Protura of Italy, with a key to species and their distribution

Abstract The Italian Protura were studied basing on 5103 specimens from 198 sampling areas, along with bibliographic data from 49 collecting sites. 17 out of the 20 Italian regions are covered. As a result, 40 species have been identified (belonging to 8 genera and 4 families), 6 of which are new records for the Italian fauna. A key to the Italian species is reported, followed by a series of distribution maps and brief remarks for some of them. A preliminary biogeographical overview allowed us to delineate the chorological categories of these species, 10 of which are actually known only in Italy. The comparison with the species richness known for some best studied Central and Eastern European Countries leads us to speculate that widening our research, Italian Protura check-list will be much implemented.


Introduction
Protura is a group of Hexapoda which has been discovered recently: the first species described is Acerentomon doderoi, collected from soil samples taken from the grounds of a small villa actually in the center of Genoa (Silvestri 1907). More detailed data about such taxon are provided in the two years immediately following by Berlese (1908aBerlese ( , 1908bBerlese ( , 1909. Knowledge of Protura has rapidly increased all over the world thanks to the careful research of many specialists. Just to mention the main publications, in 1964 Tuxen published his valuable book about the Protura of the World; Nosek's monograph on European Protura was printed in 1973; a year later Imadaté's volume about Japanese species was released (1974); while the impressive monograph about Chinese Protura was published more recently (Yin 1999).
The European research about this group, although with some exceptions, was concentrated in Central and Eastern Countries due to the work of some Authors such as Nosek, Rusek, Tuxen and, more recently, Szeptycki and Shrubovych. In Italy, knowledge regarding Protura (see species list for detailed bibliographic references) can be summarized with the identification of 31 species belonging to the Italian fauna by the national check-list (Dallai et al. 1995). The same number of species emerges by an overview of the most recent Catalogue of the World Protura (Szeptycki 2007).
With this paper we hope to lay the foundations for the advancement and improvement of studies regarding this little known taxon in Italy as well in the Mediterranean Region, one of the biodiversity hotspots on the planet, reaching the highest peaks of diversity of soil-borne organisms (e.g. Blondel et al. 2010).

Materials and methods
Many of the Protura examined in this paper were collected by colleagues and given us in tubes containing 70% ethanol. However, we have obtained some specimens by extraction from soil or litter samples by Berlese-Tullgren funnels (2.5 mm mesh size). Specimens were incubated at 40-50° C for 24 hours in lactic acid to clarify, mounted on slides in Marc André medium and were observed and identified by an interference contrast microscope.
In total 5103 specimens from 198 sampling areas were examined. 3929 specimens were identified to species level (Table 1).
In our analysis we also considered the data taken from 49 Italian collecting sites known in literature. 17 out of 20 Italian regions are covered, missing specimens from Molise, Campania and Calabria (Southern part of the peninsula).

Key to genera of Italian Protura
This key and the following ones to species are based, and adapted to the Italian fauna, on Nosek (1973) and Szeptycki (1980Szeptycki ( , 1985Szeptycki ( , 1986Szeptycki ( , 1991

Keys to species of Italian Protura
Since this key could lead to a misidentification of similar Palearctic species not already detected in Italy, we suggest a careful examination of the species' descriptions (and redescriptions) to verify the identification accuracy and also to refer to the keys to species of other European Countries (e.g. those cited at the beginning of the key to genera) as well as to the monographic papers published on certain genera (e.g. Rusek 1975;Szeptycki 1993).

Italian Protura
This section provides summaries on species known to date belonging to Italian fauna. For each one the amount of material examined (PI = pre-imago, MJ = maturus junior, LII = larva II, LI = larva I, undet = undetermined), a short description of the global distribution from Szeptycki (2007) and, when necessary, some remarks are given. For the new recorded Italian species more geographical details (locality, province and region) are given. The maps (Figs 1-25) show the collecting areas in Italy: blue dots represent collecting sites known only in literature, while the red ones correspond to samples personally analyzed by the authors.
Remarks. First Italian record in Torti (1981a). Some generic records from Lombardy (N Italy) of Hesperentomon sp. in Dematteis (1971Dematteis ( , 1972 could be attributed to this species.  (Nosek 1969), only two specimens (holotype and paratype) from Veneto (NE Italy) belonging to this species were known. In 2007 two of us (Galli and Torti) published a short note about a third specimen from Liguria (NW). Three other specimens were most recently found in samples from Piedmont (NW) and Sardinia.
Distribution. Italy, Germany. Data from Denmark and Australia should be confirmed (Szeptycki 2007).
Remarks. This species is not included in the World Catalogue (Szeptycki 2007) because it was recorded in Italy only more recently (Capurro et al. 2008b).
Type area. Tuscany, Giardino di Boboli in Florence.

