Limnocharidae, Grube, 1859

Li, Hai-Tao, Jin, Dao-Chao, Yi, Tian-Ci & Guo, Jian-Jun, 2022, Contributions to the knowledge of Eylaoidea (Acari: Hydrachnidiae) from China, European Journal of Taxonomy 787 (1), pp. 53-70 : 67

The key to the subfamilies, genera and subgenera of Limnocharidae

1. Gnathosoma attached to a long protrusible tube of soft integument, the former well separated from the first coxae; palp segments 3, occasionally 2, 4 or 5; legs without swimming seta ....................... ..................................................................... Subfamily Rhyncholimnocharinae Lundblad, 1936 2

– Gnathosoma not attached to a long protrusible tube of soft integument; gnathosoma always adjacent to the first pair of coxae; palp segments 4 or 5; swimming setae absent or present ......................... 5

2. Palp segments not fused, with 5 segments; P-V attached to the ventral surface, rather than the distal end of P-IV; dorsalia absent .................................................Genus Pentachares Li & Guo gen. nov.

– Palp segments fused, palp with 3, occasionally 2, 4 segments ......................................................... 3

3. Palp with 4 segments or occasionally 3; medial part of palp curved dorsally; without dorsalia ........ ............................................................................................ Genus Austrolimnochares Harvey, 1998

– Palp with 3 segments or occasionally 2; dorsal margin of the second palp segment straight; dorsum with or without paired sclerites ...............................Genus Rhyncholimnochares Lundblad, 1936 4

4. Terminal segment of palp relatively large, with much of the segment visible proximal to the terminal setae .............................................................................. Subgenus Paralimnochares Lundblad, 1937

– Terminal segment of palp greatly reduced, the terminal setae are prominent but the actual segment somewhat hidden .................................................. Subgenus Rhyncholimnochares Lundblad, 1936

5. Palp segments not fused, palp with 5 segments ..............Subfamily Limnocharinae Grube, 1859 6

– Palp segments fused, palp with 4 segments .... Subfamily Neolimnocharinae Gerecke et al., 2020 *

6. P-V inserted on the medioventral portion of P-IV .................... Genus Laterolimnochares Jin, 1999

– P-V normally inserted on the distal end of P-IV ....................Genus Limnochares Latreille, 1796 7

7. Legs with swimming setae .........................................................Subgenus Cyclothrix Wolcott, 1905

– Legs without swimming setae ..............................................Subgenus Limnochares Latreille, 1796

* The definition of Neolimnocharinae is mainly based on larval characters. This larval-based taxonomy results in a parallel system in Limnocharidae , for which taxa have previously been based on adults. On the other hand, Gerecke et al. (2020) provided sufficient conditions to make us think that the establishment of subfamily Neolimnocharinae is reasonable. To avoid confusion in the taxonomy, four larval-based genera (Veliacola, Archaeveliacola, Armaveliacola, Isoveliacola) and genus Neolimnochares are not listed in this adult-charactered binomial key.