Mixobates incurvatus Láska, 1954

Gerecke, Reinhard, 2021, The water mites of the family Hygrobatidae (Acari, Hydrachnidia) in Italy, Zootaxa 5009 (1), pp. 1-85 : 50-68

Mixobates incurvatus Láska, 1954

(Figs 22 A-B)

Previously published record from Italy: Calabria ( Tuzovskij & Gerecke 2003).

Habitat: Mossy riffles of low order streams, in Calabria at 1100 m .

Distribution: Central and Southern Europe, scattered - in the Mediterranean one further record from Greece (Epiros: Tuzovskij & Gerecke 2003).

Key to the hygrobatid genera and species of the Italian fauna

For an overview of the Italian water mite fauna at genus level and as a tool for distinguishing hygrobatid mites from other water mite families present in Italy, see Cicolani & Di Sabatino (2014). This key includes also Atractides ruffoi , at present recorded from Corsica only, but present in Sardinia with a rather high probability.

1 No gnathosomal bay developed; gnathosomal base broadly fused with Cx-I (Figs 22 D-E, G; 24 A, C). I-L-5/6 not particularly modified (exceptionally, a pair of characteristic short ventrodistal setae at I-L-5 as in Fig. 22 B)....................... 2

- Gnathosomal bay well developed; gnathosoma widely free, fixed to Cx-I by a tiny bridge only (Fig. 24 D). I-L-5/6 modified - I-L-5 with a pair of characteristic ventrodistal setae and a mediodistal whip-like seta, I-L-6 various in shape, often curved, with ventral setae arranged in groups (e.g., Figs 25 B, 27 P, 31 E). Genus Atractides ............................... 16

2 (1) Glandular opening on Cx-IV in the centre of the plate (Fig. 22 A). I-L-5 with a characteristic pair of short and stout ventrodistal setae (Fig. 22 B)........................................... Genus Mixobates (only species in Italy: M. incurvatus )

- Glandular opening on Cx-IV near the suture line Cx-III/IV (Figs 22 D-E, G). Ventrodistal setae on I-L-5 normal in shape, pointed. Genus Hygrobates ............................................................................. 3

3 (2) Genital field with six or more pairs of acetabula (Figs 22 D-E, G). Subgenus Rivobates .............................. 4

- Genital field with three pairs of acetabula (Figs 24 A-F). Subgenus Hygrobates .................................... 6

4 (3) Posterior margin of anterior coxal plate acute-angled (Fig. 22 D); P-4 shorter (L <140 µm) (Fig. 22 C)...................................................................................... Hygrobates (Rivobates) psammocrenicus

- Posterior margin of anterior coxal plate rounded (Figs 22 E, G); P-4 longer (L> 140 µm)............................ 5

5 (4) Male genital field shorter (L> 200 µm) and slenderer (Fig. 22 E); P-4 relatively shorter (L ratio P-3/P-4 ≥ 0.6, Fig. 22 F).......................................................................... Hygrobates (Rivobates) helocrenicus

- Male genital field longer (L <200) and broader (Fig. 22 G); P-4 relatively longer (L ratio P-3/P-4 <0.6, Fig. 22 H)................................................................................ Hygrobates (Rivobates) norvegicus

6 (3) Ventral margin P-2 straight or slightly convex, without a distal projection (Fig. 23 A)............................... 7

- Ventral margin P-2 distally distinctly protruding, forming a nose-shaped angle or a longer projection (Figs 23 B-E)........ 8

7 (6) Median length of Cx-I + gnathosoma> 350 µm. Males: P-4 length> 140, genital plate length> 170 µm. Females: P-4 length> 165, genital plate length> 175 µm. (Preferably in pools of lower order streams)........ Hygrobates (Hygrobates) setosus

- Median length of Cx-I + gnathosoma <350 µm. Males: P-4 length <130, genital plate length <160 µm. Females: P-4 length <165 µm, genital plate length <175 µm. (Preferably in higher order streams and standing waters)......................................................................................... Hygrobates (Hygrobates) nigromaculatus

8 (6) Integument lineated, distance between lines several times the width of a line (Fig. 21 A) - in juvenile specimens occasionally lines formed as irregular ridges; palp stout, P-2 with a relatively short distoventral projection (Fig. 23 C).......................................................................................... Hygrobates (Hygrobates) calliger

- Integument not lineated, reticulated (Figs 21 B-C) or smooth - if a fine striation is developed, distance between striae not exceeding width of striae; shape of palp and P-2 distoventral projection various.................................... 9

9 (8) Integument reticulated (Figs 21 B-C). P-2 with a long and slender distoventral projection (Figs 23 B, D-F).............. 10

- Integument smooth or very finely striated. P-2 distoventral projection shorter, conical or nose-shaped (Figs 23 G-H)...... 13

10 (9) Cells of membranous integument dorsally with “inner lines” (Fig. 21 C); postgenital area with a fine lineation; denticulation on P-2 rather fine (Fig. 23 D)................................................. Hygrobates (Hygrobates) cf. turcicus

- Cells of membranous integument dorsally without “inner lines” (Fig. 21 B), postgenital area reticulate; denticulation on P-2 various............................................................................................ 11

11 (10) Denticles on P-2 very fine, mostly restricted to distal projection, a few scattered over proximoventral segment margin (Fig. 23 B)....................................................................... Hygrobates (Hygrobates) arenarius

- Denticles on P-2 large, covering more than half of proximoventral margin (Figs 23 E-F)............................ 12

12 (11) Colour of sclerotized parts in living specimens usually red; ventral denticles on P-2/-3 stronger (Fig. 23 E). Male genital field with Ac more rounded, arranged in an obtuse triangle............................... Hygrobates (Hygrobates) corsicus

- Colour of sclerotized parts in living specimens sandy yellow; ventral denticles on P-2/-3 finer (Fig. 23 F). Male genital field with elongated Ac in triangular arrangement..................................... Hygrobates (Hygrobates) f luviatilis

13 (9) Males: Genital plate as long as wide or longer (Fig 24 H). Females: Two to four fine setae inserted on pregenital sclerite (Fig. 24 I)................................................................... Hygrobates (Hygrobates) trigonicus

- Males: Genital plate wider than long (Figs 24 C, E). Females: pregenital sclerite without setae (Figs 24 D, F)............ 14

14 (13) Posterior margin of Cx-I and medial margin of Cx-IV broadly rounded (Fig. 24 A). Females: Pregenital sclerite located anterior to genital plate margins (Fig. 24 B)............................................... Hygrobates (Hygrobates) foreli

- Cx-IV medially forming a more or less pronounced angle (Fig. 24 C - if medial margin of Cx-IV rounded, posterior margin of Cx-I parabola-shaped or pointed). Females: Pregenital sclerite between, or posterior to, anterior genital plate margins (Figs 24 D, F)............................................................................................... 15

15 (14) Acetabula elongated. Palp slenderer, ventral margin P-4 only slightly protruding near ventral setae insertion (Fig. 23 G). Dorsal projection of cheliceral basal segment membranous (see Gerecke 1991, Figs 53 A-D). Males: Genital plate anterior margin with a small triangular median tip projecting in a deep indentation (Fig. 24 C). Females: Genital plates with equally rounded medial margins, Ac separated by wide interspaces (Fig. 24 D)............................ Hygrobates (Hygrobates) longiporus

- Acetabula more rounded. Palp stouter, ventral margin P-4 with a little hump near ventral setae insertion (Fig. 23 H). Dorsal projection of cheliceral basal segment sclerotized. Males: Genital plate anterior margin indented, in the centre a short medial projection (Fig. 24 E). Females: Medial margin of genital plate forming an obtuse angle, Ac not separated by wide interspaces (Fig. 24 F).............................................................. Hygrobates (Hygrobates) longipalpis

16 (1) Gnathosomal rostrum strongly elongated, chelicera with a long and slender basal segment; palp slender (Fig. 25 A), P-1 longer than high and centrally narrowed, P-2/-3 without ventral extensions, P-4 often clavate, P-5 may bear cheek-like lateral extensions. Subgenus Tympanomegapus ................................................................... 17

