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. 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. References W. J. Arkell et al., 1957. Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology, Part L. Geological Society of America and University of Kansas Press. Ammonitida families Hildoceratoidea Jurassic ammonites Middle Jurassic first appearances Middle Jurassic extinctions