Polyptychitinae

Polyptychites polyptychus, from Ammonit.ru.

Belongs within: Polyptychitidae.

The Polyptychitinae are a group of ammonites known from the Lower Valanginian to Lower Hauterivian of the Lower Cretaceous (Wright et al. 1996).

Characters (from Wright et al. 1996): Very variable. In earlier groups rather evolute forms dominant, ranging from moderately inflated to very depressed, cadicone, or sphaerocone; macroconchs medium-sized, mildly to strongly variocostate. Later forms involute to evolute but on the whole only moderately inflated and large to very large, so that microconchs may be homeomorphic with earlier macroconchs. Ribbing variable; inner whorls may be smooth and constricted up to 15 mm diameter; middle and outer whorls generally with elevated or bullate primary ribs branching in simple bundles, irregularly polyschizotomously or virgatotomously or bidichotomously.

<==PolyptychitinaeWCH96
    |--Homolsomites Crickmay 1930 [incl. Wellsia Imlay 1957]WCH96
    |    |--H. stantoni (McLellan 1927) [=Holcodiscus stantoni; incl. *Hom. poecilotomus Crickmay 1930]WCH96
    |    |--H. bojarkensisWCH96
    |    |--H. oregonensis (Anderson 1938) [=Dichotomites oregonensis, *Wellsia oregonensis]WCH96
    |    `--H. pechorensisR81
    |--Dichotomites Koenen 1909 [=Bidichotomites Sazonov 1951]WCH96
    |    |  i. s.: D. bidichotomoidesWCH96
    |    |         D. crassusWCH96
    |    |         D. triptychoidesWCH96
    |    |--D. (Dichotomites)WCH96
    |    |    |--*D. (D.) bidichotomus (Orbigny 1841) [=Ammonites bidichotomus]WCH96
    |    |    `--D. (D.) grotrianiWCH96
    |    `--D. (Prodichotomites Kemper 1971) (see below for synonymy)WCH96
    |         |--D. (*P.) polytomus (Koenen 1902) [=Polyptychites polytomus]WCH96
    |         |--*Ringnesiceras’ amundense Kemper & Jeletzky 1979WCH96
    |         |--‘Ringnesiceras (*Elleficeras)’ ellefense Kemper & Jeletzky 1979WCH96
    |         `--D. (P.) hollwedensisR81
    `--Polyptychites Pavlow 1892WCH96
         |  i. s.: P. clarkiWCH96
         |         P. hapkeiWCH96
         |         P. multicostatusWCH96
         |         P. pavlowiWCH96
         |         P. sphaeroidalisR81
         |--P. (Polyptychites) [incl. Amundiptychites Kemper & Jeletzky 1979]WCH96
         |    |--*P. (P.) polyptychus (Keyserling 1846) [=Ammonites polyptychus]WCH96
         |    |--P. (P.) euomphalusWCH96
         |    |--P. (P.) keyserlingiWCH96
         |    `--*Amundiptychites’ sverdrupi Kemper & Jeletzky 1979WCH96
         |--P. (Astieriptychites Bodylevskii 1960)WCH96
         |    `--P. (*A.) astieriptychus (Bodylevskii 1960) [=*Astieriptychus astieriptychus]WCH96
         |--P. (Euryptychites Pavlow 1914) (see below for synonymy)WCH96
         |    |--P. (*E.) latissimus (Neumayr & Uhlig 1881) [=Olcostephanus latissimus]WCH96
         |    |--‘Euryptychites’ pavlovi Voronets 1962 [=*Pseudoeuryptychites pavlovi]WCH96
         |    |--P. sphaericus Koenen 1902 [=*Hollwediceras sphaericum]WCH96
         |    `--P. triplodiptychus (Pavlow 1892) (see below for synonymy)WCH96
         |--P. (Primitiviptychites Klimova 1983)WCH96
         |    `--P. (*P.) rectangulatum (Bogolovskii 1902) [=Olcostephanus rectangulatum]WCH96
         |--P. (Siberiptychites Kemper & Jeletzky in Kemper 1977WCH96
         |    `--P. (*S.) stubendorffi (Schmidt 1872) [=Ammonites stubendorffi]WCH96
         `--P. (Siberites Klimova in Gol’bert & Klimova 1983)WCH96
              `--P. (*S.) savitzkii (Klimova in Gol’bert & Klimova 1983) [=*Siberites savitzkii]WCH96

Dichotomites (Prodichotomites Kemper 1971) [incl. Elleficeras Kemper & Jeletzky 1979, Ringnesiceras Kemper & Jeletzky 1979]WCH96

Polyptychites triplodiptychus (Pavlow 1892) [=Olcostephanus (Polyptychites) triplodiptychus, *Palaeodichotomites triplodiptychus]WCH96

Polyptychites (Euryptychites Pavlow 1914) [incl. Hollwediceras Jeletzky & Kemper 1988, Palaeodichotomites Bogomolov 1989, Pseudoeuryptychites Jeletzky 1986]WCH96

*Type species of generic name indicated

References

[R81] Rawson, P. F. 1981. Early Cretaceous ammonite biostratigraphy and biogeography. In: House, M. R., & J. R. Senior (eds) The Ammonoidea: The evolution, classification, mode of life and geological usefulness of a major fossil group pp. 499–529. Academic Press.

[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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