Three species of eriophyid mites were found coexisting on leaves of mango trees in Tapu, Chiai, which is located in southwestern Taiwan. These mites were identified as Cisaberoptus kenyae Keifer, Spinacus pagonis Keifer (short setae type), and Spinacus longinquus sp. nov. (long setae type). Since the latter 2 species are similar to each other, morphometric analyses were used to discriminate between them. Distances between homologous structures (microtubercles) were measured and the ratio of these variables were calculated. Approaches used included cluster analyses, the principal component analysis, the minimum spanning tree, Burnaby's method for size adjustment, and non-metric multidimensional scaling. Males are distinguishable from females by size variables. The long setae type is separate from the short setae type by shape variables. However, the same variable could not be used to distinguish differences in sex and age of these 2 types. The major differences between the 2 Spinacus species are the length of dorsal setae (S. pagonis = 6-7, S. longinquus = 11-18), the distance between the 3rd coxal tubercles (S. pagonis = 18-27, S. longinquus = 19-23), and the distance between the 3rd ventral tubercles (S. pagonis = 12-15, S. longinquus = 11-15). This new species, S. longinquus was confirmed by the results of the above analyses.
Morphometric, Eriophyid mites, Homolog, New species, Taiwan
