Eukoenenia roscia Christian, 2014

Christian, Erhard, Isaia, Marco, Paschetta, Mauro & Bruckner, Alexander, 2014, Differentiation among cave populations of the Eukoenenia spelaea species-complex (Arachnida: Palpigradi) in the southwestern Alps, Zootaxa 3794 (1), pp. 52-86 : 75-79

Eukoenenia roscia Christian , species nova

( Figures 2 , 5 F , 6 , 9 , 11 , 12 F , 13 F , 14 F , 23–25 )

Material examined. Holotype female: Italy, Piemonte, Province of Cueno, Rossana, Grotta delle Fornaci o di Rossana (44°32′02″N, 07°25′52″E, 554 m a.s.l.); 15 August 2012, leg. E. Lana. Two paratypes: 1 male, 1 female; same locality; 16 February 2012, leg. M. Morando & E. Lana. Additional material: 1 female; same locality; 3 March 2013, leg. E. Lana.

Deposition. Museum of Natural History , Vienna, Austria, Arachnological Collection. Acquisition numbers 21.881 (holotype), 21.882 (paratype male), 21.883 (paratype female) .

Etymology. The Comune di Rossana derives its name from the Roman gens Roscia. The specific epithet roscia is used as a noun in apposition.

Diagnosis. A species with all characters of the E. spelaea complex, as described above. Body length over 1800 µm; each finger of chelicera with 8 teeth; lateral organ with 5–7 blades; 6 (5) deuto-tritosternal setae; articles I bta3 and IV bta slender; forked seta present on I bta4; proximal forked seta of I ta3 about same length as rod seta; males with more than 3+3 setae a on the sternites IV–VI (females often have 3+3); segment XI of opisthosoma with 10 setae.

Description. Morphometric data are given in Table 1 under ♀ 01, ♀ 02 (holotype) and ♂ 03.

General appearance. Body length without flagellum 1830–1960 µm. Shape and pubescence of trunk as in other members of E. spelaea complex. Trunk of living individuals orange reddish, particularly opisthosoma.

Prosoma. Frontal organ 39–42 µm long; the two lanceolate, reticulated branches have pointed tips. The 5–7 blades of the lateral organ ( Fig. 6 ) are 42–44 µm long, pointed-lanceolate and finely reticulated ( Fig. 5 F ). Propeltidium with 10+10 setae, the shortest (30–31 µm) in central position, the longest (50–54 µm) laterally in posterior half. Setae t 1, t 2 and t 3 of metapeltidium 76–82, 127–135 and 84–100 µm long, respectively. Labrum with usual cuticular pattern and 5+5 short setae. Deuto-tritosternum with 6 (3 specimens) or 5 setae (1 specimen) of 43–50 µm. First article of chelicera with a proximal longitudinal series of 6 setae (p 4 and p 6 thick; p 4 sparsely barbed, p 6 partly serrate), a distal series of 3 aligned setae (d 3 strong, smooth near base, sparsely barbed in middle, closely barbed near tip, 2.5× length of d 1 and d 2) and 1 apical seta. Hand of chelicera with 7 setae: 4 in a dorsal line, 1 ventral, 1 close to articulation of movable finger, and 1 on a tubercle of the fixed finger. Fingers with 8 teeth each. Coxal chaetotaxy as described above for spelaea group. Near the tip of the pedipalp is a curved seta that looks like a long, strongly asymmetric forked seta; one typical fs is inserted somewhat behind. Leg I with 7 trichobothria in usual arrangement and a total of 8 forked setae. Ta3 of leg I has 4 fs in distal half, arranged as 1+1+2: fs 1 about same length as nearby rs; fs 2 inserted closer to cs in the three females, but closer to m in the single male. I bta3 very slender, length/width 3.23–3.52; compared to the similarly shaped I bta3 of E. strinatii , seta r of the new species is longer and more proximally inserted, at 42–46% of article length from base ( Fig. 12 F vs. B, and Fig. 24 , I bta3/ r and I bta3/d r). I bta4 bears, close to the insertion of the trichobothrium, one fs ( Fig. 11 ; this forked seta is also present in E. spelaea from Partigiano and Griffen). IV bta slender, length/width 5.32–6.54, with 4 setae, these exhibiting some variation in length and insertion distance, but consistently r <grt <esd; tip of r does not project beyond distal end of the article ( Fig. 13 F ).

Opisthosoma. Anterior tergites with t 1, t 3, s on segment II, and usually t 1, t 2, t 3, s on III–VI. Seta t 2 absent in one female symmetrically on segment III and on the right side of IV. Sternites IV–VI each with a pair of submedian circular structures and lateral setae s 1 and s 2; females can have more than 3+3 submedian setae a at least on segment IV, the male has (4–)5 setae a on these sternites ( Figs 6 & 14 F ). The setation of the terminal segments ( Table 3 ) is partly variable, but on segment XI all specimens (N = 4) have 10 setae about as long as the segment. The 2 dorsal setae on the intermediate ring of the flagellum are as long as the 2 ventral ones. Not even fragments of the flagellum are preserved.

