Systematics of chigger mite species group nagayoi (Trombiculidae: Neotrombicula)

A.A. Stekolnikov

Parazitologiya, 33(6): 465-481 (1999) (In Russian, English summary).

S U M M A R Y

Revision of the group of chigger mite species, closely related to Neotrombicula nagayoi (Sasa e.a., 1950) is given. The range of N. nagayoi is probably restricted to the Far East. The majority of findings of "Neotrombicula nagayoi" on the territory of the former USSR (Southern Siberia, Kyrgyzstan, Kazakhstan, Caucasus, East Carpathians etc.) should be attributed to N. tianshana Shao et Wen, 1984, previously known only from the terra typica (China, East Tien Shan). N. bondari Kudryashova, 1993 and N. wendai Wen et Wu, 1984 are probable synonyms of N. tianshana. N. orestias Stekolnikov, 1994, previously known only from the terra typica (Turkmenistan, Western Kopetdagh), is for the first time reported from Kyrgyzstan.

Diagnostic characters in the nagayoi group are considered thoroughly, key for species is proposed. Intraspecific variability in N. tianshana throughout almost whole areal of this species known up to the present time is investigated by means of computer methods of multivariate analysis. Character variance in the whole nagayoi group is also investigated. In particular, it is found out, that the geographical variability in N. tianshana is associated mainly with the lengths of setae and legs, while the size of scutum and number of idiosomal setae display first of all an individual variability. At the specific level in the nagayoi group the lengths of setae and legs has also a great importance. Such similarity of intraspecific geographical variability and character variance at the specific level indicate significant closeness of species in the nagayoi group.

Study of correlations between characters in N. tianshana shows isolation of AM from other setae lengths. Previously the similar effect was discovered by the author in the study of intraspecific variability of N. delijani Kudryashova, 1977 and in the study of character variance in the vulgaris group. It is an evidence for the suggestion, that AM able to have a special significance in taxonomy of the genus Neotrombicula.