Aturus elongatus Walter, 1927

Gerecke, Reinhard, 2014, Studies on European species of the water mite family Aturidae Thor (Acari: Hydrachnidia), Zootaxa 3841 (1), pp. 1-46 : 10

Aturus elongatus Walter, 1927

Species incerta

Material examined. Type series: Syntypes MNHN 4535 " Aturus elongatus Walter Oisans 19.7.1926 Motaş 270" "XXVIII/67" [label Gerecke:] " Syntypes: ♀, 3 dn" (all specimens undissected, completely dried).

Remarks. This species was described from two sites in the Dauphiné region in SW France (Affluent du Sonnant à Sonnant, 25.05.1926 – 1 ♀; ruisseau du Pied-Moutet, Oisans, 19.09.1926 – 2 ♀♀, 1dn, 2 tn – Walter & Motaș 1927), but only the slide mentioned above is conserved in NHMB. Notwithstanding some contradictions (different collecting date on the label, none of the three preadults on the slide is a tritonymph), the specimens belong most probably to the type series. However, as the ♀ is undissected, it is surely not the one described in the original publication which includes palp and leg measurements. Walter described this species as new to science based on characters such as coloration and formation of coxae (in the deutonymph Cx-I+II medially fused) and genital plates (deutonymph with 3–4 pairs of Ac, female with 12–14, some of them located in a double row) and named it for its relatively slender idiosoma shape. In view of the lack of clear-cut diagnostic characters, a description based on females and deutonymphs (with the additional problem how to ascertain conspecifity between adults and preadult stages) cannot produce a reliable species definition in Aturus . Motaş (1928f) made the attempt to attribute males to Aturus elongatus which were found in the same geographic area, but his material is now lost completely. As to deduce from his figures and measurements, the specimens on which his description are based agree in most details with A. spatulifer (see below). The only difference is the presence of paired posterolateral grooves in the latter, while Motaş depicts for A. elongatus an unpaired depression in this area. When larger populations of A. spatulifer are studied, it is found that the medial ridge separating the named two grooves may be more or less developed. In the latter case, they merge to form an unpaired structure as depicted by Motaş. In view of the lack of material for comparison, a final decision is no more possible, but with high probability the specimens attributed to A. elongatus by Motaş represent A. spatulifer while the identity of the holotype of A. elongatus remains uncertain.