Anadenosternum okalii, Fenďa, 2017

Fenďa, Peter, 2017, A revision of the genus Anadenosternum Athias-Henriot (Acari: Mesostigmata: Parasitidae), Zootaxa 4324 (3), pp. 436-450 : 438-442

Anadenosternum okalii sp. nov.

( Figures 1–16 , 46‒48 )

Diagnosis. In female, endogynial sac with three to five sharp teeth on lateral margins, and wrinkled trapezoid structure situated posterior to the sac; ventrianal shield with 11 pairs of ventral setae. In male, genital lamella with anterolateral margins regularly curved, without any incisions or expansions; fixed digit with two larger sharp teeth anteriorly to pilus dentilis and a row of 12 minute denticles.

Description. FEMALE. Dorsal idiosoma ( Fig. 1 ). Length 460–500 µm, width 270–310 µm (n = 7). Dorsal shield divided into podonotal and opisthonotal shield by a narrow transverse fissure; both shields finely reticulated, opisthonotal reticulation stronger; transverse lines of reticulation dominant. Podonotal shield 215–230 µm long and 255–270 µm wide, with 23 pairs of smooth, needle-like, medium long (30–47 µm) setae of similar width. Podonotal setae of similar legth except of shorter setae z1, s1, s2, r2 and r4 (z 1 16–20 µm, s 1 25 –32 µm, s 2 17 –21 µm, r 2 27–28 µm, and r 4 26–32 µm). Setae j1 32–36 µm long, and r3 (60–75 µm) about 1.5–2 times the length of other podonotal setae. Opisthonotal shield 225–235 µm long and 250–275 µm wide, polytrichous, with 31–34 setae on each side of the shield (most frequently with 33 pairs of setae in four of the seven available specimens); opisthonotal setae uniform and slightly longer (40–60 µm) to those on podonotal shield, with tips reaching obviously beyond bases of following setae, and often asymmetrically inserted on both sides of the opisthosoma. Setae R1 shortened, 30 µm long, placed on anterolateral corners of opisthonotal shield or on soft integument beside the shield. Nine pairs of setae placed on dorso- and ventrolateral soft integument.

Ventral idiosoma ( Fig. 2 ). Tritosternum with narrow base (27–30µm long), and long and sparsely pilose laciniae (55–65 µm). Presternal area with two pairs of elongate and transverse shields, and one further pair of triangular shields; posterior pair of elongate shields conspicuously larger and sculptured by an oblique stria in the middle. Sternal shield weakly reticulated, 90–95 µm wide at the level of coxae II, with posterior margin concave and produced into obtuse angle, bearing three pairs of setae (30–40 µm long); the first pair of sternal setae close to anterior margin of shield. Paragynial shields long, bearing a pair of setae and extending under epigynium. Epigynium 105–110 µm long and 130–135 µm wide, subtriangular, with figura cuneata well defined. Endogynium with relatively large rounded sac having three to five sharp teeth on each side, and situated between coxae II and III; additional trapezoid wrinkled structure present at the level of coxae IV ( Figs 11 , 46–48 ). A narrow transverse strip of soft integument present between posterior margin of epigynial shield and anterior margin of ventral shield. Ventral shield well reticulated, with 11 pairs of ventral setae (30–40 µm) and three circum-anal setae (in one specimen, ventral shield with only ten pairs of ventral setae, and soft integument with the same number of setae on dorso- and ventrolateral surface). All ventrally inserted setae similar to those on dorsum. Postanal seta conspicuously longer than para-anal setae.

Gnathosoma . Epistome trispinate, medium spine about 1.5–2 times as long as lateral spines; lateral margins of epistome serrate ( Fig. 13 ). Chelicerae 135–150 µm long; movable digit 60–65 µm long, with three large teeth; fixed digit with three sharp teeth anterior to pilus dentilis and four rounded or sharp teeth posterior to pilus dentilis, the proximal one most robust; dorsal cheliceral seta delicately serrate ( Fig. 4 ). Corniculi simple, 24 µm long. Hypostome with ten rows of denticles ( Fig. 3 ). Subcapitulum with setae pc and hp1 of similar length, slightly longer (26–30 µm) than setae hp1 and hp2 (17–22 µm). Palptrochanter with seta v1 simple and seta v2 pilose; palpfemoral seta al serrate on one side, palpgenual seta al1 rodlike and seta al2 divided into four or five tines.

Legs ( Figs 6–9 ). Length of legs I–IV: leg I 470–500 µm, leg II 340–370 µm, leg III 30 0–330 µm and leg IV 460–480 µm. Coxae II and III with denticles on anterolateral distal margin. Trochanter I with rough anterior edge, seta al with one lateral tine on each side; trochanter IV with small acuminate dorsal tubercle. Seta pd1 on femur IV thickened. Tarsi II and III with setae al2, pl2, av2, pv2 and mv strongly pilose, setae al1 and pl1 slightly pilose and seta pv1 thickened and smooth; tarsus IV 150–155 µm long, with seta pd2 very long (95–105 µm), setae pv2 and pl3 pilose, and seta av1 slightly pilose. Other leg setae smooth and needle-like.

