Halozercon capitaneus, Marchenko, 2019

Marchenko, Irina I., 2019, Three new species of Halozercon (Acari: Mesostigmata: Zerconidae) from Altai Mountains in South Siberia (Russia), Zootaxa 4568 (3), pp. 401-434 : 423-431

Halozercon capitaneus sp. n.

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Diagnosis. Vertex with two pairs of setae: j1 and z1, with pair of glands ip1 inserted in middle between j1 and z1 setae. Surface of podonotal shield ornamented by small tubercles in anterior and lateral regions, median region with indistinct reticulation. All podonotal setae smooth. Opisthonotal shield with linear reticulation in median region, with small tubercles in lateral regions. Median region with 14–17 slightly serrated setae of J series. First sternal platelets divided, with pair of lyrifissures iv2. Metapodal shields absent. Setae Jv1 located in anterior margin of ventri-anal shields or in some specimens in soft cuticle between genital and ventri-anal shields. Peritremes reaching level of posterior 1/3 part of coxae II. Ventri-anal shield entire. Adult chelicera without sexual dimorphism.

Description. Female ( Figs 82–86 , 88–98 , n=3)

Dorsal idiosoma. Idiosoma suboval, 580–595 long and 377–390 wide. Anterior margin of the podonotum curved ventrally to form a vertex with two pairs of setae at arisen bases: j1 (12–15) stout, smooth and z1 setae (10– 12) smooth, thorn-like; with pair of glands ip1 inserted in middle between j1 and z1 setae. Podonotal shield strongly neotrichous with about 63–66 setae on each side, including marginal r setae; ornamented by small tubercles in anterior and lateral regions, median region with indistinct reticulation ( Figs 82 , 88–89 ). All podonotal setae smooth, 12–15 long. Four pairs of pore-like structures (glands) po1–po4 located in podonotum, glands po1 visible in ventral side. Opisthonotal shield linear reticulated in median region, with small tubercles in lateral regions; with four pairs of pore-like structures (glands) Po1–Po4 and with 48–53 neotrichous setae on each side, including marginal R setae. Median region with 14–17 slightly serrated setae of J series ( Fig. 90 ), lateral region with setae of Z, S series inserted closely, smooth or pilose ( Fig. 91 ), all setae arrangement asymmetrically, 15–20 long. All dorsal setae surrounded by enlarged basal rings. Marginal setae of r–R series neotrichous, elongated, pilose, 25–30 long, inserted on high tubercles.

Ventral idiosoma. ( Figs 83 , 92–98 ). Base of tritosternum 30–35 long and 20–22 wide, pilose laciniae free from each other along entire length, 60–65 long. Presternal (jugular) platelets irregular shape, weakly sclerotised, with pair of St1 setae (23–25). First pair of sternal platelets divided, suboval, 25–35 long and 13–18 wide, with pair of St2 setae (20–22) and pair of lyrifissures iv2 ( Figs 83 , 92–95 ). Area between jugular and first sternal platelets ornamented by small rounded tubercles. Second pair of sternal platelets divided, suboval, 30–33 long and 12–15 wide, with two pairs of setae St3, St4 (15–17) and two pairs of lyrifissures iv3, iv4 ( Figs 92–95 ). Genital shield stocky form, 58–67 long, 48–52 wide, irregularly-shaped, with individual shape in each specimen; expanded anteriorly and posteriorly; anterior margin with fine folding; with genital setae St5 (15–16) and lyrifissures iv5 on genital shield ( Fig. 95 ). Subtriangular membrane surrounds the genital shield. Endo-, exopodal and metapodal shields absent. Adgenital gland pores gv2 are multiple, dispersed over the surface: one gland opening located in soft cuticle postero-laterad of genital shield, another 4–6 openings located in ventri-anal shield. Setae Jv1 located in anterior margin of ventri-anal shields or in some specimens in soft cuticle between genital and ventri-anal shields. 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 pore-like structures inserted in peritrematal shield: gp1, gp2 and ip1–ip3. Peritremes straight or slightly curved, 123–127 long, reaching level of posterior 1/3 part of coxae II; with internal cell structure ( Fig. 96 ). Ventrianal shield entire, broad ( Figs 93, 97–98 ), 190–200 long and 325–335 wide, fused to opisthonotal shield; with festoon reticulation, with 8–9 pairs of smooth opisthogastric setae (15–20). Opisthonotal shield curved on ventral side, with 5–6 pilose setae (23–25). Anal area with simple pre-anal (13–15) and post-anal setae (17); anal opening 37 long; with two lyrifissure on each valve; cribrum located posteriorly of post-anal seta. Pair of glands gv3 located antero-laterad of para-anal setae.

Gnathosoma . ( Figs 84–86 ). Fixed digit of chelicera 60–61 long, with five teeth in addition to apical hook and leaf-shaped pilus dentilis ( Fig. 84 ); 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 subtriangular, with irregularly serrated edges and smooth pointed median projection ( Fig. 85 ). Corniculi 30–31 long and 14–15 wide. Internal malae slightly longer than corniculi, with complex three-layer structure ( Fig. 86 ). Deutosternal groove with 7–8 transverse denticulate rows. The posterior pair of lateral transverse lines archshaped, with large denticles, located at the level of pc setae. Setae h1–h3 smooth: h1 (45–47) longest, seta h2 (15– 17) shorter than h3 (25–30); pc (20–22) serrated. Palpal trochanter with seta al1 long and pilose in the distal third; with seta al2 short and smooth; palp genu with setae al1 and al2 pilose in distal third, palp apotele two-tined.

