Trombidiidae

Likely Podothrombium filipes, copyright Adam Poledníček.

Belongs within: Parasitengonina.
Contains: Allothrombiinae, Trombidiinae.

The Trombidiidae, velvet mites, are often large, bright red mites that are predatory on small invertebrates and are commonly found in soil habitats. Their larvae are parasitic on other arthropods. Most species are terrestrial; a single species Hygrothrombidium tibiotarsale, characterised by a worm-like habitus and lack of eyes and body pigments, has been described from the hyporheic instertitial of the Bhima River in India (Schwoerbel 1986).

The majority of Trombidiidae have been divided between three subfamilies. In adults of the subfamily Podothrombiinae the body hairs are fine and rarely feathered (Thor 1935). Sensillary setae of larvae are nude in Podothrombiinae but barbed or branched in Allothrombiinae and Trombidiinae (Zhang 1994). Larvae of the Holarctic genus Podothrombium are parasites on aphids. Adults of the northern European type species P. filipes have legs I and IV remarkably long, up to twice the length of the idiosoma (Schweizer & Bader 1963). Other members of the Podothrombiinae include the South American Variathrombium thibaudi and possibly the Australian Pollicothrombium miniatum (Walter et al. 2009). However, a phylogenetic analysis of larval characters by Zhang (1994) placed Pollicothrombium closer to other trombidiids than to Podothrombium, owing to the presence of two setae on coxa II in Pollicothrombium, Allothrombiinae and Trombidiinae versus a single seta in Podothrombium.

The genus Dupreia was established by Oudemans in 1941 as a supposed member of the family Smarididae; the type species is inadequately described and probably represents an unidentifiable trombidiid (Southcott 1961).

Characters (from Kethley 1990; Walter et al 2009): Adults with palptibia usually lacking large spinose setae adjacent to claw; idiosoma not constricted between legs II-III; prodorsal sclerite well developed, idionotum lacking plate posteriorly; pregenital tubercle absent. Larvae with idionotum with unpaired prodorsal plate, and unpaired scutellum bearing setae c1; urstigmata present between coxal plates I-II; femur I bearing 5 setae; femur II usually bearing 4 (rarely 5) setae; genua of legs II-III each bearing 3-4 setae.

<==Trombidiidae [Trombidides, Trombidini]
    |  i. s.: Hygrothrombidium Robaux 1969 [Hygrothrombidiinae] S86
    |           `--H. tibiotarsale Robaux 1969 S86
    |         Dupreia Oudemans 1941 (n. d.) S61
    |           `--*D. pileifera (Karpelles 1891) (n. d.) [=Smaridia pileifera] S61
    |         Metathrombium Oudemans 1910 S61
    |         Ocypete Leach 1814 [Ocypetinae] SB63
    |         Michaelia Berlese 1884 M98
    |--+--Allothrombiinae Z94
    |  `--Trombidiinae Z94
    `--Podothrombiinae [Podothrombiidae] WL09
         |--Variathrombium thibaudi WL09
         |--Pollicothrombium Southcott 1986 WL09, H98
         |    `--P. miniatum (Womersley 1934) [=Caenothrombium miniatum] H98
         `--Podothrombium Berlese 1910 Z94, H98
              |--*P. filipes (Koch 1837) [=Trombidium filipes] SB63
              |--P. bicolor SB63
              |    |--P. b. bicolor SB63
              |    |--P. b. cisalpinum Berlese 1910 SB63
              |    `--P. b. curtipes Schweizer & Bader 1963 SB63
              |--P. blanci Schweizer 1922 SB63
              |--P. dubium WL09
              |--P. filiforme WL09
              |--P. macrocarpum SB63
              |    |--P. m. macrocarpum SB63
              |    |--P. m. septentrionale Berlese 1910 SB63
              |    `--P. m. teutonicum Berlese 1910 SB63
              |--P. montanum Berlese 1910 SB63
              |--P. paucisetarum Zhang & Xin 1989 Z94
              |--P. peragile (Berlese 1884) [=Trombidium peragile] SB63
              |--P. strandi Berlese 1910 SB63
              |--P. subnudum Berlese 1910 SB63
              `--P. tubbi Womersley 1942 H98

*Type species of generic name indicated

REFERENCES

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

[M98] Michael, A. D. 1898. Oribatidae. In: H. Lohmann (ed.) Das Tierreich. Eine Zusammenstellung und Kennzeichnung der rezenten Tierformen vol. 3. Acarina pp. 1–93. R. Friedländer und Sohn: Berlin.

[SB63] Schweizer, J., & C. Bader. 1963. Die Landmilben der Schweiz (Mittelland, Jura und Alpen): Trombidiformes Reuter, mit 217 Arten und Unterarten und 193 Originalzeichnungen. Denkschriften der Schweizerischen Naturforschenden Gesellschaft [Mémoires de la Société Helvétique des Sciences Naturelles] 84 (2): i–vi, 209–378.

[S86] Schwoerbel, J. 1986. Acari: Stygothrombiidae und Thrombidiidae. In: Botosaneanu, L. (ed.) Stygofauna Mundi: A Faunistic, Distributional, and Ecological Synthesis of the World Fauna inhabiting Subterranean Waters (including the Marine Interstitial) pp. 648–651. E. J. Brill/Dr W. Backhuys: Leiden.

[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.

[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.

[Z94] Zhang, Z.-Q. 1994. Neothrombiidae (Acari: Trombidioidea) of the world: systematic review with a phylogenetic analysis and descriptions of two new genera. Oriental Insects 28: 205–237.

Last updated: 28 June 2022.