Gaeolaelaps altaiensis Joharchi, 2021

Joharchi, Omid, Döker, Ismail & Khaustov, Vladimir A., 2021, Two new species and a new record of Gaeolaelaps Evans & Till (Acari: Laelapidae) from Altai Mountains, Russia, Zootaxa 4949 (2), pp. 240-260 : 241-243

Gaeolaelaps altaiensis Joharchi sp. nov.

( Figures 1–21 )

Type material: Holotype, female, Ulaganskiy Rayon, Chuysky Trakt, Altai Republic, Russia, 50°14’N 87°42’E, 30 July 2020, alt. 1533 m, O. Joharchi coll., in the nest of Lasius sp. ( Hymenoptera : Formicidae ) (in TSUMZ). Paratypes, five females and two males same data as holotype (in TSUMZ).

Diagnosis (adult female). Dorsal shield with distinct reticulation posterior to j6, narrowing from level of setae r3, progressively tapering until s6, then more or less parallel-sided from r6 to level of S4 until rounded posteriorly; with 37 pairs of smooth setae (except J4, J5, Z5, sparsely barbed), z3 and S1 absent. Presternal area lightly sclerotised, punctate, with a few transverse curved lines, sternal shield with reticulate ornamentation laterally, smooth (or faintly reticulated) medially, anterior margin slightly concave, posterior margin more or less straight; ratio of shield length/width ≃ 0.86. Genital shield length/width ratio ≃ 2.5, faintly reticulated posterior to inverted-V ridge with 5–6 cells. Anal shield length/width ratio ≃ 1. Opisthosomal integument with eight pairs of smooth setae, peritremes short, reaching to mid-level of coxae II. Tarsus IV with two (pd2, pd3) macrosetae. Fixed digit of chelicera with seven teeth.

Description. Female (n=6) ( Figures 1–13 , 16–19 )

Dorsal idiosoma ( Figs 1 , 7–8 ). Dorsal shield 445–465 long, 228–250 wide, covering most of dorsal idiosoma; distinct reticulation posterior to j6 ( Figs 1 , 7–8 ). Shield narrowing from level of setae r3, progressively tapering until s6, then subparallel from r6 to level of S4 until rounded posteriorly and with 37 pairs of setae; 21 pairs of podonotal setae, z3 absent, 16 pairs of opisthonotal setae, including two pairs of Zx setae, S1 absent and r6 on lateral soft cuticle. All setae smooth (28–38) except J4, J5, Z5, sparsely barbed, see Fig. 1, j1 (22–24), z1 (25–27), Z5 (54–56) ( Figs 1 , 7–8 ). Shield with about 20 pairs of discernible pore-like structures, including 16 poroids (id1, id2, id4–id6, idm-idm6, is1, idx, idl1, idl3, idl4) and four gland openings (gd5, gd6, gd8, gd9), others indistinct, see Figures 1 , 7–8 .

Ventral idiosoma ( Figs 2 , 9–10 ). Tritosternum with paired pilose laciniae (79–82), fused basally (2–4), columnar base 25–27 × 12–14 wide; presternal area lightly sclerotised, punctate, with a few transverse curved lines, sternal shield length 119–122, maximum width 137–141, narrowest between coxae II (85–92), with reticulate ornamentation laterally, central part smooth or faintly reticulated ( Fig. 10 ), posterior margin almost straigh, anterior margin slightly concave; bearing three pairs of smooth setae (st1 32–34, st2 32–34, st3 31–33), never reaching base of next setae, one pair of lyrifissures adjacent to setae st1, and a pair of poroids between st2 and st3; remnants of gland pores gv1 indistinct. Metasternal setae st4 (26–28) and metasternal poroids located on soft integument; metasternal platelets absent. Endopodal plates II/III completely fused to sternal shield, endopodal plates III/IV elongate, narrow and curved, abutting posterioir part of endopodal plates II/III. Genital shield tongue-shaped, slightly expanded posteriorly past setae st5, length 166–180, maximum width 65–70, anterior margin of shield irregularly convex, overlapping posterior area of sternal shield, but not reaching base of setae st3, posterior margin rounded, surface reticulated with irregular longitudinal lines in anterior region, posteriorly with 5–6 faint cells enclosed behind an inverted-V shaped ridge; bearing a pair of simple setae st5 (24–26) ( Fig. 10 ). Shield flanked by two pairs of minute, elongate paragenital platelets; paragenital poroids iv5 located on soft cuticle lateral to shield near seta st5. Anal shield subtriangular, rounded anteriorly, length 68–76, width 68–73, anterior half lineate-reticulate, paraanal setae (27–29) shorter than post-anal seta (35–37), cribrum consisting of a terminal tuft with 3–4 irregular rows of spicules and a pair of anterior arms extending slightly beyond post-anal seta ( Figs 2 , 9 ); anal gland pores (gv3) on anterolateral margin of anal shield. Soft opisthogastric cuticle with pair of oval metapodal plates (18–20 long × 5–7 wide), an additional small round metapodal platelet more medially and eight pairs of smooth setae (Jv1–Jv5, Zv1–Zv 3) (23–26), Jv5 (36–38), and six pairs of poroids including iv5 and ivp. Exopodal platelets between coxae II–III subtriangular, those behind coxae III–IV and parapodal platelets fused, curved, extending narrowly behind coxae IV, surrounding coxa IV, gland pores gv2 on parapodal platelets ( Figs 2 , 9 ). Peritreme extending anteriorly to mid-level of coxa II; peritrematal shield narrow, expanded anteriorly, fused to dorsal shield behind setae z1 level, free from exopodal shields, bearing five pore-like structures, a lyrifissure ip and a gland pore gp at level near coxae II–III, two lyrifissures ip and a gland pore gp on post-stigmatic section ( Figs 2 , 9 ).

