Zerconopsis sibiricus Makarova & Marchenko, 2024

Makarova, O. L., Marchenko, I. I. & Lindquist, E. E., 2024, Siberian mites of the genus Zerconopsis Hull, 1918 (Mesostigmata, Ascidae): description of a new species, re-description of Z. michaeli Evans & Hyatt, 1960, and key for species identification, Zootaxa 5496 (1), pp. 1-34 : 4-15

Zerconopsis sibiricus Makarova & Marchenko sp. nov.

Zerconopsi s sp.— Marchenko, 2012: 520; Makarova et al., 2019: 62.

( Figs 1–30 )

Material examined— 122 females, 99 males, 35 deutonymphs, 1 protonymph

Diagnosis

Adult female: dorsal shield totally reticulate, covering entire dorsal idiosoma, without lateral incisions between setae s 6 and S 1; paravertical setae z 1 tiny; dorsal shield with two pairs of paddle-shaped opisthonotal setae (usually smooth Z 3 and medially ciliate Z 5); J 5 small, ciliated basally; all other setae smooth needle-like or attenuated; marginal setae r 2– r 5 inserted on shield margin; setae R 1, R 2, R 5 inserted on soft lateral cuticle; epigynal shield relatively broad, without clear ornamentation, setae st 5 and paragenital poroids on soft cuticle; ventrianal shield subrectangular, with truncate anterior and lateral margins, totally reticulate and posteriorly punctate, bearing five pairs of opisthogastric setae (JV 2– JV 5, ZV 2) in addition to three small needle-like circumanals, setae JV 1, ZV 1, ZV 3, ZV 4 on flanking soft cuticle; gnathotectum with three projections, lateral tines attenuate and dentate laterally, middle tine dilated and dentate apically; cheliceral shaft two-segmented, fixed digit with a few denticles of different size and subapical antiaxial sensorial depression; leg I shorter than idiosoma, with pretarsus and claws, tibia and genu each with 12 setae, av -2 present; leg III genu with eight setae, pv -1 present; tarsi II–IV with setae (d -1) as long as claws and significantly shorter than paradactyli.

Adult male: all dorsal marginal setae inserted as in female (r 2– r 5 on shield margin; R 1, R 2, R 5 on soft cuticle); sternitigenital shield separated from endopodal strips along coxae III–IV; ventrianal shield totally reticulate, with eight pairs of opisthogastric setae (JV 1– JV 5, ZV 1– ZV 3), ZV 4 on flanking soft cuticle; spermatodactyl with broad membranous frenulum; tarsus II without dimorphically modified setae.

