Larvae of Pentagonella acuscutellaris on back of great snipe Gallinago media, from Mąkol & Korniluk (2017).

Belongs within: Microtrombidiidae.
Contains: Guntheria, Trombicula, Neotrombicula, Leptotrombidium, Eutrombicula, Euschongastia.

The Trombiculidae are a family of predatory mites whose larvae, known as chiggers, are mostly ectoparasitic on vertebrates. Bites from chiggers induce formation of a characteristic feeding tube, the stylostome, and can cause intensely itchy lesions that may become infected. On humans, chiggers most commonly attach themselves in locations constricted by clothing, such as the armpits, ankles or belt line (Gould 1956). Adults, where known, are often predators of insect eggs (Walter et al. 2009).

Trombiculids have been divided between the subfamilies Trombiculinae and Gahrliepiinae. In larvae of Trombiculinae, the prodorsal scutum usually possesses an anteromedian seta and the basifemora and telofemora of the legs are usually distinct; in Gahrliepiinae, the scutum lacks an anteromedian seta and the basifemur and telofemur are fused in the mid and hind legs. Within Trombiculinae, Thor (1936) established the genus Pentagonella for a group of species with a distinctly pentagonal prodorsal scutum. Larvae of Neoschoengastia have distally expanded sensillae and the scutum is partially submerged beneath the dorsal cuticular striations (Gould 1956).

Characters (from Walter et al. 2009): Adults with prodorsal plate bearing no or one vi seta anteriorly; palpfemur bearing about same number of setae as genu, palptibia bearing group of lateral spinose setae in tandem; pregenital tubercle absent. Larvae with prodorsal plate bearing no or one vi seta; scutellum absent, setae c1 located on paired platelets; urstigmata present between coxal plates I and II; anal plate absent; genu II bearing three barbed setae; pretarsi I and II each bearing paired claws and claw-like empodium.

