Is it a mite?

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Nomenclature

Palpigradida (Palpigradi)

Common names

palpigrades

Probability of encounter

low

Quarantine importance

No known importance.

Similarity to mites

Small size, strong chelicerae; somewhat mite-like when the flagellum breaks off (common), but with clear opisthosomal segmentationsegmentation:
in mites distinct external segments have been lost but remnants of segmentation may be represented by hysterosomal folds or transverse arrays of setae and other cuticular sense organs.  In theory, all chelicerates have a prosoma composed of 6 segments (cheliceral, pedipalpal, and four leg-bearing segments = body segments I-VI).  Ventrally the positions of the prosomal segments can be identified by the insertions of their appendages, but dorsally they are obscured.  The opisthosoma is thought to comprise an additional 12-13 segments (body segments VII-XVIII or XIX), but appears to be somewhat to much reduced in most mites, except possibly Opilioacarida.  In early derivative Acariformes (e.g., many Endeostigmata), hysterosomal folds are thought to represent segmentation and in the Grandjean system are designated (from the sejugal furrow to the anus): C, D, E, F, H, PS AD, AN, PA.  There is disagreement in the literature over the origin of 'segments' C and D.  Adherents of Grandjean consider them to be opisthosomatic (with C probably representing a fusion of the pregenital [body segment VII] and genital [VIII] segments).  Others believe that C and D are the dorsal regions of the last two prosomal segments that bear leggs III and IV (i.e., body segments V & VI).
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Morphology

Normal adult length: <1 mm
Bodybody:
the idiosoma of mites.
tagmata: prosomaprosoma:
(= cephalothorax) the anterior body region in arachnids; usually not distinct in mites.
, opisthosomaopisthosoma:
(= abdomen) the posterior body division in arachnids; usually not distinct in mites because of the fusion of the opisthosoma with part of the prosoma to form the idiosoma.
, segmented telson (flagellum)
Eyes: absent
Antennae: absent
Mouthparts: 3-segmented chelicerae; leg-like palps
Legs: 4 pairs; legs I antenniform
Distinguishing features: tail-like flagellum; finger-like median and lateral organs; 3-segmented chelicerae

Diversity

2 families, 6 genera, >78 spp.

References

• Harvey 2003