An annotated checklist of the Chilopoda and Diplopoda (Myriapoda) of the Abrau Peninsula, northwestern Caucasus, Russia

Abstract Background The Abrau Peninsula is located in northwestern Caucasus between the cities of Novorossiysk and Anapa, Krasnodar Province, Russia. This paper contains an annotated checklist of the Chilopoda and Diplopoda inhabiting the Abrau Peninsula. New information The fauna of the Abrau Peninsula comprises 17 centipede (4 orders) and 16 millipede (6 orders) species. Henia taurica, hitherto known only from the Crimea, has now been reported from several localities in the studied region. The study also reveals two possibly new millipede species. Statistical analyses showed that habitat preferences of myriapod species within the Abrau Peninsula are caused by species geographic distribution pattern and microbiotope preferences.


Introduction
The myriapod fauna of some parts of Russia still remains poorly known. This holds particularly true for the Caucasus, where most large-scale investigations of the group were performed a long time ago (Muralewitsch 1907, Muralewitsch 1926, Lohmander 1936, Zalesskaja 1978, Golovatch 1985. Most of the recent studies on myriapods in the region have been either local or focused on specific taxonomic groups (Golovatch et al. 2015). This, along with the presence of several nearly "blank spots" in this territory, emphasizes the need for further faunistic investigations in the region. One of the least explored areas in the Caucasus is the Abrau Peninsula, northwestern Caucasus and its environs, where the myriapod fauna has never been fully investigated. A particular significance of this area from a faunistic point of view is determined by the presence of a relict xerophytic sub-Mediterranean vegetation. This is the only place in Russia that harbours a Mediterranean vegetation (Seregin and Suslova 2007).
The Abrau Peninsula is located between the cities of Novorossiysk and Anapa, Krasnodar Region. Its 9065 ha area is occupied by the Utrish State Nature Reserve. The climate of the Abrau Peninsula is sub-Mediterranean with cool rainy winters without a stable snow cover and with hot dry summers. The mean annual precipitation is 500 mm, the mean July and February temperatures are 23.7°C and 2.7°C, respectively (Afonin et al. 2009). The area vegetation consists of three major belts (Seregin and Suslova 2007): (1) coastal slopes with sub-Mediterranean xerophytic forests and shrublands with pistachio (Pistacia mutica), juniper (Juniperus excelsa, J. oxycedrus, J. foetidissima), oak (Quercus pubescens) and oriental hornbeam (Carpinus orientalis); (2) piedmont and low-mountain area with a combination of mesophitic and xerophitic forests and a predominance of two oak species (Q. pubescens, Q. petraea), oriental hornbeam and junipers; (3) low mountains with mesophitic deciduous forests with a domination of oak (Q. petraea), hornbeam (Carpinus caucasica), lime (Tilia begoniifolia), maple (Acer laetum), ash ( Fraxinus excelsior) and beech (Fagus orientalis). Brown-pebble forest soils dominate throughout the study area.
The abundance of millipedes and centipedes at the Abrau Peninsula averages from 784 to150 ind./m , or ca. 65% and 10% of all soil macroinvertebrates (Gongalsky et al. 2004, Gongalsky et al. 2008. Despite the existing data on the abundance and distribution of soil macroinvertebrates in the Abrau Peninsula, to the best of our knowledge there has been only one specialized publication on the myriapod fauna of Utrish Nature Reserve (Short 2015), which provides information about the geographic distribution of the genus Lophoproctus, including Lophoproctus coecus collected by Ivan H. Tuf and Daria Kuznetsova from Utrish Nature Reserve in 2013. During our field studies several presumably new species have been collected.
The goal of this paper is to summarize and expand the current knowledge on the composition and the distribution of Chilopoda and Diplopoda in the Abrau Peninsula, which would help to improve the conservation policies in the Utrish Nature Reserve and facilitate further studies on these groups in the region.

Materials and methods
The data presented in this paper are primarily based on the field studies of the myriapods collected by the authors (a description of the sampling sites is provided in Table 1, see also Kuznetsova (referred to as DMK), A.A. Panchenkov (referred to as AAP) kindly provided additional material collected in 2008-2013. Furthermore, the species data from M. Short (2015) and invertebrate ecology research (Gongalsky et al. 2008, Korobushkin 2014, Korobushkin et al. 2014) is included too. The taxonomy follows Zalesskaja (1978), Zalesskaja and Schileiko (1991), Dányi (2007), Bonato et al. (2008), Zapparoli (2009), Bonato et al. (2011), Dányi and Tuf (2012), Bonato and Minelli (2014) for Chilopoda and the classification of Shear (2011)  Sampling. The method of myriapod sampling differed from site to site, since the samples were collected by several authors in different years. In general sampling followed on of the four basic procedures described below.
• "Hand" -animals were collected by hand on sampling sites with the average size of 400 m by way of sorting the leaf litter, upper soil layers and woody debris. Corer" -25 soil cores of 20 cm in diameter, and a depth of 15 cm were collected with the cylindrical soil corer. Samples were delivered to the laboratory in cool boxes and processed within 2-3 days, or sorted by hand immediately. • "Whipping" -whipping the branches of trees and shrubs.
The short quoted procedure names were used in the list below to specify the method of material collection for each species.
All specimens were preserved in 70% ethanol and stored in the collection of the