Gnathosoma ( Figs 3–6 , 11–12 ). Epistome subtriangular and irregularly denticulate ( Fig. 5 ). Hypostomal groove with six transverse rows of denticles, each row with 7–12 small denticles, with smooth anterior and posterior transverse lines, groove very slightly wider anteriorly. Hypostome with four pairs of setae, internal posterior hypostomal setae h3 (31–33), h1 (28–30), h2 (20–22), palpcoxal setae (pc) (23–25) ( Figs 3 , 11 ). Corniculi robust and horn-like, extending slightly beyond palptrochanter. Supralabral process with apically tri-tined anterior projection ( Fig. 4 ). Internal malae with one pair of smooth median projections, flanked by lobes with fimbriate anterior margin; labrum with pilose surface ( Figs 3 , 11 ). Chaetotaxy of palps ( Fig. 12 ): trochanter 2, femur 5, genu 6, tibia 14, tarsus 15, all setae smooth and needle-like except al1 and al2 on palpgenu thickened, paddle-like and al on palp palpfemur thickened, d3 inserted on small tubercles, palp tarsal apotele two-tined ( Fig. 12 ). Fixed digit of chelicera with an offset distal tooth (gabelzahn), followed by six variously sized teeth, a setaceous pilus dentilis, dorsal cheliceral setae prostrate, arthrodial membrane with a rounded flap and normal filaments; cheliceral lyrifissures distinct; movable digit with two relatively large teeth ( Fig. 6 ).

Legs ( Figs 16–19 ). Legs II (293–297) and III (245–250) short, I (427–434) and IV (380–390) longer. Chaetotaxy normal for free-living Laelapidae : Leg I ( Fig. 16 ): coxa 0–0/1, 0/1–0, trochanter 1–1/1, 0/2–1 (al thickened), femur 2–2/1, 3/3–2 (ad1, pd2, pd3 slightly thickened), genu 2–3/2, 3/1–2, tibia 2–3/2, 3/1–2. Leg II ( Fig. 17 ): coxa 0–0/1, 0/1–0, trochanter 1–0/2, 0/1–1, femur 2–3/1, 2/2–1 (pd1 longer), genu 2–3/1, 2/1–2 (av thickened, pd2 longer), tibia 2–2/1, 2/1–2 (all ventral setae thickened). Leg III ( Fig. 18 ): coxa 0–0/1, 0/1–0, trochanter 1–1/1, 0/2–0, femur 1–2/1, 1/0–1 (all dorsal setae thickened), genu 2–2/1, 2/1–1, tibia: 2–1/1, 2/1–1 (all ventral setae thickened). Leg IV ( Fig. 19 ): coxa 0–0/1, 0/0–0, trochanter 1–1/1, 0/2–0, femur 1–2/1, 1/0–1 (ad2 and pd thickened; ad1 longest), genu 2–2/1, 3/0–1, tibia 2–1/1, 3/1–2 (pv thickened). Tarsi II-IV with 18 setae (3– 3/2, 3/2–3 + mv, md); with thickened some ventral and lateral setae, see Figures 17–19 . Tarsus IV with two noticeably long setae (macrosetae), pd2, pd3 (60–63) significantly longer than others, pl2, pl3 thick and blunt. All pretarsi with well-developed paired claws, rounded pulvilli and normal ambulacral stalk.

Insemination structures ( Fig. 13 ). Laelapid-type sperm access system, tubulus long, wider at the solenostome level, mesad of coxa III, and entering sacculus. Proximal ends of the tubulus swollen at junction with ramus, leading to droplet-shaped sacculus.

Description. Male (n= 2). ( Figures 14–15 , 20–21 )

Dorsal idiosoma. Dorsal shield 354–358 long, 208–213 wide; ornamentation and chaetotaxy as in female.