Legs. Lengths: I 380–385, II 315–325, III 31 5 –325, IV 375–385 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 with five lobes. Pretarsus of legs II–IV with ambulacral stalk, legs I with sessile claws. Coxae I–IV grouped closely together vertically; coxae I split on dorsal side, coxae III–IV with recesses on anterolateral side. Coxae II with antero-dorsal large sharp spine.

Male. (87, 99–101, n=2).

Dorsal idiosoma. Dorsal shield suboval shape, 515–575 long and 310–360 wide. Ornamentation and chaetotaxy similar to that of female.

Ventral idiosoma. Tritosternum as in female. Pair weakly sclerotised presternal (jugular) platelets with pair of St1 setae ( Figs 87, 99–101 ). First sternal platelet entire, with pair of St2 setae, with line ornamentation, 30–32 long and 50–55 wide. Second sternal platelet entire, subcordate shape, with indistinct reticulation; with two pairs of setae St3, St4 and one pair of lyrifissures iv 3 in antero-lateral margins; 40–42 long on median line and 48–55 wide at level of St3 setae; surrounds the genital opening. Genital opening located at level of coxae III; with a pair of eugenital setae, covering by two platelets ( Figs 100–101 ), with pair of genital sclerites. Third sternal platelet triangular, divided in three fragments, with St5 setae and pair of iv5 lyrifissures inserted in soft cuticle. Endo-, exopodal and metapodal shields absent. Peritrematal shields similar to that female, with five pairs of pore-like structures: gp1, gp2, i1 —ip3. Peritremes similar to those of female, 115–125 long. Arch of vertex with two dorsal setae: smooth, stout j1 and smooth, thorn-like z1. Ventri-anal shield broad, entire, with festoon reticulation ( Figs 87, 99 ), 165–180 long and 275–310 wide; with 7–10 pairs of opisthogastric smooth setae and 4–6 opisthonotal slightly pilose setae. Adgenital gland pores gv2 are multiple, dispersed over the surface: one pair of glands located in soft cuticle posteriorly of coxae IV, other 3–5 openings located in ventri-anal shield. Anal area as in female. Pair of glands gv3 located antero-laterad of para-anal setae. Gnathosoma . Fixed digit of chelicera 55 long, with five teeth in addition to apical hook and leaf-shaped pilus dentilis. Movable digit of chelicera the same length as fixed digit, tridentate in addition to apical hook. Male chelicera lacking spermatodactyl, without sexual dimorphism. Epistome, corniculi, internal malae, hypostomal and palpal structures as in female.

Legs. Lengths: I 325–340, II 270–285, III 270–285, IV 315–340 µm. Chaetotaxy and morphology of legs as in female. Leg II without sexual dimorphism.

Material examined. Holotype female, Russia, Altaiskii krai, North-Western Altai Mountains , Tigeretskii Range , Tigerekskii Nature Reserve , 1300 m a.s.l., 51 ̊04ʹ N, 83 ̊02ʹ E, Betula tortuosa forest, in litter, 18 June 2017, leg. I.I. Marchenko. Paratypes: 2 females, same data as holotype ; 1male, same data as holotype ; 1 male, Tigerekskii Nature Reserve , environs of Tigerek village, Kozyr Mt., 500 m a.s.l., 51 ̊04ʹ N, 83 ̊02ʹ E, in litter, 24 June 2017, leg. I.I. Marchenko.

Etymology. The species is named capitaneus , as captain of team, due to its large size compared with other species of Halozercon found in Tigerekskii Nature Reserve.

Remarks. Adults of Halozercon capitaneus are most similar to H. karacholana Wiśniewski et al. 1992 , but differ from those having larger size of idiosoma; ornamentation of dorsal shields—median regions of podonotal and opisthonotal shields with smooth reticulation; pore-like structures Po4 (glands) located in posterior part of opisthonotum at dorsal side; all podonotal setae smooth except marginal; opisthonotal setae of J series slightly serrated (which is visible only at 1000 magnification). Adults of Halozercon karacholana having smaller size of idiosoma; median regions of podonotal and opisthonotal shields with tubercles and festoon network, with tubercle or festoon patterns around J5 setae and po 3 glands ( Figs 102–103 ); Po4 glands located in posterior part of opisthonotum at ventral side; all dorsal setae pilose ( Fig. 104 ).

Figures

FIGURE 82. Halozercon capitaneus sp. n., female. Dorsal idiosoma.

FIGURES 83–86. Halozercon capitaneus sp. n., female. 83. Ventral idiosoma; 84. Chelicera; 85. Epistome; 86. Hypostome with palp trochanter.

FIGURES 88–101. Halozercon capitaneus sp. n., photos of habitus. 88–98. Female. 88. Ventral idiosoma; 89. Setae in podonotal shield; 90. Median setae in opisthonotal shield; 91. Lateral setae of opisthonotum; 92–93. Ventral idiosoma; 94. Sternal region; 95. Genital shield; 96. Peritrema; 97–98. Ventri-anal shield. 99–101. Male. Ventral idiosoma.

FIGURES 102–104. Halozercon karacholana, photos of female habitus. 102–103. Dorsal idiosoma; 104. Median setae of opisthonotal shield.