Unionicolidae

Likely Unionicola, copyright Stephen Luk.

Belongs within: Hygrobatoidea.
Contains: Neumania, Koenikea, Recifella.

The Unionicolidae are a diverse family of freshwater mites. Larvae, where known, are parasites of aquatic insects (Chironomidae or Trichoptera); adults are more diverse in habits, including predators of crustaceans, commensals or parasites of sponges, and associates of molluscs. They are divided between five subfamilies of which the Pionatacinae and Unionicola are cosmopolitan in distribution whereas Omanohydracarus, Pollicipalpus and Encentridophorus have more restricted distributions in the Palaeotropics (Walter et al. 2009). Unionicola species have five or six pairs of acetabula in the genital field whereas Pionatacinae have more than ten pairs of acetabula.

Characters (from Walter et al. 2009): Adults with dorsal and ventral shields or more soft-bodied; if with ventral shields, then openings for insertions of legs IV with large associated projections extending laterally or posteriorly; chelicerae fused or separate medially; claws simple or with clawlets; legs I often with numerous long thickened setae; glandularia absent on coxal plates IV. Larvae with cheliceral bases fused; dorsal and coxal plates reticulate; coxal plates I separate from posterior coxal group on each side; one pair of urstigmata borne distally between coxal plates I and II; coxal plates III bearing pointed projections posteriorly; legs with five movable segments; tibia I bearing nine setae (and two solenidia), including Ti10 and Ti11; tarsi I-III bearing ten setae and one solenidia; leg tarsi bearing paired claws.

