Sayanozercon ergaki, 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 : 172-177

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.15819693
persistent identifier	https://treatment.plazi.org/id/038B87E0-B120-FFCE-6AAD-5399DB7C91C7
treatment provided by	Plazi
scientific name	Sayanozercon ergaki
status	sp. nov.

Treatment

Sayanozercon ergaki sp. nov.

( Figures 37–45 View FIGURE 37 View FIGURE 38–41 View FIGURE 42 View FIGURE 43–45 )

Female ( Figs 37–41 View FIGURE 37 View FIGURE 38–41 , n=10)

Dorsal idiosoma ( Fig. 37 View FIGURE 37 ). Idiosoma rounded-oval shape, 560–575 long, 460–485 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 located in podonotal shield and r3 located in peritrematal shield; seta r3 longer than r1 (3.3–3.6 times). Setae s1, z1 and z2 lost. Length of podonotal setae and opisthonotal setae and longitudinal distances between insertions of opisthonotal setae in specific series female and male summarized in Table 5. Setae j1 longest in j- series, other similar length. Setae z4 longest in z -series. Setae s3 longest in s -series and among all podonotal setae. Seta r1 shortest in r -series and among all podonotal setae. 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) close to line connecting insertions of setae j2 and z3; gdj4 (po2) close to 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 reticulation. Medial zone betetween J–J series setae with small irregular spots visible through the cuticle. Opisthonotum with 20 pairs of setae. J -series with four pairs of setae, among which J4 longest, extend beyond the edge of the shield; setae J5 lost. Remaining series with 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. Opisthonotal shield with four pairs of glands and 13 pairs of lyrifissures located as shown in Fig. 37 View FIGURE 37 : 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 similar size, located at posterior margin of opisthonotal shield.

Ventral idiosoma ( Fig. 38 View FIGURE 38–41 ). Base of tritosternum 35–37 long, 20–25 wide; paired laciniae with three distal branches. Sternal shield 68–70 long at midline, 75–80 wide at level st2 setae; with fine reticulation and “window” with fine granular structure between st2–st3 setae; with setae st1–st3 similar in length, 17–20, smooth and pointed; with three pairs of lyrifissures iv1, iv2 and iv3 and one pair of glands gv1. Epiginal shield 125–130 long and 105–113 wide with setae st5 (22–25) on shield and pair of lyrifissures iv5. 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 and free at level coxae III–IV. Peritrematal shield truncate at posterior margin, not fused with ventrianal shield; with fibre brush of cuticular structure and with two rounded formations in inguinal region (gvi and ivi) from each side. Peritrematal shields with smooth, pointed setae r3; with lyrifissures ip1, ip2 and gland gp from each side. Peritremes short, 52–55. Latero-ventral shield weakly reticulated, extends from seta r3 to R6. 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. and with a narrow strip of darker colored cuticle about 35 µm wide. Anterior margin of ventrianal shield with two shortest pairs of setae Jv1 and Zv1 (10–12). Other setae in J -series: Jv2 (17–20), Jv3 (32–35), Jv4 (50–52), Jv5 (75-80); other setae in Z -series: Zv2 (20–22), Zv3 (27–30), Zv4 (25–27); para-anal setae 55-63, post-anal 43–50 long. Pair of glands gv3 usually located at level of posterior edge of the anus. 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 39–41 View FIGURE 38–41 ). 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) and four teeth in masticatory surface in addition to apical hook; leaf-shaped pilus dentilis and apical sensorial depression presented ( Fig. 39 View FIGURE 38–41 ). 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 ( Fig. 40 View FIGURE 38–41 ). Corniculi horn-like, internal malae extending beyond corniculi, with fimbriate lateral margins and smooth pointed apices ( Fig. 41 View FIGURE 38–41 ). Deutosternal groove with seven transverse denticulate rows. Hypostome with four pairs of setae, setae h1–h3 smooth, h1 (40–42) the longest, seta h2 (17–23) shorter than h3 (25–32), pc (30–32) serrated. Palpal chaetotaxy typical for genus Sayanozercon .

Legs. Chaetotaxy of I–IV legs is typical for Zerconidae . 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 42–45 View FIGURE 42 View FIGURE 43–45 , n=9).

