Ljania orientalis, Tuzovskij, Petr V., 2012

Tuzovskij, Petr V., 2012, Water mites of the genus Ljania Thor, 1898 (Acari: Hydrachnidia: Aturidae) in Russia, Zootaxa 3249, pp. 1-17 : 12-15

Ljania orientalis sp. n.

( Figs 24–30 )

Type series. Holotype male (slide 9641), Russia, Far East, Primory Territory, Ussuri National Park, Komarovka River, 19.05.1984, leg. T.S. Vshivkova. Paratypes: 1 male and 1 female same locality and date as holotype, leg. T.S. Vshivkova. Type material deposited in collection of the Institute for Biology of Inland Waters (Borok, Russia).

Diagnosis. Adults: Idiosoma elongate (L/W ratio 1.25–1.52), with straight anterior margin; anteromedial margins of Cx–IV very close to each other; anterior and posterior portions of medial margin of Cx–IV approximately equal in length; genital field of males with 19–22 pairs of fine setae; P–2 and P–3 subequal in length, dorsodistal setae on P–3 subequal and shorter of dorsal margin of segment, both ventral setae on P–4 placed near middle of segment; leg claws with short external and long internal clawlets.

Description. Both sexes. Idiosoma elongate (L/W ratio 1.25–1.45) with straight anterior margin.

Anterior ends of Cx–I reaching anterior margin of idiosoma ( Figs 25 , 30 ). Anteromedial margins of Cx–IV and posteromedial margins of Cx–III close to each other, anteromedial portions of Cx–III fused completely; Cx-IV with anteromedial and posteromedial margins (posterior to posteromedial indentation) approximately equal in length.

Pedipalp ( Fig. 26 ): P–3 dorsodistal setae shorter than dorsal margin of segment; P–4 ventral setae near middle of segment.

Legs: See Figs 27-29 . All leg claws with external clawlet shorter than internal clawlet.

Male. Dorsal shield L/W ratio 1.25–1.33. Genital field with 18–22 fine setae on each side. All acetabula small, but anterior acetabulum smaller than both posterior acetabula, distance between anterior acetabulum and median one equal or slightly longer than length median acetabulum; distance between anterior acetabulum and posterior one considerably longer than maximum acetabulum diameter.

Measurements (n=2). L of idiosoma 435–480, W 330–380; L of dorsal shield 405–420, W 285–305; L of anteromedial portion of Cx– IV 50 –55; L of posteromedial portion of Cx– IV 48 –53; L of genital field 58–60, W 125–130; L of genital acetabula (ac. 1–3): 12–18, 18–24, 18–24; L of capitulum 60–65; L of cheliceral basal segment 60, L of cheliceral stylet 18; L of pedipalpal segments (P–1–5): 15–18, 35–37, 30–39, 45–48, 21–24; L of leg segments I–Leg–1–6: 27–30, 35–40, 53–57, 65–70, 68–72, 84–87; II–Leg–1–6: 25–30, 33–35, 39–42, 50–55, 55– 70, 55–60; III–Leg–1–6: 35–42, 42–48, 45–48, 60–63, 65–72, 65–72; IV–Leg–1–6: 60–65, 50–55, 65–72, 83–87, 85–90, 75–78.

Female. Dorsal shield more slender than in male (L/W ratio 1.52). Genital plates L/W ratio 1.33 ( Fig. 30 ).

Measurements (n=1). Length of body 510, width 335; length of dorsal shield 480, width 318; length of anteromedial portion of Cx– IV 62; length of posteromedial portion of Cx– IV 58; length of genital plate 60, width 45; length of genital acetabula (ac. 1–3): 15, 18, 18; length of capitulum 60; length of basal segment of chelicera 60, length of cheliceral stylet 18; length of pedipalpal segments (P–1–5): 27, 40, 36, 54, 24; lengths of leg segments I– Leg–1–6: 33, 48, 60, 65, 85, 87; II–Leg–1–6: 30, 42, 45, 50, 60, 65; III–Leg–1–6: 33, 57, 55, 65, 75, 78, 70–85; IV–Leg–1–6: 60, 60, 72, 93, 95, 90.

Deutonymph. Unknown.

Larva. Unknown.

Differential diagnosis. The present species is similar to the Asian species Ljania japonica Imamura, 1956 described from a single male from Japan and L. propinqua Kim et Chung, 1996 described from several males from South Korea. The male of L. japonica is characterized by the posterior pair of setae (Si) on dorsal shield associated with glandularia, the excretory pore located dorsally, the median suture line Cx–II/III complete, P–3 dorsoproximal setae considerably shorter than dorsodistal setae, and a transverse suture line between the middle of the lateral margin of the Cx–IV and the lateral margin of the ventral shield present ( Imamura 1956). In contrast, males of L. orientalis sp. n. are characterized by setae Si on dorsal shield not associated with glandularia, the excretory pore located ventrally, the median suture line Cx- II/III incomplete, all dorsal setae of P–3 approximately equal in length, and the absence of a transverse suture line between lateral margins of Cx–IV and lateral margins of the ventral shield.

Male L. propinqua are characterized by the dorsal shield with 5 pairs of setae only, setae Hi being located distant from lateral margin of the dorsal shield in the dorsal furrow, anterior coxal plates extending beyond the anterior end of the idiosoma, I–Leg–6 with short subequal ventral setae only ( Kim and Chung 1996). In contrast, the dorsal shield in male L. orientalis sp. n. bears 6 pairs of setae (setae Hi being located close to lateral margin on dorsal shield, anterior coxal plates not extending beyond the anterior end of the idiosoma, I–Leg–6 with 1 long ventroproximal seta and several short subequal ventral setae.

Etymology. The species epithet orientalis is refers to the oriental distribution of the species in Russia.

Habitat. Running waters.

Distribution. Asia, Russia: Far East, Primory Territory.

Figures

FIGURE 30. Ljania orientalis sp. n., female: 30 — ventral view. Scale bar: 30 = 100 μm.

FIGURES 24 – 25. Ljania orientalis sp. n., male: 24 — dorsal view, 25 — ventral view. Scale bar: 24 – 25 = 100 μm.

FIGURES 26 – 29. Ljania orientalis sp. n., male: 26 — pedipalp, lateral view, 27 — Leg I, 28 — leg IV, 29 — claw of leg IV. Scale bars: 26, 29 = 25 μm, 27 – 28 = 50 μm.