Unionicolidae
    |  i. s.: Vietsatax WP99
    |--Omanohydracarus [Omanohydracarinae] WL09
    |    `--O. arabicus WL09
    |--Pollicipalpus Viets 1924 H98 [Pollicipalpinae WL09]
    |    |--P. australicus Cook 1986 H98
    |    `--P. scutatus WL09
    |--Encentridophorus Piersig 1897 H98 [Encentridophorinae WL09]
    |    |--E. sarasini Walter in Sarasin & Roux 1915 [incl. E. indicus Cook 1967, E. lundbladi Cook 1967] H98
    |    `--E. similis WP99
    |--Pionatacinae WL09
    |    |--Neumania WL09
    |    |--Koenikea WL09
    |    |--Recifella WL09
    |    |--Schadeella Lundblad 1938 RFF05
    |    |    `--S. crassipalpis Lundblad 1938 RFF05
    |    |--Neumanikea Orghidan & Gruia 1980 S86
    |    |    |--N. coenotica Orghidan & Gruia 1980 S86
    |    |    `--N. guantanamense Orghidan & Gruia 1980 S86
    |    `--Amazonella Lundblad 1930 RFF05
    |         |--A. crassipalpis Lundblad 1941 RFF05
    |         |--A. polypora Lundblad 1936 RFF05
    |         |    |--A. p. polypora RFF05
    |         |    `--A. p. curvimarginata Viets 1959 RFF05
    |         `--A. ribagai Lundblad 1930 RFF05
    `--Unionicola Haldeman 1842 RFF05 [Unionicolinae WL09]
         |  i. s.: U. aberrans Viets 1984 H98
         |         U. aculeata (Koenike 1890) BBM91
         |         U. alpa Cook 1986 H98
         |         U. annulata Lundblad 1947 H98
         |         U. assimilis Viets 1980 H98
         |         U. cirrosa Koenike 1914 H98
         |         U. clipeata Viets 1980 H98
         |         U. conjunctella Viets 1980 H98
         |         U. crassipalpis Walter in Sarasin & Roux 1915 H98
         |         U. crassipes (Müller 1776) PH91
         |           |--U. c. crassipes C91
         |           `--U. c. miyazakii Imamura 1953 C91
         |         U. davidsi Smit 1992 H98
         |         U. flabelliseta Cook 1986 H98
         |         U. foili DPD16
         |         U. formosa B91
         |         U. fossulata B91
         |         U. gracilipalpis BK91
         |         U. hammeni Smit 1992 H98
         |         U. intermedia B91
         |         U. ischyropalpus DPD16
         |         U. lasallei WP99
         |         U. laurentiana Crowell & Davids 1979 [incl. U. nearctica Crowell & Davids 1979] C91
         |         U. ligulifera Viets 1980 H98
         |         U. lindrothi Viets 1981 H98
         |         U. longiseta Walter in Sarasin & Roux 1915 [incl. U. australica Lundblad 1941] H98
         |         U. lundbladi Viets 1975 H98
         |         U. minor Soar 1900 [=U. crassipes minor] C91
         |         U. minutissima Lundblad 1947 H98
         |         U. neoaffinis Cook 1986 H98
         |         U. opimipalpis (Viets 1980) [=Unionicolopsis opimipalpis] H98
         |         U. parvipora BK91
         |         U. poundsi WP99
         |         U. procursa Viets 1980 H98
         |         U. pseudoannulata Cook 1986 H98
         |         U. scutata Viets 1980 H98
         |         U. vidrinei Cook 1986 H98
         |         U. walkeri Viets 1980 H98
         |         U. ypsilophora (Bonz 1783) BBM91
         |--U. (Unionicola) RFF05
         |    |--U. (U.) iheringi (Koenike 1890) RFF05
         |    |--U. (U.) inermis Lundblad 1941 RFF05
         |    |--U. (U.) levipalpis Besseling 1949 RFF05
         |    |--U. (U.) motasi Viets 1959 RFF05
         |    |--U. (U.) perpusilla Viets 1954 RFF05
         |    |--U. (U.) pugionipalpis Viets 1954 RFF05
         |    |--U. (U.) pusuligera Viets 1954 RFF05
         |    `--U. (U.) siolii Viets 1954 RFF05
         |--U. (Ampullariatax Vidrine 1985) RFF05
         |    `--U. (A.) ampullariae (Koenike 1890) RFF05
         |--U. (Atacella Lundblad 1937) RFF05
         |    |--U. (A.) clathrata (Lundblad 1937) RFF05
         |    |--U. (A.) entrerrianensis (Rosso de Ferradás 1976) RFF05
         |    |--U. (A.) fissipes (Koenike 1891) RFF05
         |    |--U. (A.) gigantea (Cachés & Mañé-Garzón 1973) RFF05
         |    |--U. (A.) perforata (Koenike 1890) RFF05
         |    |--U. (A.) rugosa (Koenike 1890) RFF05
         |    |--U. (A.) schubarti (Viets 1954) RFF05
         |    `--U. (A.) subrecta (Cachés & Mañé-Garzón 1973) RFF05
         |--U. (Australatax Vidrine 1985) RFF05
         |    `--U. (A.) sinuata Lundblad 1938 RFF05
         |--U. (Crameratax Vidrine 1988) RFF05
         |    |--U. (C.) acutidens (Lundblad 1936) RFF05
         |    |--U. (C.) gracilipes (Lundblad 1936) RFF05
         |    `--U. (C.) tumidipalpis (Lundblad 1936) RFF05
         |--U. (Curryatax Vidrine 1992) RFF05
         |    `--U. (C.) prehendens Viets 1954 RFF05
         |--U. (Ferradasatax Vidrine 1988) RFF05
         |    `--U. (F.) procurvipes (Koenike 1890) RFF05
         |--U. (Gledhillatax Vidrine 1992) RFF05
         |    |--U. (G.) angustipalpis (Lundblad 1937) RFF05
         |    |--U. (G.) brevisuturata Viets 1959 RFF05
         |    |--U. (G.) longipes Lundblad 1942 RFF05
         |    `--U. (G.) simplicipes (Lundblad 1936) RFF05
         |--U. (Lasalleatax Vidrine 1992) RFF05
         |    |--U. (L.) brasiliensis (Lundblad 1936) RFF05
         |    |--U. (L.) conjuncta Viets 1954 RFF05
         |    `--U. (L.) unidens Lundblad 1942 RFF05
         |--U. (Lundbladatax Vidrine 1988) RFF05
         |    `--U. (L.) fissipalpis Lundblad 1942 RFF05
         |--U. (Mitchellatax Vidrine 1992) RFF05
         |    |--U. (M.) curvitarsis Lundblad 1941 RFF05
         |    `--U. (M.) longidens Lundblad 1942 RFF05
         |--U. (Polyatacides Lundblad 1941) RFF05
         |    `--U. (P.) prominens (Koenike 1914) RFF05
         |--U. (Poundsatax Vidrine 1992) RFF05
         |    `--U. (P.) retractidens Lundblad 1937 RFF05
         |--U. (Unionicolella Lundblad 1941) RFF05
         |    `--U. (U.) pachyscelus Lundblad 1941 RFF05
         |--U. (Unionicolides Lundblad 1937) RFF05
         |    |--U. (U.) bonariensis Mauri & Alzuet 1972 RFF05
         |    `--U. (U.) sica Lundblad 1937 RFF05
         `--U. (Wilsonatax Vidrine 1992) RFF05
              |--U. (W.) plaumanni Lundblad 1937 RFF05
              `--U. (W.) viciniseta (Lundblad 1936) RFF05

