On the distribution of Astrobunus / aevipes CANESTRINI , 18 . 72 ( Arachnida : Opiliones ) in Central Europe

Published data and unpublished communications showthatthe range of Astrobunus /aevipes in Central Europe is much larger than previously believed. The present review extends the list of records to the German states of Baden~Worttemberg, Hessia, RhinelandPalatinate, Bavaria, Northrhine-Westfalia, Saxony, and Lower Saxony and provides a map of the present distribution in Germany. Furthermore, it lists new findings of A. /aevipes in the Czech Republic and Hungary (Rakaca/Serehat Valley). Records of A. /aevipes in Austria are not included in this review.


INTRODUCTION
Astrobunus Jaevipes was first recorded in Germany in Dresden (HERBST 1799, under Opilio spinosus).An additional and isolated finding was reported by Horegott (cited in MARTENS 1978) in Mainz (Rhineland-Palatinate).MARTENS (1978) stated thatthe distribution of the thermophile harvestman A. Jaevipes in Central Europe is limited to the countries of the Carpathians, the Hungarian lowland including the valleys ofthe rivers Elbe and Danube, and the plains of the river Po, with an isolated population in Mainz, Germany.However, more recent publications as well as our present data show that the range is much larger than previously believed and that the population around Mainz is not isolated.We present here a summary of all records of A. Jaevipes in Germany, the Czech Republic and Hungary, including a characterisation of the biotopes where we have found the species ourselves.These data can serve as a base for further studies in this species.

RESULTS
The new records of A. Jaevipes are summarised in Table 1 and shown in Figure 1.A colour version of the map indicating topographical features can be found at http://www.spiderling.de.vu/.The majority of the new findings presented here were obtained from pitfall traps.As the records are the result of occasional sampling in studies of numerous investigators no standard methods can be described.The single female obtained at Karlsruhe-Grbtzingen was found on April 7 th , 1994 under a stone between a hedge and a narrow pass during manual sampling.The locality is situated in a limestone area (Middle Triassic: shell limestone) between vineyards and orchards.Similarly, the findings at the "Drachenfelser Landchen", near Bonn also were made near vineyards (Trachyt-Rigosol mixed with stony loam), where over 140 individuals were pitfall-trapped in the surrounding undergrowth between March 27 th and October 10 th , 1996.

DISCUSSION
At present the known distribution of A. laevipes suggests an isolated occurrence/population in western Germany.But this might only be an artefact of insufficient knowledge.The map given by MARTENS (1978) as well as our presented data (Tab.1, Fig. 1) suggests that A. laevipes mainly used the valleys of the big streams for spreading to the south.The question is where and when the species was able to overcome the distance between the river systems of the Danube and the rivers flowing into the North Sea.The first step was to cross the Bohemian depression, a very warm area containing many southeast European floristic (e. g.lrisaphyl/a) and faunistic elements.Although our knowledge has increased, it remains uncertain how A. laevipes was able to overcome the distance between the river systems of the Elbe and the Rhine.There are at least three possibilities: 1. Along the northern border of the highlands 2. Across Thuringia along Saale-Rodach into the Main valley 3. Along the Danube and later either across AltmOhl-Regnitz, AltmOhl-Tauber or Wornitz-Jagst.
The first possibility avoids overcoming highlands, but would be an unusual route for southeast European elements.The second route demands transition of the Thuringian Forest, a rather cold area, butthis route is mostly supported by the presently known records.The third possibility is a wellknown route for several southeast European elements, which occur either in the Jagst-or the Tauber-valley (e. g. the millipede Mastigona bosniense, SPELDA 1999).However we have no records of A. laevipes from the Bavarian part of the Danube river system, which might support this route.Although MARTENS (1978) discusses the possibility of a spreading in recent times when deforestation took place it is as well possible, that the species invaded its western range just after the last glaciation before the forest had covered most parts of Germany.Or it could have invaded its range along the streams, which cause open areas along their borders by flooding.The latter possibility does not restrict the spreading to a special period.
Astrobunus /aevipes often has been confused with A. bernardinus (SCHENKEL 1926).They are believed to be sibling species (MARTENS 1978), and it is possible that these species hybridise in the Southern Alps.However there are clear differences in the ecology of the two species.
Astrobunus /aevipes is confined to low altitudes, while A. In areas where A. helferi and A. laevipes occur sympatric, A. helferi inhabits the higher altitudes but, in contrast to A. bernardinus, avoids the alpine region.It is very likely, that all three species arose from a single ancestor during the Pleistocene.To testthis hypothesis, explain the present distribution of A. laevipes, and the relationship between populations we need further investigations and a phylogenetic analysis of this species.

Figure 1 :
Figure 1: Distribution map of Astrobunus /aevipes CANESTRINI, 1872 in Germany and in the Czech Republic.

Table 1 :
Records of Astrobunus laevipes CANESTRINI, 1872 in Germany, the Czech Republic and Hungary.
~ ~ (KOMPOSCH 1997(KOMPOSCH , 1999))bution, even occurring above the timberline.It has a wide range of habitats, but avoids dry, open, southern slopes.Another species occurring parapatric to both A. /aevipes and A. bernardinus is A. helferi, occurring in the central and eastern parts of the Alps(KOMPOSCH 1997(KOMPOSCH , 1999)).It is very likely that the distribution of all three species is influenced by competition.Astrobunus /aevipes and A. bernardinus seldomly occur in sympatry (Drau-valley near Spittal, leg.Ausobsky cited in MARTENS 1978).