Taxonomic review of the subfamily Lohmannellinae (Acari: Trombidiformes: Halacaridae) with morphological comparisons among genera

Taxonomic review of the halacarid subfamily Lohmannellinae is carried out with regard to morphology, biology, habitat, geographical distribution, and bibliography. The subfamily is one of 16 subfamilies in the family Halacaridae and consists of five genera, Lohmannella, Porolohmannella, Scaptognathides, Scaptognathus, and Xenohalacarus, which include 38, 1, 11, 31, and 1 known species, respectively. The genera Scaptognathides, Scaptognathus, and Xenohalacarus are marine, Porolohmannella is a freshwater inhabitant, and Lohmannella lives in marine and freshwater. The species in this subfamily are mostly arenicolous and probably carnivorous or omnivorous in feeding habits. As for the geographic distribution, Lohmannella shows almost cosmopolitan distribution; Scaptognathus is also widely distributed except for polar regions. The genus Scaptognathides is distributed more in southern oceans than in the northern circle, and Xenohalacarus is restricted to the Coral Sea. The freshwater genus Porolohmannella has wide inland distribution except for the African, South American, Australian, and Antarctic continents. Based on morphological comparisons among five genera, Scaptognathus is regarded as the most unique taxon and Lohmannella and Porolohmannella as rather conservative taxa in the subfamily. The classification of halacarids within the subfamily Lohmannellinae has been revised by several researchers. At present, the subfamily Lohmannellinae consists of five genera: Lohmannella, Porolohmannella, Scaptognathides, Scaptognathus, and Xenohalacarus. Porolohmannella has only freshwater species, and the other genera had so far included marine species only. However, Bartsch (1996a, 2007b) tentatively moved three Porolohmannella species (P. andrei (Angelier, 1951), P. curvimandibulata (Petrova, 1969), and P. cvetkovi (Petrova, 1965)) into the marine genus Lohmannella, emphasizing their morphological similarities with Lohmannella species. In consequence,

Automated summary

The halacarid subfamily Lohmannellinae consists of five genera with species living in marine or freshwater habitats, mainly on sandy substrates. The taxonomy of this subfamily has been revised by researchers, with Lohmannella showing almost cosmopolitan distribution, while other genera have more restricted geographic ranges.