*Type species of generic name indicated

REFERENCES

[B91] Baker, R. A. 1991. Development and life-history strategies in mussel mites (Hydrachnellae: Unionicolidae). In: Schuster, R., & P. W. Murphy (eds) The Acari: Reproduction, development and life-history strategies pp. 65–73. Chapman & Hall: London.

[BBM91] Baker, R. A., S. Brett & N. Morley. 1991. Water mite larvae parasitic on insects—a study of larval structures and host relationships. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 1 pp. 493–496. SPB Academic Publishing: The Hague.

[BK91] Biesiadka, E., & W. Kowalik. 1991. Water mites (Hydracarina) as indicators of trophy and pollution in lakes. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 1 pp. 475–481. SPB Academic Publishing: The Hague.

[C91] Conroy, J. C. 1991. Acarology—a modern science. In Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 1 pp. 5–16. SPB Academic Publishing: The Hague.

[DPD16] Dabert, M., H. Proctor & J. Dabert. 2016. Higher-level molecular phylogeny of the water mites (Acariformes: Prostigmata: Parasitengonina: Hydrachnidiae). Molecular Phylogenetics and Evolution 101: 75–90.

[H98] Halliday, R. B. 1998. Mites of Australia: A checklist and bibliography. CSIRO Publishing: Collingwood.

[PH91] Punčochár, P., & J. Hrbáček. 1991. Water mites in the plankton of Hubenov Reservoir and their relations to fish stock composition. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 1 pp. 449–457. SPB Academic Publishing: The Hague.

[RFF05] Rosso de Ferradás, B. & H. R. Fernández. 2005. Elenco y biogeografía de los ácaros acuáticos (Acari, Parasitengona, Hydrachnidia) de Sudamérica. Graellsia 61 (2): 181–224.

[S86] Schwoerbel, J. 1986. Acari: “Hydrachnellae”. In: Botosaneanu, L. (ed.) Stygofauna Mundi: A Faunistic, Distributional, and Ecological Synthesis of the World Fauna inhabiting Subterranean Waters (including the Marine Interstitial) pp. 652–696. E. J. Brill/Dr W. Backhuys: Leiden.

[WL09] Walter, D. E., E. E. Lindquist, I. M. Smith, D. R. Cook & G. W. Krantz. 2009. Order Trombidiformes. In: Krantz, G. W., & D. E. Walter (eds) A Manual of Acarology 3^rd ed. pp. 233–420. Texas Tech University Press.

[WP99] Walter, D. E., & H. C. Proctor. 1999. Mites: Ecology, Evolution and Behaviour. CABI Publishing: Wallingford (UK).

Last updated: 9 July 2022.