Sayanozercon mariannae, Marchenko, 2025

Marchenko, Irina I., 2025, The new genus Sayanozercon (Acari: Mesostigmata: Zerconidae) with description of five new species from South Siberia mountains (Russia), Zootaxa 5647 (2), pp. 151-195 : 154-167

publication ID	https://doi.org/10.11646/zootaxa.5647.2.5
publication LSID	lsid:zoobank.org:pub:E7A8B8B7-7066-422B-859C-B3DB4F2F06C7
DOI	https://doi.org/10.5281/zenodo.15819685
persistent identifier	https://treatment.plazi.org/id/038B87E0-B136-FFC4-6AAD-5763DBD9929B
treatment provided by	Plazi
scientific name	Sayanozercon mariannae
status	sp. nov.

Treatment

Sayanozercon mariannae sp. nov.

( Figures 1–29 View FIGURE 1 View FIGURE 2–6 View FIGURE 7 View FIGURE 8–10 View FIGURE 11–13 View FIGURE 14–16 View FIGURE 17–23 View FIGURE 24–29 )

Female ( Figs 1–6 View FIGURE 1 View FIGURE 2–6 , 17–23 View FIGURE 17–23 , n=10)

Dorsal idiosoma ( Figs 1 View FIGURE 1 , 17 View FIGURE 17–23 ). Idiosoma pear-shaped, 540–575 long, 425–460 wide, without obvious ornamentation, divided into two shields that cover entire dorsal idiosoma.All dorsal setae smooth, pointed. Podonotal shield with 20 pairs of setae, including r1 seta inserted in dorsal side and r3 seta located in peritrematal shield, seta r3 is 3 times longer than r1. Setae s1, z1 and z2 lost. Length of podonotal setae female, male and nymphs summarized in Table2. Setae of j- series comparable length. Setae z4 and z5 the longest in z -series. Setae s3 longest in s -series and among all podonotal setae. Seta r1 shortest in r -series. Podonotal shield with three pairs of glands: gdj2 (po1), gdj4 (po2), gdz5 (po3) and five pairs of lyrifissures: idj1, idj3, idz4, ids4, idj6. Location of podonotal glands: gdj2 (po1) on line connecting insertions of setae j2 and z3; gdj4 (po2) on line connecting insertions of setae j4 and z4; gdz5 (po3) close and anterior to line connecting insertions of setae z5 and s5. Opisthonotal shield with delicate horizontal lines between setae J4 and J5. Medial zone betetween J–J series setae with small irregular spots visible through the cuticle. Opisthonotum with 20 pairs of setae. Lengths of opisthonotal setae and longitudinal distances between insertions of setae in specific series of female, male and nymphs summarized in Table 3. Set of J -series with four pair of setae, because J3 lost; setae J4, J5 shortest; setae J5 located directly above medial posterodorsal cavities. Remaining series with a full set of setae. Z -series with longest setae Z3, Z4 and Z5, extend beyond the edge of the shield. All setae of S -series extend beyond the edge of the shield, of these setae S4, S5 longest. Setae of R -series all long, of similar length. Opisthonotal shield with four pairs of glands and 13 pairs of lyrifissures as shown in Fig. 1 View FIGURE 1 : gdz6 (Po1) anteromedial to seta Z1; gdZ1 (Po2) anterolateral to seta Z1; gdZ3 (Po3) close to line connecting insertions of setae Z3 and Z4; gdZ4 (Po4) on posterior margin of shield behind insertion of seta S5; lyrifissures: ids6, idS1, idz6, idS4, idZ4, idJ4, idJ5, idJ2, idJ3, doubled idJ1 and doubled idS3. Posterodorsal cavities rounded curvings, all equal size, located at posterior margin of opisthonotal shield.