- Gnathosomal rostrum short or only slightly elongated, basal segment of chelicera stouter; palp various in shape, but P-1 normally shorter than high, or subquadratic; P-5 never with cheek-like extensions (Fig. 25 L)........................ 18

17 (16) Setae S-1/-2 short (L <65 µm), adjacent (separation <10 µm); I-L-5 shorter (length ratio I-L-5/6 <1.35 – Fig. 25 B); Vgl-1/2 separate............................................................ Atractides (Tympanomegapus) acutirostris

- Setae S-1/-2 longer (> 65 µm) and distanced (separation> 10 µm); I-L-5 relatively long (length ratio I-L-5/6> 1.35 – Fig. 25 C); Vgl-1+2 fused....................................................... Atractides (Tympanomegapus) pavesii

18 (16) I-L-5 ventral margin longer than dorsal margin, setae S-1/2 closely together, occasionally twisted, heteromorphic (S-1 strongly enlarged in proximal part, distally narrowed to a rather fine tip, slenderer than S-2); I-L-6 shortened, with a swollen base, rapidly narrowed distally (Fig. 25 F). Excretory pore sclerotized, Vgl-1+2 fused (Figs 25 D, G). Subgenus Polymegapus .. 19

- I-L-5 ventral margin shorter than dorsal margin, setae S-1/2 various in shape, if closely together, generally similar in shape and not contorted (Figs 25 K, 26 G; 27 A); I-L-6 various in shape - if shortened, equal in height or less narrowed from the base to the claw furrow (Figs 26 P, 27 I). Excretory pore and Vgl-1/2 various. Subgenus Atractides s.str...................... 20

19 (18) Genital field with numerous Ac, in general 6-10 pairs (Figs 25 D-E); dorsum and posterior venter with sclerotized muscle attachment plates.......................................................... Atractides (Polymegapus) polyporus

- Genital field with three pairs of Ac (Figs 25 G-H); dorsum and posterior venter without plates................................................................................................ Atractides (Polymegapus) orghidani

20 (18) Genital plates fused to form a circular sclerite completely surrounding the gonopore (Fig. 25 I). The ejaculatory complex may be visible by transparency in the genital field area: Males..................................................... 21

- Genital plates lying as separate paired sclerites in the membranous integument flanking the gonopore, the latter lies between a curved pregenital sclerite, and a narrower postgenital sclerite (Fig. 25 K). Eggs may be visible by transparency: Females.. 72

Males.

21 (20) Gnathosoma with projecting, pointed rostrum (Fig. 25 L); chelicera with long, weakly curved claw (L ratio basal segment/claw <1.8 – as in Fig. 31 C); integument striated; dorsal muscle insertions sclerotized as platelets; P-2 with a truncate ventrodistal hump (Fig. 25 L); I-L-5/6 robust, S-1 and -2 rather similar in shape (Fig. 25 K)........... Atractides (Atractides) subasper

- Gnathosoma with shorter rostrum; cheliceral claw relatively shorter and more curved (L ratio basal segment/claw> 1.8 – as in Fig. 10 A). Integument, dorsal muscle insertions and I-L various; S-1/- 2 in many species strongly heteromorphic..........22

22 (21) Genital field with four pairs of acetabula (Fig. 10 D). A species at present unknown in the male sex. I-L-5 with setae S-1/-2 short and blunt, placed side by side (Fig. 10 C)............................................ Atractides (Atractides) dinisi ( Atractides octoporus , a further quadracetabulate species, but in shape of mouthparts similar to A. subasper , is recorded from Central and Southern Europe, but not from Italy).

- Genital field with three pairs of acetabula.................................................................. 23

23 (22) IV-L-5 bearing a pair of long, rigid swimming setae (Fig. 26 B); setae S-1 and -2 rather heteromorphic (length ratio 1.26 – Fig. 26 A)......................................................................... Atractides (Atractides) ovalis IV-L-5 without swimming setae (Figs 29 F, I); S-1 and -2 various............................................... 24

24 (23) I-L-5 with S-1 and -2 rather similar in shape (length ratio S-1/2 1.0-1.2), sometimes inserting side by side, separation S-1-2 not exceeding 10 µm (Fig. 26 C); I-L- 6 in most cases rather stout and only weakly curved. (Species with intermediate character states may key out also on the alternative way)............................................................. 25

- I-L-5 with S-1 and -2 more heteromorphic (length ratio S-1/2> 1.2), further apart (separation> 10 µm, exceeding the maximum diameter of S-1, Figs 28 T, W); I-L-6 various in shape........................................................ 46

25 (24) Without sclerotized muscle insertions on dorsal and/or posteroventral idiosoma. However, glandular platelets may be enlarged and muscle insertions characterized by small areas of granulated integument; Vgl-1/2 may be fused or separate.......... 26

- With sclerotized muscle insertion platelets on dorsal and/or posteroventral idiosoma (as in Figs 27 L, Q, 31 N); Vgl-1+2 always fused (as in 27 D, L, N)............................................................................... 39

26 (25) Excretory pore surrounded by a sclerotized ring as large as the neighbouring glandular platelets (as in Fig. 26 D). Integument finely striated. I-L-5 relatively short (dL/HB ratio <4.3), I-L-6 slender (L/HB ratio 5.0), slightly curved, dorsal and ventral margin distally diverging (Fig. 26 C)................................................ Atractides (Atractides) tener

- Excretory pore smooth (Fig. 26 F), occasionally surrounded by fine, lip-like lines, but never by a sclerotized ring. Integument structure and shape of I-L-5/6 various..................................................................... 27

27 (26) Dorsal integument papillate (Fig. 21 D - papillosity more or less extended, occasionally restricted to a small frontal area between lateral eyes); very old specimens (with thick, leathery integument) may be completely devoid of papillae; acetabula relatively large (diameter> 40 µm, Fig. 26 E)........................................ Atractides (Atractides) walteri

- Dorsal integument without papillae; acetabula smaller (diameter <40 µm)....................................... 24

28 (27) Dorsal integument lineated (as in Fig. 21 A - interspaces between lines distinctly wider than width of individual lines)..... 29

- Dorsal integument smooth or striated (if so, interspaces between striae as wide as width of striae)..................... 32

29 (28) P-2 with a straight ventral surface (Fig. 26 H); I-L-6 strong, dorsal and ventral margins distally diverging, relatively long (L ratio I-L-5/6 <1.3) (Fig. 26 G)................................................. Atractides (Atractides) protendens

- P-2 with a distinct ventrodistal projection (Figs 26 I, L). I-L-6 slenderer and curved, with subparallel dorsal and ventral margins, relatively short (L ratio I-L-5/6> 1.5, Fig. 26 N)............................................................ 30

30 (29) Projection of P-2 strongly protruding and smooth, P-4 with both ventral setae inserting in proximal half of segment (Fig. 26 I). Genital field with 30-40 pairs of setae; Ac-3 elongated (Fig. 26 K)..................... Atractides (Atractides) pennatus

- Projection of P-2 blunt, with a rugose-denticulated surface, P-4 with distoventral seta inserting in distal half of segment (Fig. 26 L). Genital field with 30 or less pairs of setae; Ac-3 not elongated........................................... 31

31 (30) I-L-5 (Fig. 26 P) relatively shorter, with more diverging dorsal and ventral margins (dL/HB 2.9-3.1, L ratio I-L-5/6, 1.64-1.65); setae S-1/2 further away (distance 17-19 µm) and longer (L S-1> 75, S-2> 65), seta S-1 curved. Vgl-1/2 separate...................................................................................... Atractides (Atractides) legeri

- I-L-5 (Fig. 26 N) relatively longer, with subparallel dorsal and ventral margins (dL/HB> 3.5, L ratio I-L-5/6> 1.65); setae S-1/2 closer to each other (distance <15 µm) and shorter (L S-1, 68-75, S-2, 56-61), seta S-1 straight. Vgl-1+2 generally fused............................................................................. Atractides (Atractides) fonticolus

32 (28) P-2 bearing a distinct ventrodistal projection (Fig. 29 E). Anterior margin of genital plate indented (as in Fig. 29 G)....................................... Atractides (Atractides) nodipalpis (atypical specimens having S-1-2 close to each other)