Material. Holotype female, Russia, CHUKOTKA, Anadyr District, 25 km from Anadyr City, Komsomolka Mountain , 64°34’ N, 177°14’ E, 400 m a.s.l., alpine tundra, 9.VII 1974, leg. E.P. Bondarenko ( ISEA). Paratypes: CHUKOTKA, 3 females, 3 males, Anadyr District, 25 km from Anadyr City, Komsomolka Mountain, 64°34’ N, 177°14’ E, 400 m a.s.l., tundra, 6–9.VII 1974, leg. E.P. Bondarenko ( ISEA); 14 females, 10 males, Anadyr District, middle reaches of Anadyr River, 100 km from Anadyr City, environs of Krasneno Village, 64°72’ N, 175°21’ E, 10 m a.s.l., under Pinus pumila , Alnus sp. , in moss, litter and soil, 15.VII 2014, leg. A. V. Barkalov (5 females and 2 males — ZIRAS, 3 females and 2 males — SIEE, 4 females and 2 males — MMUK, 2 females and 4 males — CNC); 4 females, 2 males, Chaun Bay, Naitlin Mtn., 150 m a.s.l., Salix & Spiraea litter enriched by bird droppings, 6.VIII 1979, leg. V. Behan ( CNC); 3 females, Chaun Bay, upriver from Chaun Camp, clumps of Artemesia on top of pingo, 4.VIII 1979, leg. V. Behan ( CNC); MAGADAN REGION, 3 females, Aborigen, above alpine field station, litter in dense thicket of Betula cf. nana, AF 85, 26.VII 1979, leg. A. Fjellberg ( CNC); 2 females, Aborigen, down from T 1 S 1, mixed Pinus pumula , Betula , Larix , Alnaster litter, 24.VII 1979, leg. V. Behan ( CNC); 2 females, same data, Alnaster fruticosa , Pinus pumula litter ( CNC); 1 female, Aborigen Transect T 1 S 4, Pinus pumula litter, 25.VII 1979, leg. V. Behan ( CNC); 1 male, Aborigen, T 2 S 3, along stream from snow bed runoff, Salix , Rhododendron , Vaccinium litter, 26.VII 1979, leg. V. Behan ( CNC). KHABAROVSKII KRAI, 1 female, Bureinskii Nature Reserve, riverside of Pravaya Bureya, 51°33’ N, 134°30’ E, 1300 m a.s.l., under Larix sp. , in litter, 16.VII 2005, leg. I.I. Lyubechanskii ( ISEA); 1 females, 3 males, Larix sp. forest with Vaccinum vitis -idaea, in litter, 18.VII 2005, same district and collector (1 male — ISEA, 1 male — ZIRAS; 1 female and 1 male — MMUK); 1 male, Salix sp. — Alnus sp. shrub, in litter, 16.VII 2005, same district and collector ( ISEE); 1 female, 3 males, under Pinus sibirica , in moss, 15.VII 2005, same district and collector; 1 female, 3 male, Picea sp. forest, in moss, 24. VI 2005, same district and collector ( ISEE); AMUR PROVINCE, 4 females, Zeiskii Nature Reserve, 54°05’ N, 127°06’E., 700 m a.s.l., Quercus sp. forest, in litter, 17.IX 2010, leg. V. V. Dubatolov (2 females — SIEE, 2 females — ZIRAS); 4 females, 11 males, Betula sp. forest with Ledum palustre , in litter, 15.VII 2012, same district and collector (5 males — ISEA, 2 females and 6 males — MMUK, 2 females — CNC); ZABAIKALSKII KRAI, CHITA REGION, 1 female, 1 male, Sokhondinskii Nature Reserve, 51°48’ N, 112°31’ E, 1000 m a.s.l., Larix sp. forest, in litter, 12. VI 1991, leg. D. V. Logunov ( ISEA); 3 females, 9 males, environs of Arakhlei Lake, 59°09’ N, 112°50’ E, 1000 m a.s.l., Betula sp. - Larix sp. forest, in litter, 9. VI 2015, leg. V.A. Marchenko (1 females and 5 males — ISEA, 1 female and 1 male — MMUK, 1 female and 2 males — CNC, 1 male — ZIRAS); TUVA, WEST SAYAN Mts., 1 female, Tandinskii District, environs of Berezovka Village, 50°55’ N, 95°13’ E, 1100 m a.s.l., Betula sp. forest, in moss on decaying log, 27.VII 1976, leg. O.S. Belova ( SIEE); 7 females, 2 males, left riverside of Malyi Enissei R. (Tuvan name—Kaa-Khem River), environs of Derzig-Aksy Village (also known as Danilovka Village), 51°27’ N, 95°36’ E, 900 m a.s.l., under ferns in mixed forest, in litter, 8. VI 1976, leg. L.G. Grishina; 6 females, 3 males, same district, date and collector, under Populus tremula , in litter; 1 female, 1 male, same district, date and collector, under Ribes sp. , in litter ( ISEA); ALTAI, 1 male, Ulagan District, environs of Saratan village, along Baschkaus river, 50°25’ N, 88°22’ E, 1500 m a.s.l., taiga with Larix sibirica , Picea obovata , Pinus sibirica , in litter, 1.VII 2015, leg. I.I. Marchenko ( ISEA); KRASNOYARSKII KRAI, Norilsk Region, 1 female, 69°20’ N, 88°13’ E, 75 m a.s.l., forest-tundra, 18.VII 1998, leg. I.N. Bezkorovainaya ( ISEA).

