Is Siro carpaticus Rafalski , 1956 ( Arachnida : Opiliones ) really a rare harvestmen species ?

Siro carpaticus (Arachnida: Opiliones: Cyphophthalmi) is a harvestman endemic to the Eastern Carpathian Mountains. Although the species was known only from a few localities in Poland and Slovakia and was considered as a rare species, 51 new records from the Bieszczady Mountains are newly presented. This expands the species’ range to the Ukrainian border. The search results suggest that Siro carpaticus occurs quite commonly in Bieszczady National Park but is difficult to find due to their specific habitat.


INTRODUCTION
Siro carpaticus RAFALSKI, 1956 (Arachnida: Opiliones) is a small harvestman (1,5-1,6 mm in length) that lives in spaces under stones and in thick leaf litter of beech and mixed forests from about 300 to 1200 m above sea level (Rafalski 1958, Staręga 1976, Stašiov 2008).The area occupied by this species is a small part of the Carpathians (the East Beskid, the Słonne Mountains, the Bieszczady, the Vihorlat Mountains) situated on border between Poland and Slovakia (Rafalski 1956, 1958, 1961, Mašán 1998, 2005, Mihál et al. 2003, Stašiov et al. 2003) (Fig. 1).The distribution of Siro carpaticus is strongly disjunct from other European species of Siro LATREILLE, which have been recorded from the Balkans (S. crassus NOVAK & GIRIBET, 2006), Lombardy Alps (S. valleorum CHEMINI, 1990), and Massif Central and South France (S. rubens LATREILLE, 1804) (Karaman 2009).S. carpaticus is the northernmost member of the suborder Cyphophthalmi, which is represented in the European fauna by four additional genera occurring on the area from Portugal to the Balkans along the northern coast of the Mediterranean Sea (Staręga 1976, Giribet 2000, Błaszak 2004, Karaman 2009).Such a strong isolation of Siro carpaticus from other Cyphophthalmi (see Giribet 2000, fig.2) suggests a relictual distribution of this species.Siro carpaticus was known only from four localities in Poland until now.The localities were in the Low Beskid and the Bieszczady Mountains, on the foothills of these mountain chains (Rafalski 1956(Rafalski , 1958(Rafalski , 1961)).Subsequently, the species was found in the Slovakian part of the Bieszczady and the Beskid Mountains (Mašán 1998, Mihál et al. 2003, Stašiov et al. 2003) and in Vihorlat chain (Mašán 2005) (Fig. 1).
However, in the last 50 years in Poland there were no new records on Siro carpaticus and our knowledge on the distribution of the species was based on the old data only (Staręga 1976, 2000, Błaszak 2004).Current search for Siro carpaticus and overview of all data allow to set the new view on actual distribution of this species.

STUDY METHODS
The intensive search for Siro carpaticus have been carried out in 2010-2011 in Bieszczady Mountains, especially in the Bieszczady National Park (permissions: 57/11 and 8/11) (Rozwałka 2012).I was looking for it under the stones mainly, because such places were considered as its appropriate habitat (Rafalski 1958, Staręga 1976).Repeated attempts to use the entomological sieve turned out to be less effective.Only a few specimens were collected with help of this method, considering also the samples provided by other researchers.

New localities
The Sanocko-

DISCUSSION
Previously, Siro carpaticus was known only from four localities and some specimens (Rafalski 1958, Staręga 1976).There are marked five localities of Siro sarpaticus on the map in the Polish Red Book of Animals (Błaszak 2004) but the fifth locality was placed additionally as a result of graphic approach adopted by the authors (double marking the location situated on the UTM grid line).Furthermore, the occurrence of S. carpaticus in Slovakia (Mašán 1998, Mihál et al. 2003, Stašiov et al. 2003) had not been considered there.
According to all earlier Polish and Slovakian literature data, Siro carpaticus is a very rare harvestman known from only a few specimens (Rafalski 1956, 1958, 1961, Staręga 1966, 1976, Mašán 1998, Mihál et al. 2003, Stašiov et al. 2003, Błaszak 2004).However, this paper presents 51 new localities and over 170 collected specimens, indicating that the species is actually relatively common.The species may be even more common than would appear from these data because the studies were mainly focused on the search for new localities.For example, 26.05.2010, during purposely exploration, in district of Brzegi (Berehy) Górne 35 specimens were found in two hours.Previous opinion about rarity of this species may be a consequence of inadequate sampling.Moreover, Siro carpaticus is very difficult to find due to the small size, its cryptic habitat and presumably sedentary life style (Rafalski 1958, Staręga 1976).S. carpaticus is found under deeply embedded stones in beech (Fig. 2, 3) and mixed forests from the elevation about 300 to 1200 m (Rafalski 1958, 1961, Stašiov 2008, present data).The upper elevation limit of S. carpaticus occurrence coincides with the upper forest limit, although the harvestman is rarely found in the zone of dwarf beech forests ("Krummholz") (about 1000-1200 m el.).It is worth noting that, specimens were observed near abandoned burrows of earthworms (Oligochaeta), on several occasions.This suggests that the harvestmen might be inhabit (or move through) earthworm tunnels.Other observations show that specimens of S. carpaticus accumulates in large numbers under stones, probably because of a more stable and moderate microclimate.The species also occurs in deep layer of forest litter and in upper parts of strongly cultivated soil in woods (Rafalski 1958(Rafalski , 1961, present data), present data).Also, S. carpaticus is found in turf (moss) on open spaces, being found on overgrow by blackthorn meadows in the Słonne Mountains (locality 2) or on ruderal sites (Mihál et al. 2003).
The more complete knowledge on distribution of this species require further study.The present data suggest that Siro carpaticus occurs also in the Ukrainian part of the Bieszczady (the Eastern Bieszczady), but it is not known whether the distribution extends to east, to the Czarnohora and the Gorgany Mountains.However, the species range probably does not extends to Romania, because the opilionofauna is well known there (Babalean 2005).SUMMARY 1. Siro carpaticus is a relatively common species, in contrast to previously published information.
2. Typical habitats of S. carpaticus are undersurfaces of deeply imbedded stones in beech and mixed forests from about 300 m to 1200 m.The species occurs also in forest litter, on ruderal sites and maybe in turf of lover located meadows. 3

Fig. 1 .
Fig. 1.Distribution of currently known localities of Siro carpaticus Rafalski, 1956 in the Bieszczady NP, in Poland and in Slovakia; male habitus by Rafalski, 1958.The localities 1-3 in the text are shown on the map of Poland only, the other (4-51) -on a topographic map of the Bieszczady NP.