Siro crassus, Novak, Tone & Giribet, Gonzalo, 2006

Novak, Tone & Giribet, Gonzalo, 2006, A new species of Cyphophthalmi (Arachnida, Opiliones, Sironidae) from Eastern Slovenia, Zootaxa 1330, pp. 27-42 : 29-36

Siro crassus sp. n.

Figs 1–32

Holotype: ♂ from Velika Slavšina (46.533263°N, 15.960520°E; 290 m altitude), Slovenia, UTM code WM75 ( Fig. 1 ), 09.VI.1984, wet deep beech litter sieving, L. Slana, M. Ferenc & T. Novak leg. (TN 310/2002). Paratypes: ibid., 2 ♂, 1 Ψ (TN 310/2002); ibid., 13.X.2005, deep solid humic soil near beech roots, L. Slana Novak & T. Novak leg.: 2 Ψ (TN 139/2005); ibid., 15.X.2005: 1 ♂, 1 Ψ (TN 140/2005); Šega near Makole (46.300144°N, 15.659478°E; 350 m altitude), UTM: WM53, 09.IV.1983, forest floor, L. Slana, M. Štangelj & T. Novak leg.: 1 ♂ (LS 362/1985, rev. TN 2006). Holotype, 2 ♂ paratypes and 2 Ψ paratypes deposited in the Prirodoslovni muzej Slovenije, Ljubljana, Slovenia; ex collection T. Novak & L. Slana Novak (TN 310/2002; TN 139/2005). 1 ♂ ( MCZ 68552, ex TN 140/2005) and 1 Ψ ( MCZ 68553, ex TN 140/2005) paratypes mounted for SEM and used for DNA analysis ( MCZ DNA 101802, ex TN 140/2005) deposited in the Museum of Comparative Zoology, Harvard University (Cambridge, Massachusetts, USA); 1 ♂ (LS 362/1985) and 1 Ψ (TN 139/2005) in the Naturhistorisches Museum Wien ( Austria).

Etymology: From Latin adjective crassus , meaning solid or thick. The species epithet refers to the body shape of the new species, which is relatively large and robust for a member of the genus Siro .

Diagnosis: Relatively large, 2.2–2.6 mm in length ( Figs 2–5 ), long-legged and robust Siro species with elongated leg IV so that patella IV surpasses the posterior end of the opisthosoma ( Figs 2 , 3 ). Corona analis of male broad ( Figs 2 b, 4, 8); corona analis of female protruding, with a concentration of lateral setae on the sides ( Figs 3 b, 5, 9, 11). Anal plate of male and female with a longitudinal median keel ( Figs 8–9 ); tergite VIII of male with three anal gland pores ( Fig. 10 ). Metatarsi of legs I–IV completely ornamented with a tuberculate surface (sensu Murphree 1988) ( Figs 18, 20, 22, 24, 27 ).

Description: Total length of male holotype (in mm) (female paratype TN 310/ 2002 in parentheses) 2.29 (2.48); largest body width in prosoma behind ozophores: 1.32 (1.39); width across ozophores 1.05 (1.15); body length/width ratio 1.73 (1.78). Body orangebrown (dark to strong brown according to the Munsell’s Color Charts (2000): 7.5YR 3/3–7.5YR 4/6) in life and in ethanol ( Figs 2 , 3 ). Anterior margin of dorsal scutum slightly concave; prosomal region almost semicircular. Eyes absent. Ozophores conical, of type II (sensu Juberthie 1970), with subterminal ozopore1 and with spiral ornamentation of ozophore (sensu de Bivort & Giribet 2004). Transverse prosomal sulcus V-like; transverse opisthosomal sulci inconspicuous ( Figs 2 a, 3a). Dorsal scutum convex; maximum width in prosomal area behind ozophores. Opisthosomal part of dorsal shield slightly wider than ventral side.

Ventral prosomal complex of males ( Figs 2 b, 4, 6) with coxae I, II and IV meeting in the midline, the later for a distance longer than the gonostome length; coxae II and IV with broad endites; coxae III not meeting in the midline; coxal pores clearly visible between coxae III and IV. Projections of coxae IV endite present in the anterior portion of the gonostome wall. Coxae II free, not fused to coxae III–IV. Ventral prosomal complex of female ( Figs 3 b, 5, 7) only with coxae I and II meeting along the midline; coxae II with large endites; coxal pores not observed. Male gonostome sub-semicircular, with slightly concave posterior margin, wider than long (0.152 x 0.109 mm), and delimited laterally and antero-laterally by the elevated endites of coxae IV ( Fig. 6 ). Female gonostome semicircular anteriorly, wider than long (0.183 x 0.116 mm) ( Fig. 7 ). Gonostome of female forming a tube angled at about 45° from the body surface, as in Stylocellus globosus Schwendinger & Giribet, 2004 (see Schwendinger et al. 2004). Spiracles ( Fig. 12 ) of circular type (sensu Giribet & Boyer 2002), circular to oval in shape in male, oval in female, with a maximum diameter of 0.048 and 0.069 mm, respectively.