Other examined material: CHUKOTKA, 1 male, Chukotskii District, environs of Lorino Village, 65°34’ N, 171°29’ W, 65 m a.s.l., near of Lorino thermal springs, under Salix sp. , in litter and soil, 23.VII 2013, leg. O.L. Makarova; 1 female, 1 deutonymph, 1 protonymph, Chukotskii District, environs of Lawrentiy Village, 65°36’ N, 171°02’ W, gopher colony, Artemisia sp. , grasses, turf, 30.VII 2013, leg. O.L. Makarova; MAGADAN REGION, 18 females, 33 males, 34 deutonymphs, upper reaches of Kolyma River, Bolschoi Annachag Range, environs of Aborigen Peak, 62°05’ N, 149°24’ E, Pinus pumila litter, 24.VIII 2006, leg. A. Alfimov; 1 female, the same district, Larix sp. forest, in litter, 5.VIII 1987, leg. D.I. Berman; 1 female, Olskoye Plateau, 60°39’ N, 151°16’ E, 900 m a.s.l., Larix sp. forest, in litter, 11.VII 2011, leg. O.L. Makarova; 2 females, 1 male, Ola Lagoon, 59°35’ N, 151°24’ W, forest with Larix dahurica , Betula sp. , Ledum palustre , Cornus suecica , mosses, 22.IX 2018, O.L. Makarova; KHABAROVSKII KRAI, 1 female, Botchinskii Nature Reserve (Sovetskaya Gavan District), 48°08’ N, 139°13’ E, Abies - Picea mountain taiga, in moss, 28. VI 2016, leg. V. V. Dubatolov; ZABAIKALSKII KRAI, CHITA REGION, 15 females, 4 males, Gasimuro-Zavodskoj District, vicinity of Ushmun settlement, 51,73° N, 118,39° E, forb Larix - Betula forest on hill, litter, 17. VI 2022, leg. I.I. Marchenko; 4 females, Gasimuro-Zavodskoj District, 51,54° N, 118,40° E, forb mixed forest ( Larix , Betula ) on hill, litter, 13. VI 2022, leg. I.I. Marchenko; YAKUTIA, 1 female, environs of Ust́-Nera Village, 64°33’ N, 143°13’ E, 1400 m a.s.l., under Pinus pumila , in litter, 26.VII 1992, leg. M.B. Potapov; 1 female, Suntar-Khayata Range, upper reaches of Kyubyume River, 63°13’ N, 139°36’ E, 1450 m a.s.l., south slope, moist gramineous clearing within Larix sp. forest, in litter, 7.VII 2002, leg. O.L. Makarova; 1 female, moss with Vaccinum vitis -idaea, same district and collector, 21.VII 2002; KRASNOYARSKII KRAI, TAYMYR PENINSULA, Putorana Plateau, Yt-Kyuel Lake vic., 69°01′20″ N, 91°00′54″ E, humid Picea - Larix forest, mosses, 22.VII 1997, leg. A.B. Babenko; 1 female, Norilsk Region, vicinity of Valek settlement, 69.41° N, 88.28° E, Alnaster -dwarf Betula shrubs in floodplain, under Equisetum and Chamaenerion , litter and soil, 15.VII 2022, leg. G.N. Azarkina; 2 females, Norilsk Region, Kajerkan settlement vicinity, right bank of Ambarnaya River, 69.37° N, 87.52° E, Hedysarum meadow, turf and soil, 17.VII 2022, leg. I.I. Lyubechansky; 2 females, 3 males, near Dudinka-Alykel high-way, 69.37° N, 86.80° E, shrubby tundra with Alnaster fruticosus , dwarf Betula , Ledum palustre , Equisetum sp. , mosses, litter and soil, 10.VII2022, leg. G.N.Azarkina; YAMAL-NENETS AUTONOMOUS OKRUG, 3 females, 2 males, Gydan Peninsula, Pelyatka settlement, 69.34° N, 81.98° E, litter and soil, 10.VII 2022, leg. R.Yu. Dudko; NENETS AUTONOMOUS OKRUG, 2 females, Pechora Sea shore, Pakhancheskaya Bay, Cap Matyuj-Salya, 68°29’ N, 57°26’ E, NE slope of bedrock coast, forb-dwarf willow-mossy community with Salix polaris and Saxifraga spp. , 4.VIII 2015, leg. O.L. Makarova.

Description

Adults. Middle-sized mites with idiosoma rather broad, oval, some narrowing anteriad ( Figs 1, 2 ). Mature adults dark-yellow or brownish in colour. Idiosomal shields well sclerotised, very finely punctate; dorsal and ventrianal shields with clearly reticulate ornamentation on nearly all surfaces; sternal or sternitigenital shields with weak, mainly lateral lineation. Dorsal shield covering entire dorsal idiosoma, without midlateral incisions, with notched lateral margins bent down ventrally ( Fig. 3 ) and posterior margin smooth ( Fig. 10 ), with two pairs of paddle-like setae (usually smooth Z 3 and ciliate Z 5) and seta z 1 rudimentary ( Fig. 6 ). Other idiosomal setae subulate, needle-like or with fine, hair-like tips.

