Cosmolaelaps ekaterinae, Mašán & Babaeian, 2019

Mašán, Peter & Babaeian, Esmaeil, 2019, A new myrmecophilous mite species of the genus Cosmolaelaps Berlese, 1903 (Acari, Mesostigmata, Laelapidae) from Central Europe (Slovakia), Zootaxa 4647 (1), pp. 495-505 : 496-501

Cosmolaelaps ekaterinae sp. nov.

( Figs 1–18 )

Type material examined

Holotype female: SW Slovakia, Burda Mountains, Chľaba Village , Kováčov Settlement , edge of broadleaved de- ciduous forest ( Carpineto-Quercetum ) and meadow, subterraneous nest of Lasius umbratus colonized by Lasius fuliginosus in rotting tree stump ( Quercus sp.), 190 m a.s.l., October 24, 2018 ; paratypes (eight females and three males): with the same data as for holotype . The holotype and seven paratypes (five females and two males) are deposited in IZSAS; four paratypes (three females and one male) are in JAZM

.

Diagnosis (Adults)

Idiosoma small and less than 400 μm in length. Dorsal shield surface essentially smooth, having 39 pairs of setae plus 2–3 unpaired setae (Jx) on posteromedian area. Dorsal shield setae (except j1, z1 and J5) with well-developed basal protuberance, narrow, markedly attenuate distally and conspicuously elongate so their tips reaching beyond the insertions of the two following setae. In female, presternal platelets free, weakly sclerotized; sternal shield smooth on whole surface, almost unsclerotized in front portion so its anterior margin not distinctly defined; epigynal shield tongue-shaped, normally with one Λ-like and two or three V-like transverse sculptural lines in its posterior portion; setae ad1 on femora I and II and ad2 on femur IV thickened; pd2 on femur II and ad1 on femora III and IV thickened and spatulate. In male, holoventral shield present; cheliceral spermatodactyl well developed, about twice as long as fixed digit; femur II and telotarsus IV bearing a ventral spur. Peritrematal shields terminally slightly widened and truncate. Anterior margin of epistome convex, regularly and densely denticulate.

Description (Adults)

Female. Dorsal idiosoma ( Figs 1 , 12 ). Idiosoma oblong, ovoid, 375–395 μm long and 230–245 μm wide (n=5). Dorsal shield entire, almost completely covering dorsum, smooth except for a few lineae close to anterolateral margins, 370–390 μm long, and 225–240 μm wide nearly at level of setae z5, bearing 39 pairs of setae (j1–j6, z1–z6, s1–s6, r2–r5 on podonotal region; J1–J5, Z1–Z5, S1–S5, Px2, Px3 and two or rarely three unpaired Jx setae on opisthonotal region). Almost all dorsal shield setae similar in length, modified, scimitar-shaped, having small basal protuberance and attenuate and elongate distal section ( Fig. 2 ); only vertical (j1), paravertical (z1) and clunal setae (Z5) unmodified, simple, smooth, needle-like and markedly shorter than other setae on the shield; z1 shortest (21–25 μm), j1 (31–37 μm) similar to or slightly shorter than Z5 (33–43 μm). Most dorsal shield setae 90–105 μm in length.