Ventral idiosoma ( Figs 2–3 View FIGURE 2–6 , 18–20, 22 View FIGURE 17–23 ). Base of tritosternum 30–32 long, 25–27 wide; paired laciniae with three distal branches ( Fig. 2 View FIGURE 2–6 ). Sternal shield 68–70 long at midline, 75–85 wide at level st2 setae; with strong reticulate ornamentation except central “window” with fine lines; with setae st1–st3 similar in length, 15–20, smooth and pointed; with three pairs of lyrifissures iv1, iv2 and iv3 and one pair of glands gv1 ( Figs 3 View FIGURE 2–6 , 18, 20 View FIGURE 17–23 ). Epiginal shield 122–125 long and 110–115 wide with setae st5 (20–22) on shield and pair of lyrifissures iv5, with ornamentation and inner structure as shown in Fig. 3 View FIGURE 2–6 . Large endopodal sclerites between coxae III–IV with pair of setae st4 (18–20) and small, ovate-oblong endopodal sclerites around posterior parts of coxae IV presented. Pair of long exopodal sclerites extends from coxae IV to coxae I, closely adjacent to peritrematal shields and bend to dorsal side anteriorly. Pair of peritrematal shields adjacent to additional latero-ventral shields anteriorly at level of coxae II and free at level of coxae III–IV. Peritrematal shield truncate at posterior margin, not fused with ventri-anal shield; with fibre brush of cuticular structure and two conspicuous rounded poroids in inguinal region (gvi and ivi) ( Figs 19–20, 22 View FIGURE 17–23 ). Peritrematal shields with pair of smooth and pointed setae r3; with two pairs of lyrifissures ip1, ip2 and gland gp from each side. Peritremes short, 50–55. Latero-ventral shield weakly reticulated, extending vertically from seta r3 to R6 ( Figs 18, 20 View FIGURE 17–23 ). Adgenital sclerites presented each with 4–5 glands openings gv2. Ventrianal shield 245–250 long, 330–345 wide at level seta Zv2, with 21 smooth, pointed setae; with transversal reticulation from anterior margin to level setae Jv3. Anterior margin of ventrianal shield with two shortest pairs of setae Jv1 and Zv1 (12–13). Other setae in J -series: Jv2 (17–20), Jv3 (30–37), Jv4 (38–40), Jv5 (65–75); other setae in Z -series: Zv2 (12–13), Zv3 (18–20), Zv4 (20–22); para-anal setae 50–55, post-anal 45–50 long. Pair of glands gv3 located at level posterior margin of anal opening. Five pairs of ventrianal lyrifissures present: ivo1–ivo4 and ivp. Anal opening with two pairs of lyrifissures on each valve. Cribrum presented posteriorly of post-anal setae.

Gnathosoma ( Figs 4–6 View FIGURE 2–6 , 21, 23 View FIGURE 17–23 ). Movable digit of chelicera 55–60 long, with three teeth in addition to apical hook; fixed digit the same length, with five teeth including offset distal tooth (gabelzhan), followed by four teeth in masticatory surface in addition to apical hook and leaf-shaped pilus dentilis, apical sensorial depression presents ( Fig. 4 View FIGURE 2–6 ). Chelicera with long dorsal seta, lateral (antiaxial) and dorsal lyrifissures; with smooth arthrodial corona and suboval area (“window”) of thin cuticle on paraxial side. Epistome with irregularly serrated lateral edges, medial ridge and serrated middle process with median row of small spines; lateral margins of epistome with clearly visible structures, apparently serving as limiters for the cheliceral shafts ( Figs 5 View FIGURE 2–6 , 23 View FIGURE 17–23 ). Corniculi horn-like, internal malae extending beyond corniculi, with fimbriate lateral margins and bifurcate apices. Deutosternal groove with seven transverse denticulate rows, each row with 6–13 small denticles. Hypostome with four pairs of setae, setae h1–h3 smooth, h1 (40–42) the longest, seta h2 (23–25) shorter than h3 (28–30), pc (30–32) serrated ( Figs 6 View FIGURE 2–6 , 21 View FIGURE 17–23 ). Palpal chaetotaxy 2–5–6–12–15 with five free segments; pilose setae on palp trochanter v1 and v2; on palp femur d3, on palp genu al2; palp tarsal claw two-tined.