Ventral opisthosomal region of male without conspicuous modifications or gland openings. Opisthosomal tergite IX and sternites 8 and 9 fused into a broad, low corona analis in males ( Figs 8 ), and into a protruding corona analis with a concentration of long lateral setae in females ( Figs 9, 11 ). Anal plate oval, 0.299 mm (in males) and 0.309 (in females) mm wide; in males with a high, thin medial ridge, in female individuals with a less conspicuous one; ridge with setae ( Figs 8, 9 ). Three anal gland pores on tergite VIII of males ( Fig. 10 ). Cuticle with tuberculate-microgranular surface (sensu Murphree 1988; this is referred to as “ornamented” hereafter), nearly uniform in dorsal areas and in ventral areas including coxae; tuberculate elements typically elongated behind gonostome and around spiracles. An additional microtuberculate pattern present in the ventral opisthosomal region where different segments merge ( Fig. 13 ), possibly indicating the location of arthrodial membranes during postembryonic development.

Chelicerae ( Fig. 14 ) relatively short and robust; basal article in males 1.13 mm long, 0.28 mm wide, with a ventral process, but without a conspicuous dorsal crest; second article 1.04 mm long, 0.19 mm wide; movable finger 0.38 mm long; all articles with few setae, the proximal one almost entirely granulated; 9 uniform denticles on the cutting edge of each cheliceral finger ( Fig. 15 ). Second cheliceral segment not ornamented.

Palp ( Fig. 16 ) 1.93 mm long, smooth, slightly ornamented on coxa and trochanter. Measurements of palpal articles in male holotype, length/width (L/W ratio) in mm: Trochanter 0.249/0.108 (2.31), femur 0.521/0.106 (4.92), patella 0.355/0.093 (3.82), tibia 0.403/0.087 (4.63), tarsus 0.347/0.089 (3.90); claw 0.05 mm long ( Fig. 17 ).

Legs ( Figs 18–27 ; Table 1 ) relatively long and robust. Leg I of holotype longer than leg II; leg I of female paratype TN 310/2002 slightly shorter than leg II. Except for the tarsi, all articles ornamented on legs I–IV. Tarsus IV of male entire, with a broad adenostyle ( Figs 24, 26 ) (0.067/ 0.050 mm), subcylindrical at the base, with lateral pore; distal margin at 41% of tarsal length. Claws hooked, smooth, without dentition or lateral pegs ( Figs 19, 21, 23, 25 ).

Spermatopositor ( Figs 28–30 ) short, typical of sironids, smooth, measuring 0.272/ 0.144 mm; movable fingers 0.015 mm long, slightly curved outwards, ending as hooks ( Fig. 28 , see arrow; nearly straight and one behind the other), shorter than the membranous median lobe; microtrichial formula: 3, 14, 6+6 (n = 1). Gonopore complex not observed.

Ovipositor ( Figs 31–32 ) 1.37 mm long, typical of Siro (see Juberthie 1967a), composed of two apical lobes and 31 circular articles (n = 1), each with 8 short setae equal in length; these setae slightly longer on the 2nd and 3rd subterminal articles, and about three times longer on the terminal circular article; most-basal article without setae. Apical lobes each with a long terminal seta and 12–13 setae slightly increasing in length towards the tip; sensitive processes with 2–3 branches carrying 5–6 simple and 2–3 bifurcate setae. Receptaculum seminis in proximal half of apical lobe, elongated, consisting of two sacs. The largest of several eggs: 0.58 mm long, 0.45 mm wide.

Variation: Range of body length: Males (n = 5), and females (n = 4) in parentheses: 2.20–2.29 (2.40–2.61).

Distribution and ecology: So far this species has been found in two localities in northeastern Slovenia ( Fig. 1 ). In 1984, four S. crassus sp. n. and four C. duricorius (TN 311/2002) specimens were collected, found syntopically within 20–30 cm deep, wet, undecomposed leaf litter of European beech ( Fagus sylvatica Linnaeus, 1753 ) covering a shallow natural ditch with trickling water. In 2005, a dozen of microhabitat types were systematically investigated at the type locality, and four further specimens of S. crassus sp. n. were found, but only in deep solid humic soil (color according to Munsell’s Color Charts (2000): 10YR 1/1) near beech roots.

