Ixodidae
Template:Short description Template:Automatic taxobox
The Ixodidae are the family of hard ticks or scale ticks,<ref name=NCBI>Template:Cite web</ref> one of the three families of ticks, consisting of 750 species, Template:As of.<ref name=":0">Guglielmone, A. A., Petney, T. N., & Robbins, R. G. (2020). Ixodidae (Acari: Ixodoidea): descriptions and redescriptions of all known species from 1758 to December 31, 2019. Zootaxa, 4871(1). https://doi.org/10.11646/zootaxa.4871.1.1</ref> They are known as 'hard ticks' because they have a scutum or hard shield, which the other major family of ticks, the 'soft ticks' (Argasidae), lack. They are ectoparasites of a wide range of host species, and some are vectors of pathogens that can cause human disease.<ref>Sonenshine, D. E., & Roe, R. (2014). Biology of ticks. (Second edition). Oxford University Press.</ref>
Description
The Ixodidae are distinguished from the Argasidae by the presence of a scutum.<ref name="Cox">Template:Cite book</ref> In both the nymph and the adult, a prominent gnathosoma (or capitulum, mouth and feeding parts) projects forward from the animal's body; in the Argasidae, conversely, the gnathosoma is concealed beneath the body.Template:Citation needed
Ixodidae attach to a host bite painlessly and are generally unnoticed, and they remain in place until they engorge and are ready to moult; this process may take days or weeks. Some species drop off the host to moult in a safe place, whereas others remain on the same host and only drop off once they are ready to lay their eggs.Template:Citation needed
Classification
The Ixodidae is divided into two groups: the Prostriata and the Metastriata, distinguished by the position of the anal groove, which is anterior in the former, and posterior in the latter.<ref>Template:Cite book</ref> The Metastriata are further divided into two lineages, Amblyocephalus and Haematobothrion.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> As of 2025, the Ixodidae is composed of 769 extant species in 18 genera, in addition to two fossil genera.<ref name=":0" />Template:Cladogram
| Lineage | Genera | # of Species | |
|---|---|---|---|
| Prostriata | Ixodinae | Ixodes Latreille, 1795 | 274 |
| Metastriata | Amblyocephalus | Amblyomma Koch, 1844 | 135Template:Efn |
| Anomalohimalaya Hoogstraal, Kaiser & Mitchell, 1970 | 3 | ||
| Cosmiomma Schulze, 1919 | 1 | ||
| Dermacentor Koch, 1844 | 43 | ||
| Hyalomma Koch, 1844 | 28 | ||
| Margaropus Karsch, 1879 | 3 | ||
| Nosomma Schulze, 1919 | 1Template:Efn | ||
| Rhipicentor Nuttall & Warburton, 1908 | 2 | ||
| Rhipicephalus Koch, 1844 | 90 | ||
| Haematobothrion | Alloceraea Schulze, 1919<ref name=":1">Template:Cite journal</ref> | 6 | |
| Archaeocroton Dumbleton, 1943<ref name=":2">Barker, S. C., & Burger, T. D. (2018). Two new genera of hard ticks, Robertsicus n. Gen. And Archaeocroton n. Gen., and the solution to the mystery of Hoogstraal's and Kaufman's "primitive" tick from the Carpathian Mountains. Zootaxa, 4500(4). https://doi.org/10.11646/zootaxa.4500.4.4</ref> | 1 | ||
| Bothriocroton Keirans, King & Sharrad, 1994 | 7 | ||
| Cryptocroton Barker & Barker<ref name=":3">Template:Cite journal</ref> | 1 | ||
| Haemaphysalis Koch, 1844 | 170Template:Efn | ||
| Sharifiella Santos Dias, 1958<ref name=":4">Template:Cite journal</ref> | 1 | ||
| Unresolved | Africaniella Travassos Dias, 1974<ref name="hornok">Template:Cite journal</ref> | 2 | |
| Robertsicus Barker & Burger, 2018<ref name=":5">Barker, S. C., & Burger, T. D. (2018). Two new genera of hard ticks, Robertsicus n. Gen. And Archaeocroton n. Gen., and the solution to the mystery of Hoogstraal's and Kaufman's "primitive" tick from the Carpathian Mountains. Zootaxa, 4500(4). https://doi.org/10.11646/zootaxa.4500.4.4</ref> | 1 | ||
| 769 | |||
Fossil generaTemplate:Efn
- †Compluriscutula - 1 species, Poinar and Buckley 2008 Burmese amber, Myanmar, Cenomanian
- †Cornupalpatum - 1 species, Poinar and Brown 2003 Burmese amber, Myanmar, Cenomanian
The Ixodidae is also sometimes classified by its subfamilies, but the current formulations do not encompass all species. There are currently five recognised subfamilies:
- Amblyomminae - comprising Amblyomma.
- Bothriocrotoninae - comprising Bothriocroton.
- Haemaphysalinae - comprising Haemaphysalis.
- Ixodinae - comprising Ixodes.
- Rhipicephalinae - comprising Dermacentor, Margaropus,<ref>Barker, S.C., Kelava, S., Murrell, A., Cho, M., Teo, E.J.M., Nakao, R. & Apanaskevich, D.A. (2025) Margaropus Karsch, 1879 is not closely related to Boophilus Curtice, 1891 (Acari: Ixodidae). Zootaxa, 5569 (3), 477–492. https://doi.org/10.11646/zootaxa.5569.3.4</ref> Rhipicephalus, Rhipicentor, Hyalomma and Nosomma.Template:Efn
Medical importance
Many hard ticks are of considerable medical importance, acting as vectors of diseases caused by bacteria, protozoa, and viruses, such as Rickettsia and Borrelia.<ref name="Cox"/> Other tick-borne diseases include Lyme disease, babesiosis, ehrlichiosis, Rocky Mountain spotted fever, anaplasmosis, Southern tick-associated rash illness, tick-borne relapsing fever, tularemia, Colorado tick fever, Powassan encephalitis, and Q fever.<ref>Template:Cite web</ref> Ixodid ticks are the primary vectors of tick paralysis, which can affect domestic dogs, cats and livestock, as well as humans.<ref>Template:Cite journal</ref>