Maxinia arctomontana, Lindquist, Evert E. & Makarova, Olga L., 2012

Lindquist, Evert E. & Makarova, Olga L., 2012, Review of the mite subfamily Arctoseiinae Evans with a key to its genera and description of a new genus and species from Siberia (Parasitiformes, Mesostigmata, Ascidae), ZooKeys 233, pp. 1-20 : 5-10

Maxinia arctomontana sp. n. Figs 135

Material.

Holotype, female: EAST SIBERIA, YAKUTIYA, Suntar-Khayata Range, upper reaches of Kyubyume R., 63°13'N, 139°36'E, 1850 m a.s.l., SW slope, bird outlook with gramineous vegetation, 19.VII 2002, O.L. Makarova (ZIRAS).

Paratypes: 16 females, 3 males with same data as for holotype (ZIRAS); 6 females, 1 male, the same district, 1600 m a.s.l., snowbed, litter under Rhododendron aureum , 29.VII 2002, O.L. Makarova (CNC); MAGADAN REGION, 8 females, 2 males, 3 protonymphs, 1 larva, Olskoye Plateau, upper reaches of Ola R., 1149 m a.s.l., snowbed, litter under Rhododendron redowskianum , 10.VIII 2011, O.L. Makarova (ZIRAS).

Other material: YAKUTIYA, 3 females, vicinity of Ust-Nera settlement, 1400 m a.s.l., litter under Pinus pumila , 26.VII 1992, M.B. Potapov; 1 female, Khalerchinskaya Tundra, 69°24'N, 158°37'E, VIII 1991, O.V. Starikova; 4 females, mouth of Kolyma R., 69°32'N, 160°44'E, Pokhodskaya Yedoma, dwarf shrub ( Vaccinium vitis-idaea , Betula sp.) thicket, 18-19.VII 1994, A.B. Babenko; 2 females, delta of Yana R., Shirokostan Peninsula, vicinity of Ledyanoye Lake, Dryas community on south slope of valley, 4-6.VIII 1994, A.B. Babenko; 2 females, the same district, date and collector, forb-grassy meadow; MAGADAN REGION, 6 females, 1 male, upper reaches of Kolyma R., Aborigen Mt., Betula exilis thicket within icing in valley, litter, 23.VIII 2006, A.A. Alfimov; TAYMYR PENINSULA, 1 female, vicinity of Pyasino Lake, Nyapan’ Upland, Dryas -community on hill, 10.VII 1999, O.L. Makarova; 1 female, vicinity of Ragozinka R., 72°57'N, 80°56'E, "lemming hay" on slope, 10.VII 1983, A.B. Babenko; 1 female, mouth of Tareya R., hummocky tundra, 28.VII 2010, O.L. Makarova; 3 females, 3 protonymphs, 72°50'N, 101°15'E, bank of Zakharova Rassokha R., mossy tundra, 3.VII 2011, A.V. Barkalov; YAMAL PENINSULA, 2 females, Seyakha Lake, tundra, litter, 9.VII 1986, V.I. Bulavintsev; 1 female, Yakhadyyakha R., 72°53'N, 70°56'E, lemming hill with Poa arctica , 21.VIII 1994, A.B. Babenko; VAIGATCH ISLAND, 1 female, VII 1984, V.I. Bulavintsev; SOUTH SIBERIA, 5 females, Rudnyi Altai Mts., Ivanovskyi Belok Mt., 3.VII 1983, I.P. Vtorov; 1 female, West Sayan Mts., Alashskoye Upland, 2200 m a.s.l., Dryas -community, 20.VII 2001, S.K. Stebaeva; 2 females, the same region, vicinity of Sut-Khol Lake, Larix - Vaccinium vitis-idaea -mosses-community, 27.VII 2001, S.K. Stebaeva.

Description.

Middle-sized dark-yellow or brownish mites with rather broad, somewhat pyri-form idiosoma (Figs 1, 2). Idiosomal shields well sclerotized, very finely punctate, with clearly reticulate ornamentation on nearly all surfaces except peritrematal plates. Many setae of body and appendages with fine, hair-like tips, which often are broken off. Dorsal shield rather broad, covering entire dorsal idiosoma, without lateral incisions.

