Leiobunum rupestre ( Herbst, 1799 )

Martens, Jochen & Schönhofer, Axel L., 2016, The Leiobunum rupestre species group: resolving the taxonomy of four widespread European taxa (Opiliones: Sclerosomatidae), European Journal of Taxonomy 216 (216), pp. 1-35 : 5-9

Leiobunum rupestre ( Herbst, 1799)

Figs 1 A–B, 2, 3A–B, 4A–B, H–G, 5A–C

Phalangium bicolor Fabricius, 1793: 429 . The name was synonymized with Gyas annulatus by Latreille (1804), which was missed by several subsequent authors; some of these used it as valid name, in synonymy of, or in relation to, L. rupestre (e.g., C.L. Koch 1847, 16: 56; redescription).

Opilio rupestris Herbst, 1799: 4 , fig. 1 (material from the type locality Sachsen, i.e., Saxony, examined). Leiobunum ovale C.L. Koch, 1848: 59 , fig. 1540.

Liobunum glabrum L. Koch, 1869: 4 , 6–7.

Leiobunum ovale – Roewer 1910: 203. — Šilhavý 1956: 174. — Novak & Gruber 2000: 299.

Phalangium bicolor – Simon 1879: 181. — Roewer 1910: 203 (both also listing Phalangium annulatum in synonymy). — Lessert 1917: 16.

Liobunum rupestre – Simon 1879: 181. — Cantoni 1882: 194. — Hansen 1884: 500. — Kraepelin 1896: 222. — Roewer 1910: 197, 203. — Lessert 1917: 15. — Roewer 1923: 890 (partim). — Hadži 1931: 145. — Šilhavý 1956: 174, figs 437–443.

Liobunus rupestris – Müller & Schenkel 1895: 819.

Liobunum glabrum – Simon 1879: 181.

Nelima glabra – Roewer 1910: 239. — Hadži 1931: 148.

Leiobunum rupestre – Šilhavý 1948: 9, 24, table 6, figs 4–6. — Martens 1978: 408–412, figs 778–780, 788. — Komposch 1998: 26–27, 34, figs 5, 10, 14, 21.

Taxonomic history

At first glance rather complex, but many distributional records from East central, Northwest and North Europe in reality refer to Leiobunum ‘ tisciae ’ (see below, L. gracile ). L. rupestre is a montane species and well known from low to mid-altitudes of the central and eastern Alps and mountainous areas in the Czech Republic and north of the Alps in Germany. Its genital morphology is quite characteristic and was first reliably depicted by Šilhavý (1948, figs 4–6; 1956, figs 437–439), fully in accordance with drawings in Martens (1978, fig. 778) and Komposch (1998, figs 9–10). Leiobunum populations in the Carpathians, Poland ( Staręga 1976), southern Finland ( Heinäjoki 1944), along the Baltic coast hinterland and Denmark were also largely affiliated to L. rupestre ( Martens 1978, fig. 787), though erroneously. These older determinations mostly neglected the genital morphology of these crucial northern populations, which was reconsidered after Avram (1968) published a new species, L. tisciae , clearly distinct from rupestre but similar in external morphology. Due to its wide distribution, the majority of available names for the eastern and northern populations can be assigned to the synonym of its oldest name L. gracile (see below).

Excluding the complex synonymy of L. tisciae ( gracile ), only one uncertain affiliation remains for L. rupestre : the name Liobunum glabrum L. Koch, 1869 . Šilhavý (1956: fig. 443) originally treated ‘ glabra’ as the juvenile L. rupestre , but later used this name to distinguish allopatric populations of western L. rupestre and eastern L. ‘ glabra ’ (later named L. tisciae ) in former Czechoslovakia ( Šilhavý 1981). This was contradicted by Staręga (2004), because the type locality of L. glabrum, Meran (northern Italy, southern Alps), is situated deeply within the territory of L. rupestre ( Martens 1978) . We suggest following Hadži (1931) and Martens (1978) to correctly place Leiobunum glabrum in the synonymy of L. rupestre .

Diagnosis

A medium-sized Leiobunum species with blackish upper side, except for broad, white markings on Ceph disto-laterally in male ( Figs 1A , 3A ), broad, blackish irregular saddle-like marking all over the length of the body in female with extended white markings laterally from Ceph to abd Area II and a cross stripe all over area V ( Figs 1B , 3B ). In both sexes series of para-median lines of small white spots on the abd areae I–V are absent. Contrasting yellowish underside including coxae of all appendages. Wings of truncus penis broad, broadest in lower third part of truncus ( Fig. 5 A–B). Coxa IV with retrolateral row of granules.