Ventral idiosoma ( Fig. 3 ). Tritosternum with long columnar base and two long and distinctly pilose laciniae. Presternal region and anterior part of sternal shield weakly sclerotized and defined, with a pair of small and indistinctive presternal platelets. Sternal shield subquadrate, 105–114 μm long, 85–93 μm wide at level of setae st2, 79–83 μm wide at level of constriction between coxae II, and smooth throughout except for a few lineae on lateral margins; lateral margins well sclerotized, posterior margin usually straight, sometimes slightly convex or concave; shield with two pairs of distinct lyrifissures (iv1, iv2) and three pairs of subequal setae (st1–st 3 24–29 μm). Metasternal setae (st 4 25–28 μm) and associated lyrifissures (iv3) placed on soft integument, iv3 rarely on posterior margin of sternal shield (on one side only). Epigynal shield oblong, well elongate, slightly wider in anterior portion, tongueshaped, 185–195 μm long, 67–76 μm wide at level of genital setae (st 5 24–26 μm), hyaline anteriorly (hyaline part approximately reaching level of iv2), regularly rounded posteriorly, bearing one pair of setae (but asymmetrically duplicate in illustrated specimen) and with typical pattern of transverse lines as in Figs 4 and 14 ; genital lyrifissures (iv5) situated on soft integument behind st5. Peritremes normal, with anterior ends reaching slightly beyond dorsal setae s1; peritrematal shields narrow, with short post-stigmatic sections terminally slightly widened and truncate. Soft integument between setae ZV1 and oval metapodal platelets with two pairs of small, narrow, irregular sclerites; anterior pair transversely oriented. A slot-like adgenital sclerite close to each lateral margin of epigynal shield present (one or both of them often partly or completely fused to the shield). Anal shield subtriangular, widely rounded anteriorly, similar in length and width (58–62 μm long and wide), smooth or with short transverse lines in anterior part, bearing three circum-anal setae, and a pair of marginal gland pores (gv3) more or less aligned with posterior margin of anal opening; postanal seta slightly thickened, moderately longer than adanals (pa 28–32 μm, ad 17–20 μm); anus with submedial position on the shield. Soft lateral and opisthogastrict integument bearing 17–19 pairs of setae. Opisthogastric setae JV1, JV2, JV3, ZV1 and ZV2 simple, needle-like and shorter when compared with other scimitar-shaped setae on opisthogaster; setae in JV and ZV rows becoming progressively longer posteriorly (JV 1 24–28 μm, JV 2 26–33 μm, JV3 39–44 μm, JV4 55–63 μm; ZV 1 23–26 μm, ZV2 34–38 μm, ZV3 51–59 μm).

Sperm induction system ( Fig. 3 ). All parts including infundibula, tubuli and sacculus foemineus well sclerotized and distinct. Tubuli long, moderately widened at solenostomes, each with a poculiform distal end entering the sacculus.

Gnathosomal structures ( Figs 5–7 , 15 ). Epistome regularly convex, with anterior margin bearing denticles of similar sizes ( Fig. 5 ). Deutosternal furrow with six transverse lines of 8–18 denticles each; corniculi horn-like, parallel to each other, not reaching middle of palp femur; internal malae with median projections contiguous and with lightly serrate margins; laterally, four to six setiform tines on each side, some tines subdivided ( Fig. 6 ). Palp apotele 2-tined. Cheliceral digits of similar lengths; movable digit 29–34 μm long, with two closely set teeth in addition to distal hook; fixed digit with five or six small teeth in addition to apical hook and minute setiform pilus dentilis; arthrodial process as a coronet-like fringe; dorsal cheliceral seta and antiaxial lyrifissure not discerned ( Fig. 7 ).

Legs ( Figs 8–11 ). All legs with well-developed pretarsus and ambulacral apparatus (including pulvillus and two claws), shorter than idiosoma: legs I 300–325 μm, legs II 225–250 μm, legs III 205–220 μm, and legs IV 270–290 μm long. Leg segments not spurred ventrally, with normal chaetotactic pattern: leg I—coxa 0-0/1, 0/1-0, trochanter 1-1/1, 0/2-1, femur 2-2/1, 3/3-2, genu 2-3/2, 3/1-2, tibia 2-3/2, 3/1-2; leg II—coxa 0-0/1, 0/1-0, trochanter 1-0/1, 0/2-1, femur 2-3/1, 2/2-1, genu 2-3/1, 2/1-2, tibia 2-2/1, 2/1-2; leg III—coxa 0-0/1, 0/1-0, trochanter 1-1/1, 0/2-0, femur 1-2/1, 1/0-1, genu 2-2/1, 2/1-1, tibia 2-1/1, 2/1-1; leg IV—coxa 0-0/1, 0/0-0, trochanter 1-1/1, 0/2-0, femur 1-2/1, 1/0-1, genu 2-2/1, 3/0-1, tibia 2-1/1, 3/1-2; tarsi II–IV—18 setae each. Leg setae mostly uniform in shape, smooth and needle-like; setae ad1 on femora I and II and ad2 on femur IV moderately thickened; pd2 on femur II and ad1 on femora II and III modified, thickened, widened toward their apex and spatulate (see detail in Figs 9 and 11 ).

