Dorsum (a), venter (b) and mandibles (c) of male Leioseius minusculus, from Schweizer (1961).

Belongs within: Gamasina.
Contains: Arctoseius, Asca, Antennoseius.

The Ascidae are a group of predatory mites mostly found in soil and arboreally suspended humus and litter (Lindquist et al. 2009). They are mostly generalised forms; many more specialised taxa previously treated as ascids have been reassigned to distinct families.

The two subfamilies Arctoseiinae and Ascinae can be distinguished based on setal counts: Arctoseiinae usually have four pairs of lateral setae on the opisthonotum, together with seven setae each on genua and tibiae III and IV, whereas Ascinae usually have five lateral opisthonotal setae, and eight to ten setae on genua and tibiae III and IV (Krantz & Ainscough 1990). Members of the Arctoseiinae are generally unspecialised in habit and are found among soil litter and on vegetation. Zerconopsis is distinguished from other genera by the presence of paddle-shaped setae on the dorsum (at least the pairs s4 and Z5) and a pair of elongate dorsal setae on each of tarsi II–IV. Iphidozercon has the vertex of the dorsal shield strongly arched downwards so the vertical setae j1 are not visible from above, and long peritremes with their anterior extremities recurved (Evans & Till 1979).

Genera of Ascinae include Arctoseoides and Leioseius which occur in salt marshes and the seashore and are covered by a schizodorsal shield. Separate podonotal and opisthonotal shields are present in Antennoseius, Asca, Gamasellodes and Protogamasellus (Evans & Till 1979).

Characters (from Lindquist et al. 2009): Deutonymphs and adults with more than twenty pairs of dorsal shield setae; setae J1 present. Movable cheliceral digit usually bidentate; male chelicera with spermatodactyl. Female with third pair of sternal poroids on posterolateral corners of sternal shield, with sternal setae st4 usually free on soft cuticle; male with endopodal strips beside coxae III–IV usually free or narrowly connected to sternitigenital shield.