- P-2 ventral margin straight or slightly convex (Figs 12 E, 27 C)................................................ 33

33 (32) I-L-6 straight, or only very weakly curved; tips of S-1/2 reaching halfway or less I-L-6 (Figs 27 A, 12 C-D); anterior margin of genital field forming an extended, Ac-free area (Figs 27 B, 12 G)............................................... 34

- I-L-6 curved; tips of S-1/2 reaching halfway or beyond I-L-6 (Fig. 27 F); shape of genital field and Vgl-1/2 various...... 35

34 (33) Small in dimensions (median suture Cx-I+II <70, I-L-5 length <100 µm); I-L-6 longer than I-L-5 (Fig. 27 A); anterior margin of genital field strongly bowed (Fig. 27 B); Vgl-1/2 on two separate platelets.......... Atractides (Atractides) subterraneus

- Major in dimensions (median suture Cx-I+II> 90, I-L-5 length> 110 µm); I-L-6 shorter than I-L-5 (Figs 12 C-D); anterior margin of genital field equally rounded; Vgl-1+2 may be fused (Fig: 12 F-G).............. Atractides (Atractides) graecus

35 (33) Vgl-1+2 fused, on a single platelet (Fig. 27 D). P-2 ventral margin equally rounded (Fig. 27 C)...................... 36

- Vgl-1/2 on two separate platelets (Fig. 3 D). P-2 ventral margin various, occasionally slightly protruding in distal part..... 37

36 (35) Gonopore in a more anterior position, Ac-3 flanking its posterior fifth only (Fig. 27 D)...... Atractides (Atractides) spinipes

- Gonopore in a more posterior position, Ac-3 flanking its posterior third (Fig. 27 E)........ Atractides (Atractides) oblongus

37 (35) Genital field with small, rounded Ac (maximum diameter <30 µm), arranged in a weakly curved line (Figs 3 C-D).................................................................................... Atractides (Atractides) asinus

- Genital field with large, subtriangular Ac (maximum diameter> 40 µm), in triangular arrangement (Fig. 27 H).......... 38

38 (37) I-L-6 short (length <90 µm, length ratio I-L-5/6> 1.5), with converging dorsal and ventral margins; length S-1/2 <60 µm (Fig. 27 K); mature specimens with extended ventral sclerotization (all coxal plates may be fused to a coxal shield, Vgl-3 fused to posterior margin of Cx-IV)..................................................... Atractides (Atractides) vaginalis

- I-L-6 longer (length> 100 µm, length ratio I-L-5/6 <1.5), with dorsal and ventral margins parallel until the base of the claw furrow; length S-1/2> 60 µm (Fig. 27 I); secondary sclerotization weak, coxae always in three groups, Vgl-3 not fused to posterior margin of Cx-IV....................................................... Atractides (Atractides) adnatus

39 (25) Excretory pore surrounded by a distinct sclerotized ring (Fig. 27 N) or embraced by a U-shape sclerite (Fig. 27 L)........ 40

- Excretory pore without sclerotization (as in Fig. 27 D)....................................................... 44

40 (39) Ventral seta on I-L-5 inserted in proximal part of segment, distinctly more away from S-1 than from segment base (Fig. 5 B)............................................................................. Atractides (Atractides) asticae

- Ventral seta on I-L-5 inserted in centre or distal part of segment, more away from segment base than from S-1 (Fig. 27 P)... .................................................................................................. 41

41 (40) Acetabula relatively large (diameter> 40 µm); excretory pore sclerite U-shaped (Fig. 27 L), only occasionally closed to a ring. P-4 ventral setae not associated with projections (Fig. 27 M)........................... Atractides (Atractides) brendle

- Acetabula smaller (diameter <40 µm); excretory pore sclerite ring-shaped (Fig. 27 N); P-4 ventral setae associated with prominent projections (Fig. 27 O)....................................................................... 42

42 (41) S-1/-2 very short (L <40 µm, about 1/3 L I-L-6), with blunt, knob-shaped tips (Fig. 27 P); P-2 with a slightly protruding ventrodistal margin; P-4 sword seta near distoventral seta (Fig. 27 O). Setae of Dgl-1 at frontal idiosoma margin long and fine........................................................................ Atractides (Atractides) pumilus

- S-1/-2 longer (L> 50 µm, at least half L I-L-6), their tips various in shape (Figs 31 D, 32 I); P-2 with a rounded ventrodistal margin; P-4 sword seta near proximoventral seta (Figs 28 B, D). Setae of Dgl-1 at frontal idiosoma margin short, willow leafshaped (Fig. 27 Q).................................................................................... 43

43 (42) Cx-I+II medial suture line shorter (L <60 µm, <40% of total coxal shield L), posteromedial margin forming a right or obtuse angle (Fig. 28 A); ventral surface of P-2 and -3 covered by a dense, fine denticulation (Fig. 28 B visible at high magnification only).................................................................... Atractides (Atractides) denticulatus

- Cx-I+II medial suture line longer (L> 90 µm,> 40% of total coxal shield L), posteromedial margin forming an acute angle (Fig. 28 C); ventral surface of P-2 and -3 smooth (Fig. 28 D).............................. Atractides (Atractides) latipalpis

44 (39) S-1/-2 short (L <45 µm), placed side by side, their tips reaching 1/3 or less of the way up I-L-6; I-L-6 straight (Fig. 28 E).............................................................................. Atractides (Atractides) clavipes

- S-1/-2 long (L> 45 µm), slightly separated (3-7 µm), their tips reaching half-way up I-L-6; I-L-6 curved (Figs 28 F, H)... 45

45 (44) Genital field small (L/W <110/120, Ac diameter <35 µm, Fig. 28 G); I-L-5 short (L <120 µm, L ratio I-L-5/6 <1.35 – Fig. 28 F)......................................................................... Atractides (Atractides) loricatus

- Genital field large (L/W> 120/130, Ac diameter> 35 µm, fig. 28 H); I-L-5 longer (L> 120 µm, L ratio I-L-5/6> 1.35 – Fig. 28 H)................................................................ Atractides (Atractides) macrolaminatus

46 (24) Both P-2 and P-3 with ventral projections (Figs 28 K, N)..................................................... 47

- P-3 without ventral projection; a projection may be present or absent on P-2 (Figs 28 R, U)......................... 48

47 (46) Integument striated; I-L-5 long (L> 200 µm, ratio I-L-5/6> 1.5), I-L-6 proximally thickened (Fig. 28 L); Ac-3 elongated and drop-shaped (Fig. 28 M).................................................... Atractides (Atractides) gibberipalpis

- Integument lineated; I-L-5 shorter (L <200 µm, ratio I-L-5/6 <1.4), I-L-6 proximally not particularly thickened (Fig. 28 O); Ac-3 round (Fig. 28 P)......................................................... Atractides (Atractides) inflatus

48 (46) Excretory pore with (more or less extended) sclerotization (Figs 28 Q, S); Vgl-1+2 often fused....................... 49

- Excretory pore unsclerotized, Vgl-1/2 generally separate, rarely fused........................................... 53

49 (48) Excretory pore sclerotization reduced to a knob-shaped structure at posterior edge; anterior margin of genital plate indented; Vgl-1/2 separate (Fig. 28 Q); distoventral margin of P-2 strongly protruding to form a pointed projection (Fig. 28 R).................................................................................... Atractides (Atractides) ruffoi

- Excretory pore sclerotization complete, ring-shaped; anterior margin of genital plate convex, without indentation; Vgl-1+2 fused (Fig. 28 S); ventral margin of P-2 equally rounded (Fig. 28 U)............................................ 50

50 (49) I-L-5 relatively slender (L/HB> 3.5), dorsal and ventral margins only slightly diverging distally (Fig. 28 T); posterior margin of genital plate in the centre weakly concave (Fig. 28 S)............................. Atractides (Atractides) anellatus

- I-L-5 more enlarged (Figs 28 W, 29 A - L/HB <3.3); posterior margin of genital plate various....................... 51

