👉 The term "xiphodontidae" refers to a group of extinct marine fish that lived during the Paleozoic era (around 350 million years ago) and are known for their distinctive flattened heads, which resemble those of ancient humans. These fish were classified as part of the Osteichthyes family, which includes modern-day tetrapods such as humans and other mammals. The xiphodontidae had a variety of adaptations that allowed them to survive in aquatic environments