Female. Idiosomal dorsum. Dorsal shield length 500–588 by 310–372 width, moderately broad, lD/wD 1.51– 1.63, its maximal width at level of setae Z 2 ( Figs 3 , 10 ). Podonotal region normally bearing 22 pairs of simple setae (j 1– j 6, z 1– z 6, s 1– s 6, r 2– r 5), with honeycomb ornamentation in lateral areas ( Fig. 10 ). Opisthonotal region with 14 pairs of setae (S 2 always absent, R 1, R 2, R 4, R 5 on soft cuticle), mainly reticulate. Two symmetric semitransverse ornament lines between setae j 6 and Z 1 always present and a clear transverse line behind setae J 3 extending to behind setae Z 3 often discernible ( Figs 3 , 10 ). Among podonotal setae, z 1 shortest, tiny (4–6); s 6 longest, attenuate (36–46); needle-like setae j 3, j 5, j 6, z 2, z 4, z 5, s 1, s 2 and sometimes z 6 distinguished by shorter length (16–24) in comparison with other setae (20–32). Opisthonotal region with seta J 1 short (18–23), subulate; setae J 2– J 4 longer (29–44), attenuate; seta J 5 shortest (15–19), spine-like with basal barbs ( Fig. 6 ); paddle-like setae Z 3 (42–50) usually smooth and Z5 (48–62) ciliated in middle part ( Figs 6 , 10 ); seta Z 1 38–44 long, Z 2 42–47; length of S setae increasing posteriad from 30–44 to 48–58; marginal setae R 1, R 2, R 5 (29–40) on soft cuticle, inserted ventrally ( Fig. 9 ). Podonotal region with seven pairs of pore-like structures including enlarged gland pores gdz 4, small gland pores gdj2 and five pairs of poroids (idj 1 elongate); opisthonotal region with 13 pairs of pore-like structures including three pairs of enlarged gland pores gdz 6, gdZ 3 and gdZ 4 ( Fig. 10 ). All glands each with a single orifice.

Idiosomal ventrum. Base of tritosternum narrow, longer (32–34) than wide (17–20); laciniae 92–104 long, fused for nearly one third of entire length, with sparse long barbs in free part and short lateral spicules in fused area ( Fig. 4 ). Presternal platelets small (9–16 x 18–38), indistinct, sometimes bipartite, partly punctate ( Figs 7–9 ). Sternal shield 112–125 length by minimal width between coxae II 68–76, consolidated with endopodal platelets between coxae I–II (shield width on this level 152–179) and between coxae II–III (shield width on this level 118–162); apices of endopodal platelets between coxae I–II encompassing opening of gland gvb 1, or sometimes separated; anterior and posterior margins of shield straight, concave or irregular; lateral parts of shield weakly lineate-reticulate, besides two–three transverse lines hardly visible between levels of setae st 1 and st 2 in pairs; shield with typical setae st 1–3 (20–23) and lyrifissures iv 1–3, vestigial gland pores gv 1 sometimes visible on its posterior margin ( Fig. 8 ). Setae st 4 (20–23) on soft cuticle. Endopodal strips between coxae III and IV free, well developed ( Fig. 9 ). Epigynal shield length 112–144 by 83–90 wide, without distinct ornament, with lateral margins slightly widened behind level of st 5 setae and short convex hyaline flap extending to posterior margin of sternal shield ( Figs 9 , 11 ); setae st 5 (20–23) and paragenital poroids iv 5 on soft cuticle. Two pairs of postgenital platelets often fused into entire sclerite adjacent to epigynal shield, one more pair of bacilliform platelets formed between setae JV 1 and ZV 1. Two pairs of oval metapodal platelets present, larger lateral platelet 22–33 x 12–16, smaller platelet 15 x 7. Exopodal platelets between coxae II–III and III–IV small, triangular or rhomboid, hardly visible in ventral aspect; platelets between coxae II–III bearing gland pore gvb 2. Ventrianal shield expansive, roundish-quadrangular, wider (225–272) than long (162–203), lVA/wVA 0.69–0.80, fully reticulated, with more distinctive pattern in anterior part and fine punctation behind setae JV 3 ( Fig. 14 ). Anterior margin of ventrianal shield straight or weakly concave, posterior margin broadly convex with narrow cribrum between gland pores gv 3 (with one opening); shield bearing one pair of anterolateral poroids and five pairs of opisthogastric setae, JV 5 (35–42) longer than others, namely JV 2, JV 3, JV 4, ZV 2 (22–34); para-anal setae (20–22) inserted at level of posterior margin of anus, nearly as long as post-anal seta (20–24), all circumanal setae needle-like, rarely post-anal seta subulate. Ventral soft cuticle with four pairs of opisthogastric setae, JV 1, ZV 1, ZV 3 (14–23), and ZV 4 (25–31). Peritrematal shield rather wide, rugose, fused with dorsal shield anteriorly and exopodal platelet enveloping coxa IV posteriorly ( Figs 9 , 13 ); lyrifissures ip 1–3 and gland pores gp 1–2 present. Peritreme relatively wide (276–296 x 10–13), reaching level of seta z 1 anteriorly. Gland pore gv 2 with one opening, close to exopodal platelet behind coxa IV posteriorly ( Figs 9 , 13 ). Spermathecal apparatus not distinguishable.

