Neha Patil (Editor)

Forresteria

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Kingdom
  
Animalia

Class
  
Cephalopoda

Order
  
†Ammonitida

Rank
  
Genus

Phylum
  
Mollusca

Subclass
  
†Ammonoidea

Family
  
†Collignoniceratidae

Similar
  
Ammonites, Gleviceras, Fagesia, Dipoloceras, Fuciniceras

Forresteria is an extinct genus of cephalopod belonging to the subclass Ammonoidea that flourished during the late Turonian and early Coniacian of the Late Cretaceous. and were global in extent. Forresteria alluaudi and Forresteria hobsoni are considered marker fossils for the lower Coniacian in the American West.

Contents

Description

Although the whorl section and ornament of Forresteria are variable, it is easily distinguished from Barroisiceras by the presence of mid-lateral tubercles on the inner whorls, which later disappear or fuse with either umbilical or ventrolateral tubercles. Four subgenera are recognized

  • F.(Forresteria): Whorl section moderately to very inflaced. Mid-lateral tubercles fuse with ventrolateral.
  • F.(Reesideoceras): Whorl section less inflated than with F.(Forresteria). Mid-lateral tubercles fuse with the umbilical. Keel disappears on outer whorl leaving venter flat or concave, bordered by ventrolateral clavi.
  • F. (Harleites): Shell compressed, with high keel and steep umbilical wall. Early whorls have weak umbilical, strong mid-lateral, and fine, feeble ventrolater tubercles.
  • F.(Zumpangoceras): Inclusion doubtful. Known only from crushed specimens from Mexico. Mid lateral tubercle strengthens with age.

    • Species

    species in Forresteria include:

  • Forresteria alluaudi (Boule, Lemoine and Thévenin, 1907)
  • Forresteria brancoi
  • Forresteria hobsoni
  • Forresteria neo-mexica
  • Forresteria petrocoriensis (Coquand, 1859)
  • Forresteria peruana


    • Forresteria was named for Robert Forrester of Salt Lake City, Utah.

    References

    Forresteria Wikipedia
    (Text) CC BY-SA