Eukoenenia gallii

Christian, Erhard, 2009, A new soil-dwelling palpigrade species from Northern Italy (Palpigradi: Eukoeneniidae), Zootaxa 2136, pp. 59-68 : 60-65

Eukoenenia gallii , species nova

Material examined. Holotype female: Italy, Liguria, Savona Province, Bergeggi (44°15′27″N, 8°26′35″E); 5 July 2007, leg. M. Capurro, D. Duradoni & L. Galli. Seven paratypes: 1 male (6 March 2007), 3 females (5 July 2007), 1 female (13 June 2007), 1 juvenile male (30 July 2007) and 1 juvenile female (30 July 2007). One larva (5 July 2007) is not included in the type series. All specimens with same locality and collectors as the holotype.

Deposition. Museum of Natural History, Vienna, Austria, Arachnological Collection. Acquisition numbers 21.700 (holotype), 21.701–21.707 (paratypes).

Etymology. I dedicate the new species to Dr Loris Galli (Università degli Studi di Genova), who provided the specimens and ecological information.

Diagnosis. Adult specimens small (body length <1 mm) and slender, with no obvious narrowing behind segment VIII of opisthosoma; with a 14-jointed flagellum of little more than half the body length; each finger of chelicera with 8 teeth; 3 blades in lateral organs; 5 (4) deuto-tritosternal setae; 3, 3, and 2 setae on coxae II–IV thickened; setae r and grt on I bta3 longer than the segment; IV bta just 2.68 times longer than wide, with setae grt, r and 2 esd, the stiff seta r being as long as the segment; genital region of adult female with 11+11 setae on first lobe (including 2+2 sternal and 4+4 apical), and 3+3 on second lobe; genital region of adult male with 11+11 setae (including 2+2 sternal) and 2+2 fusules on first lobe, 4+4 setae on the second and 4+4 setae on the third lobe; first genital lobe of male without apical projections; tergite II with t, t1, t3 and s, tergites III–VI additionally with t2; sternite VI with a1, a2, s1 and s2, sternites IV and V additionally with a3; segment XI with 10 setae; pubescence of segments IX–XI reduced to a circular fringe.

Description of the adult stages. Morphometric data are given in Tab. 1.

General appearance: Body length without flagellum 890–980 μm (holotype: 980). Body slender; opisthosoma lanceolate without sudden narrowing between segments VIII and IX, maximum width VIII/IX = 1.14–1.30 ( Figs. 1 , 16). Most of the body surface densely pubescent, except segments IX–XI. Flagellum little more than half the body length, conspicuously wide at the base.

Prosoma: Frontal organ 19–21 μm long, the two lanceolate branches (12–13 μm) show pointed tips and irregular reticulation ( Fig. 2 ). The three elements of the lateral organ (12–14 μm) are similar to the frontal organ branches, but more slender and more finely reticulated ( Fig. 3 ). Propeltidium with 10+10 setae, the postero-lateral setae longer than the central ones (20:13 μm). Setae t1, t2 and t3 of the metapeltidium 25, 43 and 29 μm long ( Fig. 4 ). Labrum with the usual cuticular pattern and 5+5 short setae. Deuto-tritosternum with 5 setae (4 in the male and one female), forming an obtuse angle ( Fig. 5 ). First joint of chelicera with a basal group of 6 setae (setae 4 and 6 thickened), in the distal half with 3 aligned setae of which the last is three times the length of the others, and 1 apical seta. Hand of chelicera with 1 ventral and 6 dorsal setae. Fingers of chelicera with 8 teeth each, fixed finger additionally with a basal denticle ( Fig. 6 ). Pedipalp with 2 forked setae (as in Fig. 7 ) near tip of tarsus 3, the apical one twice as long as the other. Coxal chaetotaxy: pedipalp coxa with 17–18 setae, one or two of the basal macrochaetae with a denticle at foot of shaft ( Fig. 8 ); coxa I with 14–15 setae, the longest one reaching 70% of coxa length; coxa II with 3 thick ( Fig. 9 ) and 9–10 normal setae; coxa III with 3 thick and 8–9 normal setae; coxa IV with 2 thick and eight normal setae. Apically, the thick coxal setae bear an inclined hair-like appendage (slightly stronger than adjacent pinnation), thus resembling setae such as esd on IV bta. Leg I ( Fig. 10 ): bta3 just slightly longer than wide; r somewhat longer than grt, both setae longer than the segment; 7 trichobothria in usual arrangement; 8 forked setae: 5 on ta3 (middle seta of apical group of three is twice length of others), and 1 on ta2, bta2 and bta1 each. Leg IV ( Fig. 11 ): bta short, 2.68 times longer than wide, with 4 setae (grt, r and 2 esd); r> esd> grt; stiff seta r as long as segment, inserted clearly below middle of segment. Unlike the completely pubescent legs I–III, leg IV shows glabrous areas on the ventral surface of the proximal joints, including the tibia.

