Squid-like creatures that lived more than 60 million years ago could swim rapidly, supporting claims that they swam freely rather than just near the ocean bottom.

Credit: Biol. Lett.

Fossils of belemnitid marine animals from 200 million to 66 million years ago are common, but Christian Klug at the University of Zurich in Switzerland and his colleagues report three Acanthoteuthis belemnitid specimens from Germany with soft tissue components that have never been seen in such fossils before (reconstruction pictured). The tissue included fossil fins and organs called statocysts, which detect the direction and acceleration of movement through water. These suggest that the animals, which are relatives of modern squid, were fast-swimming predators.

This and other fossil evidence suggests a free-swimming, rather than an ocean-bottom-dwelling, lifestyle for belemnitids.

Biol. Lett. 12, 20150877 (2016)