Cosmolaelaps lasiophilus Joharchi, 2022

Joharchi, Omid, Döker, Ismail & Khaustov, Vladimir A., 2022, New species and new records of Cosmolaelaps Berlese (Acari: Laelapidae) from Russia, with a review of the Russian species of the genus, Zootaxa 5133 (4), pp. 486-508 : 489-494

Cosmolaelaps lasiophilus Joharchi sp. nov.

( Figures 8–24 )

Type material. Holotype, female, vicinities of Uspenka, Tyumen Province, Russia, 57°04'N, 65°04'E, 18 October 2021, Alexander A. Khaustov coll., in the nest of Lasius niger (L.) ( Hymenoptera : Formicidae ) (in TUMZ). Paratypes: five females, same data as holotype (in TUMZ).

Diagnosis (adult female). Dorsal shield with weak reticulate ornamentation, bearing 39 pairs of relatively long (sub-equal), knife-shaped setae, mostly reaching base of next posterior setae in series, Z5 shorter than J5 (ratio of J5 / Z5 length ≃1.5); presternal area lightly sclerotised, anterior margin of shield hardly conspicuous, posterior margin distinctly concave, ratio of shield length/width (at broadest level) ≃ 0.8; genital shield ratio of length/ width (at broadest level) ≃ 2.4, shield ornamented posteromedially by 7–8 cells flanked by a median Λ-shaped ornamentation, anal shield ratio of length/width (at broadest level) ≃ 1.2, circum-anal setae smooth and subequal, post-anal seta thickened; distance between genital and anal shields is shorter than length of anal shield. Fixed digit of chelicera with six teeth of various sizes. Legs without spatulate setae but most setae conspicuously thickened and some inserted on small tubercles. Legs I and IV shorter than length of idiosoma.

Description. Female (n=6)

Dorsal idiosoma ( Figs 8 , 13, 15, 16 ). Dorsal shield oval shaped, small, 389–406 long, 256–265 wide, covering entire dorsal idiosoma, shield with weak reticulation, more distinct in opisthonotal and lateral regions. Shield with 39 pairs of almost uniform length setae (28–40), including two pairs of Zx setae between J and Z setae and three unpaired supernumerary seta Jx between J2 and J4, except j1, Z5 (14–18) simple and thickened, j1 apically bent (hook shaped), z1 (15–18) and J5 (21–24) shorter ( Figs 15, 16 ). All setae slightly swollen near the base and pointed at tip (knife-shaped), reaching base of following setae, setae of central area shorter (not reaching base of following setae) ( Figs 8 , 13, 15, 16 ). Dorsal shield with 22 pairs of pore-like structures, including seven pairs of gland openings (gd1, gd2, gd4, gd5, gd6, gd8, gd9) and 15 pairs of poroids, id6 indistinct. Shape, position and relative length and shape of setae shown in Figures 8 , 13 .

Ventral idiosoma ( Figs 9 , 14, 17 ). Tritosternum with paired pilose laciniae (64–68), fused basally (3–5), columnar base 23–27 × 12–15 wide; presternal area lightly sclerotised, with a few transverse curved lines, merged to sternal shield. Sternal shield (length 92–96) narrowest between coxae II (74–80), widest (114–118), anterior margin of shield hardly conspicuous, posterior margin distinctly concave, anterolateral corners narrowly extending between coxae I–II, distally bearing gland pores gvb; endopodal elements between coxae II and III fused with shield and endopodal elements III/IV elongate, narrow and curved. Sternal shield with three pairs of smooth setae (st1 31–33, st2 28–30, st3 24–27) and two pairs of slit-shaped pore-like structures (iv1 adjacent to setae st1; iv2 between st2 and st3), setae not reaching base of following setae, shield with lineate-reticulate ornamentation on lateral surface, longitudinally median part smooth (or faintly reticulated) ( Figs 9 , 14 ). Metasternal setae st4 (24–27) and metasternal poroids located on soft integument; metasternal platelets absent. Genital shield flask-shaped, slightly expanded laterally past level of setae st5, length 165–180, maximum width 71–75, posterior margin rounded, anterior hyaline margin of shield irregularly convex, overlapping posterior area of sternal shield (extending beyond base of setae st3), shield ornamented posteromedially by 7–8 cells flanked by a median Λ-shaped ornamentation, bearing a pair of simple setae st5 (22–24) ( Figs 9 , 14 ). 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 65–70, width 52–55, anterior half lineate-reticulate, para-anal setae and post-anal seta subequal in length (15–18), post-anal seta thicker, cribrum consisting of a terminal tuft with 3–4 irregular rows of spicules, anteriormost rows of spicules extending slightly beyond post-anal seta ( Figs 9 , 14, 17 ); anal gland pores (gv3) on anterolateral margin of anal shield. Soft opisthogastric cuticle surrounding genital and anal shields with one pair of suboval metapodal plates (17–19 long × 4–6 wide), six pairs of poroids (five ivo; ivp) and 16 pairs of moderately thick setae (Jv1–Jv5, Zv1– Zv 5, R1–R4, UR2–UR3); almost all setae uniform in length (11–16), and arising on small sclerotised platelet, except Jv1–3 and Zv1 longer (20–24) and setiform ( Figs 9 , 14, 17 ). Peritrematal shield well developed laterad peritremes, bearing one gland pore and one poroid at level near coxae II–III, post-stigmatic extension of shield relatively wide, not reaching posterior level of coxae IV, with two pairs of poroids and one pair of gland pores; anterior region of peritrematal shield fused to anterior margin of dorsal shield behind setae z1. Peritremes long, extending to mid-level of coxa I (near s1). Two exopodal platelets between coxae II–III and III–IV present, anterior platelet small and subtriangular, those between coxae III–IV slightly extending posteriorly; parapodal platelets strip-like, bearing gland pore gv2 ( Figs 9 , 14 ).

