Gaeolaelaps euparadactylifer 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 : 248-253

Gaeolaelaps euparadactylifer Joharchi sp. nov.

( Figures 22–40 )

Type material: Holotype, female, Teletskoye Lake , Altai Republic, Russia, 51°21’N 87°45’E, 1 August 2020, A. A. Khaustov coll., from moss on the shore of the Teletskoye Lake (in TSUMZ) . Paratypes, 11 females and five males same data as holotype (in TSUMZ) .

Diagnosis (adult female). Dorsal shield oval shaped, covering entire idiosoma; shield with obvious reticulation, more distinct in opisthonotal (posterior to j6) and lateral regions; with 39 pairs of smooth and relatively long setae (except J3–J5, Z5, sparsely barbed), mostly reaching to base of following in series. Presternal area sclerotised, punctate, with a few transverse curved lines, sternal shield with punctate-reticulate ornamentation throughout, anterior margin straight, posterior margin of shield irregular; ratio of shield length/width ≃ 0.8. Genital shield, with length/width ratio ≃ 1.7, protruding at level between setae st5 and Zv1, surface reticulated with irregular diagonal lines and polygonal cells, posteriorly 8–9 cells surrounded by a Ʌ-shaped line. Anal shield with length/width ratio ≃ 1. Opisthosomal integument with eight pairs of smooth setae, peritremes short, reaching to mid-level of coxae II. Some leg setae on tarsi II–IV spine-like (mostly ventral and lateral setae). Tarsus IV with four noticeably long setae (macrosetae) (ad2, ad3, pd2, pd3), paradactyli on pretarsi II–IV well elongated and curved. Fixed digit of chelicera with 6–7 relatively blunt teeth.

Description. Female (n=12) ( Figures 22–38 )

Dorsal idiosoma ( Figs 22 , 28 ). Dorsal shield oval shaped, 575–601 long, 313–374 wide, covering entire idiosoma; shield with obvious reticulation, more distinct in opisthonotal (posterior to j6) and lateral regions ( Figs 22 , 28 ). Shield with 39 pairs of relatively long setae, mostly reaching to base of following in series: 22 pairs of podonotal setae, 17 pairs of opisthonotal setae, including two pairs Zx setae, r6 on lateral soft cuticle.All setae smooth (55–69) (except J3–J5, Z5, sparsely barbed, see Fig. 22 ), j1 (31–34), z1 (35–37), Z5 (75–77) ( Figs 22 , 28 ). Shield with about 21 pairs of discernible pore-like structures, including 16 poroids (id1, id2, id4–id6, idm1–idm6, is1, idx, idl1, idl3, idl4) and five gland openings (gd2, gd5, gd6, gd8, gd9), others indistinct, Figs 22 , 28 .

Ventral idiosoma ( Figs 23 , 29 ). Tritosternum with paired pilose laciniae (97–100), fused basally (4–5), columnar base 33–35 × 14–19 wide; presternal area sclerotised, punctate, with a few transverse curved lines, sternal shield length 135–145, maximum width 160–181, narrowest between coxae II (103–113), with punctate-reticulate ornamentation throughout ( Figs 23 , 29 ), anterior margin straight, posterior margin of shield irregular; bearing three pairs of smooth setae (st1, st2, st3 45–49), never reaching base of next setae (except st2), one pair of lyrifissures adjacent to setae st1, and a pair of poroids between st2 and st3; gland pores gv1 present on posterior shield margin. Metasternal setae st4 (40–44) and metasternal poroids located on soft integument (occasionally one poroid located on posterolateral angles of sternal shield, see Fig. 22 ); metasternal platelets absent. Endopodal plates II/III completely fused to sternal shield, endopodal plates III/IV elongate, narrow and curved. Genital shield tongue-shaped, protruding at level between setae st5 and Zv1, length 220–225, maximum width 118–127, anterior margin of shield convex, overlapping posterior area of sternal shield, but not reaching base of setae st3, posterior margin rounded, surface reticulated with irregular diagonal lines and polygonal cells, posteriorly 8–9 cells surrounded by a Ʌ-shaped line; bearing a pair of simple setae st5 (36–39) ( Figs 23 , 29 ). Shield flanked by two pairs of minute, oval paragenital platelets; paragenital poroids iv5 located on soft cuticle lateral to shield near seta st5. Anal shield subtriangular, rounded anteriorly, length 97–105, width 103–110, anterior half lineate-reticulate, para-anal setae (36–42) shorter than post-anal seta (41–45), cribrum consisting of a terminal tuft with three irregular rows of spicules and a pair of anterior arms extending slightly beyond post-anal seta ( Figs 23 , 29 ); anal gland pores (gv3) on anterolateral margin of anal shield. Soft opisthogastric cuticle with pair of oval metapodal plates (26–33 long × 8–10 wide), an additional small round metapodal platelet more medially and eight pairs of smooth setae (Jv1–Jv5, Zv1–Zv 3) (31–35), and six pairs of poroids including iv5 and ivp. Three exopodal platelets between coxae I–II, II–III and III-IV present, anterior two platelets subtriangular, those behind coxae III–IV and parapodal platelets fused, curved, extending narrowly behind coxae IV and surrounding coxa IV, gland pores gv2 on parapodal platelets ( Figs 23 , 29 ). Peritreme extending anteriorly to mid-level of coxa II; peritrematal shield 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 23 , 29 ).

