What is a tick classified as? - briefly
A tick is an arachnid belonging to the order Acari, subclass Parasitiformes. It is more closely related to spiders and mites than to insects.
What is a tick classified as? - in detail
Ticks belong to the phylum Arthropoda, class Arachnida, and subclass Acari. Within Acari they are placed in the order Ixodida, which separates them from other mite groups.
The order contains three recognized families:
- Ixodidae – hard ticks, characterized by a scutum covering the dorsal surface.
- Argasidae – soft ticks, lacking a scutum and possessing a leathery, flexible cuticle.
- Nuttalliellidae – a single‑species family that exhibits traits of both hard and soft ticks and represents a basal lineage within Ixodida.
Hard ticks (Ixodidae) possess a rigid dorsal shield, a capitulum that projects forward, and a lengthy feeding period that can last several days. Soft ticks (Argasidae) have a more rounded body, a concealed capitulum, and typically feed for minutes to hours. Nuttalliella, the sole member of Nuttalliellidae, displays a combination of these features and provides insight into the evolutionary transition between the two main families.
Ticks share a common ancestor with other mites, forming the cohort Acari. Molecular phylogenetics places Ixodida as a monophyletic group nested within the larger mite clade, confirming that ticks are a specialized lineage of arachnids adapted to hematophagy. Their classification reflects both morphological specializations and genetic relationships, establishing ticks as distinct arachnid parasites within the Acari subclass.