Legs. Chaetotaxy of legs I–IV: coxae 2, 2, 2, 1; trochanters 6 (1 1/3 1), 5 (1 1/3 0), 5 (1 1/3 0), 5 (1 1/3 0); femora 13 (2 5/4 2), 11 (2 5/3 1), 6 (1 4/1 0), 6 (1 4/1 0); genua 13 (2 6/3 2), 11 (2 5/2 2), 10 (2 4/2 2), 10 (2 5/2 1); tibiae 14 (2 6/4 2), 10 (2 4/2 2), 9 (2 3/2 2), 9 (2 3/2 2); tarsi I–49 (6 29/9 5), II–IV 18 (3 7/5 3). Chaetotaxy of I–IV legs is typical for Zerconidae ( Halašková, 1969; Sikora, 2014). Pretarsus of legs II–IV with ambulacral stalk, tarsi I with sessile claws. Coxae I with dorsal incision, coxae II with antero-dorsal spine.

Male. ( Figs 7–10 View FIGURE 7 View FIGURE 8–10 , 24–29 View FIGURE 24–29 , n=10).

Dorsal idiosoma. ( Fig. 7 View FIGURE 7 ). Dorsal idiosoma pear-shaped, 450–485 long, 340–355 wide. Ornamentation, chaetotaxy, adenotaxy and poroidotaxy of dorsal shields as in female. Lengths of podonotal setae of males summarized in Table 2. Lengths of opisthonotal setae and longitudinal distances between insertions of setae in specific series of male summarized in Table 3.

Ventral idiosoma. ( Figs 8 View FIGURE 8–10 , 24, 26–29 View FIGURE 24–29 ). Tritosterum form as in female. Sternal shield fused with genital shield with area of weak sclerotisation and weak reticulation between setae st1 and st2. Sternigenital shield with area of weak sclerotisation and weak reticulation between setae st1 and st2, 150–155 long with four pairs of setae st1–st4 (15–18), three pairs of lyrifissures iv1, iv2 and iv5, one pair of glands gv1 and genital opening opposite coxae III. Eugenital setae presented as shown in SEM photo ( Fig. 26 View FIGURE 24–29 ). Peritrematal shields each with short peritrema, with smooth and pointed seta r3, with lyrifissures ip1, ip2 and glands gp ( Figs 24, 26, 28–29 View FIGURE 24–29 ). Peritrematal shields connected posteriorly to each other by fibre brush of cuticular structure with two pairs of rounded formations hollow inside (inguinal poroids gvi and ivi) ( Figs 26–29 View FIGURE 24–29 ). Latero-ventral shields shaped as in female, with reticulate ornamentation ( Fig. 24 View FIGURE 24–29 ). Ventrianal shield with weakly transversal reticulation, 200–218 long and 280–290 wide; with 19 smooth and pointed setae, setae Zv1 lost; with five pairs of lyrifissures ivo1–ivo4, ivp and pair of glands gv3. Length of ventrianal setae: Jv1 (12–13), Jv2 (16–18), Jv3 (25–30), Jv4 (27–40), Jv5 (65–75), Zv2– Zv4 (16–18), para-anal setae 40-50, post-anal 38–42 long. Multiple glands gv2 with 4–5 openings located on anterior margin of ventrianal shield. Anal opening with two pairs of lyrifissures on each valve. Cribrum presented posteriorly of post-anal seta.

Gnathosoma ( Figs 9–10 View FIGURE 8–10 , 25 View FIGURE 24–29 ). Movable digit of chelicera 42–45 long, with three teeth in addition to apical hook, fixed digit the same length, with six teeth, including offset lateral-distal tooth (gabelzhan), followed by five teeth in masticatory surface in addition to apical hook and leaf-shaped pilus dentilis, apical sensorial depression presents ( Figs 9 View FIGURE 8–10 , 25 View FIGURE 24–29 ). Male chelicera with dorsal seta, lyrifissures and arthrodial corona as in female. Epistome ( Fig. 10 View FIGURE 8–10 ), corniculi, internal malae and palpal structures as in female.

Legs. Chaetotaxy and morphology of legs as in female.

Deutonymph ( Figs 11–13 View FIGURE 11–13 , n=8).

Dorsal idiosoma. Dorsal idiosoma pear-shaped, 445–475 long, 360–375 wide, divided into two shields ( Fig. 11 View FIGURE 11–13 ). All dorsal setae smooth and pointed. Podonotal shield with 20 pairs of setae, setae s1 and z2 absent, three pairs of glands gdj2, gdj4, and gdz5 located as in adults; without reticulation. Opisthonotal shield weakly ornamentated, with 20 pairs of setae, pair of setae J3 absent, with four pairs of glands: gdz6, gdZ1, gdZ3 and gdZ4. Most dorsal lyrifissures not visible. Lengths of podonotal setae of deutonymphs and lengths of opisthonotal setae and longitudinal distances between insertions of setae in specific series summarized in Table 3.