Gnathosoma ( Figs 10–12 , 18, 19 ). Anterior margin of epistome convex, irregularly denticulate, with smooth median spike ( Fig. 11 ). Hypostomal groove with six transverse rows of denticles, each row with 8–19 small denticles, with smooth posterior transverse line, groove wider anteriorly, progressively narrowing from anterior to posterior, anteriormost row slightly convex ( Figs 10 , 18 ). Corniculi horn-like, internal malae longer than corniculi, comprising a pair of pilose median projections, and 7–9 lateral, longer, tentacle-like, smooth projections ( Fig. 10 ); labrum acuminate, considerably longer than internal malae, fringed; hypostomal and capitular setae smooth, h3 (34–40)> h1 (28–31)> pc (21–25)> h2 (11–14) ( Figs 10 , 18 ). Chaetotaxy of palps: trochanter 2, femur 5, genu 6, tibia 14, tarsus 15, all setae smooth except palpfemur with seta d3 thickened and inserted on small tubercles, seta al thickened and apically subspatulate; palpgenu with al1 stout, al2 paddle-like; palp tarsal claw two-tined ( Fig. 19 ). Supralabral process indistinct. Fixed digit of chelicera with an offset and subapical tooth (gabelzhan), followed by five teeth, a setaceous pilus dentilis, dorsal cheliceral seta prostrate, arthrodial membrane with a rounded flap and normal filaments; cheliceral lyrifissures distinct, movable digit of chelicera bidentate ( Fig. 12 ).

Insemination structures ( Fig. 20 ). Laelapid-type sperm access system, tubulus long, wider at the solenostome level of coxa III and entering sacculus via a pair of circular openings. Sacculus irregular, the proximal ends of the tubulus slightly swollen at the junction with ramus, ends of ramus with considerably horn-like projection.

Legs ( Figs 21–24 ). Legs II and III short (260–278, 240–255), I and IV longer (365–385, 347–364) (excluding pre-tarsus). Chaetotaxy normal for free-living Laelapidae (sensu Evans, 1963a): Leg I ( Fig. 21 ): coxa 0-0/1, 0/1-0, trochanter 1-1/1, 0/2-1 (al and ad thickened), femur 2-3/1, 2/3-2 (al1, ad3 and pd2 thickened), genu 2-3/2, 3/1- 2 (dorsals and laterals thickened and ad1–3 inserted on small tubercles), tibia 2-3/2, 3/1-2 (dorsals and laterals thickened). Leg II ( Fig. 22 ): coxa 0-0/1, 0/1-0, trochanter 1-0/1, 0/2-1 (al slightly thickened), femur 2-3/1, 2/2-1 (ad1, pd1 and pd2 thickened and inserted on small tubercles, pd2 longest), genu 2-3/1, 2/1-2 (dorsals thickened and inserted on small tubercles), tibia 2-2/1, 2/1-2. Leg III ( Fig. 23 ): coxa 0-0/1, 0/1-0, trochanter 1-1/1, 0/2-0 (ad slightly thickened), femur 1-2/1, 1/0-1 (ad1, pd and pl thickened, ad1 inserted on small tubercle), genu 2-2/1, 2/1-1 (all setae on segment slightly thickened), tibia: 2-1/1, 2/1-1 (all setae on segment slightly thickened). Leg IV ( Fig. 24 ): coxa 0-0/1, 0/0-0, trochanter 1-1/1, 0/2-0 (ad thickened), femur 1-2/1, 1/0-1 (ad1 and ad2 thickened and inserted on small tubercles), genu 2-2/1, 3/0-1 (dorsals thickened), tibia 2-1/1, 3/1-2 (dorsals and laterals thickened, al2 inserted on small tubercle). Tarsi II–IV with 18 setae (3- 3/2, 3/2-3 + mv, md); almost all setae on tarsus II–IV thickened, see Figures 22–24 . All pretarsi with well-developed paired claws, rounded pulvilli and normal ambulacral stalk.

Male. Unknown.

Etymology. The specific name of the new species is derived from its occurrence in nests of ants of the genus Lasius and Greek ΦΙΛία (philia), meaning "friendship" or "fondness".

