Halozercon alataus, Marchenko, 2021

Marchenko, Irina I., 2021, Four new species of Halozercon (Acari: Mesostigmata: Zerconidae) from South Siberia Mountains (Russia) with a key to all known species, Zootaxa 4941 (2), pp. 151-185 : 152-161

Halozercon alataus sp. n.

Diagnosis. Podonotum with pair of lateral longitudinal and a pair of central rounded fields free of ornamentation, with clearly visible fields of sigillae. Opisthonotum with specific pattern of J -setae arranged in the shape of a forked tail. Vertex with pair of ip1 glands, inserted outside z1 setae. First and second sternal shields divided. Adult peritremes shorter than in deutonymph, reaching level of middle of coxae II anteriorly. Gnathosoma of both sexes with pair of arcuate sclerotised ridges located behind the pc setae; movable digit of male chelicera with sexual dimorphism—apical hook of movable digit flat-rounded anteriorly. Adult pretarsus of legs II–IV with distinctive shape of median pulvillus—rounded in form, reaching the distal ends of the paradactyls.

Description. Female ( Figs 1–6 , and 14–17, n=10)

Dorsal idiosoma ( Figs 1 , 14, 16 ). Idiosoma suboval, 490–525 long and 300–350 wide. Anterior margin of the podonotum curved ventrally to form a vertex; two setae inserted on the ventral side of idiosoma: seta j 1 (17–19) and seta z 1 smooth (10–12), with pair of glands ip1 inserted between seta z1 and pore po1. Podonotal shield strongly neotrichous with 27–31 lateral setae of z, s -series, 29–33 setae of r -series from each side and 28–32 central setae of j -series. Podonotum ornamented with small tubercles arranged in festoons and scaly patterns in anterior and median regions of the shield, with a pair of lateral longitudinal and a pair of central rounded fields free of ornamentation, with clearly visible fields of sigillae. A large number of setae on the dorsal shields are located on enlarged, oval bases. Most setae in podonotum smooth, except slightly pilose medial setae in most posterior row. Anterior setae are the shortest (13–15), the rest are longer (17–20). Four pairs of pore-like structures (glands) po1–po4 located in podonotum, glands po1 visible in ventral side, po3 the smallest. Opisthonotum neotrichous, without reticulation, with 17–22 lateral setae of Z, S series in asymmetrical location, 19–22 of R -series on each side, 23–29 setae of J - series in median region. The location of J -setae has a specific pattern in the form of a forked tail. All lateral and median opisthonotal setae are slightly pilose, 25–27 long. All opisthonotal setae located on enlarged, oval bases. Area between median and lateral groups of setae with pair of longitudinal fields free of ornamentation, with clearly visible fields of sigillae. Four posterodorsal sigillae present, median pair are smaller than lateral ones. Four pairs of pore-like structures Po1–Po4 inserted in opisthonotum. Pores Po4 visible in ventral side. Marginal dorsal setae of r–R series (33–40) inserted on high tubercles (12–15), slightly curved and densely feathered.

Ventral idiosoma. ( Figs 2 , 15–17 ). Base of tritosternum 25–32 long and 12–17 wide, paired pilose laciniae free from each other along entire length, 47–50 long. Pair of St 1 setae in soft cuticle (12–15). First sternal platelets divided, suboval 25–27 long and 15–17 wide; with pair of St 2 setae (12–15) and pair of lyrifissures iv 2. Second pair of sternal platelets divided, suboval, with two pairs of setae St 3, St 4 (12–15) or in some specimens pair of St 4 setae inserted in soft cuticle; with two pairs of lyrifissures iv 3, iv 4. Area around the sternal shields is covered with small tubercles. Genital shield 52–57 long, 50–57 wide, irregularly-shaped; expanded posteriorly; with genital setae St 5 (12–13) and lyrifissures iv 5. Subtriangular membrane is covered with the genital shield. Genital shield with complex formation, including one median unpaired cap and two pairs of fine sclerites, a short anterior pair and elongate posterior pair. Endo- and exopodal shields absent. Adgenital gland pores gv2 are multiple, dispersed over the surface: one pair of gland openings located in soft cuticle postero-laterally of genital shield, other 6–8 openings located on ventri-anal shield from each side. Soft cuticle between genital and ventri-anal shields with pair of setae Jv 1. Peritrematal shields fused anteriorly forming a vertex and fused with dorsal shield laterally; strongly sclerotised, postero-lateral ends are drawn back; ornamented with festoon reticulation along entire length. Five pairs of porelike structures inserted in peritrematal shields: gp1, gp2 and ip1–ip3. Peritremes slightly sinuous, 105–112 long, reaching level of middle of II coxae anteriorly. Ventri-anal shield broad, 135–145 long and 280–300 wide, fused to opisthonotal shield posteriorly at level of post-anal seta; with deep incisions between marginal sides of opisthonotal shield, with festoon reticulation, with seven pairs of smooth opisthogastric setae inserted asymmetrically (12–15) and lateral rows of opisthonotal setae, inserted posteriorly of incisions, each with 8–9 pilose setae on high tubercles. Anal area with smooth para-anal (12–15) and post-anal setae (17–20); anal opening with two lyrifissures on each valve; cribrum located posteriorly of post-anal seta. Pair of glands gv 3 located antero-laterally of para-anal setae.