Gnathosoma . Gnathotectum narrow (17–20), triramous; middle process widening and ciliate apically, slightly longer (22–23) than side processes dentate laterally ( Fig. 5 ). Subcapitulum ( Fig. 21 ) longer (104–112) than wide (86–92). Deutosternum of middle width (13–19), with seven rows of denticles (8–15 denticles in each row) bordered by weakly formed lateral lines. Hypostomatic pairs hp 1 (52–56) and hp 3 (44–52) much longer than hp 2 (22) and pc (24–29), all setae attenuate. Corniculi of moderate length and width, 30–34 x 12–14. Internal malae as long as corniculi, weakly tapering to tip, with lateral margins fimbriated proximally. Chelicera not robust, long, its length without basal segment 168–188; cheliceral digits of moderate size (lCh/lD 8.3–9.6 %), one and a half longer than corniculus. Fixed digit of chela grooved distally, ending in apical hook and two small denticles marking groove margins ( Fig. 12 ); masticatory surface with one large blunt tooth in paraxial position and rather long, attenuate pilus dentilis in antiaxial position; tip of digit with lateral depression enclosing sensorial pit; chelaseta large (16–17), rod-like, obtuse; lateral lyrifissure hardly visible, dorsal lyrifissure not distinct. Movable digit (48–52) bidentate, apical hook acute; arthrodial membrane shortly ciliate. Palp length 128–130; internal seta of trochanter (52–60) as long as hp 1 and much longer than external seta (15–17); palp with typically specialised setae on femur (al) and genu (al -1, al -2) thick, 14–17 in length, with symmetrical tip ( Fig. 16 ); palp tarsus with three setae peculiar in form—the longest thin seta, thick truncate seta, and attenuate s-like curved seta ( Fig. 20 ).

Legs. Legs of moderate length (I 333–410, II 300–372, III 305–328, IV 375–460); leg I shorter than dorsal shield. Length of tarsus I 95–116, tarsus IV 125–148. Leg chaetome as described for genus ( Lindquist & Evans, 1965); setation of legs I, II, III, IV, genua: 12–10–8–7; tibiae: 12–9–7–7; seta av -2 on genu I and tibia I present ( Fig. 23 ), seta pv -1 on genu III present. Setae of legs generally short, only tarsus I distally with long thin setae ( Fig. 17 ); most dorsal setae on femora, genua and tibiae of all legs spiniform ( Fig. 23 ); tarsi II–IV each with dorsoproximal setae ad -2, pd -2 elongated and curved ( Fig. 19 ). Ambulacrum I inserted on pedicel ( Fig. 17 ), claws I (9–13) smaller than claws II–IV (15–19). Tarsus I with seven rod-like solenidia (five of them inserted apically) and rigid subapical sensillum s (25–27 long) with lanceolate tip, deviated upward; one large (40–49) dorsal seta in the middle part of tarsus straight, clearly erect ( Fig. 17 ). Ambulacra of legs II–IV (length 29–38) with long paradactyli (22–30) extending clearly beyond apices of claws ( Fig. 19 ). Tarsi II–IV with apical setae ad -1 and pd -1 thin, small (14–19), much shorter than ambulacra. Four subapical setae on tarsi II–IV almost evenly distant from apex, of similar length, ventral setae av -1 and pv -1 slightly thicker and shorter (15–18) than lateral setae al -1 and pl -1 (18–20).

Male. Idiosomal dorsum. Dorsal shield length 450–505 by 275–325 width, lD/wD 1.51–1.80. Chaetotaxy and ornamentation of dorsal shield similar to that of female but larger number of podonotal setae (j 1– j 6, z 1– z 5, s 4, s 5) subulate. Dorsal setae commonly slightly shorter than in female, setae z 1 3–5; j 1, s 1, s 2 16–20; r 2– r 5 22–26; s 6 32–39; other podonotal setae 14–24 in length; J 1 16–22; J 5 14–19; length of J 2– J 4 increasing posteriad from 25–28 to 32–40; length of S 1, S 3– S 5 increasing posteriad from 36–44 to 44–50; setae Z 1, Z 2, Z 4 30–40; paddle-like setae Z 3 38–42, Z 5 50–62; marginal podonotal r 2– r 5 setae on the shield, marginal setae R 1, R 2 (20–28) and R 5 (28–35) on soft cuticle as in female.