MALE. Dorsal idiosoma ( Fig. 15 ). Length 450 µm, width 260 µm (n=1). Dorsal shields, reticulation and chaetotaxy as in female. Podonotal shield 210 µm long, laterally expanded and completely fused to peritrematal shield; opisthonotal shield 220 µm long, laterally and posteriorly expanded to capture the setae placed on soft membrane in the female, and completely connected to ventrianal shield. Length of dorsal setae: most podonotal setae 35–45 µm, j1 32µm, z1 17µm, s1 30µm, s2 18µm, r2 25µm, r3 60, r4 25 µm, opisthonotal setae 40–50 µm, R1 30 µm.

Ventral idiosoma ( Fig. 16 ). Tritosternum with shortened base and long laciniae (50 µm). Presternal area with one pair of small and subtriangular shields. Genital lamella 45 µm wide and 60 µm long, regularly narrowed posteriorly, and well sclerotised laterally; apodemes relatively long, narrow and pointed, well sclerotised, having a small spike on inner margins, and extending to level of sternal setae st2 ( Fig. 12 ). Holoventral shield present, sternal portion 90 µm wide at the level of coxae II, weakly reticulated. Sternal setae subeqaul, 30–35 µm long. Opisthogaster with strong reticulation, ventral setae 30–35 µm long. Other characters as in female.

Gnathosoma . Epistome trispinate, middle spine slightly longer than lateral spines; short lateral margins close to lateral spines serrate ( Fig. 14 ). Chelicerae 110 µm long, movable digit 55 µm long, edentate in proximal part, distally with three small sharp teeth and one larger bifid tooth situated between terminal hook and large and basally widened tooth; spermatotreme in the form of narrow fissure ( Fig. 5 ). Arthrodial corona modified into a setiform brush. Fixed digit with two larger teeth anterior to pilus dentilis and a row of 12 minute denticles; dorsal seta pilose. Hypostome and subcapitulum as in female. Corniculi simple, 22 µm long. Pedipalps as in female.

Legs. Length of legs I–IV: leg I 470 µm, leg II 330 µm, leg III 310 µm, and leg IV 430 µm. Coxae II and III with anterolateral distal margin serrated. Trochanter IV with small dorsal acuminate tubercle. Legs II slightly thickened, ventrally spurred ( Fig. 10 ). Spur on femur II thumb-like, having distinct axillar process; the process conical and mounted on common base. Genu II with small knob-like spur; spur on tibia II thin, tapered terminally, and directed forward. Tarsus IV 140 µm long. Setation of legs as in females.

Specimens examined. Holotype female: North Italy , Bergamo City, Parco Fratelli Locatelli Park, park with various broad leaved deciduous trees, leaf litter and soil detritus, altitude 245 m, 19 May 2015, leg. P. Mašán. Paratypes: six females and one male, same data as holotype. The type specimens are deposited at the Institute of Zoology , Slovak Academy of Sciences , Bratislava , Slovakia (holotype, three paratype female, one paratype male); and at the Acarological Collection in Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, Slovakia (three paratype females).

Etymology. This species is named in honour of the late Ilja Okáli, eminent Slovak entomologist and museologist, a man with a great personal charisma, and former director of the Natural History Museum in Bratislava.

Remarks. This is the first record of the genus Anadenosternum from Italy.

Figures

FIGURES 1 – 5. Anadenosternum okalii sp. nov. 1. Female, dorsal idiosoma; 2. Female, ventral idiosoma; 3. Female, ventral hypostome, and pedipalp; 4. Female, lateral chelicera; 5. Male, lateral chelicera. Scale bars 100 µm (Figs 1 – 3), 20 µm (Figs 4 – 5).

FIGURES 6 – 14. Anadenosternum okalii sp. nov. 6. Female, leg I without tarsus, dorsal view; 7. Female, leg II, dorsal view; 8. Female, leg III, dorsal view; 9. Female, leg IV, dorsal view; 10. Male, leg II without tarsus, anterolateral view; 11. Female, endogynium; 12. Male, genital lamella; 13. Female, epistome; 14. Male, epistome. Scale bars 100 µm (Figs 6 – 10), 20 µm (Figs 11 – 14).

FIGURES 15 – 16. Anadenosternum okalii sp. nov., male. 15. Dorsal idiosoma (dashed setae are depicted also on Fig. 16); 16. Ventral idiosoma. Scale bars 100 µm.

FIGURES 40 – 48. Endogynium of females. 40 – 45. Anadenosternum azaleense. 46 – 48. Anadenosternum okalii sp. nov. Not scaled.