Gnathosoma . ( Figs 3–5 ). Fixed digit of chelicera 47–50 long, with five teeth in addition to apical hook and leafshaped pilus dentilis ( Fig. 3 ); movable digit the same length with three teeth in additional to apical hook. Chelicera with long dorsal seta (20), lateral (antiaxial) and dorsal (paraxial) lyrifissures; with arthrodial corona. Epistome with irregularly serrated lateral edges and smooth pointed median projection ( Fig. 4 ). Corniculi 25–27 long and 10–12 wide. Internal malae slightly longer than corniculi ( Fig. 5 ). Deutosternal groove with seven transverse denticulate rows, with three paired smooth lateral transverse lines. The posterior fourth pair of lateral transverse lines archshaped, with large denticles, located at the level of pc setae. Pair of arcuate sclerotised ridges located behind the pc setae. Setae h1–h3 smooth: h1 (30–32) longest, seta h2 (10–12) shorter than h3 (20–25); pc (15–17) serrated. Dorsal side of gnathosoma with pair of protruding wedge-shaped structures between palpal coxa and trochanter, lateral to epistome. Palpal chaetotaxy 2–5–6–12–15, palp with five free segments; palp trochanter with seta al 1 long and pilose in the distal third; with seta al 2 short and smooth; palp genu with setae al 1 and al 2 pilose in distal third, palp apotele two-tined.

Legs. ( Figs 6 , 63a ). Lengths: I 300–335, II 250–285, III 235–275, IV 285–340 μm. 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), 12 (2 6/2 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), 10 (2 4/ 2 2); tarsi 49, 18 (3 7/5 3), 18 (3 7/5 3), 18 (3 7/5 3). All legs with pair of sclerotised claws and pulvillus. Enlarged pair of median pulvillus rounded in form, reaching the distal ends of paradactyls. Pretarsus of legs II–IV with ambulacral stalk, I legs with sessile claws. Coxae I–IV are grouped closely together vertically; pair of coxae I split on dorsal side, III–IV coxae with recesses on anterolateral side. Coxae II–III with antero-dorsal spines: coxae II with large sharp spine, coxae III with small one.

Male ( Figs 7–8 , n=10).

Dorsal idiosoma. Dorsal shield suboval shape, 475–490 long and 300–315 wide. Ornamentation and chaetotaxy similar to that of female.

Ventral idiosoma ( Fig. 7 ). Base of tritosternum 25–27 long and 12–15 wide, pilose laciniae 47–50 long. Pair of presternal setae St 1 in folded soft cuticle. First sternal platelets entire, with pair of St2 setae, with linear and festoon ornamentation, 27–32 long and 40–47 wide, surrounded by many small tubercles. Second sternal platelet entire, subcordate shape, without distinct ornamentation; with two pairs of setae St3, St4 and two pairs of lyrifissures iv3, iv4 on anterior margin; 25–27 long on median line and 45–47 wide at level of St3 setae; surrounds the genital opening. Genital opening located at level of coxae III; with a pair of eugenital setae, covered by two platelets. Third sternal platelet entire, triangular, 25–30 long and 32–37 wide, with pair of St5 setae and pair of iv5 lyrifissures. Sternal setae St 1– St5 equal length (10–12). Endo- and exopodal shields absent. Peritrematal shields similar to that female, with five pairs of pore-like structures: gp1, gp2 and ip1–ip3. Arch of vertex with two dorsal smooth setae j1 (15–17) and z1 (10–12). Peritremes similar to those of female. Ventri-anal shield broad, 145–157 long and 255–260 wide, fused to opisthonotal shield as in female; with 7–8 pairs of opisthogastric smooth setae inserted asymmetrically, 12–17 long and lateral rows of 8–9 opisthonotal pilose setae at high tubercles, inserted posteriorly of incisions. Adgenital gland pores gv2 are multiple, dispersed over the surface: one pair of glands located in soft cuticle posteriorly of coxae IV, other 4–5 openings located in ventri-anal shield. Anal area with preanal (12–15) and post-anal setae 17 long, anal opening with two lyrifissure on each valve; cribrum present. Pair of glands gv3 located antero-laterally of para-anal setae.

