Micromegistus sp., photographed by S. E. Thorpe.

Belongs within: Mesostigmata.
Contains: Celaenopsoidea, Fedrizzioidea.

The Trigynaspida are a group of large mesostigmatan mites that are primarily associated with arthropods or reptiles, either as commensals or parasites. They are divided between two major lineages with the Antennophorina being generally more heavily sclerotised with fully separate tritosternal laciniae and no claws on the first legs. The Cercomegistoidea tend to be less sclerotised with the tritosternal laciniae usually fused for more than half their length while claws may be present on the first legs. Within the Cercomegistoidea, members of the family Cercomegistidae are associated with arthropods whereas other families are free-living predators in soil (Lindquist et al. 2009).

Within the Antennophorina, species of Antennophorus, the Aenictequoidea and the Parantennuloidea have chelicerae with teeth absent, reduced or modified whereas other superfamilies have chelicerae with well-developed, sclerotised teeth (Lindquist et al. 2009).

Characters (from Lindquist et al. 2009): Movable cheliceral digit with medial or terminal dendritic, brushlike, or filamentous ventral excrescences. Oviporus usually covered by two latigynal and one mesogynal shields that may be variously coalesced or reduced; median element (mesogynal shield) nude, subtriangular by often reduced of insensibly fused to other elements; latigynal shields each with one to many setae, free or fused posteriorly to ventral elements and/or medially to each other. Femur IV with 4-11 setae. Tarsus IV usually with setae av4 and pv4 present in adults and deutonymphs (usually on free intercalary sclerite in adult).

