Is it a mite?

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Nomenclature

Ricinuleida (Ricinulei)

Common names

ricinuleids

Probability of encounter

low

Quarantine importance

No known importance, although of potential conservation concern as threatened cave or rainforest dwelling species.

Similarity to mites

Hexapod larvae, gnathosoma, more or less mite-like build; however, ricinuleids have opisthosomas with three series of dorsal sclerites and clear ventral segmentation.

Morphology

Normal adult length: <10 mm
Body tagmata: gnathosoma, prosoma, idiosoma
Eyes: lens absent (pigment spot may be present)
Antennae: absent
Mouthparts: 2-segmented chelicerae; long, elbowed palps
Legs: 4 pairs (3 pairs in larvae); tarsi I & II with sensory pits
Distinguishing features: cucullus (shelf over mouthparts), elbowed palps, postabdomen

Comments: Ricinuleids and mites (Acari
Factsheet for:Acari
Glossary:Opilioacariformes:
an obsolescent supraordinal term used for the Opilioacarida.
) are the only arthropods with a capitulum, i.e., with the cheliceral and pedipalpal segments separated from the remainder of the prosoma by a circumcapitular groove.

Diversity

1 family (Ricinoididae), 3 geographically +/- discrete genera (Brazil to Honduras: Cryptocellus; Panama to Texas: Pseudocellus; Africa: Ricinoides), >55 spp.

References

• Harvey 2003