Hidden Identity or Newcomer – A Case Study of Empitrombium (Actinotrichida: Parasitengona: Microtrombidiidae) in Europe

Five Empitrombium species have been described from the Nearctic, Neotropical and Palaearctic Realms. The recent discovery of Empitrombium in Poland and France is the first record of the genus for the European part of the Palaearctic. The observations of Empitrombium paludosum sp. nov. at one locality in south-western Poland carried out for three consecutive years, vote for the presence of an established population and, at the same time, translate into widening the distribution of Empitrombium in the northern hemisphere, crossing the limit of 50 degrees north latitude. A second direct correlation of larvae and postlarval forms through laboratory rearing has been proceeded for genus members. Detailed insight into the morphology of active life instars revealed that the traits of active postlarval forms of Empitrombium overlap with the traits known for some genera of Microtrombidiidae, while the larvae bear an unusual combination of morphological characters, hitherto considered typical for higher and for lower microtrombidiids. The DNA sequences of the mitochondrial gene (cytochrome c oxidase subunit I), here provided for the first time for the genus members, further confirmed a separate generic status of Empitrombium.