Piona longipalpis

Piona longipalpis, underside male 12-08-2013
On the male, the pair of the fused third and fourth coxae
are lying together along the median line.
The genital fields lay against the (deep) genital pit
and are fused with the fourth coxae.
Piona longipalpis, underside female 12-08-2013
The female has a wider median space between the pair of the fused third and fourth coxae.
The genital fields are smaller than those of the male. They are connected medial with a small chitin bridge. And because the genital pore is larger than that of the male, their distance to the coxae is larger.

Piona coccinea


By the striking large genital fields with the many acetabula, you can easily recognise Piona longipalpis, the feature is more striking than the longer palps that gave the species its name. I think they look like solidified foam. According to the identification keys, there are more than 60 acetabula on one field (Smit, 2018 and Viets, 1936). Viets (1936) adds that the female has two larger acetabula on each field, but that is not clearly visible here. At the picture of the male though, we can see a larger acetabule on each side of the genital pit.

Among the scooped watermites was not only P. longipalpis, but also specimen of the more common Piona coccinea. Compare the ventral side of the (female) specimen on the picture at right, with that of the P. longipalpis female above. P. coccinea also has quite a number of acetabula, but less than 60. And the genital fields are relatively smaller and more separate from each other. And the coxae and legs have a lighter colour.

Piona longipalpis, onderzijde palp mannetje 12-08-2013

Left: a ventral view of the palp of the male specimen P. longipalpis, with the two larger pegs on P-IV (the fourth segment). Viets (1936) called the peg(s) "Haarhöcker", meaning hairbump(s).

P. coccinea also has two larger pegs on P-IV.

Piona longipalpis, underside male 12-08-2013
Ventral side of the male (trapped in a small drop of water)
Piona longipalpis, onderzijde mannetje 12-08-2013Detail male: third leg foot (III-P-6) and the concave segment on the fourth leg (IV-P-4).

Please click on the pictures below to see other pages on Piona longipalpis.

Piona longipalpis female 12-08-2013
page 1
Piona longipalpis 06-04-2011
page 2
Piona longipalpis, male, underside 12-08-2013
page 3

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© G.H. Visser 24-04-2022
rev. 03-05-2022

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