51 (50) I-L-5 strongly inflated like a longish disc (I-L-5 dL/HB ratio <2.5, Fig. 28 W), palp rather stout, (L/H P-2 <1.5; P-3 <1.7; P-4 <2.5, Fig. 28 V)............................................................... Atractides (Atractides) latipes

- I-L-5 and palp slenderer (I-L-5 dL/HB ratio 3.1-3.2; L/H P-2 ≥ 1.5; P-3, 1.9; P-4> 2.7, Figs 29 A, C).................. 52

52 (51) Major in size (idiosoma L> 550, Cx-I+II mL> 130, P-4 L> 120); P-3 stouter (L/H <1.8), P-4 slenderer and relatively longer (L/H> 3.4, L ratio P-2/P-4, <0.6) (Fig. 29 B); IV-L-5 dL/vL ratio <1.4, S-1/-2 closer to each other (distance 15); I-L- 6 in the centre strongly narrowed (Fig. 29 A)............................................ Atractides (Atractides) gracilipes

- Minor in size (idiosoma L <500, Cx-I+II mL <130, P-4 L <100); P-3 slenderer (L/H> 1.8), P-4 stouter and relatively shorter (L/H <3.2, L ratio P-2/P-4> 0.6) (Fig. 29 D); I-L-5 dL/vL ratio> 1.4, S-1/-2 more away (distance> 20); I-L- 6 in the centre less narrowed (Fig. 29 C)....................................................... Atractides (Atractides) giustinii

53 (48) I-L-5 relatively long, I-L-6 short and thickened, L ratio I-L-5/6> 1.5, I-L-6 L/HB, <6.0); S-1-2 separation <20 µm (Figs 26 N, P); integument lineated; P-2 with a ventrodistal projection (Figs 26 I, L, Q).................................... 54

- If length ratio I-L-5/6> 1.5, then I-L-6 slenderer, and vice versa; integument, setal separation and shape of P-2 various... 56

54 (53) Ventrodistal projection of P-2 strongly protruding and smooth; both ventral seta insertions of P- 4 in proximal part, dividing the segment into sectors 2:1:3, sword seta anterior to distoventral seta (Fig. 26 I); genital field with 30 or more pairs of setae (Fig. 26 K)...................................................................... Atractides (Atractides) pennatus

- Ventrodistal projection of P-2 blunt, with rugose-denticulated surface; distoventral seta of P-4 inserted in the distal half of the segment, insertion of sword seta various (Figs 26 L, Q); genital field setae less numerous........................... 55

55 (54) Genital field with concave anterior margin and relatively large acetabula (diameter> 45 µm, Fig. 26 O); I-L-5 distally strongly enlarged (L/HB <3.4), seta S-1 curved, S-2 slightly thickened (L/W ≥ 5.0) (Fig. 26 P). P-4 sword seta proximal to distoventral seta (Fig. 26 Q); Vgl-1/2 separate.................................................. Atractides (Atractides) legeri

- Genital field with convex anterior margin and relatively small acetabula (diameter <45 µm, Fig. 26 M); I-L-5 not strongly enlarged in distal part (L/HB> 3.5), S-1 straight, S-2 strongly thickened (L/W <5.0) (Fig. 26 N); P-4 sword seta on the level of distoventral seta (Fig. 26 L); Vgl-1+2 generally fused............................ Atractides (Atractides) fonticolus

56 (53) P-2 with a ventrodistal projection – this projection may be pointed and smooth (Figs 29 E, H), or blunter and with an irregular, rugose surface (Figs 29 N, P)........................................................................... 57

- P-2 without a ventrodistal projection, at most protruding convexly protruding (Figs 30 C, F) [in A. glandulosus , a species with large glandular platelets and I-L-5 distally strongly inflated, P-2 distoventrally with a little projecting double hump (Fig. 30 B)]................................................................................................. 64

57 (56) Anterior margin of genital plate indented and here bearing a small medial extension like a notch in a bed (Fig. 29 G); integument finely striated....................................................................................... 58

- Anterior margin of genital field convex or weakly concave (Figs 29 M, O, Q); integument lineated (as in Fig. 21 A)...... 59

58 (57) Distomedial margins of IV-L-4/5 equally convex, only slightly extending beyond the base of subsequent segments (Fig. 29 F); P-4 sword seta shorter than maximum height of the segment, in most cases inserting on, or distally from, the level of the proximoventral seta (Fig. 29 E)................................................ Atractides (Atractides) nodipalpis

- Distomedial margins of IV-L-4/5 forming pointed lateral sheaths flanking the base of the subsequent segments (Fig. 29 I); P-4 sword seta as long as the maximum height of the segment, inserted proximal to the proximoventral seta (Fig. 29 H)................................................................................... Atractides (Atractides) robustus

59 (57) Acetabula very large (maximum diameter >> 50 µm), in triangular arrangement (Fig. 29 M); P-2 ventrodistal projection relatively short, nose-shaped, with a rugose surface (Fig. 29 K); I-L-5 relatively long (L ratio I-L-5/6> 1.4, Fig. 29 L)................................................................................... Atractides (Atractides) fissus

- Acetabula minor in size (maximum diameter <40 µm), in a weakly curved line; I-L-5 relatively shorter (L ratio I-L-5/6 ≤ 1.4)................................................................................................ 60

60 (59) Vgl-1/2 separate; P-2 distoventral projection blunt, rugose (Figs 29 N, P)........................................ 61

- Vgl-1+2 fused; P-2 distoventral projection slender, pointed (Figs 29 S-T)........................................ 63

61 (60) Suture lines Cx-II/III indistinct, all coxae fused to form a unique coxal shield (Fig. 29 O); P-4 ventral setae close to each other (distance <20), sword seta near distoventral seta (Fig. 29 N)........................... Atractides (Atractides) remotus

- Coxae in three groups, anterior and posterior coxal plates separated by membranous integument (as in Fig. 30 A); P-4 ventral setae away from each other (distance> 20 µm), sword seta insertion between ventral setae (Fig. 29 P)................. 62

62 (61) Genital field on each side along gonopore with 7-8 setae in a single line flanking medial margin of Ac-1 (Fig. 29 R)................................................................................ Atractides (Atractides) inflatipalpis

- Genital field on each side along gonopore with 12-20 setae arranged in double or triple lines, posteriorly extending until the anterior margin of Ac-3 (Fig. 29 Q)............................................ Atractides (Atractides) valencianus

63 (60) Palp stouter (P-3 L/H 2.3-2.5) (Fig. 29 T); L-5 thinner (HA 38-43, HB 43-48), S-2 longer (65-68 µm) (Fig. 15 A)...................................................................................... Atractides (Atractides) lunipes

- Palp slenderer (P-3 L/H 2.5-2.8) (Fig. 29 S); L-L-5 thicker (HA 44-49, HB 48-56), S-2 longer (68-81 µm)........................................................................................... Atractides (Atractides) corsicus

64 (52) Glandularia enlarged (diameter 30-40 µm), Vgl-3 fused to Cx-IV (Fig. 30 A); P-4 sword seta more proximal, away from distoventral seta (Fig. 30 B).................................................. Atractides (Atractides) glandulosus

- Glandularia minor in size (diameter <30 µm); Vgl- 3 in most species separate from Cx-IV (Fig. 30 O); P-4 sword seta near distoventral seta (Figs 30 C, F).......................................................................... 65

65 (64) I-L-6 as long as, or only slightly shorter than, I-L-5 (L ratio I-L-5/6 <1.2); S-1 apically thickened and obliquely truncated (Figs 30 D-E)............................................................................................ 66

- I-L-6 relatively shorter (L ratio L-L-5/6> 1.2); S-1 pointed or truncated, in the latter case not as strongly thickened (Figs 30 M, Q)................................................................................................. 68

66 (65) Integument striated; I-L-6 very long and slender (L/HB ≥ 10.0), S-1 L> 120 µm (Fig. 30 D); palp slender (P-3 L/H ratio> 2.0, Fig. 30 C).................................................................... Atractides (Atractides) distans

