Halozercon kumir, 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 : 170-175

Halozercon kumir sp. n.

Diagnosis. Vertex with pair of ip1 glands, inserted between j1 and z1 setae.Podonotum with pair of lateral longitudinal and a pair of central rounded fields free of ornamentation, with clearly visible fields of sigillae. Central region of opisthonotum ornamented by tubercles in a reticulation pattern. In female, second sternal platelets rather large, converging closely at their postero-medial edges. Adult peritremes shorter than in deutonymph, reaching anterior level of coxae III. Female and male chelicera with six or seven teeth on fixed digit, without sexual dimorphism. Pretarsus of legs II–IV with enlarged pair of median pulvillus of pointed shape, significantly protruding above the claws and paradactyls.

Description. Female ( Figs 37–43 and 48–54 , n=10)

Dorsal idiosoma ( Figs 37 , 48–49 ). Idiosoma suboval, 625–675 long and 400–450 wide. Anterior margin of the podonotum curved ventrally to form a vertex; two smooth setae inserted on the ventral side of idiosoma: seta j 1 (20–25) and seta z1 (10–12), with pair of glands ip1 inserted between setae j 1 and z1. All setae on dorsal shield are located on rounded bases. Podonotal shield strongly neotrichous with 13–15 central setae of j -series, 22–24 lateral setae and 30–32 setae of r -series from each side. Podonotum ornamented with small tubercles in lateral regions and enlarged tubercles fused into a scaly pattern in anterior region of shield, with reticulate pattern in central region. Also podonotal shield with a pair of longitudinal fields between central and lateral regions and pair of central rounded fields free of ornamentation, with clearly visible fields of sigillae. Most setae in podonotum smooth, except some slightly pilose in most posterior row. Podonotal central setae 17–20 long, lateral setae 15–17 long. Three pairs of glands po1, po2 and po4 located in podonotum, glands po3 not visible. Opisthonotum strongly neotrichous, ornamented by enlarged tubercles fused into reticular pattern in the center, with four pairs of pore-like structures Po1–Po4, though Po4 visible in ventral side. Area between central and lateral groups of setae with pair of longitudinal fields free of ornamentation, with clearly visible fields of sigillae. All opisthonotal setae pilose. Central region with 13–15 setae of J -series, 20–25 long, inserted asymmetrically, with 20–26 lateral, 20–22 long and 21–15 setae of R -series (27–30 long) on each side. Marginal setae of r–R series inserted on high tubercles (12–15), curved and densely feathered. Four posterodorsal sigillae approximately equal size.

Ventral idiosoma. ( Figs 38–39 , 50 ). Base of tritosternum 30–32 long and 20–23 wide, paired pilose laciniae free from each other along entire length, 65–70 long. Pair of St1 setae at soft cuticle, 22–25 long. Other sternal setae St2–St5 shorter, 17–19 long. First sternal platelets divided, small, suboval, 15–25 long and 12–15 wide; with pair of St2 setae and lyrifissures iv2. Second sternal platelets divided, with fused posterior-medial edges, with two pairs of setae St3, St4 and two pairs of lyrifissures iv3, iv4. Area around first sternal shields covered with small tubercles. Genital shield 70–75 long, 50–60 wide, irregularly-shaped; expanded posteriorly; with genital setae St5 on the shield or in soft cuticle; lyrifissures iv5 inserted in soft cuticle. Subtriangular membrane is covered by the genital shield. Genital shield with complex internal structure, typical for genus Halozercon . 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, with five or four pairs of pore-like structures: gp1, gp2 and ip1–ip3, sometimes pore ip2 not distinct. Peritremes slightly sinuous, 125–135 long, reaching level of mid-line of II coxae. Ventri-anal shield entire, broad, 195–210 long and 330–355 wide, fused to opisthonotal shield along the lateral margins, with festoon reticulation, with 9–10 smooth opisthogastric setae, inserted asymmetrically from each side, median setae of Jv -series (22–25) longer than other (15–17); marginal rows of opisthonotal setae on high tubercles. Adgenital gland pores gv2 are multiple, dispersed over the surface: one pair of gland openings located in soft cuticle postero-lateral of genital shield, other 6–10 openings located in ventri-anal shield from each side. Anal area with smooth para-anal (15–17) and post-anal setae (22); anal opening with two lyrifissures on each valve; cribrum located posteriorly of para-anal seta. Pair of glands gv 3 located anteriorly of para-anal setae.