Idiosomal ventrum ( Fig. 18 ). Tritosternum slightly smaller than in female: base 20–22 long, 10–14 wide; pilose laciniae 94–98 long, proximally fused. One pair of presternal shields present (11–14 x 32–42). Sternitigenital shield united with endopodal platelets developed between coxae I–II and II–III; its anterior margin almost straight, posterior margin truncate; shield length 177–202, width at level of anterior margin 136–156, width at midlevel of coxae II 56–68, width at level of middle angles 120–148, width at midlevel of coxae IV 40–50. Endocoxal angular platelets between coxae III–IV free. Sternitigenital shield laterally with weak linear ornamentation, with setae st 1– st 5 (15–22) and three pairs of lyrifissures iv 1– iv 3; vestiges of glands gv 1 not discernible. Genital sclerite transverse oval (12–14 x 29–32), abutting anterior margin of sternitigenital shield; inner funnel weakly constricted ( Fig. 15 ). Podal and peritrematal shields as in female. Poroids iv 5 inserted on soft cuticle between sternitigenital and ventrianal shields. Ventrianal shield 187–215 long and 212–250 wide at level of setae ZV 2, lVA/wVA 0.80– 0.93, fully reticulated, with fine punctation behind setae JV 3, subtrapezoid in form, consolidated with metapodal platelets, often with anterolateral angles asymmetrically developed ( Fig. 18 ). Ventrianal shield with eight pairs of opisthogastric setae (JV 1— JV 5, ZV 1– ZV 3), three circumanal setae (17–25 long), three pairs of poroids and a pair of gland pores gv 3; setae ZV 4 (22–24) on soft cuticle. Cribrum formed as in female. Among opisthogastric setae, JV 4, JV 5 longest (25–35), JV 1, ZV 1, ZV 3 shortest (15–21), other setae 18–25.

Gnathosoma . Form and size of gnathotectum similar to female, subcapitulum (92–96 x 75–86) and corniculus (28–30 x 10–12) smaller; hypostomatic setae hp 1 (64–74) longer than in female. Cheliceral digits (42–46) shorter than in female, lCh/lD 9.05–9.74 %; fixed digit with structures similar to female ( Fig. 22 ) but arthrodial membrane with longer ciliae; movable digit with one large tooth and tube-like spermatodactyl protruding shortly beyond tip of digit (length of free part 24–28), with oblique tip and broad dorsal membranous frenulum (visible in lateral aspect). Palp as in female but internal seta of trochanter much shorter (42–44).

Legs. Length of legs I–IV: 330–384 (shorter than idiosoma), 280–364, 275–336, and 360–440, respectively; length of tarsus I 85–102, tarsus IV 110–152. Legs without dimorphically modified setae. All ambulacral structures as in female but smaller; ambulacra II–IV 28–30 long, with paradactyli 18–26 long and claws 14–15 long; tarsi II–IV with apical setae ad -1 and pd -1 11–13 long, four subulate subapical setae of similar length (13–17).

Deutonymph. Idiosomal dorsum. Dorsal shield 424–464 x 234–268, lD/wD 1.6–1.8, almost fully reticulate, often with three transverse ornamental lines more clearly formed ( Fig. 24 ); lateral shield margin behind s 6 often with desclerotised area, or narrow fold, or small broad incision ( Fig. 24 ); shield bearing 14 pairs of podonotal setae (j1–j6, z2–z6, s4–s6) and 14 pairs of opisthonotal setae; seta S 2 absent, setae z 1, s 1– s 3, r 2– r 5, R 1, R 2, R 5 on soft cuticle. Length of subulate j 1 13–17, tiny z 1 4–7, ciliate J 5 11-–13, paddle-shaped Z 3 and Z 5 33–40 and 55–61 respectively, other dorsal setae lengths 12–44; gland pores as in adults, poroid set reduced to three podonotal pairs and five opisthonotal pairs, barely discernible.

Idiosomal venter. Tritosternum as in adults, somewhat smaller. Presternal sclerites not formed. Sternitigenital shield weakly sclerotised, smooth excepting lineate between coxae IV, strongly narrowing posteriorly ( Fig. 25 ), 190– 212 length by maximal width before coxae II (112–126) and minimal width between coxae IV (15–32), bearing setae st 1– st 3 and lyrifissures iv 1- iv 3; setae st 4, st 5 (and sometimes asymmetrically lyrifissure iv3) on soft cuticle; st 1- st 5 length 17–19. Peripodal platelets and gland pores gvb 1, gvb 2 not discernible. Ventrianal shield semiquadrangular, with irregular anterior and lateral margins, wider (164–196) than long (104–116), lVA/wVA 0.57–0.65, fully reticulate and finely punctate behind JV 4 level, with no or with one or two (JV 3, JV 4) pairs of opisthogastric setae ( Figs 25, 28, 29 ) and three circumanal setae of similar form and size (para-anal setae 15–17, post-anal seta 19–20), cribrum and gv 3 as in adults. Opisthogastric cuticle with one pair of round or oval metapodal platelets (10–12 in diameter, or 15–19 x 9–11), seven to nine pairs of setae, among them ZV 1 shortest (9–11), JV 5 longest (19–28), and two pairs of small sclerites between metapodal platelets, bacilliform transverse sclerite (1–3 x 19–22) and tiny circular sclerite (4 in diameter). Peritrematal shield weakly developed; peritreme anteriorly reaching level of gland pore gdj 2, 224–240 long, 6–7 wide.