Gnathosoma . Fixed digit of chelicera with five teeth (two large and three small) in addition to apical hook and leaf-shaped pilus dentilis ( Fig. 8 ). Movable digit of chelicera the same length as fixed digit (42–45), tridentate in addition to apical hook, with arthrodial corona at base of digit. Apical hook of movable digit flat-rounded anteriorly. Chelicera with dorsal seta, antiaxial and dorsal (paraxial) lyrifissures. Male chelicera with sexual dimorphism of movable digit. Epistome, corniculi, internal malae, hypostomal and palpal structures as in female.

Legs. Lengths: I 300–325, II 260–275, III 260–275, IV 300–325 μm. Chaetotaxy and morphology of legs as in female. Leg II without sexual dimorphism.

Deutonymph ( Fig. 9 , n=10).

Dorsal idiosoma. Dorsal shield suboval shape, 410–430 long and 265–275 wide. Anterior margin of the podonotum curved ventrally to form a vertex, with setae j1, z1 and pair of pores po1. Porotaxy and neotrichy as in adults. Opisthonotal shield with specific pattern of location of J -setae in the form of a forked tail.

Ventral idiosoma ( Fig. 9 ). Pair of St1 setae inserted in folded soft cuticle. First sternal platelets slightly distinct with pair of St2 setae; other setae St3–St5 of sternal region inserted in soft cuticle. Peritrematal shields narrow, fused with dorsal shield laterally, with festoon reticulation along entire length. Peritrematal pore-like structures not visible. Peritremes wavy, 150 long, longer than in adults, reaching level of anterior spine of coxae II anteriorly. One pair of adgenital gland pores gv2 located in soft cuticle posteriorly to coxae IV. Opisthogastric area with 6–8 pairs of simple setae inserted in soft cuticle asymmetrically. Anal shield with pair of para-anal and post-anal setae; with cribrum and pair of gv3 glands located antero-laterally to para-anal setae. Opisthonotal shield is curved on the ventral side posteriorly, does not connect with anal shield.

Gnathosoma . As in adults.

Legs. Lengths: I 260–285, II 215–240, III 210–240, IV 260–285. Chaetotaxy of legs as in adults.

Protonymph ( Figs 10–11 , n=10).

Dorsal idiosoma ( Fig. 10 ). Dorsal idiosoma 315–320 long and 210–215 wide, with weakly sclerotised podonotal and pygidial shields, ornamented with small tubercles. Anterior margin of podonotum curved ventrally to form a vertex, with pilose setae j1. Podonotum with five pairs of setae in j -row (j1, j3–j6), z-row with pairs of recognisable z5 and z6 setae, with ten setae of s -series and 20–21 setae in r -row and two pairs of visible pores po2, po4 from each side. Pygidial region with two pairs of setae in J -row, with 9–12 setae in lateral margins and 11–12 setae in R -row from each side. Four pairs of pores present.

Ventral idiosoma ( Fig. 11 ). Presternal and sternal platelets not distinct. Sternal setae St1–St3 and St5 inserted in soft folded cuticle; St5 minute seta. Peritrematal shields and pore-like structures of peritrematal regions not distinct. Peritremes very short (17–25), with internal cell structure; with thin ducts leading from stigmata. Adgenital gland pores gv2 not distinct. Opisthogastric area with five pairs of simple setae inserted in soft cuticle: Zv1 minute as St5 setae. Anal shield with cribrum, pair of glands gv3, para-anal and post-anal setae. Opisthonotal shield is curved on the ventral side, does not connect with anal shield.

