Piona alpicola (Neuman, 1880) – female – identification almost certain

fig 10 piona alpicola ? dorsal view

This water mite is a Piona, probably a Piona alpicola. Length 1.4mm. From Saint Marin Au Laërt. June 2011.

My description of this piona.

Lenght 1.4mm.
Shape of the body an oval a litlle bit truncated at the posterior end.
Malpigian vessel bright orange (fig 60).
Palpi vey thick at the base.
Palpi length more than 0.5mm
Eyes dark brown.
Coxae not joint at all and rather well apart.
Particularity at the posterior end of first coxae (fig 80).
Genital area sickle shaped with a yellow line in the midle (fig 40).
Sclerites at the both end of the genital area well visible (fig 30).
No acetabulae visibles on my pictures.
A lot of strong setae on the legs (fig 30 and 70).

Specie possible following Soar & Williamson.

Piona controversiona female. S&W volume 2 – page 201 – plate 40.

For this identification

Length up to 1.6mm.
Outline oval, with the anterior end emarginate.
Colour green with black patches about the reddish yellow Malpigian vessel.
Palpi thicker than the first pair of legs.
Epimera : like piona uncata but rather more widely separated
Genital area : very closed to the figure 1, plate 40 of S&W

Against this identification of Piona controversiosa.

Elements not visible or evident on my pictures.

Palpi : Near the middle of the flexor surface of the fourth segment, two noticeable papillae and at the distal inner end a chitinous peg (my fig 50 show the end of the palpi seen from the ventrl surface but the description of S&W is not eviendent at all to recognize).
Epimera : on the outer half of posterior margin of fourth pair, a group of hairs close to the edge (invisible on my pictures).
Genital area : outer edge rounded, inner edge very slightly concave.
Genital area : each plate with about thirteen acetabula.

A CHECKLIST OF THE WATER MITES OF FRANCE

In this paper published by Harry S MIT1 and Reinhard GERECKE in the review Acarologia 50-1 of april 2010, the Piona uncata controversiosa (Piersig, 1896) is considered as a synonime of Piona alpicola (Neuman, 1880). This Piona alpicola had already been found in the departement of Pas de Calais in France.

The other synonimous are : Piona uncata (Koenike, 1888) and Nesaea viridis Koch, 1836.

Catalogue des hydrachnides (1887).

In their « catalogue des hydrachnides recuillies dans le nord de la France », Barois and Moniez wrote that the Nesaea viridis Koch (considered by Gerecke as Piona alpicola) is a specie rather common in their (my) arrea.