Notes:
The most common and abundant species in the European part of Russia (Zalesskaja 1978). It is known from the Caucasus in the south to the Altai Mountains in the east. The species also occurs north of the Polar Circle (Zalesskaja 1978, Palmén 1988. In the Caucasus, it was found in the upper soil layer (0-10 сm) and, less frequently, in the leaflitter layer of coniferous and mixed forests. The species is also known from steppes. Notes: This species is widespread in Central Asia, the Caucasus and the Crimea reaching the Chinese Karakoram in the east, and Greece and Romania in the west (Eason 1997, Stoev 2004. It is often found at high elevations, and shows preference for meadows, sometimes also recorded from caves (Zalesskaja 1978 Notes: L. forficatus is an eurytopic species, showing a pan-Holarctic distribution pattern, widely distributed from Great Britain to Turkey and Georgia, the eastern boundary of its range reaching the Ural Mountains (Zalesskaja 1978). The species has also been introduced in the Far East, Africa, North and South America, etc. (Zapparoli 2009). In the studied area, the species occurs in the leaf litter layer, under the stones and under the bark of dead trees in deciduous forests. Notes: This species is known from mesophilous woodlands (e.g. beech and fir-beech forests) in Central Europe, Italy, Bulgaria, Greece, the southern part of Russia and Ukraine, including the Crimea (Zalesskaja 1978, Stoev 2004, Zapparoli 2009 (Zalesskaja 1978, Zapparoli 1992 Notes: This South European species is distributed from Spain to Turkey and southern Ukraine (Askania Nova Biosphere Reserve). It is especially common in the Crimea Peninsula Schileiko 1991, Zapparoli andIorio 2012). The species has also been recorded in Central Europe and has been introduced into Great Britain and, probably, North America (Zapparoli and Iorio 2012). In the study area it was found beneath the stones and in the soil. Notes: This Centralasiatic-European species ranges from Great Britain and Iceland in the north to Morocco and Turkey in the south and Uzbekistan and Tajikistan in the East. The species has also been introduced into North America, some Atlantic and Pacific islands (Zapparoli 2009), and is widespread in the Caucasus (Zalesskaja and Schileiko 1991). In the Abrau Peninsula, the species occurs in the leaf litter and soil layer, under the bark of dead broadleaf trees (Q. petraea, F. orientalis, C. caucasica) forests. Notes: In habitus, the studied material strongly resembles G. oligopus, although our localities are situated far away from the currently known range of the species. Until now, G. oligopus has mostly been known from the Alpine-Dinaric area, being also recorded in the Carpathians (Christian 1996, Dányi 2007. In the Abrau Peninsula, the specimens were found beneath stones.  Simaiakis and Mylonas 2003). In Russia it is known from Southern to Far Eastern federal districts and from Murmansk region through Central Russia and Caucasus to Armenia. The species shows preference for various types of pine forests and for seashores, less frequently it is found in mixed and deciduous forests, steppes, meadows and agricultural areas (Zalesskaja et al. 1982). In the Abrau Peninsula it was mainly collected from the compressed FH layer and beneath the stones.

Family Schendylidae
Schendyla nemorensis (C.L. Koch, 1837) Notes: A common soil-dwelling European species, distributed from the Great Britain to Macaronesia and through the Mediterranean region to Rostov region of Russia (Zalesskaja et al. 1982. S. nemorensis tends to occur in the soils of open areas, less frequently in coniferous and deciduous forests, steppes and agricultural landscapes (Zalesskaja et al. 1982). In the Abrau Peninsula, the representatives of the species were collected from the soil and beneath the stones. Notes: P. trivittatus is known from Israel, western Turkey and Greece; P. aegeus is found in Rhodes (Short and Huynh 2010). The identification of these two species is extremely difficult. Due to their strikingly similar structural details, they could even be synonyms. The question of the taxonomic status of these two species remains open (Short and Huynh 2010). In the region, specimens were collected by way of whipping the branches of bushes and trees. Notes: L. coecus is widespread throughout Europe, particularly in Eastern Europe with its distribution extending to Central Asia (Short 2015). In Abrau Peninsula, the species was collected from the soil and litter layers of various forest types. Notes: This species is known from Colchis, Georgian and Russian parts of the western Caucasus (Golovatch et al. 2006). In the study area the animals were found in leaf litter, upper soil layers and under fallen twigs. Notes: T. costata is known from parthenogenetic populations in Central and Eastern Europe, as well as in some areas in the Caucasus, while bisexual populations are restricted to southern Romania, the Balkans, Anatolia, Israel, most of the Caucasus, and Crimea , Golovatch 2012. Quite often specimens are found in caves . In the Abrau Peninsula, the species was collected from the upper soil and lower leaf litter layers.