Opisthosoma: The chaetotaxy of the opisthosoma is given in Tab. 2. Tergite II with t, t1, t3 and s, tergites III–VI additionally with t2. The unpaired median seta t is inserted caudal to the line t1–t1. Tergal setae s are more slender and lack a typical basal ring (Fig. 12). Sternite VI with a1, a2, s1 and s2, sternites IV and V additionally with a3 (Fig. 13). Sternal setae s1 and s2 with normal basal ring and a slender and evenly tapering shaft. Setae of the a-groups considerably thicker and subcylindrical, setae a1 slightly longer than the distance between them (19:18, 20:16 and 21:18 μm on the sternites IV–VI of holotype). Pair of sternal pores situated caudal to line a1–a1, most markedly so on sternite VI. Segments VII–XI with rich chaetotaxy and showing some variation in the number of setae, but segment XI with 10 setae throughout: 17–18, 15–16, 12–14, 12 (10 in one female), and 10. The longest setae of XI are shorter than the segment length (about 50:70). The pubescence of segments IX–XI is largely reduced: the surface is glabrous except for a small posteroventral area on segment IX and a circular single-row fringe of somewhat longer (max. 6 μm) hair-like structures. The fringe runs along the connecting line of the setal bases on IX and X, and caudal to this line on XI (Figs. 14, 15).

The flagellum is connected to segment XI via an intermediate ring with 2 short dorsal and 2 longer and thicker ventral setae (Figs. 14, 15); the part of the flagellum distal of the intermediate ring (present only in the holotype) is composed of 14 articles (Fig. 16), short (506 μm = 52% of body length), and evenly tapering from the wide basal articles; article 2 wider than long; articles 1–14 bear 10, 10, 9, 8, 8, 8, 8, 8, 8, 8, 7, 7, 7, 6 (+ 1 short apical) setae; the spikes of the apical crown (Fig. 17) are long on articles 1, 2, 3, 5, 7, 9, and short on the others.

Female genital area ( Fig. 18 ): First lobe shaped as an obtuse-angled triangle without apical indentation; with uniform pubescence and 11+11 setae: 2+2 sternal setae (st1, st2) followed, on the lobe proper, by 3+3, 1+1, 1+1 and 4+4; of the 4 apical setae, a3 is somewhat longer (12 μm) than the others. Two halves of second lobe with 3 setae each. A nearly linear group of 3 gland orifices (2 μm in diameter) lies on either side on the interior surface of the first lobe, an L-shaped group of 4 orifices on either half of the second lobe. The optical section of the spermatheca is roundish, 13–16 μm in diameter.

FIGURES 12–17. Eukoenenia gallii , opisthosoma. 12, chaetotaxy and pubescence of tergite V (plane of symmetry indicated by black line); t–s = 100 μm. 13, chaetotaxy and pubescence of sternite IV (plane of symmetry indicated by black line); a1–s2 = 88 μm. 14, lateral view of segments IX–XI and intermediate ring of the flagellum (juvenile female), showing fringes of hair-like cuticular structures and lack of pubescence (except a ventral area on sternite IX). 15, dorsal view of segment XI and the intermediate ring, showing fringes and lack of pubescence. 16, tip of opisthosoma and flagellum (holotype); length of flagellum 506 μm. 17, articles 1–5 of flagellum (same specimen).