Gnathosoma . Gnathosomal structures in general as in adults, some smaller. Cheliceral length without basal segment 140–152, movable digit 38–46 long.

Legs. Legs of moderate length (I 300–305, II 284–308, III 268–280, IV 328–348); leg I clearly shorter than dorsal shield. Length of tarsus I 82–96, tarsus IV 104–120. Leg chaetome as in adults. Ambulacra II–IV 22–28 long, claws II–IV (14–16) longer than claw I (9–11); paradactyli (18–21) and tarsal setae (d -1) (8–9) relatively shorter than in adults.

Protonymph. Idiosomal dorsum. Idiosoma 356 long, 212 wide. Dorsal shields weakly sclerotised, almost smooth, with most setae needle-like or attenuate ( Fig. 26 ). Podonotal shield 251 x 207, with medially convex posterior margin, bearing 11 pairs of setae, j 1– j 6, z2, z 4, z 5, s 4, s 5, and no fewer than four pairs of pore-like structures including opening of gland gdj 4; seta s 4 (26) longest, other setae 12–13. Marginal setae r 2, r 3, and r 5 on lateral soft cuticle. Pygidial shield 88 x 200, subquadrangular or transversely oval, with eight pairs of setae, two pairs of lyrifissures, and openings of glands gdZ 3, gdZ 4; setae Z3 and Z5 paddle-shaped, Z 5 59 long, relatively longer than in deutonymph and adults; setae J 3, J 4 (14–16) and J 5 (8) much shorter than Z 4, S 4, S 5 (29–34). Interscutal soft cuticle with seven pairs of setae (setae J 1, J 2 11–12 long, Z 1, Z 2 27–29), five pairs of mesonotal sclerites of different sizes, and two or three discernible pairs of free lyrifissures; largest anterior mesonotal sclerite (11 x 52) bearing gland pores gdz 6 and one pair of poroids.

Idiosomal venter. Tritosternum as in adults ( Fig. 27 ). Sternal shield poorly sclerotised, smooth, with three pairs of setae and two pairs of lyrifissures. Seta st 5 present on soft cuticle. Anal shield rounded triangular (74 x 108), with para-anal setae nearly as long as post-anal seta, with relatively broad cribrum, and with prominent opening of gland gv 3 located on slight projection. Opisthogastric soft cuticle with four pairs of setae and three pairs of poroids. Peritreme short of reaching level of anterior margin of coxa III, 62 long, 7 wide.

Gnathosoma . Gnathosomal structures in general as in adults, but poorly seen in a single specimen. Cheliceral length without basal segment 132, movable digit 38 long.

Legs. Leg size and structures not discernible in the single specimen.

Variability. The species is rather stable morphologically. The adult variability concerns mainly the form of the female sternal shield ( Figs 7–9 ); sometimes the symmetrical or asymmetrical absence of podonotal seta z 3, marginal seta R 5, and opisthogastric seta ZV 4; the length and form of some idiosomal setae (for example, some podonotal setae and post-anal seta may be subulate or attenuate); the number of dentate rows on the deutosternum (rarely six rows instead seven); the degree of coalescence of exopodal platelets in front of coxae II with the sternitigenital shield in males; in females, dermal gland gv 1 may be developed (vestigial) or not ( Figs 7, 8 ) and seta ZV 2 sometimes inserted off ventrianal shield. In one female, a single extra seta was observed between opisthonotal setae J 2– J 2. In deutonymphs, symmetrically or asymmetrically, lyrifissure iv3 can be inserted on soft cuticle flanking the sternitigenital shield ( Fig. 26 ), and setae JV 3 can be inserted off the ventrianal shield ( Fig. 29 ), setae ZV 1 and R 2 are sometimes absent; the form of the sternal and ventrianal shields varies ( Figs 28, 29 ); lateral margins of dorsal shield are sometimes symmetrically or asymmetrically with an incision ( Fig. 24 ).

Remarks. In the proceedings of a regional conference, T.G. Poletaeva briefly noted the characteristic of a single female of «Zerconopsi s sp.» possessed with two paddle-shaped dorsal shield setae found in the Chita Region ( Poletaeva, 1996). Subsequently, in her PhD thesis she again described some structures of that species (named as “ Zerconopsis alexandrovae sp. nov. ”; Poletaeva, 1998). Illustrations given in her thesis included the presence of two paddle-shaped dorsal shield (opisthonotal) setae (a unique feature among member species of the genus), and the locality (Arakhlei Lake, Chita Region, Zabaikalskii Krai)—the same locality as presented in our material, above, for Zerconopsis sibiricus sp. nov. That information led us to conclude that « Zerconopsis alexandrovae » is identical with Z. sibiricus . However the above-mentioned presentations of Poletaeva (1996, 1998) do not satisfy the criteria of publication according to Article 8 of the International Code of Zoological Nomenclature (1985, 1999), leading us to consider Zerconopsis alexandrovae Poletaeva, 1998 as a nomen nudum.

