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

Belongs within: Parasitengonina.
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 1956 S61
    |    `--Gahrliepia Oudemans 1912 H98 (see below for synonymy)
    |         |--G. disparunguis Oudemans 1929 (see below for synonymy) H98
    |         |--G. morobensis (Gunther 1939) [=Walchia morobensis] H98
    |         `--G. suduski UKK96
    |--Walchiinae G56
    |    |--Walchia Ewing 1932 T35
    |    |    |--‘Trombidium’ ewingi Fuller 1949 [incl. T. glabrum Walch 1927 non Duges 1834, *Walchia glabra] G56
    |    |    `--W. americana Ewing 1942 G56
    |    `--Pseudoschoengastia Lipovsky 1951 G56
    |         |--*P. hungerfordi Lipovsky 1951 G56
    |         |--P. occidentalis Brennan 1952 G56
    |         `--P. scitula Brennan & Jones 1959 QV01
    `--Trombiculinae [Schoengastiini, Trombiculini] WL09
         |--Novotrombicula Womersley & Kohls 1947 S61
         |--Babiangia Southcott 1954 S61
         |--Trombicula B91
         |--Heterotrombidium Verdun 1909 T35
         |--Doloisia Oudemans 1910 T35
         |--Schoengastiella Hirst 1915 T35
         |    `--S. tauffliebi Lavoipierre 1955 L55
         |--Neotrombicula T35
         |--Leptotrombidium G56
         |--Eutrombicula G56
         |--Euschongastia G56
         |--Schoengastia Ouddemans 1910 T36
         |    |--S. gutekunsti Goff 1981 H98
         |    |--S. schueffneri G56
         |    `--S. vandersandei G56
         |--Neoschoengastia Ewing 1929 T35
         |    |--*N. americana (Hirst 1921) G56 (see below for synonymy)
         |    |--N. ewingi Wharton & Hardcastle 1946 H98
         |    |--N. fullbergae Brennan 1948 G56
         |    |--N. posekanyi Wharton & Hardcastle 1946 (see below for synonymy) H98
         |    `--N. retrocincta Gunther 1939 H98
         `--Pentagonella Thor 1936 T36
              |--*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 1960 QV01
  Parasecia gurneyi (Ewing 1937) QV01
  Euschoengastoides QV01
  Beamerella autoascuta K06
  Hooperella vesperuginis K06
  Microtrombicula B91
    |--M. carmenae K06
    `--M. eltoni WL09
  Trombiculindus Radford 1948 S61
  Ascoschoengastia Ewing 1946 H98
    |--A. deficiens Lester 19845 H98
    |--A. incurva (Womersley 1952) [=Trombicula incurva, Eutrombicula incurva] H98
    |--A. indica (Hirst 1915) [=Schoengastia indica, Neoschoengastia indica] H98
    |--A. loveridgei Lawrence 1951 L51
    |--A. rattus (Womersley & Heaslip 1943) (see below for synonymy) H98
    |--A. rhabdomyia Lawrence 1951 S69
    |--A. setosa Goff 1979 H98
    `--A. transvaalensis L51
  Blankaartia Oudemans 1911 B91, S94
    |--B. acuscutellaris WL09
    `--B. nilotica AL37
  Cheladonta B91
  Chiroptella Vercammen-Grandjean 1960 H98
    `--C. geikiensis Goff 1979 H98
  Diplectria B91
  Eltonella B91
  Heaslipia B91
  Helenicula Audy 1954 H98
    `--H. kohlsi (Philip & Woodward 1946) [=Neoschoengastia kohlsi, Schoengastia kohlsi] H98
  Laurentella B91
  Myotrombidium B91
  Neosomia B91
  Octasternala B91
  Paraschoengastia B91
  Rudnicula Vercammen-Grandjean 1964 H98
    `--R. barbarae (Domrow 1964) [=Trombicula barbarae] H98
  Sasatrombicula Vercammen-Grandjean 1960 H98
    `--S. alicola (Domrow 1961) [=Trombicula alicola, T. alicota (l. c.)] H98
  Toritrombicula B91
  Trombigastia Vercammen-Grandjean & Brennan 1957 H98
    `--T. alcithoe Domrow 1959 [=Riedlinia alcithoe, Trombigaster (l. c.) alcithoe] H98
  Walchiella B91
  Dolichotrombicula pectinata Feider 1977 DC91
  Vatacarus Southcott 1957 WP99, S61
    `--V. ipoides WP99
  Womersia strandtmanni WP99
  Tragardhula nilotica (Trägårdh 1905) [=Trombidium niloticum] S94
  Austracarus Lawrence 1949 CH98
  Hirsutiella zachvatkini S91
  Guntheria H98
  Herpetacarus Vercammen-Grandjean 1960 H98
    `--H. bidentatus (Womersley 1952) [=Schoengastia bidentata] H98
  Myotrombicula Womersley & Heaslip 1943 H98
    `--M. vespertilionis Womersley & Heaslip 1943 H98
  Schoutedenichia Jadin & Vercammen-Grandjean 1954 H98
    |--S. emphyla (Domrow 1960) [=Guntherana emphyla] H98
    |--S. empusa Domrow 1984 H98
    `--S. mimema Donrow 1984 H98
  Vercammenia Audy & Nadchatram 1957 H98
    |--V. gloriosa Domrow 1969 H98
    `--V. zweifelorum Domrow et al. 1983 H98
  Whartonacarus Vercammen-Grandjean 1960 H98
    `--W. shiraii (Sasa et al. 1952) [=Trombicula shiraii] H98
  Hoffmaniella DPD16
  Discotrombidium villasiense Feider 1977 DC91
  Nothotrombicula deinacridae Dumbleton 1947 SL71

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

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

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

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


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Last updated: 26 June 2022.

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