NATURA SLOVENIAE 24(2): 5-18 Prejeto / Received: 15. 11. 2022 SCIENTIFIC PAPER Sprejeto / Accepted: 20. 12. 2022 Biotehniška fakulteta Univerze v Ljubljani in Nacionalni inštitut za biologijo, Ljubljana, 2022 An updated checklist of the extant freshwater ostracods (Podocopida, Ostracoda, Crustacea) of Slovenia Nataša MORI1, Ali ŠALAMUN2 1National Institute of Biology, Večna pot 111, SI-1000 Ljubljana, Slovenia; E-mail: natasa.mori@nib.si 2Centre for Cartography of Fauna and Flora, Tacenska 20, SI-1000 Ljubljana, Slovenia; E-mail: ali.salamun@ckff.si Abstract. The article presents an updated checklist of the extant freshwater ostracods in Slovenia. The data were obtained from the published scientific literature up to 2012 and from field collections after 2012, mainly from springs and groundwaters and, to a lesser extent, from ponds and other surface waters. The erroneous and invalid species names cited in the existing literature are listed to avoid further misquotations. The updated checklist contains a total of 70 valid species names. The species belong to 3 superfamilies, 9 families and 32 genera. The species-richest is the family Candonidae (36 species), followed by the family Cyprididae (22 species). Further field samplings are needed to complete the species list, with the focus on the eastern and southeastern parts of Slovenia, and on the sampling of surface waters. Additionally, more in-depth literature investigations and examinations of old museum collections across Europe need to be carried out to obtain all existing data. Moreover, many stygobiotic species (i.e., species inhabiting exclusively subterranean waters), new for science, collected over the last 20 years, need to be scientifically described. Lastly, the Slovenian National Red list on ostracods needs to be urgently updated. Key words: Ostracoda, species, distribution, freshwater, groundwater, non-marine Izvleček. Posodobljen seznam recentnih dvoklopnikov (Podocopida, Ostracoda, Crustacea) celinskih voda Slovenije – V članku je predstavljen posodobljen seznam recentnih dvoklopnikov celinskih voda Slovenije. Podatki o vrstah so pridobljeni iz objavljene znanstvene literature do leta 2012 in dopolnjeni s terenskimi podatki, zbranimi po letu 2012, predvsem kot rezultat vzorčenja izvirov in podzemnih voda, v manjši meri pa ribnikov in drugih površinskih voda. Da bi se izognili nadaljnjim napačnim navedbam v znanstveni literaturi, navajamo tudi seznam neveljavnih imen vrst ter napačnih navedb imen iz obstoječe literature. Posodobljeni seznam vsebuje 70 veljavnih imen vrst. Vrste pripadajo 3 naddružinam, 9 družinam in 32 rodovom. Vrstno najbolj bogata je družina Candonidae (36 vrst), sledi ji družina Cyprididae (22 vrst). Za dopolnitev seznama vrst so potrebna nadaljnja terenska vzorčenja, s poudarkom na vzhodnem in jugovzhodnem delu Slovenije ter na vzorčenju površinskih voda. Dodatne, predvsem starejše podatke je treba izbrskati tudi s pomočjo podrobnega pregleda starejše literature in obstoječih muzejskih zbirk na evropskem nivoju. Poleg tega je treba opisati številne stigobiotske vrste (t.j., vrste, ki naseljujejo izključno podzemne vode), nove v znanosti, zbrane v zadnjih 20 letih. Nenazadnje, nujna je posodobitev nacionalnega rdečega seznama dvoklopnikov. Ključne besede: Ostracoda, vrste, porazdelitev, celinske vode, podzemne vode, nemorski 6 Nataša MORI & Ali ŠALAMUN: An updated checklist of the extant freshwater ostracods … / SCIENTIFIC PAPER NATURA SLOVENIAE 24(2): 5-18 Introduction Ostracods are one of the oldest crustacean groups, inhabiting