Sayanozercon adelaidae, 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 : 167-171

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.15819691
persistent identifier	https://treatment.plazi.org/id/038B87E0-B125-FFC0-6AAD-51F5DC9997CB
treatment provided by	Plazi
scientific name	Sayanozercon adelaidae
status	sp. nov.

Treatment

Sayanozercon adelaidae sp. nov.

( Figures 30–36 View FIGURE 30 View FIGURE 31–33 View FIGURE 34 View FIGURE 35–36 )

Female ( Figs 30–33 View FIGURE 30 View FIGURE 31–33 , n=4)

Dorsal idiosoma ( Fig. 30 View FIGURE 30 ). Idiosoma pear-shaped, 475–500 long, 330–340 wide, without obvious ornamentation, divided into two shields that cover entire dorsal idiosoma. All dorsal setae smooth and pointed. Podonotal shield with 21 pairs of setae, including r1 located in podonotal shield and r3 located in peritrematal shield; seta r3 is 4 times longer than r1. Setae z1 and z2 lost. Length of podonotal setae female and male summarized in Table 4. Setae of j- series j1–j4 comparable length, setae j5 and j6 the shortest. Setae z4 the longest in z -series. Setae s1 shortest and s3 longest in s -series. 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) posterior to insertion of seta s1, close to line connecting insertions of setae j2 and z3; gdj4 (po2) on line connecting insertions of setae j4 and z4; gdz5 (po3) on line connecting insertions of setae s4 and s5. Opisthonotal shield with delicate horizontal lines between setae J2 and J5, with 21 pairs of setae. Lengths of opisthonotal setae and longitudinal distances between insertions of setae in specific series of female and male summarized in Table 4. J -row with five pairs of short setae J1–J5, among which J4, J5 shortest; setae J5 located directly above medial posterodorsal cavities. Remaining series also with a full set of setae. Z -series with longest setae Z4 and Z5 extend beyond the edge of the shield and short setae Z1–Z3 comporable length. S -series with longest setae S5 extend beyond the edge of the shield, setae S2–S4 short, comparable length. Setae of R -series all long, similar length. Opisthonotal shield with four pairs of glands and 13 pairs of lyrifissures located as shown in Fig. 30 View FIGURE 30 : 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 ( Fig. 31 View FIGURE 31–33 ). Base of tritosternum 30–32 long, 20–23 wide; paired laciniae with three distal branches. Sternal shield 68–70 long at midline, 67–70 wide at level st2 setae; with reticulate ornamentation, with setae st1–st2 similar in length, 17–19, st3 15–16, all smooth and pointed; with three pairs of lyrifissures iv1, iv2 and iv3 and one pair of glands gv1. Epiginal shield 105–107 long and 83–85 wide with setae st5 (17–20) on shield and pair of lyrifissures iv5. Pair of setae st4 (17–19) located outside large endopodal sclerites between coxae III–IV; small ovate-oblong endopodal sclerites behind 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 of coxae III–IV. Peritrematal shields with smooth and pointed seta r3; two lyrifissures ip1, ip2 and gland gp from each side. Peritrematal shields truncate at posterior margin; with fibre brush of cuticular structure and two rounded formations in inguinal region (poroids gvi and ivi) from each side. Peritremes are very short, 30–32. Latero-ventral shields weakly reticulated extend from seta r3 to R6. Adgenital sclerites presented each with 4–5 gland openings gv2. Ventrianal shield reticulated, 210–215 long, 275–280 wide at level of seta Zv2, with 21 smooth, pointed setae. Anterior margin of ventrianal shield with two shortest pairs of setae Jv1 and Zv1 (10–12). Other setae in J -series: Jv2 (15–17), Jv3 (20–23), Jv4 (30–32), Jv5 (40–43); other setae in Z -series: Zv2 (10–12), Zv3 (20–22), Zv4 (15–17); para-anal setae 43–45, post-anal 30–32 long. Pair of glands gv3, five pairs of ventrianal lyrifissures ivo1–ivo4 and ivp presented. Anal opening with two pairs of lyrifissures on each valve. Cribrum presented posteriorly of post-anal setae.