Ventral idiosoma. Sternal shield with smooth, pointed setae st1–st5, where s t5 inserted on soft cuticle, with two pairs of visible lyrifissures iv1 and iv2 ( Fig. 12 View FIGURE 11–13 ). Sternal setae are equal length: st1–st3 23–25, st4–st5 (12–15). Metapodal platelets large, triangular shapes, free from ventrianal shield. Peritremes long 165–175, reaching to mid coxae I. Narrow strip of sclerotised cuticle adjacent laterally along of peritrema; with gland gp on it. Marginal setae r3 located on soft cuticle. Pair of small rounded formations (inguinal poroids gvi and ivi) and glands gv2 with three openings located behind coxa from each side. Ventrianal shield with transversal reticulation; wider than long (180– 192 x 270–275), with 17 smooth pointed setae; with pair of glands gv3 and cribrum. Opisthogastral setae Jv1 and Zv1 located on soft cuticle, anteriorly of ventrianal shield. Length of opisthogastral setae: Jv1–Jv2 (10–15), Jv3–Jv4 (25–27), Jv5 (63–65), Zv1 and Zv4 (7–10), Zv3 (15-17). Para-anal setae (37–39), post-anal (50–55) long.

Gnathosoma ( Fig. 13 View FIGURE 11–13 ). Denticulation of chelicera as in female. Epistome with irregularly serrated lateral edges serrated middle process with median row of small spines and three branches in top; lateral margins of epistome with clearly visible structures as in adults.

Legs. Chaetotaxy and morphology of legs as in female.

Protonymph ( Figs 14–16 View FIGURE 14–16 , n=1).

Dorsal idiosoma ( Fig. 14 View FIGURE 14–16 ). Dorsal idiosoma suboval form, 387 long and 295 wide, without ornamentation of podonotal and pygidial shields. All dorsal setae smooth and pointed. Podonotal shield with 15 pairs of setae: six pairs of setae in j -row (j1–j6), z -row with three pairs of setae (z3–z5), s -row with four pairs of setae (s3–s6) and two pairs of setae in r -row (r3, r5), with one pair of visible glands gdz5. Lengths of podonotal setae of protonymphs summarized in Table 2. Lengths of opisthonotal setae and longitudinal distances between insertions of setae in specific series of protonymphs, summarized in Table 3. Opisthonotal region presented by one large pygidial shield with 14 pairs of setae: J -row with four pairs of setae (J1–J2, J4–J5), pair of J3 setae absent, Z -row with five pairs (Z1–Z5), S -row with four pairs (S2–S5), R -row with one pair of setae R1 and two pairs of visible glands gdZ3 and gdZ4. Posterodorsal cavities presented.

Ventral idiosoma ( Fig. 15 View FIGURE 14–16 ). Tritosternum as in adults. All ventral setae simple form. Sternal shield with three pairs of setae St1–St3 equal length (17–20), seta St5 minute (5–6). Peritrematal shields not distinct. Peritremes very short (35), with pairs of thin ducts leading from stigmata. Adgenital pores and pair of glands gv2 not visible. Opisthogastric area with one pair of Jv1 setae (12) inserted in soft cuticle. Ventrianal shield with transversal reticulation, with nine setae: Jv2 (23), Jv5 (63), Zv2 (12), para-anal setae (27) and post-anal seta (43); pair of glands gv3. Cribrum present posteriorly to post-anal seta. Anus with two anal lyrifissures on each valve.

Gnathosoma ( Fig. 16 View FIGURE 14–16 ). Corniculi, internal malae as in adult; epistome with irregularly serrated lateral edges, serrated middle process with median row of small spines and three branches in top. Lateral structures of epistome presented.

