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Hildoceratinae
Extinct subfamily of molluscs From Wikipedia, the free encyclopedia
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Hildoceratinae is an extinct subfamily of cephalopods belonging to the family Hildoceratidae. Ammonites of this subfamily had shells with elliptical or quadrate whorl section with keel or tricarinate, bisulcate venter. Ribs were variable, from falcate to strongly angled and from fine to strong. They can be interrupted by spiral groove in midlateral part of the shell. While some species can be smooth, strongly ribbed ones can have tubercules. Microconchs have short lappets that is in its shape similar to the shape of growth lines in spiral midlateral groove.[1]
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Genera
- Hildaites Buckman, 1921
- Orthildaites Buckman, 1923
- Cingolites Sassaroli et Venturi, 2010
- Hildoceras Hyatt, 1867
- Urkutites Géczy, 1967
- Parahildaites Blaison, 1967
- Mercaticeras Buckman, 1913
- Hildaitoides Hillebrandt, 1987
- Atacamiceras Hillebrandt, 1987
- Neolioceratoides Cantaluppi, 1970
Alternative classification
Genera Praemercaticeras Venturi, 1981, Mercaticeras Buckman, 1913, Pseudomercaticeras Merla, 1932, Merlaites Gabilly, 1974, Crassiceras Merla, 1932, and Pseudocrassiceras Rulleau et Jattiot, 2019 have also been classified as belonging to a separate subfamily Mercaticeratinae Guex, 1974.[3]
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Distribution
Members of this subfamily lived from the upper Pliensbachian to upper Toarcian stages of early Jurassic. Distribution has been worldwide.[1][2]
References
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