Trombidiformes Temporal range: Devonian–present PreꞒ Ꞓ O S D C P T J K Pg N
Trombidium holosericeum
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Class:	Arachnida
Superorder:	Acariformes
Order:	Trombidiformes
Suborders
See text

The Trombidiformes are a large, diverse order of mites.

Taxonomy

In 1998, Trombidiformes was divided into the Sphaerolichida and the Prostigmata.^[1] The group has few synapomorphies by which it can be defined, unlike the other major group of acariform mites, Sarcoptiformes.^[1] Its members include medically important mites (such as Demodex, the chiggers, and scrub-itch mites) and many agriculturally important species, including the spider mites (Tetranychidae).^[1] The superfamily Eriophyoidea, traditionally considered members of the Trombidiformes, have been found to be basal mites in genomic analyses, sister to the clade containing Sarcoptiformes and Trombidiformes.^[2]

The 2004 classification retained the two suborders, comprising around 125 families and more than 22,000 described species.^[3]

In the 2011 revised classification, the order now contains 151 families, 2235 genera and 25,821 species, and there were another 10 species with 24 species that present only as fossils.^[4] These 151 families were classified into the same two major suborders^[4]：

• Sphaerolichida OConnor, 1984: Now contains only two families;
• Prostigmata Kramer, 1877: Still the biggest branch in this taxon, with four infraorders and 40 superfamilies.