Male genital area ( Figs. 19– 22 ): Two halves of first lobe not gaping, the lobe appears as a single element, wider than long; common distal margin of the two uniformly pubescent halves is straight, not extended into a pair of flaps, with a faint medial indentation; with 11+11 setae (one asymmetrically missing in the paratype): 2+2 sternal setae (st1, st2) followed, on the lobe proper, by 4+3 (1 missing), 2+2, and 3+3; the latter are inserted on the distal margin, along with 2+2 fusules (f1 = 21 μm, f2 = 26 μm). Two flaps of second lobe each with a pointed tip and 4 setae (a, b, c, d). Two flaps of the third lobe bifurcate with pointed tips and 4 setae each (w, x, y, z).

Description of immature stages. Morphometric data are given in Table 1.

Juvenile female and juvenile male (larves B and C sensu Condé 1996): Lateral organ with two blades. Labrum with 4+4 setae. Deuto-tritosternum with 3 setae. Fingers of chelicera with 7 teeth. Chaetotaxy of propeltidium and metapeltidium complete. Coxae II–IV with 3, 3, and 1 thickened setae. Trichobothria as in adult. No forked seta on bta 1. IV bta with complete setation. Tergites II–VI with 2+2 setae (t and t3 missing) between the setae s. Sternites IV–VI as in adult, except for absence of setae s2; gland orifices present. Segments VII–XI with 11, 12, 9, 9 and 8 setae. Primordia of genital lobes developed on segments II and III. Segment II shows 1+1 (st1), segment III 2 +2 sternal setae (st2, st3) in both sexes. Indented anterior lobe of the juvenile female ( Fig. 23 ) with 3+3 long and 2+2 minute subapical setae; posterior lobe with 1+1 long setae. Juvenile male ( Fig. 24 ) bears two rows of 2+2 and 3+3 long setae on deeply indented anterior lobe; 2+1 minute setae (1 missing asymmetrically), similar to those of the juvenile female, on a structure that might develop into the middle lobe; and 1+1 long setae on posterior lobe.

Larva (larve A sensu Condé 1996), sex indeterminable: Lateral organ with one blade. Labrum with 3+3 setae. Deuto-tritosternum with 1 seta. Fingers of chelicera with 7 teeth. Chaetotaxy of propeltidium and metapeltidium complete. Coxae II–IV with 3, 3, and 0 thickened setae. Five trichobothria, those of bta1 missing. No forked seta on bta 1. IV bta with 2 setae (grt and 1 esd missing). Tergites II–VI with 2+2 setae (t and t3 missing) between the setae s. On sternites IV–VI, only setae a1 and a2 are developed, setae s missing; no paramedian gland orifices discerned. Segments VII–XI with 6, 8, 8, 8, and 8 setae. Genital region ( Fig. 25 ) shows no primordia of lobes; segment II bears 2+2 sternal setae (st1, st2), segment III 3 +3(st1, st2, st3). One pair of segment II setae might shift to the first lobe in the subsequent stage. Similarly, st1 of segment III might develop into the single pair and finally into the external pair of setae on the caudal genital lobe of the successive stages.

TABLE 1. Morphometric data of the eight type specimens and one larva of Eukoenenia gallii . Measurements are presented in micrometers (whole numbers), indices are given as decimals. L = body length, B = length of propeltidium, P = pedipalp, I = leg I, IV = leg IV, ti = tibia, bta = basitarsus, ta = tarsus, a = width of IV bta at the insertion of seta r, er = distance between the basis of IV bta and the insertion of seta r. Setae typeset in italics. m = male, f = female, juv. = juvenile, * = holotype.