Legs. Lengths: I 215–235, II 175–200, III 175–200, IV 215–235.Chaetotaxy of I–IV legs: coxae 2, 2, 2, 1; trochanters 4, 4,4, 4; femora 10, 8, 5, 4; genua 8, 6, 6, 5; tibiae 8, 6, 7, 7; tarsi II–IV: 17, 17, 17.

Larva ( Figs 12–13 , n=2).

Dorsal idiosoma ( Fig. 12 ). Dorsal idiosoma 230–232 long and 160–164 wide with podonotal and pygidial shields. Podonotal shield with nine pairs of setae, including five pairs of j -row (setae j2 absent); setae j1 stout, pilose, the longest (20), located on anterior margin of shield on tubercles. Pygidium with pair of pores Po3 and eight pairs of setae, including two pairs of simple setae in J -row, two pairs of lateral pilose setae in soft cuticle and four large curved, pilose setae of R -row on enlarged tubercles from each side.

Ventral idiosoma ( Fig. 13 ). Tritosternum as in adults. Sternal setae St1–St3 inserted in soft cuticle. Peritremes and stigma absent. Pore-like structures not visible. Four pairs of opisthogastric setae inserted in soft cuticle, of which seta Jv2 the longest; three pairs of marginal setae brush-shaped. Anal shield with pair of glands gv3, pair of pilose para-anal and simple post-anal setae.

Legs. Lengths: I 200, II 162, III 162–175 μm.

Material examined. Holotype—female, Russia, Altai Mountains, Ust-Koksa Distr., Krasnaya Mountain, 50 05ʹ N, 85 11ʹ E, 1900 m a.s.l., alpine meadows with Pinus sibirica , Abies sibirica , Larix sibirica , in litter, 23 July 2017, leg. I.I. Marchenko. Paratypes: 11 females, 1 male, same geographical and location data as holotype; 8 females, 3 males, same geographical data, 2000 m a.s.l., alpine tundra with Betula rotundifolia , in litter, 23 July 2017, leg. I.I. Marchenko; 6 females, 2 males, same geographical data, 1770 m a.s.l., alpine meadows with Pinus sibirica , Abies sibirica , Picea obovata , in litter, 24 July 2017, leg. I.I. Marchenko; 12 females, 6 males, same geographical data, 1700 m a.s.l., Pinus sibirica – Abies sibirica – Picea obovata forest, in litter, 23 July 2015, leg. I.I. Marchenko; 18 females, 3 males, same geographical data as holotype, 900 m a.s.l., Pinus sibirica – Abies sibirica – Picea obovata forest, in litter, 10 June, 2013, leg. I.I. Marchenko; 13 females, same geographical data, 1600 m a.s.l., Pinus sibirica – Abies sibirica forest, in litter, 26 July 2017, leg. I.I. Marchenko.