<==Ascidae [Antennoseiidae, Ascaidae, Vitzthumiidae]
    |  i. s.: Africoseius Krantz 1962FH93
    |           `--A. areolatus Krantz 1962FH93
    |         Proctogastrolaelaps McGraw & Farrier 1969FH93
    |           `--P. libris McGraw & Farrier 1969FH93
    |    |--Xenoseius clayiLKW09, KA90
    |    |--ArctoseiusH98
    |    |--Zerconopsis Hull 1918ET79
    |    |    |--*Z. remiger (Kramer 1876) [=Gamasus remiger]ET79
    |    |    |--Z. decemremiger Evans & Hyatt 1960FH93
    |    |    |--Z. labradorensis Evans & Hyatt 1960FH93
    |    |    |--Z. michaeli Evans & Hyatt 1960FH93
    |    |    |--Z. muestairiLKW09
    |    |    `--Z. unaka De Leon 1964FH93
    |    `--Iphidozercon Berlese 1903ET79 [incl. Arctoseiopsis Evans 1954FH93]
    |         |--*I. gibbus (Berlese 1903) [=Eviphis gibbus]ET79
    |         |--I. aegypticus Hirschmann 1966H66
    |         |--I. brasiliensis Hirschmann 1966H66
    |         |--I. californicus Chant 1963FH93
    |         |--I. corticalis Evans 1958H98
    |         |--I. kargi Hirschmann 1966H66
    |         |--I. longitrichus Hirschmann 1966H66
    |         |--‘Seiulus’ minutus Halbert 1915 [=*Arctoseiopsis minutus]E57
    |         `--I. schusteri Hirschmann 1966H66
    `--Ascinae [Ascainae, Ascini]LKW09
         |--Ectoantennoseius Walter 1998LKW09, W98
         |    `--*E. kitchingi Walter 1998W98
         |--Diseius ulmiW98
         |--Anystipalpus Berlese 1911LKW09, LW89
         |    `--*A. percicola Berlese 1911LW89
         |--Neojordensia Evans 1957ET79
         |    |--*N. levis (Voigts & Oudemans 1904)ET79 [=Seiulus levisFH93, Lasioseius levisS61]
         |    |--N. orientalis Chant 1963FH93
         |    `--N. tennesseensis De Leon 1963FH93
         |--Gamasellodes Athias-Henriot 1961ET79, FH93
         |    |--*G. vulgatior Athias 1961ET79
         |    |--G. adrianae Walter 2003W03
         |    |--G. bicolor (Berlese 1918)FH93 (see below for synonymy)
         |    |--G. claudiae Walter 2003W03
         |    |--G. ericae Walter 2003W03
         |    |--G. garmani Hurlbutt 1970FH93
         |    |--G. hildaeW03
         |    |--G. major Athias-Henriot 1961W03, FH93
         |    |--G. insignis [=Iphidozercon insignis]H70
         |    |--G. minorH70
         |    |--G. plaireW03
         |    |--G. rectiventris Lindquist 1971FH93
         |    |--G. seminudus (Ryke 1962) [=Digamasellus seminudus]H70
         |    `--G. vermivorax Walter 1987FH93
         |--Protogamasellus Karg 1962ET79
         |    |  i. s.: P. ascleronodulusLKW09
         |    |         P. brevicornisJ88
         |    |         P. machadoi Genis, Loots & Ryke 1967 [=P. primitivus machadoi]J88
         |    |         P. minimus Jordaan 1988J88
         |    |         P. minutusWP07
         |    |         P. scuticalis Genis, Loots & Ryke 1967J88
         |    |--P. (Protogamasellus)FH93
         |    |    |--P. (P.) mica (Athias-Henriot 1961)FH93, H98 (see below for synonymy)
         |    |    `--P. (P.) dispar Genis, Loots & Ryke 1967FH93
         |    `--P. (Protogamasellodes Evans & Purvis 1987)EP87
         |         |--P. (P.) hibernicus Evans 1982FH93
         |         `--P. (P.) massulus (Athias-Henriot 1961) [=Rhodacaropsis massula]FH93
         |--Leioseius Berlese 1916ET79 [incl. Arctoseiodes Willmann 1949FH93]
         |    |--*L. minusculus (Berlese 1905)ET79 [=Ameroseius minusculusFH93]
         |    |--L. australis Luxton 1984L90
         |    |--L. californicus Chant 1963FH93
         |    |--L. crassipes (Berlese 1910) [=Ameroseius crassipes, Lasioseius (Leioseius) crassipes]H98
         |    |--L. elegantulus Schweizer 1949S61
         |    |--L. elongatusET79
         |    |--L. favosus (Berlese 1910) [=Ameroseius favosus, Lasioseius (Leioseius) favosus]H98
         |    |--‘Arctoseius’ ibericus Willmann 1949 [=*Arctoseiodes ibericus]ET79
         |    |--L. littoraleH83
         |    |--L. setosulus (Berlese 1916) [=Lasioseius (Leioseius) setosulus]FH93
         |    |--L. singularis Karg 1962K91
         |    |--L. ulmiW03
         |    |--L. vallaensis Luxton 1989H98
         |    `--L. venustulusS61
Nomina nuda: Iphidozercon literatus Lindquist 1963FH93
             Iphidozercon reticaelatus Lindquist 1963FH93
             Leioseius tuberculatus Lindquist 1963FH93

Gamasellodes bicolor (Berlese 1918)FH93 [=Gamasellus (Digamasellus) bicolorFH93, Iphidozercon bicolorH70, Leioseius bicolorH70; incl. Gamasellus americanus Garman 1948FH93, Digamasellus americanusH67, Gamasellodes americanusH70, Digamasellus circuliformis Leitner 1949FH93, D. shealsi Costa 1962FH93, Gamasellodes shealsiH70]

Protogamasellus (Protogamasellus) mica (Athias-Henriot 1961)FH93, H98 [=Rhodacarellus micaH98; incl. *P. primitivus Karg 1962ET79, FH93, P. primitivus similis Genis, Loots & Ryke 1967J88]

*Type species of generic name indicated


[E57] Evans, G. O. 1957. An introduction to the British Mesostigmata (Acarina) with keys to families and genera. Journal of the Linnean Society of London, Zoology 43: 203–259.

[ET79] Evans, G. O., & W. M. Till. 1979. Mesostigmatic mites of Britain and Ireland (Chelicerata: Acari-Parasitiformes). An introduction to their external morphology and classification. Transactions of the Zoological Society of London 35: 139–270.