marine, freshwater and semi- terrestrial habitats, mostly in free-living, but also in parasitic/commensal forms (Horne 2003, Karanovic 2012). Currently, approximately 8,000 extant species are described, which is around 12% of all described crustacean species in the world (Karanovic 2012). Class Ostracoda is divided into exclusively marine subclass Myodocopa and subclass Podocopa, containing marine, freshwater, semi-terrestrial, commensal and fossil species (Horne et al. 2002). Non-marine, free-living and commensal species of the order Podocopida compose over 25% of all known extant ostracod species (Meisch et al. 2019), with estimations that up to 57,000 species were found as fossils over different geological periods, starting from the Early Ordovician (Paleozoic, in rocks about 485 million years old) (Horne et al. 2002, Salas et al. 2007). The first ostracod was reported and named in 1746 by Carl von Linné as Monoculus conchapedata. This species was later renamed Cypris pubera O.F. Müller, 1776 (Mesquita- Joanes et al. 2020). For Slovenia, the first mention on living (extant) ostracods is, not surprisingly, from groundwaters, mostly due to high interest of European zoologists to explore Slovenian karst region, especially caves. In 1882, the German zoologist Gustav Joseph published an extensive report on 109 arthropod species found in so called »stalactite caves« from Krain (Joseph 1882). Among these, an ostracod Cypris stygia n. sp., described as stygobiotic species »similar to Cypris ovum but flatter« was listed. The locality for this species was indicated as the cave Podpeška jama (Podpeč, Videm-Dobrepolje). However, this species was later never described, with no drawings provided either. Similarly, ten-years later, in 1893, two ostracod species were reported from the larger dripping pool in the cave Črna jama in Postojna (Schmeil 1893). The species were named Typhlocypris schmeili and Cypria pellucida by G.W. Müller, as explained in Schmeil (1893), but later never described. The first currently known record of still valid ostracod species from Slovenia dates to 1920, when the French zoologist Paul Paris reported on Typhlocypris eremita (Veydovský, 1882), again from the cave Podpeška jama near the village Videm-Dobrepolje (Paris 1920). Paris provided drawings of his findings, too. It is highly likely that the same species was collected also by Joseph forty years before, but as no evidence exists, it is only a presumption. Further research in ostracods in Slovenia in the following decades is described in details in Mori & Meisch (2012). In 1996, the first preliminary species list of freshwater ostracods, containing 47 species, was published by Hugh Griffiths and Anton Brancelj, including mostly records from caves, springs and high mountain lakes (Griffiths & Brancelj 1996). In 2012, a first comprehensive checklist of freshwater ostracod species from Slovenia was presented in this journal, containing 61 extant freshwater ostracod species (Mori & Meisch 2012). Due to the first author’s continuous field sampling and recording of ostracod distribution across a diversity of aquatic habitats in Slovenia and due to an updated taxonomical nomenclature published by Meisch et al. (2019), the updated checklist of extant freshwater ostracods was prepared. Nataša MORI & Ali ŠALAMUN: An updated checklist of the extant freshwater ostracods … / SCIENTIFIC PAPER 7 NATURA SLOVENIAE 24(2): 5-18 Materials and metods The presented species list of extant freshwater ostracods has been extracted from the Slovenian