This species was described one more time in a monograph released in a local publishing house in Russian ( Poletaeva et al., 2022) as Zerconopsis alexandrova Poletaeva, Kleusova, Larina & Chistyakova, 2022 (p. 22, 23). Its diagnosis contains mistakes and lapses that require re-examination of the types. That publication did not include information about the type deposition (as well as the date of collection and collector name). It therefore does not satisfy the requirements for names published after 1999, according to Articles 13 and 16 of the International Code of Zoological Nomenclature (1999). Thus, we consider Zerconopsis alexandrova Poletaeva, Kleusova, Larina & Chistyakova, 2022 as a nomen nudum. The monograph in general contains some errors. For example, concerning the species in question, it was reported that “dorsal shield shows almost all body”, “ first pair of genital setae is disposed…” (p. 22), and the differential diagnosis refers to the item [86] devoted to (!) North American Zerconidae (p. 23).

Differential diagnosis. Adults and deutonymph of Zerconopsis sibiricus sp. nov. can be distinguished from all other species of the genus by the presence of only two pairs of large paddle-shaped setae on the dorsal shield, both inserted in the opisthonotal region (Z 3, Z 5). Another member of Zerconopsis with two pairs of dorsal paddle-shaped setae, Z. unaka De Leon, 1964 , is possessed one pair (s 4) inserted in the podonotal part of shield and one pair (Z 5) inserted in the opisthonotal part ( De Leon, 1964).

Etymology. The specific name indicates its main geographical range.

Distribution. At present known from zonal and mountainous taiga landscapes as well as from southern tundra areas of the Russian Far East, Siberia, and north-eastern Europe ( Fig. 30 ).

Ecology. Recorded from the litter of different mesophytic forests (coniferous and deciduous), and dry and humid tundra sites including various meadows and shrub communities. Population density varies strongly from single individuals to 85 ind./dm 2 (Magadan Region, litter of Pinus pumila , 24.VIII 2006, our unpublished data), as well as the female / male ratio varying from 3:1 to 1:5 (see MATERIAL). Most recorded specimens are adults. Our abundant material, collected mainly in summer, includes only one protonymph of this species found 30.VII 2013 in the Chukotka tundra. Numerous deutonymphs (40% of population) were found only once in subalpine dwarf pine forest (Magadan Region) 24.VIII 2006. All these data argue for an early season reproducing of Z. sibiricus sp. nov. and a one year duration of its life cycle. Its record in upper reaches of Kyubyume River, 63°13’ N, 139°36’ E, Yakutia, only 160 km distant from the Cold Pole of the Northern Hemisphere ( Fig. 30 ), indicates a high cold tolerance of this species.

Figures

FIGURE 30. Distribution records of Zerconopsis sibiricus sp. nov., original.

FIGURES 1–2. Zerconopsis sibiricus sp. nov., female, micrograph habitus images. 1. dorsal view; 2. ventral view. Scale 100 μm.

FIGURES 3–9. Zerconopsis sibiricus sp. nov., female. 3. dorsal shield; 4. tritosternum; 5. gnathotectum; 6. some setae of dorsal shield; 7, 8. sternal shield; 9. idiosoma ventrally. Scales: 3, 9 100 μm; 4, 6 25 μm; 5 10 μm; 7, 8 50 μm.

FIGURES 10–15. Zerconopsis sibiricus sp. nov. 10–14. female; 15. male. 10. dorsal shield; 11. epigynal shield; 12. cheliceral digits, paraxial view; 13. peritrematal shield; 14. ventrianal shield; 15. anterior part of sternitigenital shield. Scale: 10, 13, 14 50 μm; 11, 12, 15 25 μm.

FIGURES 16, 17. Zerconopsis sibiricus sp. nov., female. 16. palpal trochanter, femur, and genu; 17. tarsus I. Scale 25 μm.

FIGURES 18–23. Zerconopsis sibiricus sp. nov., 18, 22. male; 19–21, 23. female. 18. idiosomal venter; 19. tarsus II; 20. palpal tarsus; 21. subcapitulum; 22. cheliceral digits, antiaxial view; 23. leg I (without tarsus). Scale: 18 100 μm; 19, 21, 22 25 μm; 20 10 μm; 23 50 μm.

FIGURES 24–29. Zerconopsis sibiricus sp. nov., 24, 25, 28, 29. deutonymph; 26, 27. protonymph. 24. idiosomal dorsum; 25. idiosomal venter; 26. idiosomal dorsum; 27. idiosomal venter; 28, 29. opisthogastric region. Scale 50 μm.