Gnathosoma ( Figs 24–27 , 30–32 ). Epistome with rounded anterior margin and irregularly denticulate ( Figs 26 , 30 ). Hypostomal groove with six transverse rows of denticles, each row with 14–20 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 (43–45), h1 (37–39), h2 (24–27), palpcoxal setae (pc) (33–35) ( Fig. 24 ). Corniculi robust and horn-like, extending slightly beyond palptrochanter. Supralabral process with short conical apicoventral projection ( Figs 25 , 30 ). Internal malae with one pair of smooth median projections, flanked by lobes with fimbriate anterior margin; labrum with pilose surface ( Fig. 24 ). Chaetotaxy of palps ( Fig. 32 ): trochanter 2, femur 5, genu 6, tibia 14, tarsus 15, all setae smooth and needle-like except al1, al2 on palp genu and al, d3 on palp trochanter thickened, al2 and al paddle-like on palpgenu and femur, respectively, palp tarsal apotele two-tined, second tine with distal knob ( Fig. 32 ). Fixed digit of chelicera with an offset distal tooth (gabelzahn), followed by six relatively blunt and variously sized teeth, a setaceous pilus dentilis, dorsal cheliceral setae thick, arthrodial membrane with a rounded flap and normal filaments; cheliceral lyrifissures distinct; movable digit with two relatively large and blunt teeth ( Fig. 27 , 31 ).

Legs ( Figs 34–38 ). Legs II (385–405) and III (360–374) short, I (530–565) and IV (515–538) longer. Chaetotaxy normal for free-living Laelapidae : Leg I ( Fig. 35 ): coxa 0–0/1, 0/1–0, trochanter 1–1/1, 0/2–1 (ad & al thickened), femur 2–2/1, 3/3–2 (ad3, pd1, pd2 slightly thickened), genu 2–3/2, 3/1–2 (all dorsal setae slightly thickened), tibia 2–3/2, 3/1–2 (all dorsal setae slightly thickened). Leg II ( Fig. 36 ): coxa 0–0/1, 0/1–0, trochanter 1–0/2, 0/1–1, femur 2–3/1, 2/2–1 (pd1, pl longer, ad1 inserted on small tubercle), genu 2–3/1, 2/1–2 (pd2 longer), tibia 2–2/1, 2/1–2 (all ventral setae thickened). Leg III ( Fig. 37 ): coxa 0–0/1, 0/1–0, trochanter 1–1/1, 0/2–0 (al & ad thickened), 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. 38 ): coxa 0–0/1, 0/0–0, trochanter 1–2/1, 0/1–0, femur 1–2/1, 1/0–1 (ad2 and pd thickened; ad1 longest and inserted on small tubercle), genu 2–2/1, 3/0–1 (ad1 and pd2 inserted on small tubercles), tibia 2–1/1, 3/1–2 (all ventral setae thickened). Tarsi II-IV with 18 setae (3– 3/2, 3/2–3 + mv, md); with thickened some ventral and lateral setae, see Figures 36–38 . Tarsus IV with two noticeably long setae (macrosetae), ad2, ad3 (63–70), pd2 (82–89) & pd3 (94–100) significantly longer than others, pl2, pl3 thick and blunt. All pretarsi with well-developed paired claws, rounded pulvilli and paradactyli on pretarsi II–IV well elongated and curved (see Figs 34–38 ).

Insemination structures ( Fig. 33 ). 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=5). ( Figures 39, 40 )

Dorsal idiosoma. Dorsal shield 435–445 long, 258–265 wide; ornamentation and chaetotaxy as in female.

Ventral idiosoma ( Fig. 39 ). Sternal, genital, endopodal, ventral and anal shields fused into holoventral shield, 370–380 long from anterior to posterior margins of shield, (95–105) wide at level of st2, (95–105) at st3 level and (198–206) at broadest point (behind parapodals), anterolateral edges of shield fused to endopodals between coxae I-II; shield reticulate throughout, with five pairs smooth sternal setae (st1–5), and four pairs of smooth ventral setae (Jv1, Jv2, Zv1, Zv2), plus three smooth circumanal setae, post-anal seta (38–41) longer than para-anals (32–35), with six pairs of poroids and a pair of gland pore (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 ( Fig. 39 ). Soft opisthogastric cuticle with two pairs of simple setae, and three pairs of poroids. Peritremes and peritrematal shields similar to those in female.