Ostracoda Database (ODS) established in 2022 (Mori in prep.), built by the first author of that publication and incorporated in the database of the Center for Cartography of Fauna and Flora (CKFF). The ODS includes the published data on ostracod species from Slovenian localities and the unpublished data from the Slovenian Ostracoda Species Collection (OSCS), stored at the National Institute of Biology, Ljubljana and managed by the first author. The taxonomy and nomenclature have been updated according to the recent revision of extant non-marine Ostracoda by Meisch et al. (2019). Only valid species are included in the present updated checklist for Slovenia. During the history of Ostracoda research in Slovenia, many species were reported in different publications but never described (e.g., nomina nuda). Some of them were repeatedly cited in subsequent publications. To avoid future misquotations, all these names are separately listed and explanations added. A brief description on ecology of newly discovered species for Slovenia after 2012 (Mori & Meisch 2012) and their localities are also provided. Results List of species and nomenclatorial remarks The updated checklist of extant freshwater ostracods of Slovenia contains 70 valid species (Tab. 1). The species-richest is the superfamily Cypridoidea, containing 36 species from the family Candonidae, 22 species from the family Cyprididae, and 3 and 2 species from the families Ilyocyprididae and Notodromadidae, respectively. Only 6 species belong to the superfamily Cytheroidea and one to the superfamily Darwinuloidea. 8 Nataša MORI & Ali ŠALAMUN: An updated checklist of the extant freshwater ostracods … / SCIENTIFIC PAPER NATURA SLOVENIAE 24(2): 5-18 Table 1. List of extant freshwater ostracod species with at least one recorded report from Slovenia. Nomenclature follows Meisch et al. (2019). Syn. – synonym (including only synonyms reported from locations from Slovenia). *stygobiotic species (i.e., species inhabiting exclusively subterranean waters) Tabela 1. Seznam recentnih vrst dvoklopnikov z vsaj enim zabeleženim podatkom iz Slovenije. Nomenklatura se naslanja na Meisch et al. (2019). Sin – sinonim (navedeni so sinonimi samo za vrste, ki so bile najdene v Sloveniji). *stigobiontske vrste (tj. vrste, ki naseljujejo izključno podzemne vode) Taxonomic name/species References Class Ostracoda Latreille, 1802 Subclass Podocopa Sars, 1866 Order Podocopida Sars, 1866 Suborder Cypridocopina Baird, 1845 Superfamily Cypridoidea Baird, 1845 Family Cyprididae Baird, 1845 Genus Bradleycypris McKenzie, 1982 Bradleycypris obliqua (Brady, 1868) Griffiths & Brancelj 1996 Genus Bradleystrandesia Broodbakker, 1983 Bradleystrandesia fuscata (Jurine, 1820) Mori et al. 2021 Genus Cavernocypris Hartmann, 1964 Cavernocypris subterranea (Wolf, 1920) Brancelj et al. 1995 Genus Cypridopsis Brady, 1867 Cypridopsis vidua (O.F. Müller, 1776) Griffiths & Brancelj 1996 Genus Dolerocypris Kaufmann, 1900 Dolerocypris fasciata (O.F. Müller, 1776) Bioportal 2022a Dolerocypris sinensis Sars, 1903 Petkovski 1960a Genus Eucypris Vávra, 1891 Eucypris pigra (Fischer, 1851) Mori et al. 2011 Eucypris virens (Jurine, 1820) Griffiths & Brancelj 1996 Genus Heterocypris Claus, 1893 Heterocypris incongruens (Ramdohr, 1808) Griffiths & Brancelj 1996 Heterocypris reptans (Kaufmann, 1900) Petkovski 1964 Genus Potamocypris Brady, 1870 Potamocypris fallax Fox, 1967 Griffiths & Brancelj 1996 Potamocypris fulva (Brady, 1868) Mori et al. 2011 Potamocypris pallida Alm, 1914 Mori et al. 2011 Potamocypris similis G.W. Müller 