<==Trigynaspida [Trigynaspides]
    |--Cercomegistoidea [Cercomegistides, Cercomegistina]LKW09
    |    |--Seiodes Berlese 1887FH93 [SeiodidaeLKW09]
    |    |    `--*S. ursinus Berlese 1887E57
    |    |--Pyrosejus [Pyrosejidae]LKW09
    |    |--Asternoseius [Asternoseiidae]LKW09
    |    |    `--A. ciliatusLKW09
    |    |--Saltiseius Walker 2000 [Saltiseiidae]W00
    |    |    `--*S. hunteri Walker 2000W00
    |    |--DavacaridaeLKW09
    |    |    |--Davacarus reginaldiLKW09
    |    |    `--Acanthodavacarus klompeniLKW09
    |    `--CercomegistidaeLKW09
    |         |  i. s.: ‘Cyclothorax’ latronis Vitzthum 1937J60
    |         |         ‘Physalozercon’ paguroxenus André 1937J60
    |         |--VitzthumegistusLKW09
    |         |--Celaenogamasus Berlese 1901K72
    |         |--Cercoleipus Kinn 1970FH93
    |         |    `--C. coelonotus Kinn 1970FH93
    |         |--Cercomegistus Berlese 1914H98
    |         |    |--C. abires Domrow 1976H98
    |         |    |--C. bruckianus Berlese 1914K67
    |         |    |--C. evonicus Kinn 1967K67
    |         |    `--C. simplicior Vitzthum 1935K67
    |         `--Holocercomegistus Evans 1958K72
    |              |--*H. agelenophilus Evans 1958K72
    |              `--H. costai Kinn 1972K72
    `--Antennophorina [Antennophorides]LKW09
         |--Antennophorus Haller 1877FH93 [Antennophoridae, AntennophoroideaLKW09]
         |    |--*A. uhlmanni Haller 1887ET79
         |    |--A. donisthorpei Wheeler 1910FH93
         |    |--A. foreli Wasmann 1902V25
         |    |--A. grandis Berlese 1903V25
         |    `--A. wasmanni Wheeler 1910FH93
         |    |--Stenosternum Kramer 1898FH93 [incl. Hoplomegistus Berlese 1904FH93; HoplomegistidaeLKW09]
         |    |    |--S. armiger (Berlese 1888) [=Megistanus armiger, Hoplomegistus armiger]FH93
         |    |    |--S. bruneti (Turk 1948) [=Syngynaspis bruneti]FH93
         |    |    `--S. truittae (Butler & Hunter 1966) [=Hoplometistus truittae]FH93
         |    `--Megisthanus Thorell 1882H98 [Megistanidae, MegisthanidaeLKW09]
         |         |--M. antennaepes (Say 1821) [=Gamasus antennaepes]FH93
         |         |--M. brachyurus Thorell 1882V25
         |         |--M. floridanus Banks 1904FH93
         |         |--M. gigantodes Stoll 1893FH93
         |         |--M. modestus Berlese 1910 [=Megistanus modestus]H98
         |         |--M. obtusus Kramer 1895V25
         |         |--M. testudo Thorell 1882 [=Megistanus testudo]H98
         |         `--M. thorelli Womersley 1937H98
         |    |--Aenicteques [Aenictequidae]LKW09
         |    |    `--A. chapmaniLKW09
         |    |--Physalozercon [Physalozerconidae]LKW09
         |    |    `--P. raffrayiLKW09
         |    |--Ptochacarus Silvestri 1911H98 [PtochacaridaeLKW09]
         |    |    |--P. banksi Womersley 1958H98
         |    |    |--P. daveyi Silvestri 1911 [=Ptocharus daveyii (l. c.)]H98
         |    |    `--P. silvestrii Womersley 1958H98
         |    `--MessoracaridaeLKW09
         |         |--LeptantennusLKW09
         |         `--Messoracarus Silvestri 1912H98
         |              |--M. emarginatus (Banks 1916) [=Antennophorus emarginatus]H98
         |              `--M. mirandusLKW09
              |--Philodana Kethley 1977FH93 [PhilodanidaeLKW09]
              |    `--P. johnstoni Kethley 1977FH93
              |--Promegistus Womersley 1958H98 [PromegistidaeLKW09]
              |    `--P. armstrongi Womersley 1958H98
              |    |--Parantennulus scolopendrarum (Berlese 1886)LKW09, V25
              |    |--DiplopodophilusLKW09
              |    `--Micromegistus Trägårdh 1948H98
              |         |--M. bakeri Trägårdh 1948FH93
              |         `--M. gourlayi Womersley 1958H98
                   |--Pseudomegistus Kethley 1977H98
                   |    `--P. australis (Banks 1916) (n. d.) [=Paramegistus australis]H98
                   |--Echinomegistus Berlese 1904FH93
                   |    |--E. caputcarabiAL37
                   |    `--E. wheeleri (Wasmann 1902) [=Antennophorus wheeleri]FH93
                   `--Ophiomegistus Banks 1914H98
                        |--O. australicus (Womersley 1958) [=Neomegistus australicus]H98
                        `--O. clelandi Womersley 1958H98

*Type species of generic name indicated


[AL37] André, M., & É. Lamy. 1937. Les Idées actuelles sur la Phylogénie des Acariens. Published by the author: Paris.

[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.

[J60] Johnston, D. E. 1960. Laelaptid mites associated with hermit crabs (Paguridea). The genera Aspidilaelaps and Cyclothorax (Acarina—Mesostigmata). Acarologia 2 (4): 442–445.

[K67] Kinn, D. N. 1967. A new species of Cercomegistus (Acari: Mesostigmata) from California. Acarologia 9 (3): 488–496.

[K72] Kinn, D. N. 1972. A new species of Holocercomegistus, including some observations on the chaetotaxy of the pedipalpal and ambulatory appendages of the Cercomegistidae (Acarina). Acarologia 13 (2): 258–265.

[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.

[V25] Vitzthum, H. 1925. Fauna sumatrensis. (Beitrag no. 5). Acarinae. Supplementa Entomologica 11: 1–79.

[W00] Walter, D. E. 2000. A jumping mesostigmatan mite, Saltiseius hunteri n. g., n. sp. (Acari: Mesostigmata: Trigynaspida: Saltiseiidae, n. fam.) from Australia. International Journal of Acarology 26: 25–31.

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