Some vertebrates that are both amniote or anamniote. "Cotylorhynchus" were considered a part of the first wave of amniote diversity. The anuran striatum is homologous to a portion of the amniote basal ganglia. However, establishing their position within the amniote evolutionary tree has proven difficult. Claws appear to have evolved separately in the amphibian and amniote line. Each foot held 5 digits, the pattern seen in their amniote descendants. The former places the remaining lepospondyls into a single clade along the amniote stem. However, "Protoclepsydrops" had primitive vertebrae with tiny neural processes typical of their amniote ancestors. The palate (roof of the mouth) had some similarities with both amniote and non-amniote tetrapods. This would explain the scarcity of egg fossils in the paleozoic amniote fossil record. However, later studies have not consistently placed "Casineria" as an early amniote. The sex of most amniote vertebrates, such as mammals and birds, is determined genetically. "Casineria" pushes back the origin of amniote lineages much earlier than was previously assumed. Amniote tetrapods began to dominate and drove most amphibian tetrapods to extinction.