Lohmannellinae Viets, 1927

Abé, Hiroshi, 2021, Taxonomic review of the subfamily Lohmannellinae (Acari: Trombidiformes Halacaridae) with morphological comparisons among genera, Zootaxa 4980 (2), pp. 201-255 : 207

Subfamily Lohmannellinae Viets, 1927

[Type: Lohmannella Trouessart, 1901 ]

Diagnosis. Idiosoma obovoid. Four dorsal plates (AD, right and left OC, and PD) and four ventral plates (AE, right and left PE, and GA) fundamentally present, but OC occasionally reduced. Palpi slender, two- or four- segmented, and placed dorsally or laterally on the gnathosoma base. Rostrum elongate, almost the same length as the palpi, and parallel-sided for most of the length. Lc developed, but median claw sometimes vestigial.

Remarks. The subfamily Lohmannellinae was originally erected by Viets (1927a) to include two genera Lohmannella Trouessart, 1888 , and Scaptognathus Trouessart, 1889 . At that time, Porolohmannella violacea was incorporated into Lohmannella in the Viets’s system. Afterwards, the genus Porolohmannella was established by Viets (1933) based on Porolohmannella violacea as the type. At present, Lohmannellinae consists of five genera: Lohmannella Trouessart, 1888 ; Porolohmannella Viets, 1933 ; Scaptognathus Trouessart, 1889 ; Scaptognathides Monniot, 1972 ; and Xenohalacarus Otto, 2000 . Bartsch (1996a) moved three freshwater species in the genus Porolohmannella into Lohmannella . Therefore, Porolohmannella contains a single freshwater species and Lohmannella consists of a large number of marine, brackishwater, and freshwater species. Scaptognathides was established by Monniot (1972) based on Scaptognathides planus as the type collected from the Bermudas. Xenohalacarus was most recently erected by Otto (2000a) based on Xenohalacarus longirostris as the type from the Queensland Plateau in Australia. At present, Xenohalacarus contains a single species.

As mentioned before, Newell (1984) raised this subfamily to the familial rank Lohmannellidae , which in those days included marine and freshwater genera with dorsally attached palpi on the base of the gnathosoma . However, as Otto (2000b) mentioned, the dorsally attached palpi on the gnathosoma would be considered a plesiomorphic state, because this characteristic spreads over various taxa in Acari . Therefore, in the present paper, Lohmannellinae retains its subfamilial rank, because positive evidence of the alteration could not be obtained under the existing circumstances. However, there still remains a possibility that the constituent of the subfamily will be changed depending on a phylogenetic tree-topology. Especially, as Otto (2000a) suggested, the assignment of Xenohalacarus to Lohmannellinae was tentative and the systematic position has not been verified in recent molecular phylogenetics. Further molecular phylogenetic work will be required before an explicable system can be attained.