The number of ethnic groups of Madagascar has long been a point of contention and debate. The island of Madagascar is predominantly populated by people broadly classified as belonging to the broader Malagasy ethnic identity. This group is further sub-divided into 18 or more ethnic groups, although divisions are commonly based more on cultural or political factors than actual physiological distinctions. In addition, communities of Indians and Arabs have long been established on the island and have assimilated into local communities to varying degrees, in some places having long since become identified "Malagasy" ethnic groups, and in others maintaining distinct identities and cultural separation. More recent arrivals include Europeans and Chinese immigrants.