Wallace Line Line. Wallace Line The Wallace Line or Wallace's Line is a faunal boundary line drawn in 1859 by the British naturalist Alfred Russel Wallace and named by English biologist Thomas Henry Huxley, that separates the ecozones of Asia and Wallacea, a transitional zone between Asia and Australia. West of the line are found organisms related to Asiatic species; to the east, a mixture of species of Asian and Australian origin is present. Wallace noticed this clear division during his travels through the East Indies in the 19th century. The line runs through Indonesia, between Borneo and Sulawesi (Celebes), and through
Mainland Southeast Asia Thailand, Laos, Cambodia and Vietnam). To the south it forms the Malay Peninsula, on which are located Southern Thailand and Peninsular Malaysia; the latter is variably considered part of Mainland Southeast Asia or separately as part of Maritime Southeast Asia. Mainland Southeast Asia contrasts with Maritime Southeast Asia, mainly through the division of largely land-based lifestyles in Indochina and the sea-based lifestyles of the Malay and Philippine archipelagos, as well as the dividing line between the Austroasiatic, Tai–Kadai, Sino-Tibetan languages (spoken in Mainland Southeast Asia) and Austronesian languages (spoken in Maritime Southeast Asia). The countries of mainland Southeast Asia received