Foerste 1935 P68
       |       |--C. minor Foerste 1935 P68
       |       |--C. nutatum T64
       |       |--C. perexpansum Foerste 1935 P68
       |       |--C. popoagiense Foerste 1935 P68
       |       |--C. rotundum P68
       |       |--C. turgidum T64
       |       `--C. vicinum Foerste 1935 P68
       `--Phragmoceratidae T64
            |--Protophragmoceras Hyatt in Zittel 1900 T64
            |    `--*P. murchisoni (Barrande 1866) [=Cyrtoceras murchisoni] T64
            |--Endoplectoceras Foerste 1924 T64
            |    `--*E. secula (Barrande 1865) [=Trochoceras secula] T64
            |--Sthenoceras Flower in Flower & Teichert 1957 T64
            |    `--*S. aduncum (Barrande 1866) [=Cyrtoceras aduncum] T64
            `--+--Tubiferoceras Hedström 1917 T64
               |    |--*T. proboscideum (Hedström 1917) [=Phragmoceras proboscideum] T64
               |    `--T. prominens T64
               |         |--T. p. prominens T64
               |         `--T. p. minus T64
               |--+--Pristeroceras Ruedemann 1925 T64
               |  |    `--*P. tumidum Ruedemann 1925 T64
               |  `--Phragmocerina Flower 1948 T64
               |       |--*P. osculum (Ruedemann 1916) [=Gomphoceras osculum] T64
               |       `--P. litchfieldensis T64
               `--Phragmoceras Broderip in Sowerby in Murchison 1839 (see below for synonymy) T64
                    |--*P. arcuatum Sowerby 1839 T64
                    |--P. altidorsatum Foerste 1930 P68
                    |--P. altum Foerste 1936 P68
                    |--P. broderipi Teichert 1964 (see below for synonymy) T64
                    |--P. colliciare Foerste 1930 P68
                    |--P. compressum Sowerby 1839 T64
                    |--P. cuneiforme Foerste 1930 P68
                    |--P. ellipticum P68
                    |--P. farcimen T64
                    |--P. hoyi Whitfield 1878 P68
                    |    |--P. h. hoyi P68
                    |    `--P. h. ‘compressum’ Whitfield 1878 non Sowerby 1839 P68
                    |--P. labiatum Whitfield 1878 P68
                    |--P. lamellosum T64
                    |--P. ontarioense P68
                    |--P. parvum P68
                    |--P. transversale T64
                    `--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

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