Ixodida (Metastigmata)

Superorder Parasitiformes

  Order Ixodida

     Families: Ixodidae, Argasidae, Nuttalliellidae

 

Common names: hard ticks, soft ticks

 

Probability of Encounter: medium

 

Quarantine importance: Very high.  Ticks are the most important group of disease vectors after the mosquitoes.

 

Diagnosis.  Large parasitiform mites (to 6 mm unfed, 3 cm when engorged) with slicing mouthparts and a denticulate hypostome produced anteriorly.  Integument leathery to papillate, dorsum with or without a prodorsal scutum (covering most of dorsum in males) and with or without one pair of ocelli.  Stigmatal openings on sieve plates behind coxae IV or lateral to coxae III-IV.  Palps 3-4 segmented without apotele.  Tarsus I with Haller's organ well developed.

 

Similar taxa.  Macronyssidae (Mesostigmata) are superficially tick-like mites that feed on the blood of reptiles (Ophionyssus), birds and mammals (Ornithonyssus), but unlike ticks, have a well developed tritosternum, palp apotele, etc.

 

Ecology & Distribution.  Obligate blood-sucking parasites of vertebrates. Living in nests, in soil, on vegetation, and on animals.  Nuttalliellidae is poorly known and restricted to southern Africa; the other two families occur worldwide.  The paralysis tick (Ixodes holocyclus) is a common ixodid tick in eastern Australia.

 

References

Johnston, D.E.  1982.  Acari.  In: Parker, S.P. (ed.)  Synopsis and classification of living organisms.  McGraw-Hill, New York, p. 111.

Klompen, J.S.H. and Oliver Jr., J.H.  1993.  Haller’s organs in the tick family Argasidae (Acari: Parasitiformes: Ixodida).  J. Parasitol. 79: 591-603.

Krantz GW.  1978.  A Manual of Acarology.  OSU Bookstores: Corvallis.

Roberts FHS.  1970.  Australian Ticks.  CSIRO: Melbourne.

Sonenshine DE.  1991.  The Biology of Ticks.  Oxford University Press: Oxford.