Prehistoric anchovies: the terror of the seas . This appears to reveal the fossil remains of two fish that sported fanged teeth on their lower jaws and a huge saber tooth on top. These teeth are so unusual that scientists have baptized one of them as Monosmilus chureloides , which comes from the Greek words monos (unique) and smil’e (knife) and chureloides, which refers to a demon with large teeth from folklore of various South Asian countries, including Pakistan, where the fossil was unearthed.
The new study reports the discovery of these close predatory cousins of modern anchovies, which were much larger and with this impressive set of teeth.
When mass extinction events occur, the species that survive adapt and change, generating a sudden increase in anatomical transformations . It is likely that precisely this happened to these fish during the final Cretaceous extinction.
The two fossils of the genus Clupeiform, Clupeopsis and Monosmilus found in Belgium and Pakistan, respectively, were adapted to be larger with lower jaw fangs and a single upper saber tooth.
Clupeopsis straeleni , found in Belgium, lived during the early Eocene epoch, about 50 million years ago. It was about 11 inches long.
Monosmilus chureloides , found in Pakistan, lived about 45 million years ago, during the Middle Eocene, in the shallow seas of what is now Pakistan. It was 1 meter long.
This adaptation of these particular now extinct carnivorous fish is an example of remarkable trophic innovation by a group whose modern representatives feed on plankton .
Referencia: Alessio Capobianco et al. Large-bodied sabre-toothed anchovies reveal unanticipated ecological diversity in early Palaeogene teleosts, Royal Society Open Science (2020). DOI: 10.1098/rsos.192260
