''Ermoceras'' is a genus of ammonite belonging to the Thomboceratidae family of the Middle Jurassic ( u Baj) found in deposites of central Arabia, Sinai, and Algeria with strong primary and secondary ribs and a single row of lateral tubercles; described as having a deep ventral groove Arkell et al 1957, Mesozoic Ammonoidea,

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and co ...

, Part L, Ammonoidea ''Telermoceras'', with low, depressed whorls, and ''Kosmermoceras'' with high, compressed whorls are considered subgenera of ''Ermoceras'' Both are from the same time and region. ''Telermoceras'' has coarse secondary ribs and a deep umbilicus surrounded by large tubercles or spines. ''Kosmermoceras''has fine sharp to coarse ribbing and a flattish venter ''Ermoceras'' ''s.l.'' is derived from '' Arkelloceras''. Westermann (1965)Westernamm ,G. E. G. 1965.Septal and Sutural Patterns in Evolution and Taxonomy of Thamboceratidae and Clydoniceratidae (M Jurassic Ammonitina).Jour of Paleontology 39(5)864-874, Sept tentatively placed ''Ermoceras'' in the Thamboceratidae, based on sutural morphology, removing it from the

Stephanoceratidae Stephanoceratidae is a family of planulate and coronate ammonites within the Stephanoceratoidea.Arkell, Kummel, and Wright, 1957. Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Shells are evolute so that all whorl ...

where it was previously included.

References

Jurassic ammonites Jurassic animals of Africa Bajocian life Ammonitida genera Stephanoceratoidea {{ammonitina-stub