Dorsal idiosoma. ( Fig. 42 View FIGURE 42 ). Dorsal idiosoma pear-shaped, 475–485 long, 370–375 wide. Ornamentation, adenotaxy and poroidotaxy of dorsal shields as in female. Podonotal chaetotaxy of male as in female. Length of opisthonotal setae in male has sexual dimorphism in J -series, setae J3 and J4 shortest vs female in which these setae are the longest. Lengths of podonotal, opisthonotal setae and longitudinal distances between insertions of setae in opisthonotal series of male summarized in Table 5.

Ventral idiosoma. ( Fig. 43 View FIGURE 43–45 ). 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, 160–165 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 not visible under light microscopy. Peritrematal shields with short peritrema, smooth, pointed seta r3, two lyrifissures ip1, ip2 and gland gp from each side. 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) on posterior margins. Latero-ventral shields shaped as in female, with longitudinal reticulation. Ventrianal shield with weak transversal reticulation, 210–215 long and 285–290 wide; with 19 smooth and pointed setae, setae a Zv1 absent; with five pairs of lyrifissures ivo1–ivo4, ivp and pair of glands gv3. Length of ventrianal setae: Jv1 (10–13), Jv2 (15–18), Jv3 (25–30), Jv4 (30–35), Jv5 (63–70), Zv2– Zv4 (15–20), para-anal setae 40-50, post-anal 37–40 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 44–45 View FIGURE 43–45 ). Movable digit of chelicera 42–45 long, with three teeth in addition to apical hook, fixed digit the same length, with offset lateral-distal tooth (gabelzhan), followed by five teeth in masticatory surface in addition to apical hook; leaf-shaped pilus dentilis and apical sensorial depression presented ( Fig. 44 View FIGURE 43–45 ). Denticulation of male fixed digit has sexual dimorphism – five teeth in masticatory surface vs female with four teeth in masticatory surface. Male chelicera with dorsal seta, lyrifissures and arthrodial corona as in female. Epistome ( Fig. 45 View FIGURE 43–45 ), corniculi, internal malae and palpal structures as in female.

Legs. Chaetotaxy and morphology of legs as in female.

Juveniles not found.

Material examined. Holotype female, Russia, KHAKASSIA, West Sayan Mt., 40 km from Abaza city along Korasibo river, 52° 35’ N, 90° 08’ E, 700 m a.s.l., taiga with Abies sibirica – Picea obovata – Pinus sibirica , in litter, 25. VI 2013, leg. I.I. Marchenko. Paratypes: 2 females, 2 males, same data as holotype; KRASNOYARSKII KRAI, 1 female, 2 males, West Sayan Mt., Ergaki Ridge, pass Olenya Rechka, 52° 48’ N, 93° 14’ E, 1479 m a.s.l., taiga with Abies sibirica – Pinus sibirica , in moss, 20.VII 2018, leg. I.I. Marchenko; 1 female, West Sayan Mt., Ergaki Ridge, 52° 49’ N, 93° 17’ E, 1400 m a.s.l., road to Visit Center, taiga with Abies sibirica – Pinus sibirica , in moss, 4. VI 2024, leg. I.I. Marchenko; 7 females, 6 males, West Sayan Mt., Ergaki Ridge, 52° 46’ N, 93° 21’ E, 1117– 1250 m a.s.l., taiga along Tushkanchik river, Abies sibirica – Pinus sibirica , in moss, leg. I.I. Marchenko; TUVA, 3 females, 1 male, Mongun Taiga Ridge, near Khindigtik-Khol lake, 50° 21’ N, 89° 49’ E, 2300 m a.s.l., alpine tundra, in moss, 3.VII 2013, coll. A. Kostyunin.

Etymology. New species S. ergaki is named after Ergaki Ridge in Western Sayan Mountains in southern Siberia of Russia, where most of the material of this species was found.

Remarks. Distinguishing characters of adults of Sayanozercon ergaki sp. nov. are: large size of idiosoma; setae s1 lost on podonotal shield; opisthonotal shield with four pairs of setae in J -series, among which pair of J5 setae not developed. Sayanozercon ergaki sp. nov. with sexual dimorpism of chaetotaxy in J -series: in female seta J1 shortest, and setae J3 and J4 longest; seta J3 extends beyond base of J4, seta J4 extends beyond the edge of opisthonotal shield; in male setae J3, J4 shortest; pair of J4 setae does not approach posterodorsal cavities. Both sexes with longest setae Z3, Z4, Z 5 in Z -series; Z3 and Z4 extend beyond the edge of shield; setae in S -series all long extend beyond edge of opisthonotal shield. 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 smooth pointed apices; fixed digit of chelicera with sexual dimorphism – five teeth in female and six teeth in male.