Unionicola arcuata Wolcott 1898
Creators: name: Tuzovskij, Petr V.
name: Semenchenko, Ksenia A.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Trombidiformes
Unionicolidae
Unionicola
Unionicola arcuata

description: Unionicola arcuata (Wolcott, 1898)
(Figs 43A–D, 44A–B)
Material examined. 2 males, 3 females: Russia, Primory Territory, Khankaysky District, Khanka Lake, region of Luzanovaya hill, 10.08.2012, from mantle cavity of Sinanodonta schrencki Moskvicheva, leg. S.G. Surmach; 3 males, 3 females: Russia, Primory Territory, Nadezhdensky District, former riverbed of Ananevka, 12.10.2005, from mantle cavity of Cristaria sp., leg. M.B. Shedko; 1 female, Russia, Primory Territory, Oktyabrsky District, former riverbed lake near station Razdolnaya, 15.09.2010, from mantle cavity of Sinanodonta primorjensis Bogatov & Zatravkin, leg. V.V. Bogatov.
Diagnosis. Adults. Dorsum without any platelets; coxal plates III+IV subquadrate with convex medial margin; P-3 with long proximal and short distal setae, P-4 slightly tapering distally, with three small unequal tubercles, P-5 with three unequal distal spines; genital acetabula 16–35 pairs in females and 21–34 pairs in males; genital field of female with two wide plates; genital plates of male wide, fused to each other posteriorly; legs without swimming setae, IV-Leg-6 curved; leg claws stout sickle-shaped with short dorsal clawlet and long ventral one.
Description. Both sexes. Dorsum without any platelets. Anterior and posterior coxal groups (Figs 43A, 44A) divided by wide interspace, sclerites, bearing setae and glandularia Le, not larger than sclerites bearing other idiosomal setae. Apodemes of first coxal groups short and truncated. Coxal plates III+IV subquadrate (L/W ratio 0.94–1.28) with rounded medial margin. Surface of all coxal plates punctated.
Pedipalps (Fig. 43C) short and stocky: P-2 with five setae; P-3 with long proximal and short distal setae; P-4 slightly tapering distally, with three tubercles two of which bearing seta, lateral tubercle longer than other tubercles; P-5 short, with three unequal distal spines.
Legs long and slender, last segments more slender, with widened distal dorsal setae, IV-Leg-6 curved (Fig. 43D); all segments, except trochanter, cylindrical; legs II–III with 2–3 short thin setae. Claws of all legs thick sickle-shaped with short dorsal clawlet and long ventral one (Figs 43E, F).
Male. Genital plates of male wide, fused to each other posteriorly, with 21–34 pairs acetabula and 9–10 short, thin setae; two acetabula on each plate enlarged (Fig. 43B).
Measurements (n=2). Idiosoma L 1275–1290; coxae III+IV L 408–541, W 376–425; genital plates L 224–237, W 138–151; pedipalpal segments (P-1–5) L: 27–34, 148–152, 72–82, 124–138, 70–77; leg segments L: I-Leg- 1–6—92 –104, 165–166, 172–184, 238–264, 231–250, 158–172; II-Leg- 1–6—92 –100, 165–191, 244–303, 343–363, 336–365, 237–244; III-Leg-1–6—105–106, 185–191, 230–231, 270–284, 323–342, 283–284; IV-Leg- 1–6—172–195, 198–231, 277–310, 320–366, 449–495, 403–442.
Female. Genital field with two wide acetabular plates, with 16–35 acetabula and 9–11 thin unequal setae; three to four acetabula on each side enlarged (Fig. 44B).
Measurements (n=2). Idiosoma L 1224–1258; coxae III+IV L 415–595, W 442–460; genital plates L 231–237, W 165–198; pedipalpal segments (P-1–5) L: 28–36, 138–140, 79–85, 131–145, 72–73; leg segments L: I-Leg- 1–6—92 –105, 172–178, 173–191, 251–270, 231–264, 165–178; II-Leg- 1–6—92 –99, 198–204, 271–290, 356–382, 373–402, 242–264; III-Leg-1–6—112–113, 190–198, 244–257, 280–303, 344–370, 296–297; IV-Leg- 1–6—198–205, 199–230, 290–327, 363–396, 488–525, 448–455.
Larva. Unknown.
Deutonymph. See Imamura 1953b.
Habitat. Lakes, rivers, brooks.
Hosts. Unionidae. Very numerous hosts species on different countries and continents (Imamura 1953a; Wen & Zhu 1999; Wu et al. 2012; Edwards & Vidrine 2013). Hosts in Russia: Sinanodonta schrencki, S. primorjensis, Cristaria sp. (this study).
Distribution. Russia (Primory Territory) (this study), China (Wen & Zhu 1999), North America (Vidrine 1986; Edwards & Vidrine 2013). This species is reported from Russia for the first time.
Remaks. Wu et al. (2012) indicated with DNA analyses that this species includes a number of host-associated if not geographical associated cryptic species. M.F. Vidrine (1986) indicated that at least 3 host-associated species were discernable among North American populations, but he did not separate these species at that time. Additional researches may explicate the species-level taxonomy of these mites.
description: Published as part of Tuzovskij, Petr V. & Semenchenko, Ksenia A., 2015, Water mites of the genus Unionicola Haldeman, 1842 (Acari, Hydrachnidia, Unionicolidae) in Russia, pp. 401-456 in Zootaxa 3919 (3) on pages 451-453, DOI: 10.11646/zootaxa.3919.3.1, http://zenodo.org/record/241378