Ixodidae

The Ixodidae are the family of hard ticks or scale ticks,[1] one of the two big families of ticks, consisting of over 700 species. They are known as 'hard ticks' because they have a scutum or hard shield, which the other big 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.

Ixodidae
Temporal range: Cretaceous–present
Ixodes ricinus (engorged)
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Ixodida
Superfamily: Ixodoidea
Family: Ixodidae
C. L. Koch, 1844

Description

They are distinguished from the Argasidae by the presence of a scutum.[2] 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.

They differ, too, in their lifecycle; Ixodidae that attach to a host bite painlessly and are generally unnoticed, and they remain in place until they engorge and are ready to change their skin; 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.

Classification

There are 702 species in 14 genera.[3]The family contains these genera:[3]

  • Amblyomma – 130 species (includes some of Aponomma)
  • Anomalohimalaya – three species
  • Bothriocroton – seven species
  • Cosmiomma – one species
  • Cornupalpatum – one species
  • Compluriscutula – one species
  • Dermacentor – 34 species (includes Anocentor)
  • Haemaphysalis – 166 species
  • Hyalomma – 27 species
  • Ixodes – 246 species
  • Margaropus – three species
  • Nosomma – two species
  • Rhipicentor – two species
  • Rhipicephalus – 82 species (includes Boophilus)

Medical Importance
See also: Tick-borne disease

Many hard ticks are of considerable medical importance, acting as vectors of diseases caused by bacteria, protozoa, and viruses, such as Rickettsia and Borrelia.[2] The saliva of female ticks is toxic, causing ascending paralysis in animals and people, known as "tick paralysis." Tick species that are commonly associated with tick paralysis are Dermacentor andersoni, Dermacentor occidentalis, Dermacentor variabilis, and Ixodes holocyclus.[4]

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.[5]

See also

References
  1. "Ixodidae". NCBI taxonomy. Bethesda, MD: National Center for Biotechnology Information. Archived from the original on 14 May 2018. Retrieved 28 September 2017. Lineage( full ) cellular organisms; Eukaryota; Opisthokonta; Metazoa; Eumetazoa; Bilateria; Protostomia; Ecdysozoa; Panarthropoda; Arthropoda; Chelicerata; Arachnida; Acari; Parasitiformes; Ixodida; Ixodoidea
  2. D. H. Molyneux (1993). "Vectors". In Francis E. G. Cox (ed.). Modern parasitology: a textbook of parasitology (2nd ed.). Wiley-Blackwell. pp. 53–74. ISBN 978-0-632-02585-5. Archived from the original on 2017-02-15. Retrieved 2016-11-06.
  3. Alberto A. Guglielmone; Richard G. Robbing; Dmitry A. Apanaskevich; Trevor N. Petney; Agustín Estrada-Peña; Ivan G. Horak; Renfu Shao; Stephen C. Barker (2010). "The Argasidae, Ixodidae and Nuttalliellidae (Acari: Ixodida) of the world: a list of valid species names" (PDF). Zootaxa. 2528: 1–28. Archived (PDF) from the original on 2019-07-24. Retrieved 2015-06-28.
  4. Sirois, Margi (2015). Laboratory Procedures for Veterinary Technicians. St. Louis, MO: Elsevier.
  5. "CDC - Tick-Borne Diseases - NIOSH Workplace Safety and Health Topic". www.cdc.gov. 2018-11-14. Archived from the original on 2019-07-01. Retrieved 2019-07-01.
  • Data related to Ixodidae at Wikispecies
  • Media related to Ixodidae at Wikimedia Commons
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