- Integument lineated (as in Fig. 21 A); I-L-6 not as long and slender (L/HB <9.0), S-1 L 85-110 µm (Fig. 30 E); palp stouter (P-3 L/H ratio <1.8, Fig. 30 F)......................................................................... 67

67 (66) Setae S-1/2 further away (distance> 25 µm), L-5 with a relatively shorter ventral margin (dL/vL ratio 1.65-1.91) (Fig. 30 H); palp stout (L/H P-2, <1.3, P-3 <1.5), P-3 shorter than P-2 (L ratio P-2/P-3> 1.0), P-2 ventral margin in distal part projecting to form an obtuse angle (Fig. 30 G); Vgl-1+2 fused, or, if separate, closely in touch.......... Atractides (Atractides) castor

- Setae S-1/2 closer to each other (distance ≤ 25 µm), and I-L-5 with a relatively longer ventral margin (dL/vL ratio <1.65) (Fig. 30 E); palp slenderer (L/H P-2,> 1.4, P-3,> 1.7), P-3 longer than P-2 (L ratio P-2/P-3 <1.0), P-2 ventral margin equally slightly rounded (Fig. 30 F); Vgl-1/2 always separate....................................... Atractides (Atractides) allgaier

68 (65) Ventral setae of P-4 very long, nearly as long as L P-2+P-3 (Fig. 30 I); acetabula in triangular arrangement (Fig. 30 K); Vgl-3 separate from Cx-IV......................................................... Atractides (Atractides) longisetus

- Ventral setae of P-4 distinctly shorter than P-2+P-3 (Figs 17 B, 30 L); arrangement of acetabula and Vgl-3 various....... 69

69 (68) Vgl-3 fused to Cx-IV (as in Fig. 30 A); acetabula large (maximum diameter> 45 µm), in triangular arrangement (posterior margin of Ac-1 adjacent to anterior margin of Ac-3 – Fig. 30 N).................... Atractides (Atractides) panniculatus

- Vgl-3 separate from Cx-IV (Fig. 8 A); acetabula smaller (maximum diameter <45 µm), arranged in a curved line (posterior margin of Ac-1 away from anterior margin of Ac-3 – Figs 30 O-P, R)............................................ 70

70 (69) Genital field anterior margin medially protruding to form an obtuse angle (Fig. 30 O)...... Atractides (Atractides) cydonius

- Genital field anterior margin straight, slightly convex or concave (Figs 30 P, R)................................... 71

71 (70) I-L-5 rather large (dL 180-214, HB> 55, Fig. 30 Q)................................... Atractides (Atractides) pollux

- I-L-5 minor in size (dL 158-180, HB <55, Fig. 30 S)................................ Atractides (Atractides) fluviatilis

Females:

72 (20) Gnathosoma with projecting, pointed rostrum (as in Figs 25 L); chelicera with long, weakly curved claw (L ratio basal segment/ claw <2.0 - Fig. 31 C); integument striated; dorsum with enlarged glandularia and one pair of muscle insertions sclerotized as platelets (Fig. 31 A); genital field with large pregenital sclerite and three pairs of acetabula (Fig. 31 B); P-2 ventral margin equally rounded; I-L-5/6 robust, S-1 and -2 rather similar in shape (as in Fig. 25 K)........ Atractides (Atractides) subasper

- Gnathosoma with shorter rostrum; cheliceral claw relatively shorter and more curved (L ratio basal segment/claw> 2.0 – Fig. 5 A); integument, palp and I-L-5 and -6 various; S-1/-2 may be strongly heteromorphic............................. 73

73 (72) Genital field with four pairs of Ac (Fig. 10 D). ( Atractides octoporus , a further quadracetabulate species, but in shape of mouthparts similar to A. subasper , is recorded from Central and Southern Europe, but not from Italy)................................................................................................. Atractides (Atractides) dinisi

- Genital field with three pairs of acetabula (as in Fig. 31 B).................................................... 74

74 (73) IV-L-5 bearing a pair of long, rigid swimming setae (Fig. 26 B); S-1/-2 rather heteromorphic (length ratio 1.2); I-L-6 relatively short (length ratio I-L-5/6, 1.6 - as in Fig. 26 A)....................................... Atractides (Atractides) ovalis

- IV-L-5 without swimming setae (Figs 29 F, I); S-1/-2 and I-L-5/6 various........................................ 75

75 (74) Excretory pore with a sclerotized ring (as in Fig. 28 S), or associated with a sclerite (as in Fig. 28 Q).................. 76

- Excretory pore smooth (as in Figs 26 F; 30 A, O; 32 N)...................................................... 86

76 (75) At least some of the dorsal and posteroventral muscle insertions sclerotized as plates or platelets (as in Figs 27 Q, 31 N)... 77

- Dorsal and posteroventral integument without sclerotized muscle insertions...................................... 81

77 (76) Excretory pore sclerite incomplete, inversely horseshoe-shaped or reduced to a small dot at posterior edge of pore (as in Fig. 27 L); Ac large (maximum diameter> 50 µm)......................................... Atractides (Atractides) brendle

- Excretory pore sclerotized ring complete (as in Fig. 27 N); Ac maximum diameter <50 µm......................... 78

78 (77) Ventral seta on I-L-5 inserted in proximal part of segment, distinctly more away from S-1 than from segment base (Fig. 5 B)............................................................................. Atractides (Atractides) asticae

- Ventral seta on I-L-5 inserted in centre or distal part of segment, more away from segment base than from S-1 (as in Fig. 27 P)................................................................................................. 79

79 (78) Length of S-1/2 about 1/3 of I-L-6, <40 µm (Fig. 27 P); prominent tubercles associated with P-4 ventral setae insertions (Fig. 27 O); setae of Dgl-1 at frontal idiosoma margin long and fine.......................... Atractides (Atractides) pumilus

- Length of S-1/2 about half that of I-L-6,> 50 µm (as in Fig. 31 D); tubercles associated with P-4 ventral setae insertions less prominent (as in Figs 28 B, D); setae of Dgl-1 at frontal idiosoma margin willow-leaf shaped (as in Fig. 27 Q)........... 80

80 (79) Cx-I+II with long median suture line (length> 90 µm,> 40 % of total coxal field length); without denticulation on ventral surface of P-2 and -3 (as in Fig. 28 D)............................................ Atractides (Atractides) latipalpis

- Cx-I+II with shorter median suture line (length <90 µm, <40 % of total length of the coxal field), ventral surface of P-2 and -3 finely denticulate (as in Fig. 28 B)........................................... Atractides (Atractides) denticulatus

81 (76) Integument lineated (as in Fig. 21 A); S-1-2 away from each other (distance 35-52 µm, Fig. 31 E)................................................................................................ Atractides (Atractides) anellatus

- Integument striated; S-1-2 various, often closer to each other.................................................. 82

82 (81) I-L-5 enlarged (L/HB ratio <3.9, Figs 31 F-H)............................................................. 83

- I-L-5 slenderer (L/HB ratio> 4.2, Figs 31 K-M)............................................................ 85

83 (82) I-L-5 extremely enlarged, oval disk-shaped (L/HB ratio <2.6, Fig. 31 F).................. Atractides (Atractides) latipes

- I-L-5 slenderer (L/HB ratio> 2.8, Figs 31 G-H)............................................................ 84

84 (83) Major in size (idiosoma L> 600, Cx-I+II mL> 130, P-4 L> 120 µm); P-3 stouter (L/H <2.1); P-4 slenderer (L/H> 4.5) and relatively longer (L ratio P-2/P-4, <0.6); IV-L-5 dL/vL ratio <1.4, dL/HB ratio 3.5-3.7; S-1/-2 closer to each other (distance 25 µm); I-L- 6 in the centre strongly narrowed (Fig. 31 H).............................. Atractides (Atractides) gracilipes

- Minor in size (idiosoma L <600, Cx-I+II mL <130, P-4 L <100 µm); P-3 slenderer (L/H> 2.2); P-4 stouter (L/H <4.0) and relatively shorter (L ratio P-2/P-4> 0.6); I-L-5 dL/vL ratio> 1.4, dL/HB ratio 2.9-3.2; S-1/-2 more away (distance> 35 µm); I-L- 6 in the centre less narrowed (Fig. 31 G)........................................ Atractides (Atractides) giustinii