Character m f 1* f 2 f 3 f 4 f 5 m juv. f juv. larva L 970 980 890 950 950 960 840 800 690 B 221 218 218 225 220 218 167 168 160 P ti 70 70 71 71 74 70 57 54 43 P bta 1 26 27 23 26 25 21 21 18 18 P bta 2 28 26 24 26 26 26 21 20 17 P ta 1 16 15 14 13 14 15 13 12 10 P ta 2 21 20 20 19 18 21 20 17 16 P ta3 36 35 34 37 38 36 31 29 28 I ti 69 67 70 68 67 70 55 51 40 I bta1+2 57 57 55 59 57 57 47 44 36 I bta 3 27 27 28 27 26 25 24 22 18 I bta 4 30 26 29 30 27 26 27 24 20 I ta 1 15 15 15 15 14 15 14 12 12 I ta 2 21 21 22 22 20 20 19 17 17 I ta3 67 66 63 66 65 67 57 56 52 I bta3 grt 35 32 30 35 34 31 28 27 23 I bta3 r 35 35 32 36 37 34 30 29 25 IV ti 72 71 71 71 70 70 56 55 48 IV bta 47 45 46 47 45 47 40 37 32 IV ta 1 32 30 29 28 32 31 26 25 22 IV ta2 34 41 33 36 37 33 33 32 31 a 17 17 16 20 19 16 17 17 16 er 16 15 16 15 16 17 15 15 12 IV bta grt 27 26 22 23 25 26 23 22 --

IV bta esd 34 33 31 33 35 33 29 30 23 IV bta r 44 45 42 43 44 42 35 35 31 IV bta / r 1.07 1.00 1.10 1.09 1.02 1.12 1.14 1.06 1.03 IV bta / er 2.94 3.00 2.88 3.13 2.81 2.76 2.67 2.47 2.67 IV bta / ti 0.65 0.63 0.65 0.66 0.64 0.67 0.71 0.67 0.67 B / IV bta 4.70 4.84 4.74 4.79 4.89 4.64 4.18 4.54 5.00

TABLE 2. Eukoenenia gallii n. sp. Opisthosomal chaetotaxy of adult (5 f, 1 m) and immature (1 f juv., 1 m

juv., 1 larva) specimens. * = missing in juvenile female and male; framed: missing in the larva.

Adult Immature

Tergite Sternite Tergite Sternite II t t 1 t 3 s st1 st 2 t 1 t 2 s st1 st2*

III t t 1 t 2 t 3 s st2 st 3 t 1 t 2 s st1* st2 st 3 IV t t 1 t 2 t 3 s a1 a2 a3 s1 s 2 t 1 t 2 s a1 a2 a3 s 1 V t t 1 t 2 t 3 s a1 a2 a3 s1 s 2 t 1 t 2 s a1 a2 a3 s 1 VI t t 1 t 2 t 3 s a1 a2 s1 s 2 t 1 t 2 s a1 a2 s 1 VII 17 (4 f, 1 m), 18 (1 f) juv 11 larv 6

VIII 15 (2 f), 16 (3 f, 1 m) juv 12 larv 8

IX 12 (3 f), 13 (1 f, 1 m), 14 (1 f) juv 9 larv 8

X 10 (1 f), 12 (4 f, 1 m) juv 9 larv 8

XI 10 (5 f, 1 m) juv 8 larv 8

Figures

FIGURES 1 – 9. Eukoenenia gallii. 1, habitus of paratype female; body length 960 μm. 2, frontal organ; length of blades 12 μm. 3, lateral organ; length of blades 13 μm. 4, propeltidium (with setal bases circled) and metapeltidium. 5, anterior part of prosoma with deuto-tritosternum. 6, hand and fingers of chelicera; total length 135 μm. 7, forked seta on the second basitarsus of leg I; length 14 μm. 8, proximal setae of pedipalp; arrow points to a basal denticle. 9, normal and thickened setae on coxa of leg II.

FIGURES 10 – 11. Eukoenenia gallii. 10, tip of leg I, with setae grt and r on the third basitarsus. 11, tip of leg IV, with setae grt, r and 2 esd on the basitarsus.

FIGURES 18 – 25. Eukoenenia gallii, genital region. 18, adult female. 19, adult male. 20 first genital lobe of male. 21 second genital lobe of male. 22 third genital lobe of male, scale bar (figs 20 – 22) 20 μm. 23, juvenile female. 24, juvenile male. 25, setation of sternites II and III of larva.