We report the discovery of a 2n = 30 karyotype race in the Australian diplodactyline gecko Diplodactylus tessellatus. The new chromosome race has four large metacentric pairs and 11 acrocentric pairs, a unique complement among diplodactyline geckos. Three karyotypic races are now known from D. tessellatus. One retains the ancestral Diplodactylus 2n = 38 all-acrocentric karyotype, whereas the 2n = 30 and the 2n = 28 races appear to have been derived from a 2n = 38 karyotype via fusion of four or five pairs of acrocentrics. Diplodactylus tessellatus and its relatives in the Diplodactylus vittatus species complex are now known to possess five different diploid number complements; 2n = 38, 36, 34, 30, and 28, more variation than any other diplodactyline gecko genus or species group for which data are available.