85 (82) Excretory pore sclerite reduced to a small dot at posterior edge of pore (as in Fig. 28 Q); I-L-4 distal margins forming strongly developed sheaths flanking base of I-L-5; I-L-6 slender and distinctly narrowed in the centre (L 188-190 µm, L/HB ratio> 8.0) (Fig. 31 I)..................................................................... Atractides (Atractides) ruffoi

- Excretory pore sclerite ring complete (Fig. 26 D); I-L-4 distal margins not forming extended sheaths; I-L-6 shorter and stouter (L ca. 160 µm, L/HB ratio <6.0, as in Fig. 26 C)...................................... Atractides (Atractides) tener

86 (75) Dorsal integument papillate (Fig 21 D), papillae visible at least in the interocular region (old specimens, with a thick and leathery integument can lose papillosity); S-1/–2 short (<60 µm), separation about 7 µm (Fig. 31 K)................................................................................................ Atractides (Atractides) walteri

- Dorsal integument without papillae, position and shape of S-1/ -2 various........................................ 87

87 (86) S-1 and -2 very short and similar in shape (L <50 µm, <50 %), with very small separation or placed side by side; I-L-6 stout and weakly curved, maximum H distally (Figs 31 L-M)...................................................... 88

- S-1 and -2 longer (> 50 µm,> 50 % I-L-6), with greater separation; I-L-6 various, often slender and curved (Figs 31 O)... 90

88 (87) I-L-6 slender (ratio L/maximum H> 5.5), S-1 and -2 pointed (as in Fig. 27 A)......... Atractides (Atractides) subterraneus

- I-L-6 stout (ratio L/maximum H <5.0), S-1 and -2 with blunt tips (Figs 31 L-M).................................. 89

89 (88) I-L-5 equal in L to, or only slightly longer than, I-L-6 (L ratio I-L-5/6 about 1.0) (Fig. 31 L).. Atractides (Atractides) clavipes

- I-L-5 distinctly longer than I-L-6 (L ratio I-L-5/6> 1.2) (Fig. 31 M)...................... Atractides (Atractides) graecus

90 (87) Muscle insertions sclerotized as platelets (Fig. 31 N); Vgl-1+2 fused; S-1-2 separation small (5-6) (Fig. 31 O)........... 91

- Muscle insertions unsclerotized; Vgl-1/2 and S-1-2 separation various.......................................... 88

91 (90) Dorsal sclerite platelets large, maximum diameter largest dorsal plates> 100; acetabula diameter> 40 µm................................................................................... Atractides (Atractides) macrolaminatus

- Dorsal sclerite platelets smaller, maximum diameter largest dorsal plates <100, acetabula diameter <40 µm........................................................................................ Atractides (Atractides) loricatus

92 (90) Integument lineated (as in Fig. 21 A)..................................................................... 93

- Integument finely striated or smooth.................................................................... 107

93 (92) I-L-6 relatively short (L ratio I-L-5/6> 1.6 – as in Figs 26 N, P)............................................... 94

- I-L-6 relatively longer (L ratio I-L-5/6 <1.4 – Figs 31 T, V, X, see also Fig. 26 G)................................. 96

94 (93) I-L-6 extremely shortened (L ratio I-L-5/6, 2.0 – as in Fig 26 P), bowed ventrodistal margin of P-2 rugose (Fig. 31 Q)................................................................................... Atractides (Atractides) legeri

- I-L-6 relatively longer (L ratio I-L-5/6 <1.8 – as in Fig. 26 N), bowed ventrodistal margin of P-2 smooth (Fig. 31 P, R)..... .................................................................................................. 95

95 (94) P-4 sword seta halfway between ventral setae (Fig. 31 P); I-L-5 stout (L/HB ratio <4.3), S-1/2 short, S-2 thickened (L S-1/2 <80/70 µm, L/W ratio S-2 <5.0), separation S-1-2 <15 µm; I-L-6 short and stout (L <150 µm, L/HB ratio <6.0)................................................................................... Atractides (Atractides) fonticolus

- P-4 sword seta near distoventral seta (Fig. 31 R); I-L-5 slenderer (L/HB ratio> 4.3), S-1/2 longer, more similar in shape (L S- 1/2,> 90/70 µm, L/W ratio S-2> 7.0), separation S-1-2> 15 µm; I-L-6 longer and slenderer (L> 150 µm, L/HB ratio> 6.5)........................................................................... Atractides (Atractides) pennatus

96 (93) Both P-2 and P-3 ventrally covered by fine denticulation, P-3 with a gentle swelling (Fig. 31 S)................................................................................................... Atractides (Atractides) inflatus

- P-2 and P-3 ventrally not finely denticulate, without swelling................................................. 97

97 (96) S-1/-2 similar in shape and close to each other (separation <15 µm); I-L-6 stout, dorsal and ventral margins equally diverging, ratio L/maximum H (at base of claw furrow) <5.5 (as in Fig. 26 G)................... Atractides (Atractides) protendens

- S-1/-2 various in shape, but separation> 15 µm; I-L-5/6 various, but ratio L/maximum H I-L-6 always> 6.0............ 98

98 (97) S-1 distally thickened, with an abruptly truncated tip (Figs 31 T, V, X).......................................... 99

- S-1 distally narrowed, pointed or only very slightly truncate; I-L-5 longer than I-L-6 (length ratio I-L-5/6> 1.10); I-L-5 slenderer (length/maximum height ratio> 3.3), with relatively long ventral margin (ratio dorsal length/ventral length <1.7), S-1 various in shape (Figs 14 A, 16 A, 20 B).............................................................. 101

99 (98) I-L-5 shorter, with lower H measurements (maximum values: dL 188, HA 60, HB 62, HC 92 µm), but with a relatively long ventral margin (ratio dL/vL 1.8) (Fig. 31 T); palp segment P-2 relatively slender (L/H 1.6); Vgl-1/-2 never fused to each other....................................................................... Atractides (Atractides) allgaier

- I-L-5 longer, with higher H measurements (minimum values: dL 192, HA 60, HB 65, HC 108 µm), ventral margin may be relatively shorter (ratio dL/vL up to 2.3) (Figs 31 V, X), palp segment P-2 stouter (L/H <1.5); Vgl-1/-2 may be fused to each other.............................................................................................. 100

100 (99) Minor in size (e.g., Cx-I+II mL <110, genital plate L/W <105/30, Ac maximum L <30 µm; P-3 L <75, P-4 L <110 µm; I- L-5 L <220, I-L-6 L <200 µm); P-3 stouter (L/H 1.8-2.0) and relatively shorter (L ratio P-3/-4, 0.7-0.8) (Fig. 31 U); I-L-5 with relatively shorter ventral margin (ratio dL/vL 2.0-2.3, Fig. 31 V)......................... Atractides (Atractides) castor

- Major in size (e.g., Cx-I+II mL> 110, genital plate L/W> 110/35, Ac maximum L> 30 µm; P-3 L> 100, P-4 L> 115 µm; I-L- 5 L> 240, I-L-6 L> 210 µm); P-3 slenderer (L/H> 2.0) and relatively longer (L ratio P-3/-4, 0.9-1.0) (Fig. 31 W); I-L-5 with relatively longer ventral margin (ratio dL/vL 1.7-1.9, Fig. 31 X)......................... Atractides (Atractides) pollux

101 (98) Genital field with Ac in subtriangular arrangement, Ac-3 at medial genital plate margin closer to Ac-1 (Fig. 32 B)...... 102

- Genital field with Ac arranged in a weakly curved line, Ac-3 at medial genital plate margin more away from Ac-1 (Figs 11 F, 14 C, 16 B; 32 N). Four species difficult, if at all, to distinguish in the female sex................................ 104

102 (101) Suture Cx-I+II short (L <130 µm) (Fig. 32 A). Two species at present not distinguishable in the female sex................................................................................ Atractides (Atractides) fissus / longisetus

- Suture Cx-I+II longer (L> 130 µm)..................................................................... 103

103 (102) Ac minor in size (maximum diameter generally <45 µm), more elongated (Fig. 32 C)..... Atractides (Atractides) remotus