Distribution.
Recorded from nearly whole Europe (with exception of Scandinavia), but all of the older data should be confirmed (Szeptycki 2007).
Remarks. New record for the Italian fauna.
Remarks. Species confirmed for Italy. Bibliographic data from Fratello and Gioia (1975).
Remarks. We have not yet been able to analyse the type material from Villetta Dinegro (Genoa Town). Four specimens originally labelled as "cotypus doderoi" in Genoa Museum collection have been recently identified by the authors as A. italicum.  Rusek, 1966 http://species-id.net/wiki/Acerentomon_fageticola Distribution. Central Europe.

Acerentomon fageticola
Remarks. Three specimens from Veneto (Cison, Treviso), and two from Liguria (Lavagna, Genoa) were identified by Prof. Nosek as Acerentomon fageticola and cited in a short note by Torti (1995a). These and some other similar specimens should be considered as individual variations of A. italicum: this hypothesis seems to be maintained by the coexistence in the same localities of individuals showing a continuum of diagnostic characters (foretarsal sensilla, chaetotaxy, pleural pectines) ranging from the A. fageticola to the A. italicum extremes, while we have not yet found sites where only "fageticola-type" specimens have been collected.
We hope that our current redescription of Acerentomon italicum could shed more light on the differences between this species and the related A. fageticola.
This species has been cited here and in the identification key only for exactness of information.
Distribution. West and Central Europe, recorded also from Africa (Uganda -introduced?).
Type area. Trentino Alto Adige, Tiarno. Distribution. Mediterranean Europe; all data from the Central and North Europe should be checked (Szeptycki 2007).
Distribution. Probably widely distributed in Europe, but all data before 1986 should be checked -they most likely concern not only E. armatum, but also some other similar species (Szeptycki 2007).
Remarks. New record for the Italian fauna.
Remarks. This species is not included in the World Catalogue (Szeptycki 2007) because it was recorded in Italy only more recently (Capurro et al. 2008a).                Nosek, 1969 http://species-id.net/wiki/Eosentomon_romanum Fig. 24 Type area. Lazio, Rome.

Conclusion
In Figures 26 and 27 the distribution of the sampling sites in Italy and the species richness in the Italian regions are shown, respectively. Unfortunately we regret for the lack of samples from Molise, Campania and Calabria (Southern part of the peninsula); but, apart from that, comparing maps on these Figures, it is clear that the species richness reflects the sampling effort in the different regions, with higher numbers of species known from regions such as Piedmont, Veneto and Liguria, where many more samples have been collected (for a detailed analysis of Protura of Liguria see Capurro et al. 2009).
According to the analysis made in this paper, we have been able to identify 40 Protura species in Italy, belonging to the families Hesperentomidae (1), Protentomidae (6), Acerentomidae (26) and Eosentomidae (7). At the species level, according to Vigna Taglianti et al. (1992), it is possible to outline the chorological categories shown in Table 2.
Based on the findings, the Italian fauna is mainly composed of species having a European or Mediterranean distribution. With regard to the 10 species known only in Italy, it cannot be said to be endemic due to the poor level of knowledge of this taxon. For the same reason, that given in Table 2 should be considered only a preliminary attempt at classification, which, most likely, is susceptible to changes in the future.   The number of species and genera known in the European Countries (according to Szeptycki 2007; updated data for Austria and Ukraine are taken respectively from Christian 2011 and Shrubovych 2010) is shown in Table 3.
It seems rather unlikely that generally poorer (in terms of biodiversity) Countries such as Poland, Ukraine, Austria and Germany have more Protura species than Italy. It's more likely that this gap is due to a lack of knowledge of the Italian fauna. In support of this hypothesis, a year spent on sampling project in a small cork oak wood in Liguria (NW Italy) led us to identify (Capurro et al. 2011) 11 species. We therefore assume that is extremely possible that other species distributed in neighbouring Countries -or Palearctic ones as well (see as is the case of Acerentulus terricola) -could be found in Italy.
We therefore hope that in the future we will be able to deepen and broaden our research to obtain a more accurate picture of Protura's ecology and distribution.