[FH93] Farrier, M. H., & M. K. Hennessey. 1993. Soil-inhabiting and free-living Mesostigmata (Acari-Parasitiformes) from North America: an annotated checklist with bibliography and index. North Carolina Agricultural Research Service, North Carolina State University, Technical Bulletin 302: i–xvi, 1–408.

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

[H83] Hammen, L. van der. 1983. Contribution to the knowledge of the soil-fauna of New Guinea. Zoologische Verhandelingen 206: 1–36.

[H66] Hirschmann, W. 1966. Gangsystematik der Parasitiformes. Teil 15. Gänge von Litoralmilben und neue Litoralmilbenarten. Acarologie: Schriftenreihe für Vergleichende Milbenkunde 9: 25–44.

[H67] Hurlbutt, H. W. 1967. Digamasellid mites associated with bark beetles and litter in North America. Acarologia 9 (3): 497–534.

[H70] Hurlbutt, H. W. 1970. Gamasellodes bicolor (Berlese, 1918) (Acarina: Ascidae) and its relatives. Acarologia 12 (3): 474–478.

[J88] Jordaan, L. C. 1988. A redescription of Protogamasellus scuticalis Genis, Loots & Ryke (Acari: Ascidae) and a new species from the Afrotropical region. Phytophylactica 20: 35–38.

[K91] Koehler, H. H. 1991. A five year study on the secondary succession of Gamasina on a ruderal site: the influence of recultivation. 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. 373–383. SPB Academic Publishing: The Hague.

[KA90] Krantz, G. W., & B. D. Ainscough. 1990. Acarina: Mesostigmata (Gamasida). In: Dindal, D. L. (ed.) Soil Biology Guide pp. 583–665. John Wiley & Sones: New York.

[LKW09] Lindquist, E. E., G. W. Krantz & D. E. Walter. 2009. Order Mesostigmata. In: Krantz, G. W. & D. E. Walter (eds) A Manual of Acarology 3rd ed. pp. 124–232. Texas Tech University Press.

[LW89] Lindquist, E. E., & D. E. Walter. 1989. Antennoseius (Vitzthumia) janus n.sp. (Acari: Ascidae), a mesostigmatic mite exhibiting adult female dimorphism. Canadian Journal of Zoology 67: 1291–1310.

[L90] Luxton, M. 1990. The marine littoral mites of the New Zealand region. Journal of the Royal Society of New Zealand 20 (4): 367–418.

[S61] Schweizer, J. 1961. Die Landmilben der Schweiz (Mittelland, Jura und Alpen): Parasitiformes Reuter, mit 246 Arten und Varietäten und 268 meist kombinierten Originalzeichnungen. Denkschriften der Schweizerischen Naturforschenden Gesellschaft [Mémoires de la Société Helvétique des Sciences Naturelles] 84: i–vii, 1–207.

[W98] Walter, D. E. 1998. Ectoantennoseius kitchingi n. gen., n. sp. (Acari: Ascidae) from the rainforest canopy and a cladistic hypothesis about its relationships. International Journal of Acarology 24 (1): 45–51.

[W03] Walter, D. E. 2003. The genus Gamasellodes (Acari: Mesostigmata: Ascidae): new Australian and North American species. Systematic and Applied Acarology Special Publications 15: 1–10.

[WL95] Walter, D. E., & E. E. Lindquist. 1995. The distributions of parthenogenetic ascid mites (Acari: Parasitiformes) do not support the biotic uncertainty hypothesis. Experimental and Applied Acarology 19: 423–442.

[WP07] Walter, D. E., & H. Proctor. 2007. Using your genetic system to win friends and obfuscate theorists: patterns in the distribution of genetic sex determination in the Parasitiformes. In: Morales-Malacara, J. B., V. M. Behan-Pelletier, E. Ueckermann, T. M. Pérez, E. G. Estrada-Venegas & M. Badii (eds) Acarology XI: Proceedings of the International Congress pp. 637–643. Instituto de Biología and Faculdad de Ciencias, Universidad Nacional Autónoma de México, Sociedad Latinoamericana de Acarología: México.

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