Legs. Chaetotaxy of legs I–IV: coxae 2, 2, 2, 1; trochanters 4, 4, 4, 4; femora 10 (2 4/2 2), 8 (1 4/2 1), 5 (1 3/1 0), 4 (1 3/0 0); genua 8 (1 4/2 1), 6 (1 4/0 1), 6 (1 4/0 1), 5 (1 4/0 0); tibiae 8 (1 4/2 1), 7 (1 3/2 1), 7 (1 3/2 1), 7 (1 3/2 1); tarsi II–IV 17 (3 7/4 3). Pretarsus of legs II–IV with ambulacral stalk, tarsi I with sessile claws. Coxae I with dorsal incision, coxae II with antero-dorsal spine. Protonymphal chaetotaxy of legs I–IV is typical for Zerconidae ( Halašková, 1969) .

Larvae not found.

Material examined. Holotype female, Russia, Baikal Region, BURYATIA Republic, Kabanskii district , environs of Tankhoi village , foot of Khamar-Daban Ridge , forest in valley of Kurkavka river , 51° 33’ N, 105° 09’ E, 470 m a.s.l., in litter, 9.VIII 2014, leg. I.I. Marchenko. GoogleMaps Paratypes: 10 females, 8 males, same data as holotype GoogleMaps ; 4 females, same geographical data, 51° 35’ N, 104° 22’ E, 500 m a.s.l., forest in valley of Osinovka river , in litter, 9.VIII 2014, leg. I.I. Marchenko GoogleMaps ; 4 females, same geographical data as holotype, 51° 47’ N, 105° 24’ E, 500 m a.s.l., taiga along estuary of Pereemnaya river , in litter, 10.VIII 2014, leg. I.I. Marchenko GoogleMaps ; IRKUTSKAYA OBLAST: 3 females, 2 males, same geographical data, environs of Vydrino village , foot of Khamar-Daban Ridge, Monomakh Mt., 51° 23’ N, 104° 38’ E, 400 m a.s.l., mixed forest, in litter, 23. VI 2021, leg. I.I. Marchenko GoogleMaps ; 7 females, 7 males, same geographical data, environs of Vydrino village , 51° 22’ N, 104° 39’ E, 500 m a.s.l., taiga Abies sibirica – Pinus sibirica along Snezhnaya river, road to Taltsinsky Peak, in litter, 23–28. VI 2021, leg. I.I. Marchenko GoogleMaps ; 3 females, 4 males, same geographical data, environs of Vydrino village , 51° 22’ N, 104° 39’ E, 700 m a.s.l., taiga Abies sibirica – Pinus sibirica along Snezhnaya river, road to Taltsinsky Peak, in litter, 26. VI 2021, leg. I.I. Marchenko. GoogleMaps

Other material: 1 female, 2 males, 5 deutonymphs, data as holotype; 1female, 2 deutonymphs, 1 protonymph, Baikal Region, BURYATIA Republic, Kabanskii district, environs of Tankhoi village, foot of Khamar-Daban Ridge, 51° 47’ N, 105° 24’ E, 51°, 500 m a.s.l., taiga along estuary of Pereemnaya river, in litter, 10.VIII 2014, leg. I.I. Marchenko; 1 deutonymph, same geographical region, environs of Vydrino village 22’ N, 104° 39’ E, 500 m a.s.l., taiga Abies sibirica – Pinus sibirica along Snezhnaya river, road to Taltsinsky Peak, in litter, 23. VI 2021, leg. I.I. Marchenko.

Etymology. The new species S. mariannae is named in honor of my acarologist teacher, author of numerous species and publications on Mesostigmata mites of Siberia – Marianna S. Davydova (1918–1994).

Remarks. The distinguishing characters of adults of Sayanozercon mariannae sp. nov. are: large size of idiosoma; pair of setae s1 is lost on podonotal shield; opisthonotal shield with four pairs of setae in J -series, among which pair of J3 setae is lost; setae in J -series comparatively short, among which setae J4 and J5 the shortest; setae Z3, S2, S3 and S4 long, extend beyond the edge of opisthonotal shield. Podonotal gland gdz5 (po3) located close and anterior to line connecting insertions of setae z5 and s5; Location of opisthonotal glands: gdz6 (Po1) anteromedial to seta Z1; gdZ1 (Po2) anterolateral to seta Z1. Gnathosoma with internal malae with bifurcate apices; fixed digit of chelicera with sexual dimorphism – five teeth in female and six teeth in male.