who discovered the first skull of a fossil ape on rusinga island
Rusinga Island All the species of Proconsul were among the 64 and all were given the name africanus, although many were reclassified into nyanzae, major and heseloni later. Mary Leakey discovered the first complete skull of Proconsul, then considered a "stem hominoid", in 1948. Excavation of the fossil was completed by Louis' native assistant, Heselon Mukiri (whence Walker's 1993 name heseloni). Many thousands of fossils are now known from five major sites, with abundant hominoids including an almost complete skeleton of a second species of Proconsul, as well as Nyanzapithecus, Limnopithecus, Dendropithecus and Micropithecus,[5] all of which show arboreal rather than terrestrial adaptations. The first true monkeys do not appear until around 15 million years ago, so it is widely supposed that the diverse Early Miocene African catarrhines like those found on Rusinga filled that adaptive niche. The phylogenetic position of these primates has been debated. It has been theorized that Proconsul is a stem catarrhine and therefore ancestral to both Cercopithecids (Old World monkeys) and hominids (great apes and humans), rather than a stem hominoid.[6]
Dimetrodon Dimetrodon (/daɪˈmiːtrədɒn/ ( listen)[1] or /daɪˈmɛtrədɒn/,[2] meaning "two measures of teeth") is an extinct genus of synapsids that lived during the Cisuralian (Early Permian), around 295–272 million years ago (Ma).[3][4][5] It is a member of the family Sphenacodontidae. The most prominent feature of Dimetrodon is the large neural spine sail on its back formed by elongated spines extending from the vertebrae. It walked on four legs and had a tall, curved skull with large teeth of different sizes set along the jaws. Most fossils have been found in the southwestern United States, the majority coming from a geological deposit called the Red Beds of Texas and Oklahoma. More recently, fossils have been found in Germany. Over a dozen species have been named since the genus was first described in 1878.