Description of a new water mite species of the genus Anisitsiellides Lundblad , 1941 ( Acari , Hydrachnidia , Anisitsiellidae ) from Chile

In this paper a new water mite species of the genus Anisitsiellides is described. The material was collected by V. Stolbov in running waters of Chile. Idiosomal setae are named according to Tuzovskij (1987). Furthermore, the following abbreviations are used: P-1-5, pedipalp segments (trochanter, femur, genu, tibia and tarsus); I-Leg-1-6, first leg, segments 1-6 (trochanter, basifemur, telofemur, genu, tibia and tarsus) i.e. ILeg-1= trochanter of first leg; L – length; W – width; n = number of specimen measured; all measurements are given in micrometers (μm).

. Anisitsiellides magellanensis sp.n., male: 1dorsal view; 2ventral view.Scale bar: 1-2 = 100 μm.Description (Male).Idiosoma flat oval with small anteriomedian protrusion (Fig. 1).Dorsal and ventral shields present.Dorsal shield oval but slightly narrowed anteriorly, bearing trichobothria Oi and four pairs of setae associated with glandularia, first three pairs of glandularia associated with long setae, posterior pair of glandularia associated with short, thick setae, and without ridge on each side medial to the glandularia.Dorsal furrow moderately wide, with six pairs of glandularia, five pairs of slit organs and two pairs of minute muscle attachment sclerites in the posterior half.All idiosomal glandularia relatively large, with several comparatively long blades each.
Ventral shields (Fig. 2) oval but narrowed anteriorly, separate lateral eyes present anteriorly, tips of first coxae not projecting beyond anterior margin of idiosoma.Setae and glandularia Hv shifted to the second coxal plate more or less in a line with the posterior end of the V-shaped capitular bay.Median coxal suture line and suture lines between coxal plates I and II distinct.Suture lines between coxal plates II/III and III/IV incomplete obliterated medially; posterior margins of coxal plates IV incomplete, barely distinguishable.Genital field oval with three pairs of acetabula, four pairs of medial and four to five pairs lateral thin setae; anterior two pairs of acetabula oval subequal and larger than posterior triangular pair (Fig. 3).Excretory pore subterminal and located between setae Ci.Dorsal and ventral shields porous Capitulum with convex ventral margin, rostrum comparatively short (Fig. 4).Chelicera basal segment strong thickened proximaly, chela small sickle-shaped (Fig. 5).
Pedipalp moderately long (Fig. 6): P-1 with single dorsodistal seta; P-2 ventral margin straight, with a single ventrolateral seta and six unequal dorsal setae; P-3 ventral margin concave, with four unequal setae; P-4 with large ventral pointed projection bearing two small tubercles and three thin setae, with single spinelike seta and several thin setae distally.
Remarks.The present species is similar to the Southern-American species: Anisitsiellides chilensis Cook, 1988, A. monticolus Lundblad, 1941and A. lundbladi Cook, 1980.The male of A. chilensis is characterized by the slightly convex anterior margin of the idiosoma without anteriomedian protrusion, the dorsal shield with a distinct ridge on each side medial to the glandularia, the glandularia Hv located in the anterolateral corners of coxal plates II, the median coxal suture line and suture lines between coxal plates I and II slightly indicated (Cook, 1988).In contrast, the idiosoma with small anteriomedian protrusion (Figs 1-2), the dorsal shield without ridges on each side medial to the glandularia, glandularia Hv located slightly posterior to anterior margin and far medially from the anteriolateral corners of coxal plates II, the median coxal suture line and suture lines between coxal plates I and II distinct are charactersitic for the new species.The males of A. monticolus Lundblad, 1941 andA. lundbladi Cook, 1980 are characterized by dorsal shield with a distinct ridge on each side medial to the glandularia and absence of a pronounced setal tubercle on the ventral surface of P-4 (Cook 1980(Cook , 1988)).
Ethymology.The species is named after the Province (Magellan) where it was collected.