Complex sentence: Another two genera, "Steropodon" and "Teinolophos", were originally thought to belong to Ornithorhynchidae, however they were both placed into a new family, Steropodontidae.
Split into simpler sentences: Another two genera, "Steropodon" and "Teinolophos", were originally thought to belong to Ornithorhynchidae. However, they were both placed into a new family, Steropodontidae.