Male ( Figs 13, 15–18 ). Idiosoma 355–370 μm long (n=3). Dorsal and ventral setal lengths proportionally shorter than in female. Holoventral shield 285–295 μm long and 125–130 μm wide (behind coxae IV), with ten pairs of setae (st1–st5, JV1–JV3, ZV1 and ZV2) in addition to three circumanal setae; sternogenital surface smooth but posterior region of the shield with distinct reticula represented mostly by transverse lines ( Fig. 13 ). Posterior ends of peritrematal shields free, not fused to holoventral shield behind the coxae IV. Soft integument with 12–14 pairs of setae. Cheliceral digits of similar lengths, with indistinguishable dentation; spermatodactyl well developed, elongated, slim, progressively narrowed toward apex, with straight proximal section directed anteriorly, a small ventromedial projection pointed backward, moderate submedial curvature, distal section directed upward, and club-like tip ( Fig. 15 ); movable digit with spermatodactyl 55–58 μm in length, approximately twice longer than fixed digit (24–27 μm). Legs similar to those in female, except for femur II with a spur-like ventral projection associated with anteroventral seta ( Fig. 18 ), ventral base of telotarsus IV with small pointed or blunt projection ( Fig. 16 ), and genu IV with markedly thickened and shortened anteroventral seta having its apex truncate or bluntly rounded ( Fig. 17 ). Other characters similar to those of female.

Etymology

This species is named in honour of our colleague, acarologist Katya Sidorchuk (Paleontological Institute, Russian Academy of Sciences, Moscow), who has passed away recently, as a dedication to her memory.

Taxonomic notes

The dorsal shield chaetotaxy of Cosmolaelaps ekaterinae sp. nov., with remarkably elongate and distally attenuate setae, is unique and quite unlike any other species in the genus. Other congeners have much broader and shorter dorsal setae, and usually with their tips reaching prior to or only slightly beyond the insertions of the following setae. Nevertheless, the new species is most similar to Cosmolaelaps leptochaetes Ma & Lin, 2009 , described from China, and reported from Iran ( Ramroodi et al., 2014). The new species can be easily distinguished from C. leptochaetes by the following characters: idiosoma 275–295 μm long (590–645 in C. leptochaetes ); dorsal setae longer, with tip reaching beyond the insertions of two following setae in a row (setae only reaching beyond the insertion of the following seta in C. leptochaetes ); anterior margin of sternal shield and small presternal platelets weakly sclerotized, poorly defined (the entire sternal shield and relatively large presternal platelets well sclerotized and defined in C. leptochaetes ); peritremes relatively shorter, with anterior ends reaching slightly beyond the dorsal setae s1 (peritremes longer, reaching close to the setae z 1 in C. leptochaetes ); setae of JV and ZV rows becoming progressively longer posteriorly (all opisthogastric setae of similar length in C. leptochaetes ); spermatodactyl about twice longer than fixed digit of chelicera (only slightly longer than fixed digit in C. leptochaetes ); male femur II with a strong ventral spur associated with short and thin anteroventral seta (apparently with no ventral spur on femur II in C. leptochaetes , whereas anteroventral seta long and markedly thickened); female tarsus II relatively short and wide, stout (apparently narrower and longer in shape in C. leptochaetes ); male tarsus IV with a small ventral projection (absent in C. leptochaetes ).

Figures

FIGURES 1–7. Cosmolaelaps ekaterinae sp. nov., female. 1. Idiosoma, dorsal view; 2. Medial dorsal seta, variant forms, lateral view; 3. Idiosoma, ventral view; 4. Epigynal shield, with typical ornamentation pattern; 5. Epistome; 6. Gnathosoma with palp, ventral view; 7. Chelicera, lateral view.

FIGURES 8–11. Cosmolaelaps ekaterinae sp. nov., female, legs I–IV. 8. Leg I; 9. Leg II; 10. Leg III; 11. Leg IV.

FIGURES 12–18. Cosmolaelaps ekaterinae sp. nov. 12. Idiosoma, female, dorsal view; 13. Holoventral shield, male; 14. Sternal and epigynal shield, female; 15. Chelicera, male, lateroventral view; 16. Tarsus and tibia of leg IV, male, lateroventral view; 17. Tibia and genu of leg IV, male, ventrolateral view; 18. Femur and trochanter of leg II, male, ventrolateral view. Not scaled.