A new species of Zercon (Parasitiformes: Mesostigmata) from Norway, with notes on sexual dimorphism in Zerconidae

Abstract

In this paper we describe and illustrate Zercon hamaricus sp. nov. based on all postembryonic stages obtained from soil samples and laboratory cultures. The new species belongs to a species group in which dorsal setae J1–J4 in females are short and similar in length, and J5 are considerably longer. In most species of this group opisthonotal setae J5 and Z4 are clearly displaced anteriorly. Zercon hamaricus sp. nov. is most similar to Z. forsslundi Sellnick, 1958 and to a less extent to Z. polonicus Błaszak, 1970. The females of Z. forsslundi, Z. polonicus and Z. hamaricus sp. nov. can be distinguished based on the range of J5, the length and character of the Z and S-series setae, the distance between setae Z5 and the location of gdZ3. We also include comparative information on other related species of Zercon. The new species is one of the six known species that have clearly visible sexual dimorphism in opisthonotal chaetotaxy.