Marine vertebrates can be divided into marine fish and marine tetrapods. The first tetrapods, or land-dwelling vertebrates, were piscivorous amphibians known as labyrinthodonts. These two nerves only became discrete nerves in the ancestors of amniotes (non-amphibian tetrapods). They gave rise to insectivorous vertebrates and, later, to predators of other tetrapods. The lungs of lungfish are homologous to the lungs of tetrapods. The number of described vertebrate species are split evenly between tetrapods and fish. Terrestrial life in the Permian included diverse plants, fungi, arthropods, and various types of tetrapods. In coelacanths and early tetrapods the bone is relatively large. The neck joint evolved independently in different lineages of early tetrapods. The nostrils in most bony fish differ from those of tetrapods. Older taxa which include late stem tetrapods and early tetrapods are the Labyrinthodontia and Ichthyostegalia. Amniote tetrapods began to dominate and drove most amphibian tetrapods to extinction. This means that the common ancestor of all living tetrapods likely lived in the Carboniferous. A phylogeny of living Osteichthyes, including the tetrapods, is shown in the cladogram. A group of related species such as the tetrapods is called a "clade".