Phylogeny
The genus Hamites is of particular interest to palaeontologists because the species included in the genus span a wide range of morphologies including ones apparently similar to several more derived groups of heteromorph ammonites. The genus rapidly diversified during the Albian into a number of morphologically distinct lineages that seem to have given rise to at least three other families of heteromorphs, the Baculitidae, Turrilitidae, and Scaphitidae. The lineage that gave rise to the helical Turrilitidae, for example, had a shell that initially grew as a helix before straightening out; the Turrilitidae thus appear to have been derived from neotenic Hamites that retained the helically-coiled juvenile morphology of Hamites into adulthood.
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