Notiomastodon Notiomastodon Notiomastodon is an extinct proboscidean genus of gomphothere (a distant relative to modern Elephants) endemic to South America from the Pleistocene to the Holocene living for approximately . Proboscideans in South America were first described by Georges Cuvier in 1806 but he failed to give them specific names beyond "Mastodon". It was Fischer in 1814 who gave the “"mastodonte des cordillères"” specimen the first specific name ""Mastotherium hyodon"". In 1824, Cuvier gave the specific names of ""Mastodon andium"" to the ""mastodonte des cordillères"" specimen, and ""Mastodon humboldtii"" to the ""mastodonte humboldien"". Due to the Principle of Priority, this means
Extinct comet the Hubble search for transition comets. Comets such as C/2001 OG108 (LONEOS) may represent the transition between extinct comets and typical Halley-type comets (periods of 20–200 years) or long period comets (periods longer than 200 years). Minor planets of the group of damocloids have been studied as possible extinct cometary candidates due to the similarity of their orbital parameters with those of Halley-type comets. Dormant comets are those within which volatiles may be sealed, but which have inactive surfaces. For example, 14827 Hypnos may be the nucleus of an extinct comet that is covered by a crust several centimeters thick