Contribution to the Knowledge on Distribution of Tardigrada in Turkey

: Tardigrades have been occasionally studied in Turkey since 1973. However, species number and distribution remain poorly known. In this study, distribution of Tardigrades in the province of Karabük, which is located in northern coast (West Black Sea Region) of Turkey, was carried out. Two moss samples were collected from the entrance of the Bulak (Mencilis) Cave. A total of 30 specimens and 14 eggs were extracted. Among the specimens; Echiniscus granulatus (Doy è re, 1840) and Diaforobiotus islandicus islandicus (Richters, 1904) are new records for Karabük. Furthermore, this study also provides a current checklist of tardigrade species reported from Turkey, indicating their localities, geographic distribution and taxonomical comments.


Introduction
Caves are not only one of the most important forms of karst, but also one of the most unique forms of karst topography in terms of both size and formation characteristics, which are formed by mechanical melting and partly chemical erosion of water [1].Most of the caves in Turkey were developed within the Cretaceous and Tertiary limestone, metamorphic limestone [2], and up to now ca.40 000 karst caves have been recorded in Turkey.Although, most of these caves are found in the karstic plateaus zone in the Toros System, important caves, such as Kızılelma, Sofular, Gökgöl and Mencilis, have also formed in the Western Black Sea [3].Some invertebrate communities can adapt well to these interesting underground formations, whose habitats are found rarely on earth [4,5].Tardigrades, also known as water bears, are microscopic invertebrates that are one of these invertebrates that can survive in this environment with its harsh conditions.In general, tardigrades inhabit marine, freshwater and terrestrial environments (deserts, soil and leaf litters, mosses, lichens and liverworts, underground and marine caves throughout the world [6,7].Until now, 30 families, 142 genera and nearly 1300 tardigrade species and 34 subspecies have been reported worldwide [8].
This paper reports two tardigrade species, which were discovered for the first time from the Bulak (Mencilis) Cave, in Karabük.In addition, we also provide a full checklist of tardigrade species reported from Turkey with their localities, geographic distributions and taxonomical comments.

Materials and Methods
In March 2017, two moss samples were collected from the entrance of Bulak (Mencilis) Cave (41 • 16 30.1836"N; 32 • 37 28.4628"E), which is located nearly 8.5 km northwest of Safranbolu, the largest and most developed province of Karabük [23].Bulak (Mencilis) Cave is the fourth largest cave in Turkey with a length of approximately 6 km [24,25].
One moss sample was collected from a rock which was found around the entrance of the Cave and the other from the wall of the entrance.Both samples were put into paper bags and let dry in the laboratory.They were later examined for terrestrial tardigrades using a standard method described by Dastych [26] with modifications described by Stec and Smolak [27].The samples were placed in a beaker for rehydration with tap water in the laboratory.One day later after stirring, the water containing moss particles were poured into a 200 ml cylinder.After precipitation, approximately 50 ml of remaining sediment was taken into a glass petri dish.Tardigrades and eggs were placed from the sediment under the stereomicroscope (Leica MZ16 A).Tardigrades and their eggs were mounted on microscopic slides in Hoyer's medium and observations and the photomicrographs were made using a phase-contrast microscope (Zeiss Axio Imager M1).The species were identified using the monograph published by Ramazotti and Maucci [7] and according to Guidetti et al. [22].For genus abbreviations we referred to Perry et al. [28].All slides, which were secured with a transparent nail polish, were stored in the Ankara University, Department of Biology, Aquatic Animals Research Laboratory.

Results
In total, 30 specimens and 14 eggs were found.Within those specimens, 10 belong to the genus Paramacrobiotus Guidetti, Schill, Bertolani, Dandekar and Wolf, 2009 [29] and they have not been identified to species level due to the absence of eggs.The remaining 20 specimens and 14 eggs were identified as Ech.granulatus (Doyère, 1840) [30] and Dia.i. islandicus (Richters, 1904) [31], which are new records for the province of Karabük.
Diversity 2019, 11, x FOR PEER REVIEW 5 of 14 With our study, we added Karabük to the provinces in Turkey in which tardigrades have been recorded and thus, increased the number from 31 to 32 (see Figure 3 and Table 2 for details).Table 2.The final list of all reported tardigrade species (marine and terrestrial) from Turkey.
Reported from Afyonkarahisar and Erzurum [11,13].Table 2.The final list of all reported tardigrade species (marine and terrestrial) from Turkey.
This marine species has numerous reports from the Mediterranean Sea.In Turkey, it was found the Bosphorous at ˙Istanbul in Black Sea [19].
This cosmopolitan species group requires the majority of records to be confirmed [9,59].It has been reported from ˙Izmir, Turkey [11,12].
This species is considered cosmopolitan, but a species group the majority of records need to be confirmed [9,59].It has been reported from ˙Izmir and Mersin, Turkey [11,12].
Reported from Ankara.However, this species' presence in Turkey needs to be confirmed [9,18,61].
Considered a cosmopolitan species group, it was reported from Ankara [12].This species' presence in Turkey needs to be verified [61].Europe, Russia, North and South America [36].
Described as a cosmopolitan species group, this species was reported from Ankara and ˙Izmir, Turkey [10].
In Turkey, it has been reported from the Bosphorus of ˙Istanbul in the Black Sea [19].
This endemic species was originally reported from A grı, Erzurum and Gaziantep, Turkey [12].

Discussion
We found Dia. i. islandicus (Richters, 1904) [31] in the province of Karabük, which is located in the Black Sea Region.It had previously been reported from ˙Izmir, located in the Aegean Region of Turkey.This species has been identified from many localities in Europe, Africa, Indonesia, and North America [36].
Although taxonomic and biogeographic studies on caves harboring tardigrades have been conducted for many years, there is still poor knowledge of their patterns of diversity.Only a

Table 1 .
Measurements of selected morphological characters of largest and smallest specimens of Dia.
i. islandicus and eggs (all values in µm, pt ratios in brackets).

Table 1 .
Measurements of selected morphological characters of largest and smallest specimens of Dia.i. islandicus and eggs (all values in µm, pt ratios in brackets).Diversity 2020, 12, 95 5 of 12