BODY ( Figs 1 A–B, 3A–B). In both sexes dorsum smooth, minute granulation not even to be distinguished with magnitude 250 (compare Šilhavý 1981: fig. 4), few scattered pointed granules present; eye mound in both sexes without spines or tubercles.

DORSAL PATTERN. Male and female ( Figs 1 A–B, 3A–B): contrasting black and white (see Diagnosis).

PEDIPALPS. Male ( Fig. 4 A–B): Fe with irregular rows of marked triangular spines ventrally; dorsally nearly unarmed, ventral spines more slender than in L. gracile ; Pt slightly armed with pointed denticles laterally; Ti markedly convex in basal part and concave at ventro-distal end, therefore forming a well-marked S-bend, field of fine dark coloured granules all over the ventral side, well to be seen; Ta continuously and slightly bent to ventral. Female ( Fig. 4 G–H): similar to male, less spines on Fe and Pt, few spines on Ti proximally and no ventral granulation, Ta strait, slightly bent distally.

GENITAL MORPHOLOGY ( Fig. 5 A–C). Truncus penis stout, in ventral/dorsal view from basal opening to insertion of glans slightly and continuously tapering; distal wings covering less than half of truncus. Wings consist of two independent parts: a ventral shell-like plate, sharply cut off horizontally at upper third of wing structure, from its upper margin continuously extending to lateral side of truncus, thus partly embracing the lateral wings which extend from dorsal side of truncus via lateral side to ventral side. Their lower two thirds are covered by the ventral plate. Surface of the upper margin of the lateral wings and membranes adjacent to the truncus is invaginated forming a long double-walled internal sack. At the very distal end of truncus a small membranous oval sack with a distal opening is attached ventrally.

From lateral view truncus slightly curved (concave on ventral side), slightly tapering towards glans. Wings massively enlarged on ventral side. Glans stout, in lateral view tapering towards stylus.

Distribution ( Fig. 2 )

Main area are the eastern Alps from the eastern part of Switzerland, all over Austria, the German and Slovenian alpine parts and extending to the north-western Balkan Peninsula. Records extend southwards to Serbia (CJM6363, CIK1336, CIK1337), Croatia ( Babić 1916; Novak 2004b) and Bosnia-Hercegovina ( Martens 1978; Novak 2005). To the Northeast, the area extends into the Czech Republic: many localities in Bohemia and Moravia, mainly in the northern and southern mountains marking the borders to Austria, Germany and Poland ( Šilhavý 1981).

North of the Alps this main Alpine/Balkan area extends in isolated patches towards the northern border of low mountain ranges in Germany (Black Forest, Schwäbische Alb, Frankenalb, Bavarian Forest and Bohemian Forest; all Martens 1978), Fichtelgebirge ( Staudt 2016), Thüringer Wald (CJM 5392), Erzgebirge ( Büttner 1930), Lausitzer Gebirge ( Hiebsch 1972) and northerly up to the Saxonian Elbsandsteingebirge (CJM 4752, 4753). “ Sachsen ”, i.e., Saxony, is the type locality of rupestre , and the type material of Herbst (1799) likely originated from present South Saxony.

For Poland, Staręga (1976) indicated a number of “ rupestre ” records in the southern mountains, the Karkonosze (in German “Riesengebirge”) close to the Czech border. From the opposite Czech side, in the same mountain stock, the Krkonoše, Šilhavý (1981) pinpointed records for (true) rupestre , which he compared to “ glabra ” from his country. As these close-to-border Polish localities are situated in mountainous areas, too, they probably belong to rupestre as well. Besides, the Polish ‘ tisciae ’ (i.e., gracile , below) records are all situated in lower stretches of central and eastern parts of the country ( Staręga 1976, 2004), far from any (possible) mountainous rupestre record.

The L. rupestre area as depicted in Martens (1978: fig. 787) needs to be reduced, substracting the distribution area of. L. ‘tisciae’ (i.e., gracile , below), stretching from the Carpathians in a broad northerly area to the Baltic coast up to South Finland and in the West to Denmark and northern Germany ( Fig. 2 ). However, the remaining distribution area of L. rupestre slightly changed with respect to the Balkan area, then largely unknown, and new records in central Germany were added.

