Abstract: The aim of this paper is to determine the taxonomic position of medical gamasid mites and further explore the difference between numerical taxonomy and the traditional morphological taxonomy for medical gamasid mites. Based on hierarchical clustering analysis and principal component analysis (PCA), the numerical taxonomy on 57 species of medical gamasid mites was carried on. The results of clustering analysis based on squared Euclidean distance showed that the 57 species of medical gamasid mites were divided into the five families in the dendrogram: Laelapidae, Parasitidae, Dermanyssidae, Hirstionyssidae and Aceosejidae. Differed from the traditional taxonomic views, Hirstionyssus and Echinonyssus were separated from Laelapidae and formed an independent family-Hirstionyssidae; Ornithonyssus bacoti was assigned to Dermanyssidae instead of Macronyssidae. The classifications of the remained species were the same as those in the traditional taxonomy. The results of PCA showed that the cumulative variance of the front 14 principal components reached 85.681%. The results in the three-dimension ordination of PCA were consistent with the results in the hierarchical clustering analysis. The results of clustering analysis were consistent with those of traditional morphological taxonomy for medical gamasid mites. It was so concluded that the results of numerical taxonomy could objectively reflect the taxonomic position and affinity between medical gamasid mites.

Key words: Acari, medical gamasid mites, numerical taxonomy, hierarchical clustering, principal component analysis