Differential diagnosis. Cosmolaelaps lasiophilus is closely related to Cosmolaelaps vacua ( Michael, 1891) sensu Evans & Till (1966) , C. thysanifer Zeman, 1982 , C. transvaalensis Ryke, 1963 , C. robustus ( Berlese, 1905) , C. siberiensis Joharchi 2019 (in Joharchi et al., 2019), C. mixta ( Shcherbak, 1971b) , C. pumili ( Karg, 1988) , C. lingua ( Karg, 1987) , C. sungaris ( Ma, 1996) and C. shenyangensis ( Bei et al., 2003) in the shape of dorsal setae, which are slightly swollen near the base and pointed at tip (knife-shaped) (see Figure 8 ), with all dorsal setae of the same shape and sub-equal in length (at most reaching base of following setae), except setae j1 and Z5.

Cosmolaelaps lasiophilus differs from C. vacua by lacking spatulate setae on legs, most setae on legs conspicuously thickened and some inserted on small tubercles, while in C. vacua two spatulate setae are present on femora II and IV. Evans & Till (1966) did not provide any information about the shape of the leg setae for C. vacua , but according to the original description ( Michael, 1891) of Cosmolaelaps vacua , femora II and IV bear two spatulate setae ( Karg, 1981, Fig. 8a , also illustrated this character). It differs from C. thysanifer by setae Z5 and some opisthogastric setae thickened, versus setae Z5 brush-like and all opisthogastric setae simple and setiform in C. thysanifer . It differs from C. sungaris and C. shenyangensis by its much smaller size of body (389–406 long, 256–265wide), versus body size much larger in both of C. sungaris and C. shenyangensis (566 long × 383 wide in C. sungaris , and 567 long × 413 wide in shenyangensis ) and also differs from C. sungaris by its longer dorsal shield setae (reaching base of following setae), versus dorsal shield setae much shorter in C. sungaris (barely reaching more than half of distance of following setae in series). Cosmolaelaps lasiophilus can be readily distinguished from C. transvaalensis by some opisthogastric setae thickened and most setae on legs conspicuously thickened (some inserted on small tubercles), versus setae on both opisthogastric cuticle and legs simple in C. transvaalensis (see Ryke, 1963). It differs from C. pumili because setae Z5 are thickened, shorter than J5 and legs I, IV are shorter than length of idiosoma, while in C. pumili setae Z5 setiform, longer than J5 and legs I, IV longer than length of idiosoma. C. lasiophilus can be easily distinguished from C. robustus by the smaller size of the genital shield (there are two pairs of setae between genital and anal shields) and presternal area lightly sclerotised (with a few transverse curved lines and merged to the sternal shield), while genital shield expanded posteriorly in C. robustus , setae Zv1 and Jv1 inserted on lateral margins of shield (in addition of st5) and two triangular presternal plates present in C. robustus . Cosmolaelaps lasiophilus can be distinguished from C. lingua by its small body size (389–406 long, 256–265 wide), thick and short opisthogastric setae and presternal area lightly sclerotised (anterior margin of sternal shield hardly conspicuous), versus body larger (480–500 long, 300–330 wide), opisthogastric setae simple (setiform) and long, sclerotised platelets absent and presternal plates joined to sternal shield in C. lingua . Cosmolaelaps lasiophilus is most similar to C. siberiensis and C. mixta , but can be readily distinguished from these two species by its longer dorsal setae, some of them reach to the base of next setae, while in both C. siberiensis and C. mixta dorsal shield setae considerably shorter and none of them reach base of next. Overall C. lasiophilus can be easily distinguished from all other congeners by the following combination of characters: (1) dorsal shield bearing 39 pairs of relatively long setae (some reach base of next posterior setae in series), j1, z1 and Z5 simple, Z5 shorter than J5 (ratio of J5/ Z5 length ≃ 1.5); (2) post-anal seta thickened; (3) almost all opisthogastric setae thickened and arising on minute sclerotised platelet; (4) fixed digit of chelicera with six various size of teeth; (5) legs without spatulate setae but most setae conspicuously thickened and some inserted on small tubercles.

Figures

FIGURES 8–12. Cosmolaelaps lasiophilus Joharchi sp. nov., female. 8, dorsal idiosoma, enlarged section not to scale; 9, ventral idiosoma; 10, subcapitulum; 11, epistome; 12, chelicera.

FIGURES 13–20. DIC micrographs of Cosmolaelaps lasiophilus Joharchi sp. nov., female. 13, idiosoma in dorsal view; 14, idiosoma in ventral view; 15, general view of some podonotal setae; 16, general view of some opisthonotal setae; 17, general view of part of opisthogastric area; 18, subcapitulum; 19, distal portion of palp, with focus on tarsal claw; 20, insemination structures.

FIGURE 21–24. Cosmolaelaps lasiophilus Joharchi sp. nov., female. 21, leg I (trochanter-tibia); 22, leg II; 23, leg III; 24, leg IV.