Sex ratio: So far 5 males and 4 females were found, nearing a 1:1 sex ratio.

Figures

FIGURE 1. Localities of Siro crassus sp. n. (dots) in Slovenia.

FIGURE 2. Siro crassus sp. n., male paratype MCZ 68552 and MCZ DNA 101802: A, dorsal view; B, ventral view; C, lateral view.

FIGURE 3. Siro crassus sp. n., female paratype MCZ 68553 and MCZ DNA 101802: A, dorsal view; B, ventral view; C, lateral view.

FIGURES 4 – 5. Siro crassus sp. n., ventral view of paratypes MCZ 68552 – 68553 and MCZ DNA 101802. 5, male; 6, female. Scale bars 600 µm.

FIGURES 6 – 13. Siro crassus sp. n., paratypes MCZ 68552 – 68553 and MCZ DNA 101802. 6, ventral prosomal complex of male (scale bar 150 µm); 7, ventral prosomal complex of female (scale bar 150 µm); 8, ventral anal region of male (scale bar 150 µm); 9, ventral anal region of female (scale bar 250 µm); 10, anal gland openings (see arrows) (scale bar 30 µm); 11, anal region of female, lateral view (scale bar 200 µm); 12, left spiracle of male (scale bar 25 µm); 13 detail of the cuticular granulation of the ventral opisthosomal region (scale bar 10 µm).

FIGURES 14 – 17. Siro crassus sp. n., male paratype MCZ 68552 and MCZ DNA 101802. 14, left chelicera, retrolateral view (scale bar 250 µm); 15, detail of cheliceral fingers (scale bar 100 µm) [note that lower angled edge corresponds to the glue on the carbon tape]; 16, left palp, retrolateral view (scale bar 400 µm); 17, detail of palpal claw (scale bar 25 µm).

FIGURES 18 – 27. Siro crassus sp. n., left legs of paratypes MCZ 68552 – 68553 and MCZ DNA 101802. 18, tarsus and metatarsus of leg I of male, retrolateral view (scale bar 400 µm); 19, detail of claw I (scale bar 50 µm); 20, tarsus and metatarsus of leg II of male, retrolateral view (scale bar 400 µm); 21, detail of claw II (scale bar 50 µm); 22, tarsus and metatarsus of leg III of male, retrolateral view (scale bar 400 µm); 23, detail of claw III (scale bar 50 µm); 24, tarsus and metatarsus of leg IV of male, retrolateral view (scale bar 400 µm); 25, detail of claw IV (scale bar 50 µm); 26, detail of adenostyle (scale bar 30 µm); 27, tarsus and metatarsus of leg IV of female, retrolateral view (scale bar 400 µm).

FIGURES 28 – 30. Siro crassus sp. n., spermatopositor of male paratype LS 362 / 1985 and of holotype TN 310 / 2002. 28, male paratype, dorsal view, inverted light micrograph showing the slightly outward curved movable finger tips (see arrow) (scale bar 50 µm); 29, holotype, line drawing, dorsal view; 30, same, lateral view (scale bar 100 µm).

FIGURES 31 – 32. Siro crassus sp. n., distal portion of ovipositor of female paratype TN 310 / 2002. 31, light micrograph, slightly deformed after treatment with lactic acid (scale bar 50 µm); 32, line drawing (scale bar 100 µm).

Tables

TABLE 1. Leg measurements (in mm) in Siro crassus sp. n. Measurements refer to male holotype (female paratype in parentheses).

Leg	Trochanter	Femur	Patella	Tibia	Metatarsus	Tarsus	Total
I	0.27 (0.20)	0.76 (0.70)	0.38 (0.38)	0.46 (0.46)	0.34 (0.28)	0.66 (0.52)	2.87 (2.54)
II	0.23 (0.25)	0.71 (0.66)	0.36 (0.35)	0.42 (0.45)	0.34 (0.30)	0.61 (0.61)	2.67 (2.62)
III	0.30 (0.24)	0.54 (0.55)	0.32 (0.30)	0.38 (0.39)	0.30 (0.26)	0.58 (0.53)	2.42 (2.27)
IV	0.37 (0.33)	0.68 (0.71)	0.39 (0.39)	0.42 (0.43)	0.32 (0.46)	0.63 (0.64)	2.81 (2.96)