The female specimens of the Arrenurus genus are often difficult to determine to the species. They all have a somewhat flattened, convex body with a shell and a dorsal seam. The color is often brown or green. The small palps also look almost the same. The photos above therefore provide no certainty as to whether this is an A. buccinator female.

The upper and lower sides of this water mite. On the upper side, a few platelets can be distinguished. Furthermore, the dorsal suture is clearly visible, it is elliptical and has a large distance to the eyes. As in all Arrenurus species, the two pairs of eyes are combined into one pair.

On the underside: the epimeres and the genital with the plates, these are also provided with an armoring similar to that of the body, but with smaller "cells". The characteristics that point to A. buccinator are: (Besseling,1964 and Viets,1936)

• the gonopore membranes bear no no sclerotized patches
• the acetubala-bearing plates are (approximately) widest in the middle, they are not particularly wide, nor narrow and/or long
• the distance from the gonopore and the acetabula-bearing plates to the coxal plates is somewhat smaller than that to the posterior edge
• the distance of the fourth coxal plates is more than 1.5 times the width of one membrane
• the angle of the posterior side of the fourth coxal plates with the inner sides is (more or less) a right angle, the posterior edges are straight
• the fourth coxal plates are much broader medially than the third coxal plates
• the body has no distinct rear angles
• The length falls within the specified dimensions of 1085 to 1385 μm

An important first clue: there are no setae groups on the insides of the palps. This is not visible here, but on the next page with microscopic images. Everything points to this species, which is why I successfully went actively looking for a male specimen.