Ventral idiosoma ( Figs 14 , 20 ). Sternal, genital, endopodal, ventral and anal shields fused into holoventral shield, 305–308 long from anterior to posterior margins of shield, (79–82) wide at level of st2, (82–84) at st3 level and (141–145) at broadest point (behind parapodals), anterolateral edges of shield fused to endopodals between coxae I–II; shield surface weakly reticulate, more distinct distinct behind st5, with five pairs smooth sternal setae (st1–5), and three pairs of smooth ventral setae (Jv1, Zv1, Zv2), plus three smooth circumanal setae, post-anal seta (27–29) longer and slightly thicker than para-anals (21–23), with five pairs of poroids and a pair of gland pores (gv3) on lateral margins of shield at anterior level of anal opening, iv1 slit-like; gland pore gv2 behind coxa IV not discerned; cribrum with 3–4 irregular rows of spicules, restricted to region posterior to post-anal seta; metapodal platelets narrow and fused to shield, occasionally one side free. Soft opisthogastric cuticle with two pairs of simple setae, and four pairs of poroids. Peritremes and peritrematal shields similar to those in female ( Figs 14 , 20 ).

Gnathosoma . Epistome and subcapitulum similar to female. Fixed digit of chelicera with an offset distal tooth (gabelzahn), followed by 4–5 variously sized teeth and slender pilus dentilis. Movable digit of chelicera unidentate, spermadactyl stout, curved upward, with a large distal knob, and its free section more or less as long as movable digit ( Figs 15 , 21 ); fringed hyaline arthrodial process at base of movable digit ( Figs 15 , 21 ). Palps similar to those of female.

Legs. Chaetotaxy as in female.

Etymology. The specific name is derived from the name of the region (Altai Mountains) in which the type locality occurs.

Notes. In most species of Gaeolaelaps the dorsal shield has 39 pairs of simple setae, including two pairs of Zx setae, the peritremes usually reach anteriorly to the level of coxae I. Setae z3 are occasionally absent, S1 is rarely absent as in G. altaiensis , and sometimes the peritremes are short, ending near the middle of coxae II (as in G. altaiensis ) or even shorter, reaching to the anterior level of coxa III (e.g. G. heteroceri Trach, 2016 ). In the key to Gaeolaelaps species with short peritremes provided in Vatankhah et al. (2016), this species came to couplet 12, but the uncommon character state of 21 pairs of podonotal setae makes couplet choice problematic. According to Vatankhah et al. (2016), the combination of short peritremes (reaching to middle of coxa II) and a dorsal shield with 37 pairs of setae occurs in only three described species of Gaeolaelaps : G. vertisimilis ( Karg, 1994) , G. verticis ( Karg, 1979) , G. zhoumanshuae ( Ma, 1997) . In both G. verticis and G. zhoumanshuae setae z3 is present and setae s1–2 and Zx are absent, while in G. altaiensis setae z3 and S1 are absent. Gaeolaelaps altaiensis resembles G. vertisimilis (couplet 12 in the identification key to Gaeolaelaps species with short peritremes provided by Vatankhah et al., 2016), due to the dorsal shield having 37 pairs of setae (z3 absent) and without R series setae on lateral cuticle of dorsal shield. Gaeolaelaps altaiensis differs from vertisimilis by having 16 pairs of setae on opisthonotal region of dorsal shield (including two pairs Zx setae, S1 absent), while in G. vertisimilis opisthonotal region of dorsal shield has 18 pairs of setae (including two pairs Zx setae, S1 and R5 present on dorsal shield). Gaeolaelaps nolli ( Karg, 1962) , G. kargi ( Costa, 1968) and G. praesternalis ( Willmann, 1949) may be similar to G. altaiensis in general appearance, but G. kargi and G. praesternalis have a long peritremes nearly extending to coxa I and G. nolli having 39 pairs of setae on dorsal shield. Overall G. altaiensis can be easily distinguished from all other members of Gaeolaelaps with short peritremes (See Vatankhah et al., 2016) by the following combination of characters: (1) dorsal shield with distinct reticulation posterior to j6, narrowing from level of setae r3 and with 37 pairs of setae (z3 and S1 absent); (2) palptarsal claw two-tined; (3) peritremes short (ending near middle of coxae II); (4) tarsus and femur IV with two (pd2, pd3) and one (ad1) elongated setae, respectively; (5) fixed digit of chelicera with seven teeth.

Figures

FIGURES 1–6. Gaeolaelaps altaiensis Joharchi sp. nov., female. 1, dorsal idiosoma; 2, ventral idiosoma; 3, subcapitulum; 4, supralabral process; 5, epistome; 6, chelicera.

FIGURES 7–10. DIC micrographs of Gaeolaelaps altaiensis Joharchi sp. nov., female. 7, idiosoma in dorsal view; 8, reticulation of dorsal shield, general view of some dorsal setae, absence of setae S1; 9, idiosoma in ventral view; 10, sternal & genital shields.

FIGURES 11–15. DIC micrographs of Gaeolaelaps altaiensis Joharchi sp. nov., female. 11, subcapitulum; 12, distal portion of palp, with a focus on apotele; 13, insemination structures; male. 14, idiosoma in ventral view; 15, chelicera.

FIGURES 16–19. Gaeolaelaps altaiensis Joharchi sp. nov., female. 16, leg I (trochanter-tibia); 17, leg II; 18, leg III; 19, leg IV.

FIGURES 20–21. Gaeolaelaps altaiensis Joharchi sp. nov., male. 20, ventral idiosoma; 21, chelicera.