Gnathosoma . ( Figs 40–42 , 51 ). Fixed digit of chelicera 65–67 long, with seven teeth in addition to apical hook and leaf-shaped pilus dentilis ( Fig. 40 ); movable digit the same length with three teeth in additional to apical hook. Chelicera with long dorsal seta, lateral (antiaxial) and dorsal (paraxial) lyrifissures; with arthrodial corona. Epistome with irregularly serrated lateral edges and smooth pointed median projection ( Fig. 41 ). Corniculi 35–36 long and 12–14 wide. Internal malae slightly longer than corniculi ( Figs 42 , 51 ). Deutosternal groove with seven transverse denticulate rows and three paired smooth lateral transverse lines. The posterior fourth pair of lateral transverse lines arch-shaped, with large denticles, located at the level of pc setae. Setae h1–h3 smooth: h1 (40–45) longest, seta h2 (20–22) shorter than h3 (27–32); pc (20–22) serrated. Palpal chaetotaxy typical for genus.

Legs. ( Figs 43 , 52–54 and 63c ). Lengths: I 430–435, II 350–360, III 350–360, IV 425–440 μm. Chaetotaxy of legs typical for genus. All legs with pair of sclerotised claws and pulvillus. Pretarsus of legs II–IV with ambulacral stalk, with enlarged pair of median pulvillus pointed shape, significantly protrudes above the claws and paradactyls. Pretasus of I legs with sessile claws. Coxae I–IV grouped closely together vertically; coxae I split on dorsal side, coxae IV with recesses on anterolateral side, recesses of coxae III indeterminate. Coxae II with antero-dorsal large spines. Coxae IV with alveolar vestige of second av seta.

Male ( Figs 44–45 , n=10).

Dorsal idiosoma. Dorsal shield suboval shape, 535–560 long and 335–365 wide. Ornamentation and chaetotaxy similar to that of female.

Ventral idiosoma ( Fig. 44 ). Base of tritosternum 22–25 long and 17–19 wide, pilose laciniae 60–63 long. Pair of presternal St1 setae in folded soft cuticle. First sternal platelet entire, with pair of St2 setae, with linear ornamentation, 25–30 long and 50–55 wide. Second sternal platelet entire, subcordate shape, without distinct ornamentation; with two pairs of setae St3, St4 and two pairs of lyrifissures iv3, iv 4 in anterior margin; 25–35 long on median line and 50–57 wide at level of St3 setae; surrounds the genital opening. Genital opening located at level of coxae III; with a pair of eugenital setae (12–15), covered by two platelets. Third sternal platelet irregular shape and sizes, often 15–22 long and 12–30 wide, with St5 setae and lyrifissures iv 5 in soft cuticle; in some specimens larger (35 x 47), with St 5 in platelet. Sternal setae St1 the longest (23–25), other St2–St5 equal length (15–17). Endo- and exopodal shields absent. Peritrematal shields not fused with ventri-anal shield, with five or four pairs of pore-like structures: gp1, gp2 and ip1–ip3, sometimes pore ip2 not distinct. Peritremes similar to those of female, 112–120 long. Ventrianal shield with festoon reticulation, 160–167 long and 280–287 wide, fused to opisthonotal shield along the lateral margins, opisthogastric setae smooth, inserted asymmetrically, central setae longer (22–25) than other (12–15), lateral rows of opisthonotal pilose setae on high tubercles. Adgenital gland pores gv2 are multiple: one pair of gland openings located in soft cuticle posteriorly of IV coxae, another located in ventri-anal shield from each side. Anal area with para-anal (12–17) and post-anal setae 17–20 long, anal opening with two lyrifissures on each valve; cribrum present. Pair of glands gv3 located anteriorly of para-anal setae.