- Ac major in size (maximum diameter generally> 45 µm), more rounded (Fig. 32 D).... Atractides (Atractides) panniculatus

104 (101) Vgl-1+2 fused; S-1-2 separation> 40 µm, S-1 long and very slender (> 100 µm, ratio L/W> 10.0); I-L-6 slender (ratio length/central height> 10.0) (Figs 32 E, G)............................................................... 105

- Vgl-1/2 separate (Fig. 32 M); S-1-2 separation <40 µm, S-1 shorter and stouter (<100 µm, ratio L/W <10.0); I-L-6 stouter (ratio length/central height <10.0) (Fig. 32 I).............................................................. 106

105 (104) P-4 distoventral seta insertion closer to distal segment edge (18-20, 19-23 % ventral L, Fig. 32 F); I-L-5/-6 with generally lower measurement values (I-L-5 HA 48-53, HB 53-58, HC 85-88, S-1 L 115-118, distance S-1-2, 43-45, I-L-6 L 176-184 µm). S-1 stouter (L/W 11.5-11.8) (Fig. 32 E)............................................. Atractides (Atractides) lunipes

- P-4 distoventral seta insertion more away from distal segment edge (23-28, 26-30 % ventral L, Fig. 32 H); I-L-5/-6 with generally higher measurement values (I-L-5 HA 58-63, HB 60-69, HC 100-118, S-1 L 130-145, distance S-1-2, 48-58, I-L-6 L 188-225 µm). S-1 slenderer (L/W 12.8-16.3) (Fig. 32 G)............................... Atractides (Atractides) corsicus

106 (104) Coxal and genital fields major in dimensions (Cx-I+II mL 120-130; genital plate L/W>120/45, Ac maximum diameter 40-50 µm); pregenital sclerite narrow (Fig. 32 N); P-4 sword seta more proximal (ratio proximal/distal distance <1.2) (Fig. 32 M); I-L-5/-6 longer (L> 230/175)................................................... Atractides (Atractides) cydonius

- Coxal and genital fields minor in dimensions (Cx-I+II mL <120; genital plate L/W>110/40, Ac maximum diameter 20-40 µm); pregenital sclerite various, often broader (Fig. 32 L); P-4 sword seta more distal (ratio proximal/distal distance 1.2-1.5) (Fig. 32 K); I-L-5/-6 shorter (L <230/175). Three species at present not distinguishable in the female sex............................................................................ Atractides (Atractides) fluviatilis , inflatipalpis , valencianus

107 (92) Vgl-1+2 fused (as in Fig. 28 Q - juvenile specimens of species with generally fused Vgl-1+2 may have the platelets still separate, but closely adpressed)........................................................................ 108

- Vgl-1/2 separate (as in Fig. 28 S)....................................................................... 109

108 (107) S-1-2 separation> 12 µm; acetabula more in a weakly curved line, maximum diameter Ac-1 <Ac-3 (Fig. 32 O).................................................................................... Atractides (Atractides) spinipes

- S-1-2 separation <12 µm; acetabula more in an obtuse triangle, maximum diameter Ac-1 ≥ Ac-3 (Fig. 32 P)........................................................................................ Atractides (Atractides) oblongus

109 (107) I-L-6 as long as I-L-5 (L ratio I-L-5/6 1.0); S-1 with a truncated tip, S-1-2 separation> 40 µm; I-L-5 thickened (ratio L/HB <3.2); I-L-6 very slender (ratio L/HB> 12.0)........................................ Atractides (Atractides) distans

- I-L-6 shorter than I-L-5 (L ratio I-L-5/6> 1.1); S-1 pointed or with a fine adaxial denticle; S-1-2 separation in general << 40 µm; I-L-5 slenderer (ratio L/HB> 3.2); I-L-6 stouter (ratio L/HB <11.0)....................................... 110

110 (109) Acetabula arranged in a weakly curved line (posterior margin Ac-1 and anterior margin Ac-3 more rounded and away from each other, separation half diameter Ac-1 or more – Figs 4 A, 32 R)........................................... 111

- Acetabula in triangular arrangement (distance between posterior margin Ac-1 and anterior margin Ac-3 less than half diameter Ac-1 – Fig. 32 T)................................................................................... 112

111 (110) I-L-6 relatively long (L ratio I-L-5/6 <1.5, Fig. 4 B)................................. Atractides (Atractides) asinus

- I-L-6 relatively short (L ratio I-L-5/6> 1.5, as in Fig. 28 L)........................ Atractides (Atractides) gibberipalpis

112 (110) Setae S-1/-2 similar in shape and L, rather close to each other (separation <12 µm); I-L-6 robust (L/HB ratio <5.0) (Figs 27 I, 32 S)............................................................................................ 113

- Setae S-1/-2 more different in shape and L, more away from each other (separation> 12 µm); I-L-6 slenderer (L/HB ratio> 5.5) (Figs 32 U-V)...................................................................................... 114

113 (112) I-L-6 with distally converging dorsal and ventral margins, strongly shortened (L <100 µm, L ratio I-L-5/6> 1.6, Fig. 32 S); L medial suture Cx-I+II <120, maximum Ac diameter <50 µm; Dorsoglandularia very small, with narrow sclerotized borders........................................................................... Atractides (Atractides) vaginalis

- I-L-6 with parallel dorsal and ventral margins, relatively longer (L> 100 µm, L ratio I-L-5/6 <1.5, as in Fig. 27 I); L suture Cx-I+II> 120, maximum Ac diameter> 50 µm; Dorsoglandularia normal in size........... Atractides (Atractides) adnatus

114 (112) Glandularia large (diameter> 30 µm, as in Fig. 30 A); I-L-5 stout (L/HB ratio about 3.0, Fig. 32 U); I-L-5 dorsal and ventral margins distally strongly diverging............................................ Atractides (Atractides) glandulosus

- Glandularia minor in size (diameter <30 µm), I-L-5 slenderer (L/HB ratio> 3.3, Fig. 32 V), dorsal and ventral margins distally less diverging...................................................................................... 115

115 (114) Major in size (medial suture of Cx-I+II> 150 µm; I-L-5 L> 320 µm); P-4 sword seta very strong, near proximoventral seta (Fig. 32 X).................................................................. Atractides (Atractides) robustus

- Minor in size (medial suture of Cx-I+II <150 µm; I-L-5 L <320 µm); P-4 sword seta less strong, halfway between ventral setae (Fig. 32 W)................................................................ Atractides (Atractides) nodipalpis

Fig. 22: A-B, Mixobates incurvatus , ♀. A, coxal field and genital; B, I-L-5-6. C-D, Hygrobates (Rivobates) psammocrenicus ♂; C, palp; D, coxal field partially and genital field. E-F, Hygrobates (Rivobates) helocrenicus ♂; E, coxal field partially and genital field, F palp. G-H, Hygrobates (Rivobates) norvegicus ♂ (I 877); G, coxal field partially and genital field; H, palp. (A-B: Tuzovskij & Gerecke 2003; C-F: Gerecke & Di Sabatino 2013). Scale bars: 100 µm.

Fig. 23: Hygrobates (Hygrobates) palps. A, H. setosus ♀ ( Germany, Brandenburg) ; B, H. arenarius ♀ (I 1105); C, H. calliger ♂ (I 179); D, H. cf. turcicus ♂ (I 441); E, H. corsicus ♂ (I 359); F, H. fluviatilis ♂ ( Germany, D 113) ; G, H. longiporus ♂ ( Germany, D 630) ; H, H. longipalpis ♂ (I 38). Scale bar: 100 µm.

Fig. 24: A-B, Hygrobates (Hygrobates) foreli ; A, ♂ coxal field partially and genital field ( Germany, D BGL 521), B, ♀ genital field ( Germany, Black Forest ). C-D, Hygrobates (Hygrobates) longiporus ; C, ♂ coxal field partially and genital field ( Germany, D 630); D, ♀ genital field (I 465). E-G, Hygrobates (Hygrobates) longipalpis (I 38); E, ♂ genital, F, ♀ genital field; G, IV-L-6. H-I, Hygrobates (Hygrobates) trigonicus genital; H, male; I female. (H-I Pešić in Gerecke et al. 2016). Scale bars: 100 µm .

