Phalacrocnemidae

Phalacrocnemidae is a family of extinct acipenseriform fish that lived during the Early Cretaceous period. These fish are known from fossil remains found in Europe, particularly in the Lower Saxony Basin of Germany. The family contains a single genus, Phalacrocnemus, and two described species, Phalacrocnemus radiatus and Phalacrocnemus longimanus.

Phalacrocnemids were relatively large fish, with fossil specimens reaching lengths of over a meter. They possessed a morphology consistent with other basal sturgeon relatives, characterized by a heterocercal tail fin and ganoid scales. Their elongated bodies and prominent snouts suggest a benthic or demersal lifestyle, likely foraging for invertebrates on the seafloor. The presence of specialized cranial bones and dentition indicates a diet of soft-bodied prey.

The discovery of Phalacrocnemidae provides valuable insights into the early evolution and diversification of the Acipenseriformes, the order that includes modern-day sturgeons and paddlefishes. Their existence in the Cretaceous highlights the long evolutionary history of this lineage and their adaptation to marine and possibly brackish water environments. The fossil record of Phalacrocnemidae is limited, but their presence fills an important gap in our understanding of ancient fish fauna.