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Opilioacarida (Opilioacariformes, Notostigmata)
Superorder Parasitiformes
Order Opilioacarida
Family: Opilioacaridae
Common names: opilioacarans, opilioacarids
Probability of Encounter: very low
Quarantine importance:
None. These mites are rare and of no known
quarantine importance.
Diagnosis. Primitive mites related to
the Parasitiformes and resembling small opilionids. Soft-bodied, grey-blue to lilac in colour, usually with white
bands or stripes. Peritremes
absent; opisthosoma bearing four pairs of dorso-lateral spiracles (adults and
tritonymphs); prosoma with 2-3 pairs of lateral ocelli; gnathosoma bearing >4
pairs of ventral setae, rutella and With’s organ; chelicerae 3-segmented, with
3-5 setae and 2 lyrifissures on middle article; palps with 5 segments and well
developed claw; tritosternum unfused, with finger-like processes; coxae free;
trochanters III and IV divided; all pedal tarsi divided.
Similar taxa. Opilionida
(harvestmen) which have segmented opisthosomas and eyes (when present) on
a median turret, and Eupodidae (Prostigmata),
which have 2-segmented chelicerae, genital papillae, and often have swollen
femora IV for jumping. The only
known Australian representative of the group is currently undescribed, but has
been collected in the Kimberleys, Kakadu, and Far North Queensland.
Ecology & Distribution. Predators
and scavengers in Mediterranean and tropical habitats including rainforest litter
and caves. Australian opilioacarans
can be found under rocks in mesic gullies in dry, tropical habitats.
Adults are less than 3 mm in length,
purplish brown with white striped legs, fast moving, and feed on pollen, fungi,
and small arthropods.
References
Grandjean
F. 1936. Un acarien synthetique: Opilioacarus segmentatus With.
Bulletin, Société d'Histoire Naturelle de l'Afrique du Nord 27:
413-444.
Hammen
L van der. 1966. Studies on Opilioacarida (Arachnida). I. Description of Opilioacarus
texanus (Chamberlin and Mulaik) and revised classification of the genera. Zoologische
Verhandelingen 86: 1-80.
Hammen
L van der. 1968. Studies on Opilioacarida (Arachnida). II. Redescription of Paracarus
hexophthalmus (Redikorzev). Zoölogische Mededelingen 43: 57-76.
Hammen
L van der. 1969. Studies on Opilioacarida (Arachnida). III. Opilioacarus
platensis Silvestri and Adenacarus arabicus (With). Zoölogische
Mededelingen 44: 113-131.
Kaiser
T and Alberti G. 1991. The fine structure of the lateral eyes of Neocarus
texanus Chamberlin and Mulaik, 1942 (Opilioacarida, Acari, Arachnida,
Chelicerata). Protoplasma 163: 19-33.
Klompen
JSH. 2000. Prelarva and larva of Opilioacarus
(Neocarus) texanus (Chamberlin and Mulaik) (Acari: Opilioacarida)
with notes on the patterns of setae and lyrifissures. Journal of Natural History 34: 1977-1992.
Walter
DE and Proctor HC. 1998.
Feeding behaviour and phylogeny: Observations on early derivative Acari.
Experimental & Applied Acarology 22: 39-50.