Notes on Steatonyssus Kolenati in Korea with description of a new species (Acarina: Macronyssidae).

The three species of the genus Steatonyssus now known from the Korean Peninsula are described in all parasitic stages. These are S. heteroventralis sp. n., S. spinosus Willmann, and S. superans Zemskaya. The male of S. superans has plate divisions of a type otherwise known only in the monotypic subgenus Steatonyssella. S. superans is retained in the subgenus Steatonyssus, and the two subgenera are rediagnosed giving more emphasis to characters of the females. Steatonyssus is the largest genus in the Macronyssidae and has been recorded from every major zoogeographic region except the Australian. Till and Evans (1964) included 26 species in their revision (S. superans given in a footnote and redescribed by Evans and Till, 1964). Radovsky (1966) recognized 29 species, and Radovsky (in press) has described one additional new species. All of the confirmed hosts are bats. Previously, only two species of Steatonyssus had been found clearly within the limits of the eastern Palaearctic region, S. spinosus Willmann and S. superans Zemskaya, both from Voroshilov, Primor, USSR and S. superans also from the Omsk Region, Kazakhstan, and Turkmenia in the USSR. S. abramus Wang and S. longispinosus Wang were taken in Fukien Province, China, near the indefinite Palaearctic-Oriental boundary. The first two species and S. heteroventralis sp. n. are recorded here from the Korean Peninsula, and the female, male, and protonymph of each are described. The male and protonymph of S. spinosus were earlier described by Dusbabek (1964) as S. musculi (Schrank, 1803). Till and Evans (1964) created the subgenus Steatonyssella for Steatonyssus furmani Tipton and Boese. Among the principal features used to separate this subgenus from other Steatonyssus are the division in the male of the dorsal armature into podosomal and opisthosomal plates and the division of the ventral armature into sternogenital, ventral, and anal plates. We find that the male of S. superans agrees with Steatonyssella in these features (see also Received for publication 24 October 1966. * Department of Entomology, University of Georgia, Athens, Georgia. t G. W. Hooper Foundation, University of California, San Francisco. Zemskaya, 1966). However, none of the diagnostic characters of the female of S. furmani are found in S. superans. While the division of the male dorsal armature is a highly unusual feature, absence of the palpal process plus the combination of other characters peculiar to the female of S. furmani appear to provide a sounder basis for subgeneric separation. Therefore, we are retaining S. superans in the subgenus Steatonyssus and present the following modified diagnoses of the two subgenera. Subgenus Steatonyssella Till and Evans, 1964 Female palpal trochanter without process. Female sternal plate without any indication of a differentiated posterior band. Epigynial plate with strong longitudinal rugosities, independent of typical sculpturing, on anterior half of plate. Podosomal plate in adults with 16 setal pairs. Some pores on opisthosomal plate with thickened rims. Male dorsal armature divided into podosomal and opisthosomal plates. Monotypic: S. furmani Tipton and Boese, 1958. Subgenus Steatonyssus Kolenati, 1858 Female palpal trochanter with ventral process. Female sternal plate with differentiated posterior region, often a heavily incrassate band, but sometimes only more granular or with more compressed lines of sculpturing than on remainder of plate. Epigynial plate with fine tracery on membranous anterior region (one-third or less of plate length), without strong rugosities. Podosomal plate in female with 10 to 13 setal pairs. Pores on opisthosomal plate without thickened rims. Male dorsal armature usually entire, but may be divided as in female. Includes all described species of the genus Steatonyssus except S. furmani. Type: S. periblepharus Kolenati, 1858. Measurements are given in microns. They are based on series of 10 individuals and are given as the mean followed by the range in parentheses. The symbols used in giving measurements are the following: