Lytoceratinae

Lytoceratinae Temporal range: Pliensbachian - Cenomanian PreꞒ Ꞓ O S D C P T J K Pg N
Fossil shells of Protetragonites obliquestrangulatum from Alpes-de-Haute-Provence, on display at Galerie de paléontologie et d'anatomie comparée in Paris
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	†Ammonoidea
Order:	†Ammonitida
Family:	†Lytoceratidae
Subfamily:	†Lytoceratinae Neumayr,1875
Genera
[1] Ammonoceratites Bowditch, 1822 Argonauticeras Anderson, 1938 Wiedmann, 1962 Eulytoceras Spath, 1927 Hemilytoceras Spath, 1927 Lytoceras Suess, 1865 Spath, 1927 Uhlig, 1883 Protetragonites Hyatt, 1900 Spath, 1927 Ptycholytoceras

Lytoceratinae is a subfamily of ammonoid cephalopods that make up part of the family Lytoceratidae.

Description[]

They are characterized by shells in which the whorls bear growth lines or lamellar folds, or both, commonly corresponding to constrictions in the internal mold. The external suture, that not lying against the previous whorl, has two lateral lobes (per side), the first being much larger. The internal lobe, which lies against the previous whorl, has a cruciform dorsal lobe.

Fossil range[]

Lytoceratinae has a long stratigraphic and temporal range (196.5 to 89.3 Ma ^[1]) extending from the Early Jurassic Pliensbachian to the Late Cretaceous Cenomanian, although most included genera have much shorter ranges.

Lytoceras, the type genus, ranges from Early Jurassic to early late Cretaceous.^[2]

Ptycholytoceras is confined to the Early Jurassic Toarcian, while Hemilytoceras is present in the Late Jurassic Oxfordian-Tithonian.^[2]

Five genera are known from the Early Cretaceous. and from the Valanginian (Petrolytoceras may extend back to the Tithonian), Eulytoceras from the Hauterivian - Barremian, Argonauticeras and from the Aptian - Albian. Ammonoceratites ranges from the Aptian to the Cenomanian.^[2]

References[]

• W.J.Arkell, B.Kummel,& C.W.Wright 1957. Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology, Part L Ammonoidea. R.C.Moore, (ed).

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