Fig. 25: A-B, Atractides (Tympanomegapus) acutirostris , ♂; A, gnathosoma with right palp and chelicera in situ; B. I-L-5/6. C, Atractides(Tympanomegapus) pavesii , ♂ I-L-5/6.D-F, Atractides(Polymegapus)polyporus ;D, ♂ venter partially;E, ♀ genital field; F, I-L-5/6. G-H, Atractides (Polymegapus) orghidani ; G, ♂ genital field with excretory pore and Vgl-1+2; H, ♀ genital field. I-L, Atractides(s.str.)subasper ♂;I,genitalfieldwithsurroundingsclerites (excretoryporesmooth);K,I-L-5/6;L,gnathosomawithpalp. (A-K, Gerecke 2003). Scale bars: 100 µm.

Fig. 26: A-B, Atractidesovalis, ♂;A, I-L-5/6; B, ♀ IV-L-5.C-D, Atractidestener; C, ♂ I-L-5/6(segmentsseparated); D, ♀ excretory porewithVgl-1and-2.E-F, Atractideswalteri;E, ♂ genitalfield;F, ♀ genitalfieldandpostgenitalarea.G-H, Atractidesprotendens, ♂;G, I-L-5/6; H,palp.I-K, Atractidespennatus, ♂;I,palp;K, genitalfield(marginalsetaegivenassetalpores).L-N, Atractidesfonticolus, ♂;L,palp;M,genitalfield(marginalsetaegivenassetalpores);N,I-L-5/6.O-Q, Atractideslegeri, ♂;O,genitalfield;P,I-L-5/6;Q,palp. (A-N, Gerecke 2003, O-Q, Gerecke & Di Sabatino 2013). Scale bars: 100 µm.

Fig. 27: A-B, Atractides subterraneus , ♂; A, I-L-5/6; B, genital field and postgenital area. C-D, Atractides spinipes , ♂; C, palp; D, venter. E-F, Atractides oblongus ♂; E, genital field; F, ♀ I-L-5/6. G, Atractides asinus , ♂, genital field. H-I, Atractides adnatus , ♂; H, genital field (setae given as setal pores); I, I-L-5/6. K, Atractides vaginalis , ♂, I-L-5/6. L-M, Atractides brendle , ♂; L, genital field and postgenital area; M, palp. N-P, Atractides pumilus , ♂; N, genital field and postgenital area; O, palp; P, I-L-5/6. Q, Atractides denticulatus ♂ dorsum partially. ( Gerecke 2003). Scale bars: 100 µm.

Fig. 28: A-B, Atractides denticulatus , ♂; A, Cx-I+II partially; B, palp. C-D, Atractides latipalpis , ♂; C, Cx-I+II partially; D, palp. E, Atractides clavipes ♂, I-L-5/6. F-G, Atractides loricatus , ♂, F, I-L-5/6; G, genital field. H- I, Atractides macrolaminatus , ♂; H, I-L-5/6; I, genital field (setae partly given as setal pores); K-M, Atractides gibberipalpis , ♂; K, palp; L, I-L-5/6; M, genital field. N-P, Atractides inflatus , ♂; N, palp; O, I-L-5/6; P, genital field. Q-R, Atractides ruffoi ♂; Q, genital field and postgenital area; R, palp. S-U, Atractides anellatus ♂; S, genital field and postgenital area; T, I-L-5/6; U, palp. V-W, Atractides latipes ♂; V, palp; W, I-L-5/6. Scale bars: 100 µm. (A-P, V-W, Gerecke 2003; Q-R, Gerecke & Di Sabatino 2013).

Fig.29: A-B, Atractides gracilipes , ♂;A,I-L-5/6; B,palp.C-D, Atractides giustinii , ♂;C, I-L-5/6;D, palp.E-F, Atractides nodipalpis ♂; E, palp; F, IV-L-4-5.G-I, Atractides robustus , ♂; G, genital field (setae given as setal pores); H, palp; I, IV-L-4-5.K-M, Atractides fissus , ♂; K, palp; L, I-L-5/6; M, genital field. N-O, Atractides remotus , ♂; N, palp; O, coxal field (partial view) and genital field (setae given as setal pores).P-Q, Atractides valencianus ♂;P, palp; Q, genital field (marginal setae given as setal pores).R, Atractides inflatipalpis ♂, genital field (marginal setae given as setal pores). S, Atractides corsicus , ♂, palp. T, Atractides lunipes ♂, palp. (A-B, S, Gerecke 2014; C-D, Gerecke & Di Sabatino 2013; E-R, Gerecke 2003). Scale bars: 100 µm.

Fig. 30: A-B, Atractides glandulosus , ♂; A, venter, partially; B, palp. C-D, Atractides distans , ♂; C, palp; D, I-L-5/6. E-F, Atractides allgaier ♂; E, IV-L-4-5; F, palp. G-H, Atractides castor , ♂; G, palp; H, IV-L-4- 5. I-K, Atractides longisetus , ♂; I, palp; K, genital field (setae given as setal pores). L-N, Atractides panniculatus , ♂; L, palp; M, I-L-5/6; N, genital field (setae given as setal pores). O, Atractides cydonius ♂, venter partial- ly. P-Q, Atractides pollux ♂; P, genital field; Q, I-L-5/6. R-S, Atractides fluviatilis , ♂; R, genital field; S, I-L-5/6. (A-B, Smit et al. 2015; C-H, L-N, Gerecke 2003; I-K, Pešić 2002). Scale bars: 100 µm.

Fig. 31: A-C Atractides subasper , ♀; A, dorsum, partially; B, genital field; C, chelicera. D, Atractides latipalpis , ♂; I-L-5/6. E, Atractides anellatus ♀, I-L-5/6. F, Atractides latipes , ♀, I-L-5/6. G, Atractides giustinii , ♀, I-L-5/6. H, Atractides gracilipes , ♀, I-L-5/6. I, Atractides ruffoi , ♂, I-L-4-6. K, Atractides walteri , ♀, I-L-5/6. L, Atractides clavipes , ♀, I-L-5/6. M, Atractides graecus , ♀, I-L-5/6. N, Atractides loricatus , ♀, dorsum partially. O, Atractides macrolaminatus ♀, I-L-5/6. P, Atractides fonticolus ♀, palp. Q, Atractides legeri ♀, palp. R, Atractides pennatus ♀, palp (without P-1). S, Atractides inflatus , ♀, palp. T, Atractides allgaier ♀, I-L-5/6. U-V, Atractides castor ♀; U, palp; V, I-L-5/6. W-X, Atractides pollux ♀. W, palp; X, I-L-5/6. (A-D, F, K-L, N-P, R-T, Gerecke 2003; G, I, Q, Gerecke & Di Sabatino 2013; H, Gerecke 2014). Scale bars: 100 µm.

Fig. 32: A-B Atractides fissus , ♀; A, coxal field, partially; B, genital field. C, Atractides remotus ♀, genital field. D, Atractides panniculatus ♀, genital field. E-F, Atractides lunipes , ♀; E, I-L-5/6; F, palp. G-H, Atractides corsicus ♀; G, I-L- 5/6; H, palp. I-L, Atractides inflatipalpis , ♀; I, I-L-5/6; K, palp; L, genital field; M-N, Atractides cydonius , ♀; M, palp; N, genital field and postgenital area. O, Atractides spinipes ♀, genital field. P, Atractides oblongus ♀, genital field. Q, Atractides distans ♀, I-L-5/6. R, Atractides gibberipalpis ♀, genital field. S-T, Atractides vaginalis , ♀; S, I-L-5/6; T, genital field. U, Atractides glandulosus ♀, I-L-5/6. V-W, Atractides nodipalpis ♀; V, I-L-5/6; W, palp. X, Atractides robustus ♀, palp. (A-D, F, K-L, N-P, R-T, Gerecke 2003; G, I, Q, Gerecke & Di Sabatino 2013; H, Gerecke 2014). Scale bars: 100 µm.