Heteromorphs are ammonoids forming a conch with detached whorls (open coiling) or non‐
planispiral coiling. Such aberrant forms appeared convergently four times within this extinct …

Externally shelled cephalopods with coiled, planispiral conchs were ecologically successful
for hundreds of millions of years. These animals displayed remarkable morphological …

Snails are model organisms for studying the genetic, molecular, and developmental bases
of left–right asymmetry in Bilateria. However, the development of their typical helicospiral …

Nipponites is a heteromorph ammonoid with a complex and unique morphology that
obscures its mode of life and ethology. The seemingly aberrant shell of this Late Cretaceous …

The biomechanics of uncoiled heteromorph ammonoids with body chambers that terminate
in U-shaped hooks (ancylocones) were investigated with virtual and physical models of …

Stability–maneuverability tradeoffs impose various constraints on aquatic locomotion. The
fossil record houses a massive morphological dataset that documents how organisms have …

'Heteromorph ammonoids' encompass all ammonoid species whose shapes do not conform
to a closely coiled planispiral shell. The term is useful as a broad description for such …

Findings of ammonoid soft tissues are extremely rare compared to the rich fossil record of
ammonoid conchs ranging from the Late Devonian to the Cretaceous/Paleogene boundary …

The heteromorph ammonite Pravitoceras sigmoidale with extremely twisted retroversal hook
and its probable ancestors, Didymoceras awajiense and D. morozumii, occur mainly in the …

Computed tomography has provided a wealth of biological data that now stands beside a
vast, more traditional, morphometric database. By exploiting these two resources, we …