Geisonoceratidae

Belongs within: Orthoceratida.

The Geisonoceratidae were a Middle Ordovician to Middle Devonian family of orthocerid cephalopods distinguished by their siphucular structure.

Characters (from Sweet 1964): Orthoconic or cyrtoconic conchs with subcircular cross-section; orthochoanitic to suborthochoanitic siphuncle occupied by endosiphuncular annuli restricted to septal foramen or growing anteriorly against connecting rings; endosiphuncular annuli in advanced species fusing with those of adjacent segments to form continuous siphuncular lining.

<==Geisonoceratidae
    |--Columenoceras Barskov 1960S64
    |    `--*C. columen (Barrande 1874) [=Orthoceras columen]S64
    |--Harrisoceras Flower 1939S64
    |    `--*H. orthoceroides Flower 1939S64
    |--Joachimoceras Barskov 1960S64
    |    `--*J. micromegas (Barrande 1874) [=Orthoceras micromegas]S64
    |--Jonesoceras Barskov 1960S64
    |    `--*J. jonesi (Barrande 1874) [=Orthoceras jonesi]S64
    |--Mesnaquaceras Flower 1955S64
    |    `--*M. curviseptatum Flower 1955S64
    |--Temperoceras Barskov 1960S64
    |    |--*T. temperans (Barrande 1874) [=Orthoceras temperans]S64
    |    `--T. caucasium Zhuravleva 1978K93
    |--Virgoceras Flower 1939S64
    |    `--*V. palemon (Barrande 1870) [=Orthoceras palemon]S64
    |--Geisonocerina Foerste 1935S64
    |    |--*G. wauwatosense (Whitfield 1882) [=Orthoceras wauwatosense]S64
    |    `--G. landerensis Foerste 1935P68
    |--Protokionoceras Grabau & Shimer 1910S64
    |    |--*P. medullare (Hall 1868) [=Orthoceras medullare]S64
    |    |--P. oneidaenseP68
    |    `--P. perstrigatum Foerste 1936P68
    |--Striacoceras Flower 1936S64
    |    `--*S. typum (Saemann 1854) [=Orthoceras typum]S64
    |         |--S. t. typumS64
    |         `--S. t. betaS64
    `--Geisonoceras Hyatt 1884S64
         |--*G. rivale (Barrande 1866) [=Orthoceras rivale]S64
         |--G. bipellisT64
         |--G. clavatumT64
         |--G. rochesterense Foerste 1928P68
         |--G. scabridumS64
         `--G. teichertiT64

*Type species of generic name indicated

References

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

[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—Orthocerida. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt K. Mollusca 3. Cephalopoda—General Features—Endoceratoidea—Actinoceratoidea—Nautiloidea—Bactritoidea pp. K216–K261. The Geological Society of America and the University of Kansas Press.

[T64] Teichert, C. 1964. Morphology of hard parts. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt K. Mollusca 3. Cephalopoda—General Features—Endoceratoidea—Actinoceratoidea—Nautiloidea—Bactritoidea pp. K13–K53. The Geological Society of America and the University of Kansas Press.