Gnathosoma . Epistome and subcapitulum similar to female. Fixed digit of chelicera with five teeth of various sizes and slender pilus dentilis. Movable digit of chelicera unidentate, spermadactyl stout, long, curved backward, with round tip, and its free section more than double length of movable digit ( Fig. 40 ); fringed hyaline arthrodial process at base of movable digit ( Figs 40 ). Palps similar to those of female.

Legs. Chaetotaxy as in female.

Etymology. The specific name is derived from the Greek words (eu, true), (paradaktylos, a specific term for paired structure developed on pretarsus) and (ferein, bear); referring to the excessively developed paradactyli on tarsi II–IV.

Notes. The new species is unique within Gaeolaelaps by the form of the pretarsal paradactyli on legs II–IV. These structures are strongly elongated, apically pointed and with their tips projecting well beyond the claws ( Fig. 34 ). In the key to Gaeolaelaps species with short peritremes provided in Vatankhah et al. (2016), G. euparadactylifer came to couplet 16, but the combination of character states of iv2 pore-like and J2 located laterad J1 makes couplet choice problematic. Overall G. euparadactylifer 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 oval shaped and with 39 pairs of relatively long setae, mostly reaching to base of following in series; (2) genital shield with protruding at level between setae st5 and Zv1, surface reticulated with polygonal cells (3) peritremes short, reaching to mid-level of coxae II; (4) tarsus IV with four noticeably long setae (macrosetae) (ad2, ad3, pd2, pd3); (5) paradactyli on pretarsi II–IV well elongated and curved; (5) fixed digit of chelicera in female with 6–7 relatively blunt teeth; (6) spermatodactyl in male chelicera stout, long, curved backward, with round tip, and its free section more than double length of movable digit; (7) holoventral shield in male well reticulate throughout, usually bearing nine pairs smooth setae (st1–5, Jv1, Jv2, Zv1, Zv2), plus three circumanal setae.

Gaeolaelaps euparadactylifer most resembles G. praesternaloides ( Ma & Yin, 1998) (this species is omitted in the both identification keys to Gaeolaelaps species with short peritremes provided by Vatankhah et al., 2016 and Nemati & Mohseni, 2013), due to the dorsal shield having 39 pairs of setae and short peritremes, reaching tomid-level of coxae II. Gaeolaelaps euparadactylifer differs from G. praesternaloides by having relatively longer dorsal setae, mostly reaching to base of following in series, J2 located laterad J1, J1 almost reaching more than half the J1–J3 distance (versus dorsal shield setae shorter, never reaching base of next posterior seta in series, J2 located behind of J1 and J1 never reaching J5 insertion in G. praesternaloides ), post-stigmatal section of peritrematal shield extending nearly to middle part of coxa IV but never past it and exterior margin of post-stigmatal plate without incision (versus post-stigmatal section of peritrematal shield elongated, its tip extending beyond of coxa IV and exterior margin of post-stigmatal plate with deep incision in G. praesternaloides ), spermatodactyl in male chelicera curved backward and with round tip (versus spermatodactyl in male chelicera curved upward and with truncate tip in G. praesternaloides ), holoventral shield in male well reticulate throughout, usually bearing nine pairs smooth setae in addition to circumanals (versus holoventral shield bearing eight pairs smooth setae in addition to circumanals in G. praesternaloides ).

Figures

FIGURES 22–27. Gaeolaelaps euparadactylifer Joharchi sp. nov., female. 22, dorsal idiosoma; 23, ventral idiosoma; 24, subcapitulum; 25, supralabral process; 26, epistome; 27, chelicera.

FIGURES 28–34. DIC micrographs of Gaeolaelaps euparadactylifer Joharchi sp. nov., female. 28, idiosoma in dorsal view; 29, idiosoma in ventral view; 30, supralabral process & epistome; 31, chelicera; 32, distal portion of palp, with a focus on apotele; 33, insemination structures; 34, pretarsal paradactyli on leg IV.

FIGURES 35–38. Gaeolaelaps euparadactylifer Joharchi sp. nov., female. 35, leg I (trochanter-tibia); 36, leg II; 37, leg III; 38, leg IV.

FIGURES 39–40. Gaeolaelaps euparadactylifer Joharchi sp. nov., male. 39, ventral idiosoma; 40, chelicera.