Mastodon have been no reports of currently recognized "Mammut" species outside of North America according to Paleobiology database (which does not recognize "M. borsoni"). However, the status of "Mammut" or "Zygolophodon borsoni" in the literature appears equivocal. "Mammut" is a genus of the extinct family Mammutidae, related to the proboscidean family Elephantidae (mammoths and elephants), from which it originally diverged approximately 27 million years ago. The following cladogram shows the placement of the American mastodon among other proboscideans, based on hyoid characteristics: Over the years, several fossils from localities in North America, Africa and Asia have been attributed to "Mammut", but
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