Leiobunum apenninicum ( Martens, 1969 )

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 : 15-16

Leiobunum apenninicum ( Martens, 1969)

Figs 1 C–D, 2, 3E–F, 4E–F, M–L, 5G–J

Nelima apenninica Martens, 1969: 409 (type series SMF, examined).

Leiobunum rupestre – Trossarelli 1943: 54. — Gozo 1908: 135.

Nelima apenninica – Martens 1978: 424, figs 803–804, 809. — Chemini 1980: 79 (description of female). — Komposch 2009: 457.

Taxonomic history

Though only recently described, the status of this large species was accepted by subsequent authors ( Chemini 1980; Komposch 2009). However, similarity of genital morphology with L. ‘ tisciae ’ (now L. gracile, Martens 1978 ) later led Martens to the assumption that the scattered distribution of apenninica might represent disjunct area parts of L. gracile . This remained unpublished due to the emerging complex taxonomic situation in L. gracile / L. rupestre . Yet, many details separate both species as is further confirmed by molecular genetic analysis (J. Martens, unpublished data).

The generic affiliation of apenninica is difficult to establish. Certainly, it does not belong to the European bulk of small-bodied Nelima species like N. sylvatica Simon, 1879 , N. gothica Lohmander, 1945 and N. sempronii Szalay, 1951 , but is a large and long-legged species similar to L. gracile , less to L. rupestre . Due to the lack of coxal denticles in the type material and according to the present definition of sclerosomatid genera it was originally placed in Nelima . However, based on only a single external character, this is an artificial affiliation, that we find especially compromised in the species-pair gracile and apenninica . Leiobunum gracile shows a strong variation of number and placement of coxal denticles down to zero (CJM6357, female) and their frequent appearance in Nelima apenninica (AXLS1739 two to seven on coxa IV, in both sexes) underlines the false generic placement of apenninica . Consequently, in accordance with similar genital morphology and external characters we prefer to place apenninica in Leiobunum .

Diagnosis

A medium-sized Leiobunum species with blackish upper side, except for broad white markings of Ceph disto-laterally in male ( Figs 1C , 3E ), broad blackish irregular markings on abd areae I–V of the body. In female with mottled white markings laterally from Ceph to posterior areae, white lateral marking on abd area V and a white cross stripe all over areae VI ( Figs 1D , 3F ). In both sexes a series of para-median small white spots on the abd areae I–V, more conspicuous in male (a character similar to L. gracile ). Contrasting yellowish under side including coxae of all appendages. Wings of truncus penis robust, slightly tapering proximally.

Description

BODY ( Figs 1 C–D, 3E–F). In both sexes dorsal granulation consisting of flat, pointed granules, regularly spaced, well to be seen with 250× (comparable to L. gracile , see Šilhavý 1981: fig. 2); eye mound in both sexes with 1–3 small spines on each side, rarely absent.

DORSAL PATTERN ( Figs 1 C–D, 3E–F). See Diagnosis.

PEDIPALPS. Male ( Fig. 4 E–F): Fe with few massive spines, normally restricted to third ventro-distal part, only single spines on dorso-distal side or absent; Pt unarmed except for few small spines dorsally; Ti slighty inflated, rather short thus appearing pretty massive, brush-like hair field on ventral side, a peculiar character of its own; no spines clearly visible, likely for being of the same light colour as the embedding hair field; Ta continuously bent ventrally over its whole length. Female ( Fig. 4 M–L): Similar to male. Fe nearly smooth, spines even less than in male, tibia less inflated and slightly concave ventrally, no hair field; tarsus straight, distally inconspicuously bent ventrally, more slender and slightly longer than in male.

GENITAL MORPHOLOGY ( Fig. 5 G–J). Penis similar to L. gracile . Truncus stout and parallel-sided in the basal half from where slightly and continuously tapering to the lateral lowest parts of the wings, from there slightly enlarged to middle of the wings, then tapering to basis of glans. Lateral wings (ventral view) markedly enlarged, nearly parallel-sided over nearly their total length, pretty sharply merging to distal part of truncus. At the disto-lateral margin of the wings (close to the truncus/glans joint) wings open to a narrow slit leading to two ventro-lateral pockets. A lateral membrane in the distal half of the wings unites the dorso-lateral und the ventro-lateral part of the wings which allows for a possible inflation of the wing structure when the pockets are filled with secretion. From lateral view truncus slightly curved (concave on ventral side), slightly tapering towards middle part, then enlarging again. Wings massively enlarged on ventral side, slightly rounded convexly. Glans slender, in lateral view tapering towards stylus.

Distribution ( Fig. 2 )

It was long considered a rare and local species ( Martens 1969; Komposch & Gruber 2004; Komposch 2009; Chemini 1980) and only a few specimens were available for the original description from the Apennines ( Martens 1969). Even fewer became known from the apparently isolated area at the Italian border to Austria ( Chemini 1980) and in Austria itself ( Martens 1978; Komposch 2009) and the Southwest Alps ( Martens 1978). Presently, the area seems to be subdivided into three major parts, viz., French and Italian southwestern Alps, southern Austrian (eastern Tyrol) and Italian Alps (South Tyrol), and scattered records in the Apennines chain. Type locality is Pratovecchio in the Apennines. Yet, there was little additional locality information since its original description until the species was recently rediscovered in the Southwest French Alps in high frequency, namely in the Mercantour National Park and the Vallée des Merveilles (CJM; ALS leg., JM leg). Disregarding its specific habitats and general low sampling activity for long-legged species in the Northwest Alps, the species might have been neglected in large parts of its distributional area. Prior to its description, L. apenninicum has likely been confused with L. rupestre , as is obvious from Trossarelli’s (1943) records for the southwest Alps. The isolated record from Calabria ( Gozo 1908, L. rupestre ; included in Fig. 2 ) requires confirmation.

Ecology

This is a forest species. During the day males rest on tree trunks and rock faces; females, though not exclusively, prefer to hide on the ground in leaf litter and thus are not easy to locate. Consequently, only males have long been known, because they are easier to spot and collect. The species is locally pretty common wherever the daytime microhabitats of females are found. Otherwise, it is readily encountered at night, and this technique revealed large populations in the Mercantour National Park in the French Alps.

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. 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. 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. 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).