Other materials. ALTAI: 23 females, 19 males, 12 deutonymphs, 1 protonymph, Altai Mountains, Ust-Koksa Distr., Krasnaya Mountain, 50 05ʹ N, 85 11ʹ E, 900 m a.s.l., Pinus sibirica – Abies sibirica – Larix sibirica forest, in litter, 10 June, 2013, leg. I.I. Marchenko; 24 females, 12#, 5 deutonymphs, same geographical data, 1700 m a.s.l., Pinus sibirica – Abies sibirica – Larix sibirica forest, in litter, 23 July 2015, leg. I.I. Marchenko; 9 females, 3 males, same geographical data, alpine meadow with Pinus sibirica – Abies sibirica – Larix sibirica forest, 1900 m, in litter, 23 July 2017, leg. I.I. Marchenko; 2 larvae, same geographical data, 1900 m a.s.l., alpine meadow with Abies sibirica – Picea obovata , in litter, 18 July 2019, leg. V.K. Zinchenko; 1 female, 4 males, same geographical data, 2040 m a.s.l., alpine tundra, in moss, 23 July 2017, leg. I.I. Marchenko; 3 females, 1#, Ust-Koksa Distr., environs of Multa village, near Multinskoe lake, 50 10ʹ N, 85 57ʹ E, 1500 m a.s.l., Pinus sibirica – Abies sibirica forest, in moss, 12 July 2013, leg. I.I. Marchenko; 1 deutonymph, 1 protonymph, Ulagan Distr., 8 km from Teletskoe lake, environs of Balykcha village, 51 04ʹ N, 83 02ʹ E, 500 m a.s.l., Betula sp.– Pinus sibirica – Abies sibirica forest, in litter, 25 August, 2017, leg. I.I. Marchenko; 1 male, 1 deutonymph, Altaiskii Krai, North Altai, valley of Kumir river, 50 59ʹ N, 84 17ʹ E, 776 m a.s.l., Betula sp.– Larix sibirica–Picea obovata–Pinus sylvestris forest, in litter, leg. V.I. Rodkina; 1 female, North-West Altai, Ust-Kan Distr., environs of Chernyi Anui village, 51 22ʹ N, 84 43ʹ E, 500 m a.s.l., Betula–Larix forest, in litter, leg. I.I. Marchenko; 1 female, Central Altai, Ongudai Distr., environs of Malaya Inya village, spurs of the Saldjar Ridge, 50 27ʹ N, 86 41ʹ E, 900 m a.s.l., Larix sibirica forest, in litter, 11 June 2016, leg. I.I. Marchenko; TUVA: 4 females, 2 males, Mongun-Taiga Ridge, near Khindigtik-Khol lake, 50 21ʹ N, 89 49ʹ E, 2300 m a.s.l., alpine tundra, leg. A. Kostyunin; NOVOSIBIRSK REGION: 1 protonymph, foothills of Salair Ridge, environs of Novososedovo village, 54 38ʹ N, 83 58ʹ E, 230 m a.s.l., Betula sp. forest, in litter, 6 August 2017, leg. I.I. Marchenko; 2 deutonymphs, foothills of Salair Ridge, environs of Ust-Kamenka village, 55 01ʹ N, 83 52ʹ E, 267 m a.s.l., Betula forest, in litter, 16 August 2018, leg. I.I. Lyubechanskii; KAZAKHSTAN: 1 deutonymph, East Kazakhstan, Tarbagatai Ridge, Oklety Mountain, creek in the valley, thickets of wild Rosa sp., 47 33ʹ N, 81 45ʹ E, 1500 m a.s.l., in litter, 18 May 2017, leg. I.I. Lyubechanskii.

Etymology. The species name alataus reflects the region of its distribution in the Altai-Sayan mountainous province and translated from the Turkic languages, and which the Altai language also refers to “golden mountains”.

Remarks. Adults of Halozercon alataus sp. n. differ from all known species of the genus by special feature of arrangement of J -setae on the opistonotum in the form of a forked tail. In female, the shape of the sternal shields and length of peritremes is similar to those in H. karacholana Wiśniewski et al. 1992 , H. kazachok Marchenko, 2019 and H. capitaneus Marchenko, 2019 . Gnathosoma of both sexes of H. alataus with pair of arcuate sclerotised ridges located behind the pc setae; movable digit of male chelicera with sexual dimorphism—apical hook of movable digit flat-rounded anteriorly as in male chelicera of H. karacholana . Adult pretarsus of legs II–IV with specific median pulvillus, rounded form, reaching the distal ends of paradactyls ( Figs 6 , 63a ).

Figures

FIGURE 1. Halozercon alataus sp. n., female. Dorsal idiosoma.

FIGURES 2–6. Halozercon alataus sp. n., female. 2. Ventral idiosoma; 3. Chelicera; 4. Epistome; 5. Hypostome with palp trochanter; 6. Pretarsus of legs II–IV.

FIGURE 9. Halozercon alataus sp. n., deutonymph. Ventral idiosoma.

FIGURE 63. Pretarsi of legs II–IV of different species of Halozercon, adults. a—H. alataus sp.n.; b—H. gryphus sp.n.; c—H. kumir sp.n.; d—H. aesopi sp. n.; e—H. capitaneus; f—H. kazachok; g—H. barguzin; h—H. tigerek; i—H. karacholana.

FIGURES 14–17. Halozercon alataus sp. n., female. 14–15. SEM photos. 14. Dorsal idiosoma; 15. Ventral idiosoma. 16–17. Habitus photos. 16. Dorsal idiosoma; 17. Ventral idiosoma.

FIGURES 7–8. Halozercon alataus sp. n., male. 7. Ventral idiosoma; 8. Chelicera.

FIGURES 10–11. Halozercon alataus sp. n., protonymph. 10. Dorsal idiosoma; 11. Ventral idiosoma.

FIGURES 12–13. Halozercon alataus sp. n., larva. 12. Dorsal idiosoma; 13. Ventral idiosoma.