A Redescription of Andreacarus petersi Radford, 1953 (Acarina Laelaptidae) and Clarification of the Status of This Genus within the Subfamily Laelaptinae

Abstract

The male and female of Andreacarus petersi Radford, 1953, are redescribed, and the characters that the authors regard as important in placing this genus in the subfamily Laelaptinae are given. The hosts for all the specimens examined were giant rats of the genus Cricetomys, but insect hosts were not mentioned. Therefore, it would appear that the real parasitic relation may be between the mites and the rodents rather than the mites and an insect as indicated by Radford in the original description. The genus and species of mite, Andreacarus petersi, was first described by Radford (1953) from males and females taken by Dr. W. Peters on Hemimerus talpoides (a Dermapteron parasite of the giant rat Cricetomys gambianus) collected at Kabala, Sierra Leone, West Africa, 25 April 1950 by Dr. D. Elton. Radford placed this new genus in the subfamily Laelaptinae. Taufflieb (1956) recorded A. petersi from Brazzaville and Mayombe, Middle Congo, off Cricetomys gambianus. In this paper he stated that the mites were found separately in the hair of the rodent, and that, in one instance, specimens of Hemimerus were absent. He also described a new species of Andreacarus, A. zumpti, from specimens collected at the same time on the same host as his specimens of A. petersi. Zumpt (1961) placed the genus Andreacarus in the subfamily Laelaptinae. He doubted that the mites actually parasitize the rodent and believed that they more likely feed on Hemimerus. Because of the lack of detail in the figures, the omission of certain key features in the original description, and the association of A. petersi with an insect, Andreacarus has been ignored or incorrectly placed in two recent revisions of this group. Strandtmann and Wharton (1958) omitted this genus entirely, and Tipton (1960), apparently basing his opinion on information in the original description, stated that it cannot be considered in the subfamily Laelaptinae. Recently the authors each received material, one lot from the Congo and another from Nigeria (complete data given below), which closely resembled A. petersi as described and figured by Radford. A positive identification was made through the courtesy of Dr. G. Owen Evans of the British Museum (N.H.), London, who compared our Congo specimens with the type of A. petersi and concluded that they were conspecific. The hosts listed for these mites were rodents of the genus Cricetomys and no mention was made of an insect. Therefore, it would appear that the real parasitic relation is between the mites and the rodents as suggested by Tipton (op. cit.) and implied by Taufflieb (op. cit.). After careful examination of this material we consider Andreacarus to be a typical member of the subfamily Laelaptinae. The characteristics, listed by Tipton (op. cit.), that dictate placement of Andreacarus in this subfamily are as follows: body well sclerotized, an unadorned membranous tectum, the female chelae are toothed, the movable arm of the male chelae is elongate and fused to a greatly elongated spermodactyl, six rows of teeth with only one or two teeth per row in the deutosternal groove, genitoventral plate expanded posteriorly, peritremalia present, but separate from parapodal plates, peritremata extend to Received for publication 11 June 1962. * Scientist, U. S. Department of Health, Education, and Welfare, Public Health Service, National Institutes of Health, National Institute of Allergy and Infectious Diseases, Rocky Mountain Laboratory, Hamilton, Montana. t Lt. Colonel Keegan is assigned to the Entomology Branch, Department of Preventive Medicine, Medical Field Service School, Brooke Army Medical Center, Fort Sam Houston, Texas.