Anisitsiellides magellanensis, Tuzovskij & . & . & P- & I- & - & -, 2017

Tuzovskij, Petr V. & Stolbov, Vitaly A., 2017, Description of a new water mite species of the genus Anisitsiellides Lundblad, 1941 (Acari, Hydrachnidia, Anisitsiellidae) from Chile, Ecologica Montenegrina 10, pp. 31-34 : 31-34

Anisitsiellides magellanensis sp. n.

( Figs 1-9 )

Holotype: male, slide 9888, South America, Chile, Region de Magallanes y de la Antártica Chilena, Provincia de Tierra del Fuego, stream running into Lago Blanco (54 o 04’14”S 68 o 52’43’’W), 4.11.2015, leg. V. Stolbov. The holotype is deposited in the collection of the Institute for Biology of Inland Waters (Borok, Russia).

Diagnosis. Male. Dorsal shield without a ridges on each side medial to the glandularia; median coxal suture line and suture lines between the coxal plates I and II distinct; glandularia Hv located slightly posterior to anterior margin and far medially from anteriolateral corners of coxal plates II; IV-Leg-5 much longer than IV-Leg-6; P-4 with comparatively large ventral pointed projection bearing two small tubercles and three thin setae.

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.

IV-Legs with swimming setae, all other legs without swimming setae. Shape and arrangement of setae on I-Leg as show in figure 8. I-Leg-1-5 mainly with some thick setae, I-Leg-6 with thin setae. I-III-Legs claws with two unequal clawlets ( Fig. 9 ), claws absent from fourth legs. IV-Leg-5 much longer than IV-Leg-6 (IV-Leg-5/IV-Leg-6 L ratio 1.57) with two long swimming setae, IV-Leg-6 with three thick unequal distal setae, one short, thin seta and short terminal peg-like seta ( Fig. 7 ).

Measurements (n=1). Idiosoma L 620, W 490; dorsal shield L 560, W 410; capitular bay L 85, capitulum L 120; genital flap L 102, W 42; genital acetabula (ac-1-3) L 27, 27, 14; cheliceral segments L: base 115, chela 36; pedipalp segments (P–1–5) L: 27, 72, 48, 98, 24; legs segments L: I-Leg-1-6: 55, 60, 65, 84, 90, 102; II-Leg-1-6: 55, 60, 65, 85, 102, 110; III-Leg-1-6: 55, 60, 72, 90, 115, 108; IV-Leg-1-6: 95, 65, 90, 102, 132, 85.

Female: Unknown.

Remarks. The present species is similar to the Southern-American species: Anisitsiellides chilensis Cook, 1988 , A. monticolus Lundblad, 1941 and 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 and A. 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, 1988).

Ethymology. The species is named after the Province (Magellan) where it was collected.

Habitat. Running waters.

Distribution. South America, Chile: Magellan Province.

Figures

Figures 1-2. Anisitsiellides magellanensis sp. n., male: 1 – dorsal view; 2 – ventral view. Scale bar: 1-2 = 100 μm.

Figures 3-9. Anisitsiellides magellanensis sp. n., male: 3 – genital field; 4 – capitulum, lateral view, 5 – chelicera, 6 – pedipalp, 7 – IV-Leg-5-6, 8 – I-Leg-4-6; 9 – leg claw. Scale bars: 3-9 = 50 μm.