<Tr> <Th_colspan="2"> Related ethnic groups </Th> </Tr> <Tr> <Td_colspan="2"> see List of Indigenous Australian group names </Td> </Tr> <P> Indigenous Australians are the Aboriginal and Torres Strait Islander people of Australia, descended from groups that existed in Australia and surrounding islands prior to British colonisation . The time of arrival of the first Indigenous Australians is a matter of debate among researchers . The earliest definitely human remains found in Australia are those of Mungo Man LM3 and Mungo Lady, which have been dated to around 50,000 years BP . Recent archaeological evidence from the analysis of charcoal and artifacts revealing human use has pushed this date back further to around 65,000 B.P. Luminescence dating has suggested habitation in Arnhem Land as far back as 60,000 years BP . Genetic research has inferred a date of habitation as early as 80,000 years BP . Other estimates have ranged up to 100,000 years and 125,000 years ago . </P> <P> Although there are a number of commonalities between indigenous Aboriginal Australians, there is also a great diversity among different Indigenous communities and societies in Australia, each with its own mixture of cultures, customs and languages . In present - day Australia these groups are further divided into local communities . At the time of initial European settlement, over 250 languages were spoken; it is currently estimated that 120 to 145 of these remain in use, but only 13 of these are not considered endangered . Aboriginal people today mostly speak English, with Aboriginal phrases and words being added to create Australian Aboriginal English (which also has a tangible influence of Indigenous languages in the phonology and grammatical structure). The population of Indigenous Australians at the time of permanent European settlement is contentious and has been estimated at between 318,000 and 1,000,000 with the distribution being similar to that of the current Australian population, the majority living in the south - east, centred along the Murray River . A population collapse following European settlement, and a smallpox epidemic spreading three years after the arrival of Europeans may have caused a massive and early depopulation . </P>

When did the aboriginal tribes arrive in australia
find me the text answering this question