    |--Gahrliepiinae [Gahrliepiini]WL09
    |    |--Elianella Vercammen-Grandjean 1956S61
    |    `--Gahrliepia Oudemans 1912H98 (see below for synonymy)
    |         |--G. disparunguis Oudemans 1929 (see below for synonymy)H98
    |         |--G. morobensis (Gunther 1939) [=Walchia morobensis]H98
    |         `--G. suduskiUKK96
    |--Walchiinae [Walchiidae]G56
    |    |--Walchia Ewing 1932T35
    |    |    |--‘Trombidium’ ewingi Fuller 1949 [incl. T. glabrum Walch 1927 non Duges 1834, *Walchia glabra]G56
    |    |    |--W. americana Ewing 1942G56
    |    |    `--W. hayashiiFF22
    |    `--Pseudoschoengastia Lipovsky 1951G56
    |         |--*P. hungerfordi Lipovsky 1951G56
    |         |--P. occidentalis Brennan 1952G56
    |         `--P. scitula Brennan & Jones 1959QV01
    `--Trombiculinae [Schoengastiini, Trombiculini]WL09
         |--Novotrombicula Womersley & Kohls 1947S61
         |--Babiangia Southcott 1954S61
         |--Heterotrombidium Verdun 1909T35
         |--Doloisia Oudemans 1910T35
         |--Schoengastiella Hirst 1915T35
         |    `--S. tauffliebi Lavoipierre 1955L55
         |--Schoengastia Ouddemans 1910T36
         |    |--S. gutekunsti Goff 1981H98
         |    |--S. schueffneriG56
         |    `--S. vandersandeiG56
         |--Neoschoengastia Ewing 1929T35
         |    |--*N. americana (Hirst 1921)G56 (see below for synonymy)
         |    |--N. ewingi Wharton & Hardcastle 1946H98
         |    |--N. fullbergae Brennan 1948G56
         |    |--N. posekanyi Wharton & Hardcastle 1946 (see below for synonymy)H98
         |    `--N. retrocincta Gunther 1939H98
         `--Pentagonella Thor 1936T36
              |--*P. ardeae (Trägårdh 1904) [=Trombidium ardeae]T36
              |--P. acuscutellaris (Walch 1922) [=Trombicula acuscutellaris]T36
              |--P. fahrenholzi (Oudemans 1910) [=Microtrombidium fahrenholzi]T36
              |--P. muris (Oudemans 1910) [=Microtrombidium muris]T36
              |--P. traegardhi (Oudemans 1910) [=Microtrombidium traegardhi]T36
              `--P. yorkei (Sambon 1928) [=Trombicula yorkei]T36
Trombiculidae incertae sedis:
  Ectonyx fusicornis Brennan 1960QV01
  Parasecia gurneyi (Ewing 1937)QV01
  Beamerella autoascutaK06
  Hooperella vesperuginisK06
    |--M. carmenaeK06
    `--M. eltoniWL09
  Trombiculindus Radford 1948S61
  Ascoschoengastia Ewing 1946H98
    |--A. deficiens Lester 19845H98
    |--A. incurva (Womersley 1952) [=Trombicula incurva, Eutrombicula incurva]H98
    |--A. indica (Hirst 1915) [=Schoengastia indica, Neoschoengastia indica]H98
    |--A. loveridgei Lawrence 1951L51
    |--A. rattus (Womersley & Heaslip 1943) (see below for synonymy)H98
    |--A. rhabdomyia Lawrence 1951S69
    |--A. setosa Goff 1979H98
    `--A. transvaalensisL51
  Blankaartia Oudemans 1911B91, S94
    |--B. acuscutellarisWL09
    `--B. niloticaAL37
  Chiroptella Vercammen-Grandjean 1960H98
    `--C. geikiensis Goff 1979H98
  Helenicula Audy 1954H98
    `--H. kohlsi (Philip & Woodward 1946) [=Neoschoengastia kohlsi, Schoengastia kohlsi]H98
  Rudnicula Vercammen-Grandjean 1964H98
    `--R. barbarae (Domrow 1964) [=Trombicula barbarae]H98
  Sasatrombicula Vercammen-Grandjean 1960H98
    `--S. alicola (Domrow 1961) [=Trombicula alicola, T. alicota (l. c.)]H98
  Trombigastia Vercammen-Grandjean & Brennan 1957H98
    `--T. alcithoe Domrow 1959 [=Riedlinia alcithoe, Trombigaster (l. c.) alcithoe]H98
  Dolichotrombicula pectinata Feider 1977DC91
  Vatacarus Southcott 1957WP99, S61
    `--V. ipoidesWP99
  Womersia strandtmanniWP99
  Tragardhula nilotica (Trägårdh 1905) [=Trombidium niloticum]S94
  Austracarus Lawrence 1949CH98
  Hirsutiella zachvatkiniS91
  Herpetacarus Vercammen-Grandjean 1960H98
    `--H. bidentatus (Womersley 1952) [=Schoengastia bidentata]H98
  Myotrombicula Womersley & Heaslip 1943H98
    `--M. vespertilionis Womersley & Heaslip 1943H98
  Schoutedenichia Jadin & Vercammen-Grandjean 1954H98
    |--S. emphyla (Domrow 1960) [=Guntherana emphyla]H98
    |--S. empusa Domrow 1984H98
    `--S. mimema Donrow 1984H98
  Vercammenia Audy & Nadchatram 1957H98
    |--V. gloriosa Domrow 1969H98
    `--V. zweifelorum Domrow et al. 1983H98
  Whartonacarus Vercammen-Grandjean 1960H98
    `--W. shiraii (Sasa et al. 1952) [=Trombicula shiraii]H98
  Discotrombidium villasiense Feider 1977DC91
  Nothotrombicula deinacridae Dumbleton 1947SL71

Ascoschoengastia rattus (Womersley & Heaslip 1943) [=Neoschoengastia rattus, Ascoshoengastia (l. c.) rattus, Euschoengastia rattus, Schoengastia rattus]H98

Gahrliepia Oudemans 1912H98 [incl. Typhlothrombium Oudemans 1910 non Berlese 1910H98, Typhlotrombidium Oudemans 1928O28]

Gahrliepia disparunguis Oudemans 1929 [=Walchia disparunguis; incl. W. fulleri Vercammen-Grandjean 1971, Gahrliepia disparunguis fulleri]H98

*Neoschoengastia americana (Hirst 1921)G56 [=Schoengastia americanaH98; incl. N. entomyza Womersley 1952H98, N. scelopori Ewing 1931G56, N. scleropori (l. c.)G56]

Neoschoengastia posekanyi Wharton & Hardcastle 1946 [incl. N. rectangulare Womersley 1952, N. struthidia Womersley 1952]H98

*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.