Female genital area. First lobe has an evenly rounded or gently truncate apex, uniform pubescence and 7+3 setae on each side. The 7 setae on ventral area of lobe arranged in 4 transversal rows, 2–3–1–1 from base to tip (as in Fig. 16 , left). The innermost of the 3 apical setae measures 23–28 µm; it is always slightly shorter than the others. Each half of second lobe possesses 3 setae. The total formula is thus 7+3/3.

Male genital area. Shape and phaneres of genital area as in E. strinatii (compare Figs 18 & 19 ), chaetotactic formula 2+9+2f/3/4. Base of deeply split first lobe lies behind a row of 2+2 sternal setae. The roundish lateral extension of each half carries 3 setae, the oblong submedian extension has 6 setae and, on the apical bend, 2 fusules (f 1, f 2) that are about the same length as the neighbouring setae. No sockets visible at roots of fusules. Second lobe furcates in its distal half into two triangular, pointed flaps, each of which carries 3 setae (a, b, c) near its base, with b being more proximally inserted than a. On the third lobe the two flaps branch off closer to the base and converge apically. They are broadly triangular, end in two parallel needles and have 4 setae: w, z, y, x (from base to tip).

Figures

FIGURE 2. Study area and cave populations of palpigrades. B = Bossea, C = Caudano, F = Fornaci, L = Litrôn, M = Monfieis, P = Partigiano. Not sampled for this study: CL = Grotte de la Clue and SV = Grotte de Saint-Vincent-de-Mélan. Type localities and new species are highlighted. Base map © 2012 Google, Cne/Spot Image, Tele Atlas.

FIGURE 5. Lateral organ. B: Bossea ♀ (E. strinatii), L: Litrôn ♂ (E. bonadonai), C: Caudano ♀ (E. bonadonai), M: Monfieis ♀ (E. lanai sp. n.), F: Fornaci ♀ (E. roscia sp. n.). Images enlarged to same size to facilitate comparison. The blades are 40–50 µm long.

FIGURE 6. Lateral organ and opisthosomal chaetotaxy of Eukoenenia specimens from the six Italian cave populations. The right column shows the values for published specimens and the two comparative females (Ardovská, Griffen). The top line of each box gives the number of blades in the lateral organs (one digit, if symmetric), the three lines below give the numbers of setae a on sternites IV–VI (left ǀ right).

FIGURE 9. Above: thick setae (arrows) on the coxae of the legs II–IV of a E. roscia sp. n. ♀ from Fornaci. Below: coxa of leg III of a E. strinatii ♀ from Bossea; the four aligned thick setae and some ordinary setae are in focus. Scale bars: 50 µm.

FIGURE 11. Chaetotaxy of I bta4 of the Fornaci ♂ (E. roscia sp. n.): 5 macrosetae, 1 forked seta, 1 trichobothrium. Scale bar: 20 µm.

FIGURE 12. Third and fourth basitarsus of leg I. For better comparison of the shape, the third basitarsi are all enlarged to the same length. B: Bossea ♂ (E. strinatii), C: Caudano ♂ (E. bonadonai), L: Litrôn ♂ (E. bonadonai), M: Monfieis ♂ (E. lanai sp. n.), P: Partigiano ♀ (E. spelaea), F: Fornaci ♀ (E. roscia sp. n.), A: Ardovská ♀ (E. spelaea), G: Griffen ♀ (E. spelaea).

FIGURE 13. Basitarsus of leg IV. The basitarsi are all enlarged to the same length. Specimens as in Fig. 12.

FIGURE 14. Setae a on sternite VI. B: Bossea ♂ (E. strinatii), C: Caudano ♂ (E. bonadonai), L: Litrôn ♂ (E. bonadonai), M: Monfieis ♂ (E. lanai sp. n.), P: Partigiano ♀ (E. spelaea), F: Fornaci ♂ (E. roscia sp. n.), A: Ardovská ♀ (E. spelaea with one seta a absent as an individual aberration), G: Griffen ♀ (E. spelaea). Midline = scale bar: 50 µm.

FIGURE 16. Female genitalia. Intrapopulation variability of lobe chaetotaxy. One of the Caudano females (E. bonadonai) shown has the common number of 7+7 setae on the ventral area of the first lobe, the other female has 9+9. Scale bar: 50 µm.

FIGURE 18. Male genitalia in lateral view. The three genital lobes are nearly uncompressed. E. strinatii ♂ from Bossea. Scale bar: 50 µm.

FIGURE 19. Male genitalia in ventral view. One side of the first lobe (left), tips of the second lobe (above), and of the third lobe (below) of a E. strinatii ♂ from Bossea. Fusules are marked f1, f2. Scale bar: 50 µm.

FIGURE 23. Principal component analysis based on measurements of 29 Eukoenenia individuals (females and males) from six Italian and two comparative populations (A, G). G = Griffen, A = Ardovská, P = Partigiano, C = Caudano, L = Litrôn, F = Fornaci, B = Bossea, M = Monfieis.

FIGURE 24. Graphic representation of the measurements used for the morphometric analysis (data from Tables 1 & 2, in µm). Only females included. Initials of caves as in Fig. 23 (non-Italian comparative populations in brackets).

FIGURE 25. Graphic representation of the values of commonly used morphological indices (data from Tables 1 & 2). Only females included. Initials of caves as in Fig. 23.