Gnathosoma . ( Fig. 45 ). Fixed digit of chelicera with six or seven teeth (5–6 teeth on masticatory margin and one small offset on lateral surface of digit, near apical hook) in addition to apical hook and leaf-shaped pilus dentilis. Movable digit of chelicera the same length as fixed digit (57–59), tridentate in addition to apical hook, with arthrodial corona at base of digit. Male chelicera with long dorsal seta (22), antiaxial and dorsal (paraxial) lyrifissures, without obvious sexual dimorphism. Epistome, corniculi, internal malae, hypostomal and palpal structures as in female.

Legs. Lengths: I 400–410, II 335–340, III 335–340, IV 390–410 μm. Chaetotaxy and morphology of legs as in female. Coxae III–IV with clear visible recessions. Leg II without sexual dimorphism.

Deutonymph not found.

Protonymph ( Figs 46–47 , n=7).

Dorsal idiosoma ( Fig. 46 ). Dorsal idiosoma 340–390 long and 225–250 wide, weakly sclerotised, podonotal shield ornamented with small tubercles. Podonotal and pygidial shields with multiple sigillae as in adults. Anterior margin of podonotum curved ventrally to form a vertex, with pilose vertical setae j1. Podonotum with five pairs of setae in j -row (j1, j3–j6), with pair of recognisable z5 setae, with 10–11 setae of s -series and 22 setae of r -series and two pairs of pores po2, po4 from each side. Pygidial region with two pairs of setae in J -row, with multiple asymmetrical setae in lateral margins and 13 setae in R -row from each side. Four pairs of pores Po1–Po4 present (Po4 on ventral side).

Ventral idiosoma ( Fig. 47 ). 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 (25–30), 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. Anal shield is shaped like an inverted pear, with cribrum, pair of glands gv3, para-anal and post-anal setae. Dorsal shield is curved on the ventral side, does not connect with anal shield.

Legs. Lengths: I 270–300, II 220–275, III 220–275, IV 270–300. Chaetotaxy of legs typical for protonymphs of Halozercon .

Larva not found.

Material examined. Holotype—female, Russia, ALTAI Mountains, Ust-Kan District, Korgonskii Ridge, the upper reaches of Kuma river, 10 km from Ust-Kumir village, 50 59ʹ N, 84 09ʹ E, 1600 m a.s.l., Abies sibirica – Pinus sibirica forest, in litter, 7 July 2019, leg. R. Dudko and A. Gurina; paratypes: 8 females, 10 males, same data as holotype .

Other material. Same data as type material, 14 protonymphs.

Etymology. The species kumir named after Ust-Kumir village near Korgon Ridge in Altai Mountains and reflects the region of distribution of this species. The word kumir (in Russian) also means an idol that is admired and worshiped.

Remarks. Dorsal idiosoma of Halozercon kumir sp.n. differs from other species of genus by ornamentation of opisthonotum: tubercles of the central region rather large and fused together in a reticulation pattern. In the female, second sternal platelets are rather large, converging closely at the postero-medial edges. Female and male chelicera with six or seven teeth on fixed digit, while female chelicera of other species with five teeth. Male chelicera as in female, without sexual dimorphism. Pretarsus of legs II–IV with enlarged pair of median pulvillus pointed shape, significantly protrudes above the claws and paradactyls, similar to H. gryphus sp.n.

Figures

FIGURE 37. Halozercon kumir sp. n., female. Dorsal idiosoma.

FIGURES 38–43. Halozercon kumir sp. n., female.38.Ventral idiosoma; 39. Second sternal shield; 40.Chelicera; 41. Epistome; 42. Hypostome with palp trochanter; 43. Pretarsus of legs II–IV.

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 48–54. Halozercon kumir sp. n., SEM photos, female. 48. Dorsal idiosoma; 49. Central region of opisthonotum; 50. Sternal and genital regions of ventrum; 51. Gnathosoma, ventral view; 52. Apical part of I tarsus; 53. Tarsus of I leg; 54. Pretarsus of legs II–IV.

FIGURES 44–45. Halozercon kumir sp. n., male. 44. Ventral idiosoma; 45.Chelicera.

FIGURES 46–47. Halozercon kumir sp. n., protonymph. 46. Dorsal idiosoma; 47. Ventral idiosoma.