Ecology

This is a forest species with a high demand of air moisture. Therefore, it is confined to moist places close to streams and creeks, on tree trunks, under rotten wood and on moist rock faces. It hardly occurs in open areas, in agricultural land, urban gardens or on house walls in villages and towns, if not situated in moist forests ( Martens 1978), or at higher altitudes. Martens (1978) indicated height records from 260 m to 2160 m a.s.l. in the Austrian Alps, but likely included localities for the closely related L. subalpinum . Komposch & Gruber (2004) set the Austrian uppermost rupestre limit at 1680 m a.s.l. and for subalpinum at 2100 m a.s.l.

In all cases populations of rupestre are confined to mountainous areas of different altitudes. Only in the Saxonian Elbsandsteingebirge does rupestre live at the bottom of deeply recessed valleys which are permanently moist and where sun radiation is largely excluded from the narrow valleys by the steep rock faces.

Figures

Fig. 1. Habit of Leiobunum rupestre species group. A–B. Leiobunum rupestre Herbst, 1799, Slovenia, Pohorje Mountains, resting at rock faces. A. ♁. B. ♀. C–D. Leiobunum apenninicum (Martens, 1969), Italy, Monesi di Triora, at night. C. ♁. D. ♀. E–F. Leiobunum gracile Thorell, 1876, Denmark. E. ♁. F. ♀. Photographs: A–D by A.L.Schönhofer; E–F by S. Toft, all taken in the field.

Fig. 3. Body of Leiobunum C.L. Koch, 1839, dorsal view. A–B. Leiobunum rupestre Herbst, 1799, Germany, Mt. Arber, CJM136. A. ♁. B. ♀. — C–D. Leiobunum gracile Thorell, 1876, Denmark. C. ♁, 2 km N of Skaerbaek, CJM3530. D. ♀, Asp, CJM3531. — E–F. Leiobunum apenninicum (Martens, 1969), France, Alpes-Maritimes. E. ♁, CJM1508. F. ♀, CJM2747. Drawings by K. Rehbinder.

Fig. 5. Leiobunum, male genitalia. A–C. L. rupestre Herbst, 1799, Germany, Baden-Württemberg, CJM1954. A. Ventral view. B. Lateral view. C. Cross-section. — D–F. L. gracile Thorell, 1876, Denmark, 2 km N of Skaerbaek, CJM3530. D. Ventral view. E. Lateral view. F. Cross-section. — G–J. L. apenninicum (Martens, 1969), France, Alpes-Maritimes, CJM1508. G. Ventral view. H. Lateral view. J. Cross-section. Arrows indicate the area of the respective cross-sections.

Fig. 4. Pedipalps of the Leiobunum rupestregroup, wholepedipalps inlateral view, single femora inmedial view. — A–F. ♁♁. A–B. Leiobunum rupestre Herbst, 1799, Germany, Baden-Württemberg, CJM1954. A. Pedipalpus lateral. B. Femur medial. C–D. L. gracile Thorell, 1876, Denmark, Asp, CJM3531. C. Pedipalpus lateral. D. Femur medial. — E–F. Leiobunum apenninicum (Martens, 1969), France, Alpes- Maritimes, CJM2747. E. Pedipalpus lateral. F. Femur medial. — G–M. ♀♀. G–H. Leiobunum rupestre Herbst, 1799, Germany, Mt. Arber, CJM136. G. Pedipalpus lateral. H. Femur medial. J–K. L. gracile Thorell, 1876, Denmark, Asp, CJM3531. J. Pedipalpus lateral. K. Femur medial. L–M. L. apenninicum (Martens, 1969), France, Alpes-Maritimes, CJM2747. L. Pedipalpus lateral. M. Femur medial. Arrows indicate characters mentioned in the descriptions.

Fig. 2. Distribution of the species of the Leiobunum rupestre species group. Red squares = L. rupestre Herbst, 1799; blue circles = L. gracile Thorell, 1876; green triangles = L. apenninicum (Martens, 1969); stippled line circumscribes area of L. subalpinum Komposch, 1998. Type localities are indicated by abbreviated taxon names (ape = apenninicum; gla = glabrum; gra = gracile; lae = laeve; nor = norvegicum; rup = rupestre; sub subalpinum; tis = tisciae). Arrows indicate a specified locality, if unprecisely given, the general area is indicated (rupestre = Saxony; gracile, laeve = Scania).