Female.Idiosomal dorsum. Dorsal shield 448-520 × 296-356, moderately broad, lD/wD ca 1.34-1.62, its maximal width at level of setae S1 (Fig. 9). Podonotal region normally with 18 pairs of simple setae (s1, s2, z1 sometimes symmetrically or asymmetrically absent). Opisthonotal region with 14 pairs of setae (S2 always absent). Among podonotal setae z1, s1, s2 distinguished by much shorter length (7-11), length of j1,2 18-26, other setae 22-36. On opisthonotal region setae J1-4 (20-28) shorter than others (30-44), and J5 clearly shortest (11-15). Dorsal shield with 4 pairs of cu taneous glands gdj4, gdz6, gdZ3 and gdZ4. All marginal setae on soft cuticle (Fig. 12); 4 setae in series r (their length 16-24), 6 setae in series R (22-38); marginal poroid Rp in usual position between setae R3 and R4.

Idiosomal venter. Base of tritosternum narrow (18-22 × 11-14); laciniae with sparse large barbs, free for nearly entire length, fused basal area broadest, with short spicules (Fig. 17); length of lacinia free part 68-78. Presternal platelets 10-16 × 20-24, distinct, lineate, clearly separate from sternal shield (Fig. 12). Sternal shield wider (100-124) than long (60-72), lSt/wSt 0.48-0.64, minimal width between coxae II 62-74; consolidated with endopodal platelets between coxae I–II but not between coxae II–III. Endopodal projections between coxae I–II strong, nearly straight, their posterolateral margin concave, apices encompassing opening of gland gvb, and abutting or uniting with exopodal extensions (Figs 13-16). Sternal shield entirely reticulated; anterior margin straight or slightly concave; posterior margin straight or slightly concave. Sternal shield with typical setae st1-3 (30-34) and lyrifissures iv1-3; rarely, vestiges of gland gv1 present, off posterior margin of sternal shield. Setae st4 (22-28) on soft cuticle. Free endopodal fragments between coxae II–III well sclerotized with angular inner margin. Endopodal strips between coxae III and IV free, well developed (Fig. 18), partly hidden under epigynal flap. Epigynal shield (116-132 × 80-116) distinctly reticulated (Fig. 12), broadly axe- or flask-shaped, with broadly convex hyaline flap not extending to sternal shield, and posterior margin broadly convex; lateral margins strongly widening behind level of setae st5, but st5 (24-28) and paragenital poroids iv5 remain on soft cuticle. Two openings of gland gv2 medially to coxa IV and on posterior margin of exocoxal strip behind coxa IV usually poorly visible (Fig. 18). Two pairs of postgenital platelets in fold of soft cuticle. Ventrianal shield expansive, fully reticulated, wider (224-280) than long (165-192), lVA/wVA 0.63-0.82, consolidated with metapodal platelet sigillae laterally; anterior margin broadly concave, nearly abutting epigynal shield; posterior margin broadly convex, with cribrum a narrow band subdivided along 8 small festoons. Ventrianal shield with 6 (JV1-4, ZV2, ZV3) opisthogastric setae, plus the circumanal setae; setae similar in moderate length (22-30); paranal setae (20-26) inserted at level of anterior margin of anus, and nearly as long as postanal seta (24-32); opening of gland gv3 inconspicuous. Setae ZV1 absent, and ZV4, JV5 on soft cuticle; JV5 rather long (32-40). Exopodal strip usually fragmented alongside coxae II–III, mostly contiguous with peritrematal shield but ending freely from it, with extension that abuts or merged with endopodal extensions between coxae I–II (Figs 13-16). Peritrematal shield rather wide (Fig. 10), its anterior end united with dorsal shield, its posterior edge connecting with exopodal platelet enveloping coxa IV posteriorly; lyrifissures ip1-3 and glands gp1-2present (Fig. 18). Peritreme slightly shortened (152-180 × 9-11), not extending beyond mid-level of coxa I anteriorly. Spermathecal apparatus of laelapoid form, without sclerotized sections (Fig. 21).

