forynges

Forynges is an extinct genus of ammonoid cephalopods that lived during the Late Jurassic period, approximately 150 million years ago. The name derives from the Greek word for “spindle”, reflecting the characteristic spindle‑shaped, ribbed shells that are commonly found in fossil form. Fossil evidence suggests that forynges were nektonic predators, feeding on smaller marine organisms and likely employing a rapid, jet‑powered mode of locomotion similar to modern cephalopods.

Morphologically, the shells of forynges are typically planispiral with a tightly coiled whorl, an external siphuncle positioned ventrally, and distinct, alternating costae that may have interacted with the surrounding water to influence hydrodynamic efficiency. The aperture of the shell is relatively narrow, hinting at a beak‑like feeding structure evolved for grasping rapid prey. In many specimens, the inner chambers of the shell exhibit a tight lattice of laminae, indicating adaptations for buoyancy control in varying water depths.

Discovery sites for forynges are primarily located in the sedimentary basins of Europe and North Africa, with notable finds in the Paris Basin, the Dorset coast of England, and the Chalk Group in Eastern Europe. The distribution suggests that forynges inhabited warm, shallow epicontinental seas, thriving during a time of significant ecological diversification in marine arthropods and vertebrates.

Paleontologists use the distinct ribbing patterns and shell microstructure of forynges to identify species, and the genus is often cited in discussions regarding ammonoid evolutionary trends, including rapid shell growth rates and morphological innovations that preceded the diversification of later Jurassic cephalopods. (Jones, 2005; Martinez & Lee, 2012).