Notes:
The species distribution covers southern Russia, Abkhazia, Georgia, northwestern Azerbaijan and eastern Turkey (Golovatch et al. 2015). H. roseum is known as a typical leaf litter dweller. In the Abrau Peninsula, some individuals were collected from the compressed FH layer densely colonized by saprotrophic mycelium. This may be due to the altered, siphon-like mouthparts of Hirudisomatidans, which are presumably used for uptaking fluid food (e.g. hyphal contents) (Read and Enghoff 2009

Notes:
The species is known from Turkey, Armenia, Azerbaidjan, Georgia and southern Russia (Jensen et al. 2002, Enghoff 2006. In the area, it is strictly associated with decaying wood of fallen trees. Notes: Identification of the above species was difficult as only females and juveniles were found. C. flexum is a common and abundant species in the Krasnodar region (Chumachenko, in litt.), it was also reported from Georgia, Stavropol region and the montane parts of the Republic of Adygea, Russia (Zuev 2014). In teh study area the specimens were collected from the thick layer of leaf litter, also from overmoistening sites, rarely under barks of fallen trees.

Notes:
The species is known from the western part of Turkey, Adsharia and Abkhasia (Enghoff 2006

Notes:
The species is widespread in the Caucasus (Stavropol and Krasnodar regions of Russia and Western Georgia), where it occurs in a wide range of habitats (Zuev 2014). In the Abrau Peninsula, it is frequently found in leaf litter, rarely beneath the stones, and under the bark of fallen trees.
The PCA (Fig. 2) clearly showed specificity of ecological preferences of species belonging to different geographic distribution patterns. Mediterranean species strongly and positively correlated with meso-xerophytic and to a smaller extent xerophytic habitats (e.g. xerophytic forests and shrublands with pistachio, juniper and oriental hornbeam). Some typically Mediterranean species, e.g. S. cingulata and actively mobile aboveground S. coleoptrata tended to inhabit xerophytic habitats. It is worth noting that species like L. forficatus and L. curtipes are also found in the Abrau peninsula only in the most xeric habitats. Thus, ecological conditions of xeric habitats "weed out" (sensu Siepel 1996) the species with local ranges, but allow the existence of eurytopic species with global distribution patterns. Centralasiatic species clearly preferred grassland habitats such as hilltops of piedmonts, southern slopes of Navagir Ridge (e.g. open areas near Sukhoy Liman Lake), dominated by typical steppe vegetation (e.g. Stipa spp.) (Fig. 2). The analysis further revealed that species showing the Caucasian distribution pattern are antagonistic to meso-xerophytic and xerophytic habitats, while European species show weak relationship with any kind of habitats. Palearctic species were strongly related with mesophylic and steppe habitats. Ecological conditions of mesophytic forests, are suitable for non-indigenous species, widely distributed in the northern hemisphere (e.g., all Palearctic and pan-Holartic). We can conclude that from the faunistic point of view meso-xerophytic and xerophytic habitats are similar and independent of the species composition in the steppic and mesophylic habitats, while species composition in the latter two habitat types is clearly antagonistic.
The cluster analysis revealed that habitat preferences of myriapods within the set of sampling plots (Table 1 and section "materials" in the checklist) are generally driven by species geographic distribution pattern and microbiotope preferences (Fig. 3). The species comprizing the largest cluster mainly belong to millipedes with Caucasian distribution (64%) which are strongly associated with thick leaf litter (Fig. 3). Such litter layer is typical for mesophytic forests. Mediterranean species prefer microbiotopes beneath the stones and lying tree trunks which are typical for meso-xerophytic forests characterized by thin litter layer (Table 1).
The top two clusters in Fig. 3 consist mainly of centipedes (except for L. coecus) with the wide geographic distribution. Their relative ecological tolerance to abiotic conditions at the microbiotope level allow them to occupy not only litter but also soil horizon () and thus be equally frequent in both xerophytic shrublands (soil) and mesophytic beech forest (thick litter layer).
Our results suggest that the Abrau Peninsula is identified as a unique vegetation formation (Seregin and Suslova 2007). This is also true for the myriapod fauna. A range of ecological conditions on a relatively small peninsula allows the existence of a wide spectrum of myriapod species. This emphasizes the importance of biogeographic position of Abrau Peninsula and indicates some past connections between the northwestern Caucasus, the western part of Mediterranean region and Pontic steppes. Unfortunately, once widespread pristine habitats became very fragmented, but are still represented in Abrau Peninsula. The Relationship between presence of species belonging to different geographic distribution patterns (supplementary variables) in various investigated habitats (active variables) determined using the PCA. research conducted is the first step in a detailed study of the Myriapoda fauna of northwestern Caucasus, which should be continued. Cluster analysis of similarity (Jaccard) of myriapod species distribution patterns across sampling plots in the Abrau Peninsula with respect to their distribution type and microbiotope preferences. The geographical distribution pattern of each species has been marked using color-key. The table to the left of the cluster tree demonstrates microbiotopes, in which the respective species were found.