Gnathosoma. Gnathotectum basically triramous, with usually three short, denticulate processes (Figs 4-7), middle projection equal to or longer than lateral ones. Subcapitulum (Fig. 8) longer (98-116) than wide (71-80). Deutosternum with 7 narrow, laterally adjoined rows of denticles (2-7 denticles in each row); groove width 8-9. Hypostomatic pair hp3 (39-44) longer than other subcapitular setae (22-30); all setae simple, attenuate. Corniculi of moderate length and width, 30-36 × 11-13. Internal malae slightly longer than corniculi, gradually tapering to tip, with lateral margins fimbriated basally. Chelicera not large (Figs 19-20), its length without basal segment 128-139; cheliceral digits of moderate size (48-57, lCh/lD 9.5-12.1 %), one and a half longer than corniculus (lCh/lCo 1.48-1.75). Fixed digit of chela ending in apical hook, masticatory surface with one subapical tooth and pilus dentilis in antaxial position and four denticles in paraxial position. Movable digit (44-55) slightly shorter than fixed one, bidentate. Palp length 156-175; internal seta of trochanter (28-32) longer than external seta (19-26); palp with typically specialized setae on femur (al) and genu (al1, al2) thick with oblique tip; palp tarsus without macroseta (Fig. 11).

Legs. Legs of moderate length (I 340-396, II 272-304, III 264-296, IV 336-372); leg I shorter than dorsal shield. Length of tarsi I 92-106, II 80-90, III 84-89, IV 102-124. Leg chaetome as described for genus. Setae of legs simple, generally of moderate length; tarsi II–IV each with dorso-proximal setae ad-2, pd-2 not elongated or curved, and with al-1, pl-1 not thinner or more elongated than adjacent setae. Ambulacrum I on pedicellate base, claws I (8-10) smaller than claws II–IV (12-15). Tarsus I distally with 7 rod-like solenidia, 5 of them inserted apically. Ambulacra of legs II–IV (length 24-30) with moderately long paradactyli (9-11) extending clearly beyond apices of claws. Tarsi II–IV with apical setae ad-1 and pd-1 shorter (8-12) than claws (Fig. 3). Four subapical setae on tarsi II–IV evenly distant from apex, almost of equal length, ventral setae av-1 and pv-1 slightly weaker and shorter (18-23) than lateral setae al-1 and pl-1 (20-27).

Male.Idiosomal dorsum. Dorsal shield 396-424 × 236-276, narrower than in female (lD/wD ca 1.50-1.75), fully reticulated, with all r-R marginal setae (10 pairs) on shield, such that podonotal region with 22 pairs of setae, including r2-5, and opisthonotal region with 20 pairs of setae, including R1-6 (S2 always absent). Relative lengths of setae as on female.

Idiosomal venter. Tritosternum base (12-16 × 10-12) shorter than in female (Fig. 22). Presternal platelets connected with sternitigenital shield. Sternitigenital shield fully united with endopodal platelets developed between coxae I–II, coxae II–III, and coxae III–IV, its posterior margin sometimes with pair of indentations (Fig. 25); length of shield 136-158, width between gvb openings 92-110, width at midlevel of coxae II 64-72, width at midlevel of coxae IV 60-72. Sternitigenital shield fully reticulated, with setae st1-3 (24-30) longer than setae st4,5 (20-24), and with lyrifissures iv1,2; lyrifissures iv3 and vestiges of glands gv1 not discernible. Ventrianal shield abutting but free from sternitigenital and peritrematal shields, fully reticulated, expansive, slightly wider (194-224) than long (176-202), yet narrower than in female, lVA/wVA 0.82-0.98, consolidated with metapodal platelet sigillae laterally; anterior margin straight or slightly concave, posterior margin and cribrum formed as in female. Ventrianal shield with setation and form, placement, and lengths of setae as in female, except JV1 more removed from anterior margin and poroids iv5 present on shield. Setae ZV1 absent, ZV4 and JV5 on soft cuticle.

