NEO-SEX CHROMOSOME. “Chromosomes newly subjected to a sex chromosomal inheritance pattern in this way are called ‘neo-sex chromosomes’. A classic example is the Drosophila miranda Y-autosome fusion, which involves the homologue of the third chromosome of its close relative D. pseudoobscura.”
http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html