Leymeriellidae

Leymeriellidae is a family of Lower Cretaceous ammonites comprising rather small forms distinguished from Hoplitidae by their flattened and grooved ribs and virtual absence of umbilical tubercles. The family is derived from the Desmoceratidae. Leymeriella schrammeni anterior has evolved from Desmoceras keilhacki keilhacki.[1]

Leymeriellidae Temporal range: Albian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Order:	Ammonitida
Suborder:	Ammonitina
Superfamily:	Acanthoceratoidea
Family:	Leymeriellidae Breistroffer, 1951
Genera
See text

Taxonomic position

Leymeriellidae are currently regarded is belonging to the Acanthoceratoidea according to W. J. Kennedy et al (1980). The previous placement was in the Hoplitoidea according to W.J. Arkell et al (1957) in the Treatise on Invertebrate Paleontology, Part L.[2]

Genera

Leymeriellidae includes the following genera:

Leymeriella Jacob 1907. Shell evolute, venter flat to sulcate. Ribs single, wide spaced, grooved in outer part. Lower Albian to Middle Albian

Proleymeriella Breistroffer 1947. Shell moderately evolute, whorl section oval with constrictions present throughout. Ribs single, strong, form chevrons on a narrowly rounded to acute venter. Lower Albian

Epileymeriella Breistroffer 1947. Differs from Leymeriella in that the ribs branch from weak umbilical bullae. Lower Albian

References

1. BERT, D. Les ammonites du niveau Paquier (Albien basal, Crétacé inférieur) du Sud-Est de la France. Fossiles, 2012, 12: 4-25.
2. Arkell, W.J.; Kummel, B.; Wright, C.W. (1957). Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Lawrence, Kansas: Geological Society of America and University of Kansas Press.

• W.J. Kennedy et al. 1980. Albian and Cenomanian ammonites from the island of Bornholm (Denmark). Bull. geol. Soc. Denmark 29:203-244
• Leymeriellidae Paleobiology Database.