[B91] Brown, W. A. 1991. Host parasite relationships and distribution of larval Trombiculidae of the Philippine islands. 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. 627–632. SPB Academic Publishing: The Hague.

[CH98] Colloff, M. J., & R. B. Halliday. 1998. Oribatid Mites: A catalogue of Australian genera and species. CSIRO Publishing: Collingwood.

[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.

[DC91] Daniel, M., V. Černý, J. Štěrba & J. de la Cruz. 1991. Morphological study of adults of trombiculid mites from Cuban hot caves. 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. 2 pp. 261–263. SPB Academic Publishing: The Hague.

[FF22] Fang, Y., Y. Fang, L. Chu, Z. Zuo, L. Liu, R. Feng, Z. Zhang, X. Zhan, F. Li, C. Hu, L. Ding, M. Wu, R. Pan, R. Han, X. Xia, Y. Wen & E. Sun. 2022. The first complete mitochondrial genome of Bdelloidea (Trombidiformes, Eupodina) and comparative genomics provide insights into gene rearrangement and evolution of trombidiform mites. Journal of Stored Products Research 98: 102009.

[G56] Gould, D. J. 1956. The larval trombiculid mites of California (Acarina: Trombiculidae). University of California Publications in Entomology 11 (1): 1–116.

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

[K06] Kwiecinski, G. G. 2006. Phyllostomus discolor. Mammalian Species 801: 1–11.

[L55] Lavoipierre, M. M. J. 1955. On two new species and new records of Acarina mainly from the Ethiopian region. Parasitology 45 (1–2): 121–127.

[L51] Lawrence, R. F. 1951. New parasitic mites form South African lizards. Annals of the Transvaal Museum 31 (4): 447–459.

[O28] Oudemans, A. C. 1928. Fauna Buruana. Acari. Treubia 7 (Suppl. 2): 37–100.

[QV01] Quintero, M. M. T., M. Vargas, B. S. Hernández, P García & N. J. Otero. 2001. Ectoparasitic mites on Heteromys gaumeri in the south of Yucatan, Mexico. In: Halliday, R. B., D. E. Walter, H. C. Proctor, R. A. Norton & M. J. Colloff (eds) Acarology: Proceedings of the 10th International Congress pp. 583–585. CSIRO Publishing: Melbourne.

[S91] Shatrov, A. B. 1991. The alveolar salivary glands of the active phases of trombiculid mites (Trombiculidae). In: Schuster, R., & P. W. Murphy (eds) The Acari: Reproduction, development and life-history strategies pp. 377–378. Chapman & Hall: London.

[S61] Southcott, R. V. 1961. Studies on the systematics and biology of the Erythraeoidea (Acarina), with a critical revision of the genera and subfamilies. Australian Journal of Zoology 9: 367–610.

[S94] Southcott, R. V. 1994. Revision of the larvae of the Microtrombidiinae (Acarina, Microtrombidiidae), with notes on life histories. Zoologica 48 (2): 1–155.

[SL71] Spain, A. V., & M. Luxton. 1971. Catalog and bibliography of the Acari of the New Zealand subregion. Pacific Insects Monograph 25: 179–226.

[S69] Steyskal, G. C. 1969. The mistreatment of the Latin genitive case in forming names of parasites. Systematic Zoology 18 (3): 339–342.

[T35] Thor, S. 1935. Übersicht und Einteilung der Familie Trombidiidae W. E. Leach 1814 in Unterfamilien. Zoologischer Anzeiger 109 (5–6): 107–112.

[T36] Thor, S. 1936. Neue Gattungen in der Familie Trombidiidae W. E. Leach 1814. Zoologischer Anzeiger 114: 29–32.

[UKK96] Uchikawa, K., F. Kawamori & N. Kumada. 1996. How to sample chiggers (Trombiculidae) in field studies of scrub typhus. In: Mitchell, R., D. J. Horn, G. R. Needham & W. C. Welbourn (eds) Acarology IX vol. 1. Proceedings pp. 569–572. Ohio Biological Survey: Columbus (Ohio).

[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 3rd 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).

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