Sonniniidae Explained

Sonniniidae is a diverse family of Middle Jurassic ammonites ranging from those with stout evolute shells to those whose shells are sharply rimmed, oxyconic. The keel, which runs along the middle of the venter, is typically hollow. Sutures vary from simple to complex. The aptychus is shiny with coarse folds (Cornaptychus).

Sonniniidae are included in the superfamily Hildoceratoidea. Most lived during the middle Bajocian stage. Distribution is worldwide except for boreal.

Taxonomy

Sonniniidae is divided into subfamilies with 10 genera.^[1]

• Sonniniidae Buckman, 1892
  • Sonniniinae Buckman, 1892
    • Dorsetensia
    • Pseudoshirbuirnia Dietz, 2005
    • Shirbuirnia
    • Sonninia
    • Sonninites Buckman, 1923
  • Witchelliinae Callomon and Chandler, 2006
    • Asthenoceras
    • Fontannesia
    • Guhsania
    • Newmarracarroceras Hall, 1989
    • Witchellia

Distribution

Argentina, Canada, China, Germany, Hungary, Morocco, Saudi Arabia, Spain, the United Kingdom.^[2]

References

• W. J. Arkell et al., 1957. Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology, Part L. Geological Society of America and University of Kansas Press.

Notes and References

1. http://www.fossilworks.org/cgi-bin/bridge.pl?a=taxonInfo&taxon_no=257983 Sonniniidae entry
2. Web site: Paleobiology Database. 2014-05-28 .