MORPHOLOGICAL DIVERSITY OF THE FLEAS'' SKELETAL STRUCTURES (SIPHONAPTERA). PART 1: GENERAL CHARACTERISTIC AND THE FEATURES OF THE HEAD
Analysis of a considerable amount of data on the anatomy of 14 structures of the head capsule in 96 genera of fleas (over 90 % of the Siphonaptera genera) has shown that different flea taxa can be described based on 32 universal and specific characters, whose 135 states reflect all known diversity of the flea head morphology. 17 characters can be formulated based on universal terms applicable to any structure. Elementary characters can reflect phylogenetic affinity only in association with specific characters; these 15 characters are formulated based on specific features of the flea morphology and describe interrelations of the skeletal structures (or microstructures of a particular formation). For multi-aspect characteristics of different character states of some structures a concept of a «structural type» is used. Homoplasies of various levels comprise over one-half (53 %) of all character states in the head structure. Character states that reflect phylogenetic closeness of taxa amount for about 22 %.