Gnathosoma. Apices of gnathotectum similar to female but sometimes variously shaped in different ways (Figs 26-28). Corniculi and internal malae as in female (Fig. 24). Cheliceral digits (38-43, lCh/lD 9.1-10.7 %) longer than corniculus (30-32 × 11-12, lCh/lCo 1.22-1.34). Fixed digit with dentition similar to female (Fig. 23) except smaller number of denticles in paraxial row (2-3). Movable digit with one large denticle and simple, closed, trough-like spermatodactyl (length of free part 22-24), protruding shortly beyond tip of digit.

Legs. Length of legs I–IV 344-376, 272-284, 256-264 and 320-340 respectively; length of tarsi I–IV 96-101, 78-80, 76-80 and 100-112 respectively. Legs without dimorphically modified setae.

Deutonymph. Unknown.

Protonymph. Idiosomal dorsum. Idiosoma 304-320 × 185-212. Podonotal shield 188-200 × 176-184, reticulate, with 11 pairs of setae (Fig. 29) and no less than 5 pairs of pore-like structures including opening of gland gdj4. Pygidial shield 54-76 × 160-164, reticulate, with 8 pairs of setae and openings of glands gdZ3, gdZ4. Interscutal soft cuticle with 7 pairs of setae and 3 pairs of mesonotal sclerites, anterior sclerites bearing gland pores gdz6 and poroids idz6. Setae r2, r3, and r5 on lateral soft cuticle beside podonotal shield. All dorsal setae needle-shaped, their length 14-35, except J5 clearly shortest (7-8).

Idiosomal venter. Tritosternum as in adults (Fig. 31). Sternal shield poorly sclerotized, with 3 pairs of setae (20-24) and 3 pairs of lyrifissures; presternal platelets weakly developed. Seta st5 absent, but poroid iv5 distinct. Anal shield nearly circular, with paranal setae nearly as long as postanal seta, and usually with opening of gland gv3. Opisthogastric region with 2 pairs of fine medial sclerites, small (10-13 × 7-8) metapodal platelets, 4 pairs of setae and 5 pairs of poroids. Peritremes extending to posterior margins of coxae III.

Gnathosoma. Gnathosomal structures in general as in adults, tectum as in Fig. 30.

Legs. Leg chaetotaxy typical for protonymphs of Ascidae ( Lindquist and Evans 1965).

Larva.Idiosomal dorsum. Idiosoma 260 × 180. Podonotal and pygidial shields smooth, bearing 9 and 4 pairs of needle-shaped setae, respectively (Fig. 34). Interscutal soft cuticle with 3 pairs of narrow sclerites and 4 pairs of setae. Pygidial shield bent caudally, so setae J5 and Z4 inserted on ventral surface.

Idiosomal venter. Tritosternum in general as in adults (Fig. 32). Intercoxal region without delineated sternal shield, with 3 pairs of setae (17-18), lacking lyrifissures but with typical subdermal pair of structures between bases of legs III. Ventral soft cuticle with transverse fold nearly delineating podosomatic from opisthogastric regions. Opisthogastric soft cuticle with typical 4 pairs of opisthogastric setae plus ventrolaterally displaced dorsal setae S4, S5, Z5. Anal shield (38 × 78), transversally oval, wider than long, with circumanal setae large, paranals (54) longer than postanal (36), and with gland opening gv3 nearly posterior to paranal setae; anal valves with tiny euanal setae; cribrum undeveloped.

Gnathosoma. Hypostome, gnathotectum (Fig. 33), chelicera similar to adults, setae hp-3 and pc absent.

Legs. Leg chaetotaxy typical for larvae of Ascidae ( Lindquist and Evans 1965).

Etymology.

The species name indicates its geographical range.

Distribution.

At present known from zonal and mountainous tundra landscapes of West, Middle and East Siberian sectors (Fig. 35).

Ecology.

Recorded from dry and humid tundra sites, meadows including zoogenic ones (e.g. bird of prey outlooks) and shrub ( Pinus pumila , dwarf Betula , Rhododendron ) communities.

Variability.

The species is rather stable morphologically. The variability concerns mainly the form of gnathotectum (Figs 4-7, 26-28), the degree of coalescence of endocoxal and exocoxal elements around coxa II (Figs 13-16), sometimes the symmetrical or asymmetrical absence of setae s1, s2, z1, and the numbers of denticles in the rows on the deutosternum (usually 2-5 or 3-7).