Kingdom Animalia Class Cephalopoda Suborder Ammonitina Rank Family | Phylum Mollusca Order Ammonitida Superfamily Acanthoceratoidea | |
Similar Acanthoceratoidea, Hoplitidae, Collignoniceratidae, Desmoceratidae, Desmocerataceae | ||
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 suggested to be derived from the Desmoceratidae.
Contents
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.
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 contrictions 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