Tetranychoidea

Distinguished from other trombidiform superfamilies by the stylophore—a fused cheliceral base movable independently of the subcapitulum. The combination of elongated stylet-like cheliceral digits, well-developed peritremes with protuberant endings on the prodorsum, and tenent hairs on true claws is diagnostic. Families are distinguished by: prodorsal setae number (3 vs. 4 pairs), eye presence/absence, palptibial claw complex presence/absence, body shape (flattened vs. rounded), and setal modifications (leaf-like, flagelliform).

Mites possess cheliceral bases fused into a movable structure called a stylophore, which can be retracted into the prodorsum. Movable digits of chelicerae are greatly elongated and stylet-like, with strongly recurved bases within the stylophore. A pair of well-developed peritremes is embedded anteriorly on the prodorsum, ending in protuberant enlargements. True claws of legs bear tenent hairs. Males possess aedeagi for direct sperm transfer. Family-level diagnostic features include: Allochaetophoridae with 3 pairs of prodorsal setae (vs. 4 in other families); Linotetranidae lacking eyes, usually colourless and slender; Tenuipalpidae lacking palptibial claw complex, body often flattened with well-developed plates; Tetranychidae with eyes, 4 pairs of prodorsal setae, and palptibial complex; Tuckerellidae with expanded leaf-like dorsal setae and flagelliform setae on posterior body margin.

Occupies diverse terrestrial habitats including soil, leaf litter, bark, grasslands, and agricultural fields. Found from lowland to alpine zones, with species diversity varying by elevation. Many species are intimately associated with host plants, occurring on leaves, stems, and roots. Some families (Linotetranidae) are primarily soil-dwelling and associated with grasses and sedges; others (Tetranychidae, Tenuipalpidae) are predominantly foliar.

Cosmopolitan distribution with records from all major biogeographic regions. Documented from Iran (198 species across 39 genera), Ukraine/Transcarpathia (28 tetranychid species), Syria (16 species), Crimea, New Zealand (alpine zones), Australia, and Eocene Baltic and Rovno amber (ca. 40 mya) indicating long evolutionary history. Uneven research coverage; some regions (Yazd and Qazvin Provinces, Iran) lack records.

Exclusively herbivorous. Feeding mechanism involves piercing plant tissue with cheliceral stylets to inject saliva; fluid uptake occurs through separate channels, not via stylets. Documented feeding on stomatal openings and epidermis. Host plant associations include: palms (Arecaceae), grasses (Poaceae), oaks (Fagaceae), pines (Pinaceae), legumes (Fabaceae), roses (Rosaceae), and cushion-forming shrubs (Ericaceae). Some species exploit both aboveground and underground plant parts.

• Phoenix roebelenii - hostArecaceae; Raoiella indica feeds on stomata and epidermis
• Dracophyllum muscoides - hostEricaceae; alpine cushion fields, New Zealand
• Astragalus gossypinus - hostFabaceae; soil-associated, Iran
• Prunus armeniaca - hostRosaceae; apricot, soil beneath trees
• Prunus amygdalus - hostRosaceae; almond, soil under trees
• Quercus - hostFagaceae; litter and bark
• Pinus - hostPinaceae; soil under stone and pine

Raoiella indica has been observed with stylets inserted into leaf stomatal openings, suggesting site-specific feeding behavior. Tuckerella weiterschani (fossil) displays setae h1–h8 held erect and directed forward over the body, interpreted as a defensive posture matching extant Tuckerella species. Adoral setae function as mechanoreceptors that may guide mites to feeding sites.

Herbivorous mites exploiting plant resources; form part of food webs supporting predatory mites (Phytoseiidae) and other natural enemies. Species composition and abundance vary with altitude, temperature, humidity, and host plant availability. In Transcarpathia, tetranychid diversity peaks in lowlands (23 species), declines in foothills (19), and is lowest in mountains (11).

Multiple species are significant agricultural and ornamental plant pests, particularly in families Tetranychidae, Tenuipalpidae, and Tuckerellidae. Raoiella indica (red palm mite) has spread rapidly and damages palms globally. Spider mites (Tetranychidae) are among the most economically important mite pests. Host plants include wheat, barley, alfalfa, and fruit trees.

• Other Trombidiformes superfamiliesLack the diagnostic stylophore structure and associated cheliceral modifications of Tetranychoidea
• Tetranychidae vs. TenuipalpidaeTetranychidae possess palptibial complex and eyes; Tenuipalpidae lack palptibial claw complex and often have flattened bodies with plates
• Linotetranidae vs. other TetranychoideaLinotetranidae lack eyes and are colourless and slender, unlike other families which typically possess eyes

• mites
• acari
• phytophagous
• agricultural pests
• stylophore
• herbivory

• BugGuide
• Wikipedia
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Two Eocene species of peacock mites (Acari: Tetranychoidea: Tuckerellidae)
• A catalog of superfamily Tetranychoidea (Acari: Trombidiformes) from Iran
• Two new species of Linotetranus (Parasitiformes: Tetranychoidea: Linotetranidae) from Iran
• A Contribution to the Fauna and Biology of Tetranychid Mites of the Crimea (Acariformes, Tetranychoidea)
• Three new species of flat mites (Acari: Tetranychoidea: Tenuipalpidae) from alpine New Zealand
• Ecologo-faunistic review of tetranychid (Acariformes: Tetranychoidea) and phytoseiid mites (Parasitiformes: Phytoseiidae) in the Transcarpathian Region, Ukraine</p >
• <p class="Body">Updated contribution to the knowledge of Tetranychoidea (Acari: Tetranychidae, Tenuipalpidae) from Syria with reinstatement of genus Nuciforaella Vacante
• Cryptic false spider mites: a new genus, Austrolinus , and a review of the family Linotetranidae (Acari : Prostigmata : Tetranychoidea)
• Ultrastructure and functional morphology of the mouthparts in Raoiella mites (Tetranychoidea: Tenuipalpidae): how they use the cheliceral stylets during feeding