Gnathosoma ( Figs 32–33 View FIGURE 31–33 ). Movable digit of chelicera 52–55 long, with three teeth in addition to apical hook; fixed digit the same length, with five teeth, including offset distal tooth (gabelzhan), four teeth in masticatory surface in addition to apical hook; leaf-shaped pilus dentilis presented ( Fig. 32 View FIGURE 31–33 ). Chelicera with dorsal seta, lateral (antiaxial) and dorsal lyrifissures; with smooth arthrodial corona. Epistome with irregularly serrated lateral edges, medial ridge and irregularly serrated middle process with median row of small spines ( Fig. 33 View FIGURE 31–33 ). Corniculi horn-like, internal malae extending beyond corniculi, with fimbriate lateral margins and bifurcate apices. Hypostome with four pairs of setae, setae h1–h3 smooth, h1 (25–27) the longest, seta h2 (12–15) shorter than h3 (17–20), setae pc serrated (30–32). 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 34–36 View FIGURE 34 View FIGURE 35–36 , n=2).

Dorsal idiosoma. ( Fig. 34 View FIGURE 34 ). Dorsal idiosoma elongated oval in shape, 415–430 long, 250–265 wide. Ornamentation, chaetotaxy, adenotaxy and poroidotaxy of dorsal shields as in female. Lengths of podonotal, opisthonotal setae and longitudinal distances between insertions of setae in opisthonotal series of male summarized in Table 3.

Ventral idiosoma. ( Fig. 35 View FIGURE 35–36 ). 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, 137–150 long with four pairs of setae st1–st4 (10–15), 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 each with short peritrema (25), smooth and pointed setae r3, with two pairs of lyrifissures ip1, ip2 and pair of glands gp; connected posteriorly to each other by fibre brush of cuticular structure. Inguinal region of peritrematal shields with two pairs of rounded formations hollow inside (inguinal poroids gvi and ivi). Latero-ventral shields shaped as in female, with weak longitudinal reticulation. Ventrianal shield with weak cellular reticulation, 182–185 long and 215–225 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 (10–12), Jv2 (10–15), Jv3 (25–30), Jv4 (20–25), Jv5 (20–33), Zv2–Zv4 (10–12), para-anal setae 32–34, post-anal 30–32 long. Multiple glands gv2 with 4 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 ( Fig. 36 View FIGURE 35–36 ). Male movable digit of chelicera 40–42 long, fixed digit the same length, denticulation is not clearly visible. Dorsal seta, lyrifissures and arthrodial corona are not clearly distinguishable. Epistome ( Fig. 36 View FIGURE 35–36 ), 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, Baikal region, BURYATIA Republic, Kabanskii district, environs of Tankhoi village, Khamar-Daban Ridge, alpine meadow with tall grasses, 51° 33’ N, 105° 09’ E, 1100 m a.s.l., in litter, 13. VIII 2014, coll. L. V. Petrozhitskaya. Paratypes: 1 male, same data as holotype; 1 male, same geographical data, 51° 33’ N, 105° 09’ E, 470 m a.s.l., taiga along estuary of Pereemnaya river, in litter, 10.VIII 2014, leg. I.I. Marchenko; 3 females, same geographical data, 51° 33’ N, 105° 09’ E, 700 m a.s.l., taiga with Abies sibirica – Pinus sibirica , in litter, 14. VIII 2014, coll. L. V. Petrozhitskaya.

Etymology. The new species S. adelaidae is named in honor of prominent acarologist – Adelaida D. Petrova (Nikitina) (1932–2011), author of numerous Mesostigmata genera and species.

Remarks. The distinguishing characters of adults of Sayanozercon adelaidae sp. nov. are: mid-size of idiosoma; pair of setae s1 is present on podonotal shield; opisthonotal shield with five pairs of short setae in J -series; seta Z3 short, setae S2, S3 and S4 are also short, do not extend beyond edge of shield. Podonotal gland gdz5 (po3) located on line connecting insertions of setae s4 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.