1912 Griffiths & Brancelj 1996 Potamocypris smaragdina (Vávra, 1891) Griffiths & Brancelj 1996 Potamocypris variegata (Brady & Norman, 1889) Mori & Meisch 2012 Nataša MORI & Ali ŠALAMUN: An updated checklist of the extant freshwater ostracods … / SCIENTIFIC PAPER 9 NATURA SLOVENIAE 24(2): 5-18 Taxonomic name/species References Potamocypris villosa (Jurine, 1820) Griffiths & Brancelj 1996 Potamocypris zschokkei (Kaufmann, 1900) Brancelj et al. 1995 Genus Psychrodromus Danielopol & McKenzie, 1977 Psychrodromus fontinalis (Wolf, 1920) Griffiths & Brancelj 1996 Psychrodromus olivaceus (Brady & Norman, 1889) Griffiths & Brancelj 1996 Genus Scottia Brady & Norman, 1889 Scottia pseudobrowniana Kempf, 1971 Dole-Olivier et al. 2009 Genus Tonnacypris Diebel & Pietrzeniuk, 1975 Tonnacypris lutaria (Koch, 1838) Bioportal 2022c Family Candonidae Kaufmann, 1900 Genus Candona Baird, 1845 Candona bimucronata Klie, 1937 Griffiths & Brancelj 1996 Candona candida (O.F. Müller, 1776) Brancelj et al. 1995 Genus Candonopsis Vávra, 1891 Candonopsis scourfieldi Brady, 1910 Mori & Meisch 2012 Genus Cryptocandona Kaufmann, 1900 Cryptocandona reducta (Alm, 1914) Bioportal 2022a Cryptocandona vavrai Kaufmann, 1900 Mori et al. 2011 Genus Cyclocypris Brady & Norman, 1889 Cyclocypris globosa (Sars, 1863) Mori & Meisch 2012 Cyclocypris laevis (O.F. Müller, 1776) Griffiths & Brancelj 1996 Cyclocypris ovum (Jurine, 1820) Brancelj et al. 1995 Genus Cypria Zenker, 1854 Cypria bicolor Petkovski and Meisch, 1994 Petkovski & Meisch 1994 *Cypria cavernae Wagenleitner, 1990 Dole-Olivier et al. 2009 Cypria exsculpta (Fischer, 1855) Griffiths & Brancelj 1996 Cypria lacustris Lilljeborg, 1890 Petkovski 1960b Syn: Cypria ophtalmica f. lacustris (Lilljeborg, 1890) Cypria ophtalmica (Jurine, 1820) Klie 1931 *Cypria reptans Bronstein, 1928 Klie 1935 Syn.: Cypria stygia Klie, 1935 *Cypria sketi Petkovski, 1976 Mori & Meisch 2012 Genus Fabaeformiscandona Krstić, 1972 *Fabaeformiscandona aemonae (Klie, 1935) Klie 1935 10 Nataša MORI & Ali ŠALAMUN: An updated checklist of the extant freshwater ostracods … / SCIENTIFIC PAPER NATURA SLOVENIAE 24(2): 5-18 Taxonomic name/species References Syn.: Pseudocandona aemonae (Klie, 1935) *Fabaeformiscandona breuili (Paris, 1920) Mori & Brancelj 2011 Fabaeformiscandona brevicornis (Klie, 1925) Mori & Meisch 2012 *Fabaeformiscandona brisiaca (Klie, 1938) Mori et al. 2011 Fabaeformiscandona fabaeformis (Fischer, 1851) Mori et al. 2021 *Fabaeformiscandona latens (Klie, 1940) Mori et al. 2011 Genus Mixtacandona Klie, 1938 *Mixtacandona chappuisi (Klie, 1943) Dole-Olivier et al. 2009 *Mixtacandona laisi Klie, 1938 Dole-Olivier et al. 2009 Syn.: Mixtacandona stammeri (Klie, 1938) *Mixtacandona lattingerae Rogulj & Danielopol, 1993 Dole-Olivier et al. 2009 Genus Nannocandona Ekman, 1914 Nannocandona faba Eckman, 1914 Brancelj et al. 1995 Genus Neglecandona Krstić, 2006 Neglecandona lindneri (Petkovski, 1969) Petkovski 1969 Syn.: Candona lindneri Petkovski, 1969 Neglecandona neglecta (Sars, 1887) Brancelj et al. 1995 Syn.: Candona neglecta Sars, 1887 Genus Physocypria Vávra, 1897 Physocypria kraepelini G.W. Müller, 1903 Mori et al. 2021 Genus Pseudocandona Kaufmann, 1900 Pseudocandona albicans (Brady, 1864) Griffiths & Brancelj 1996 Pseudocandona hartwigi (G. W. Müller, 1900) Bioportal 2022b Pseudocandona lobipes (Hartwig, 1900) Mori & Meisch 2012 Pseudocandona pratensis (Hartwig, 1901) Mori & Meisch 2012 Pseudocandona rostrata (Brady & Norman, 1889) Mori & Meisch 2012 Genus Typhlocypris Vejdovski, 1882 *Typhlocypris cavicola (Klie, 1935) Klie 1935 Syn.: Pseudocandona cavicola (Klie, 1935) Syn.: Pseudocandona pretneri Danielopol, 1978 *Typhlocypris eremita (Vejdovský, 1882) Dole-Olivier et al. 2009 Syn.: Candona eremita (Vejdovský, 1882) Syn.: Pseudocandona eremita (Vejdovský, 1882) *Typhlocypris trigonella (Klie, 1931) Klie 1935 Nataša MORI & Ali ŠALAMUN: An updated checklist of the extant freshwater ostracods … / SCIENTIFIC PAPER 11 NATURA SLOVENIAE 24(2): 5-18 Taxonomic name/species References Syn.: Candona trigonella Klie, 1931 Syn.: Pseudocandona trigonella (Klie, 1931) Family Ilyocyprididae Kaufmann, 1900 Genus Ilyocypris Brady & Norman, 1889 Ilyocypris bradyi Sars, 1890 Petkovski 1958 Ilyocypris gibba (Ramdohr, 1808) Petkovski 1958 Syn.: Cypris biplicata Koch, 1838 Ilyocypris inermis Kaufmann, 1900 Griffiths & Brancelj 1996 Family Notodromadidae Kaufmann, 1900 Genus Notodromas Lilljeborg, 1853 Notodromas monacha (O. F. Müller, 1776) Petkovski 1959 Notodromas persica Gurney, 1921 Klie 1938 Superfamily Cytheroidea Baird, 1850 Family Cytherideidae Sars, 1925 Genus Cytherissa Sars, 1925 Cytherissa lacustris (Sars, 1863) Griffiths & Brancelj 1996 Family Entocytheridae Hoff, 1942 Genus Sphaeromicola Paris, 1916 *Sphaeromicola stammeri Klie, 1930 Sket 2000 Family Leptocytheridae Sars, 1925 Genus Leptocythere Sars, 1925 Leptocythere fluviatilis (Klie, 1939) Klie 1939 Family Limnocytheridae Sars, 1925 Genus Limnocythere Brady, 1868 Limnocythere inopinata (Baird, 1843) Griffiths & Brancelj 1996 Limnocythere sanctipatricii (Brady & Robertson, 1869) Griffiths & Brancelj 1996 Genus Metacypris Brady & Robertson, 1870 Metacypris cordata Brady & Robertson, 1870 Bioportal 2022a Superfamily Darwinuloidea Brady & Robertson, 1885 Family Darwinulidae Brady & Robertson, 1885 Genus Darwinula Brady & Norman, 1889 Darwinula stevensoni (Brady & Robertson, 1870) Griffiths & Brancelj 1996 12 Nataša MORI & Ali ŠALAMUN: An updated checklist of the extant freshwater ostracods … / SCIENTIFIC PAPER NATURA SLOVENIAE 24(2): 5-18 Eleven invalid species names, previously reported in the literature, were not included in the checklist: • Cypria pellucida G.W. Müller Nomen nudum in Schmeil (1893): species collected from the dripping pool in the cave Črna jama and named by G.W. Müller, but later never described. Further citations: Brancelj (1996). Mori & Meisch (2012) erroneously mentioned this record as »Cypris pellucida by G.W. Müller«. • Cypria reptans stygia Klie, 1935 Unaccepted name in Petkovski (1976): Petkovski mentioned this species when referring to Klie’s (1935) description of Cypria stygia Klie 1935, which is now a synonym of Cypria reptans Bronstein, 1928. Further citations: Sket & Brancelj (1992), Bole et al. (1993), Petkovski & Meisch (1994), Brancelj (1996), Griffiths & Brancelj (1996), Ur.l. RS (2002). • Cypris stygia n. sp. Nomen nudum in Joseph (1882): see Introduction. • Ilyocypris biplicata Koch, 1838 Unaccepted name in Petkovski (1958): this is a synonym of Ilyocypris gibba (Ramdohr, 1808). Further citations: Griffiths & Brancelj (1996). • Notodromas persica persica Gurney, 1921 Unaccepted name in Petkovski (1959). Further citations: Brancelj (1996). • Notodromas persicae Gurney, 1921 Typing error in Griffiths & Brancelj (1996). Correct name is Notodromas persica Gurney, 1921. • Physocypria cf. kliei Schäffer, 1934 Unverified identification in Griffiths & Brancelj (1996). Synonym of P. kraepelini. • Pseudocandona cf. marchica (Hartwig, 1899) Unverified identification in Griffiths & Brancelj (1996). • Pseudocandona cf. pseudoparallela (Löffler, 1961) Unverified identification in Griffiths & Brancelj (1996). Synonym of P. albicans. • Typhlocypris pretneri Danielopol, 1978 Erroneous generic assignment in Mori & Meisch (2012). The correct name is Pseudocandona pretneri Danielopol, 1978, which is a synonym of Typhlocypris cavicola (Klie, 1935) according to the updated taxonomy (Meisch et al. 2019). • Typhlocypris schmeili G.W. Müller Nomen nudum in Schmeil (1893): species collected from a dripping pool in the cave Črna jama and named by G.W. Müller, but later never scientifically described. Further citations: Brancelj (1996). Taxonomic notes Cypria lacustris Lilljeborg, 1890 and Cypria ophtalmica (Jurine, 1820) Cypria lacustris was listed as a valid species very recently (Meisch et al. 2019). Previously considered an intraspecific form of Cypria ophtalmica because of the occurrence of animals with transitional characters, mainly seen in the number and structure of the female genital processes (Meisch 2000). Meisch examined a very large number of individuals belonging to both »forms« from various regions in Europe and concluded that there were no occurrences of »transitional« animals. Moreover, the ecology of the two species differs: Cypria lacustris colonizes springs, Nataša MORI & Ali ŠALAMUN: An updated checklist of the extant freshwater ostracods … / SCIENTIFIC PAPER 13 NATURA SLOVENIAE 24(2): 5-18 waters connected to springs and the profundal zone of lakes, while Cypria ophtalmica occurs in ponds and the littoral zone of lakes (Meisch et al. 2019). Neglecandona lindneri (Petkovski, 1969) and Neglecandona neglecta (Sars, 1887) The genus Neglecandona Krstić, 2007, with Neglecandona lindneri (Petkovski, 1969) as the type species, was established to include the three species of the so-called neglecta-group of Candona Baird, 1845 recorded from Slovenia (Meisch et al. 2019). Genera Typhlocypris Vejdovský, 1882 and Pseudocandona Kaufmann, 1900 The treatment of the genera Typhlocypris Vejdovský, 1882 and Pseudocandona Kaufmann, 1900 follows Namiotko et al. (2014) and Meisch et al. (2019). Notes on species new for Slovenia Bradleystrandesia fuscata (Jurine, 1820) The species was collected by the first author in small water bodies fed by groundwater, in the forest, southeast from the Čukova jama pond near the Bobovek village, Kranj (46,2727 lat, 14,3623 lon), during field sampling on 30.VIII.2021 (Mori et al. 2021). The species is widespread, occurring in the Palearctic, Nearctic and Neotropical zoogeographical regions (Meisch et al. 2019) and usually occurs in seasonal pools located in the open field or in woodland where it produces large populations. It is rarely reported from permanent waters, such as fish ponds, littoral zones of lakes, and springs (Meisch 2000). Cryptocandona reducta (Alm, 1914) The species was collected during the Bioblitz event in 2017 at Draga pri Igu (Bioportal 2022a). It was collected by the first author from a littoral zone of the pond Rezani ribnik v Dragi (45,9364 lat, 14,5506 lon), from a muddy bottom, on 20.V.2017. The species is widespread in the Palearctic zoogeographical region (Meisch et al. 2019) and is usually found in springs, water connected to springs, and in the sublittoral and profundal zones of standing waters (Meisch 2000). Dolerocypris fasciata (O. F. Müller, 1776) The species was collected during Bioblitz in 2017 at Draga pri Igu (Bioportal 2022a). It was collected by the first author from two ponds overgrown by dense macrophyte vegetation: Rezani ribnik v Dragi (45,9364 lat, 14,5506 lon) and Srednji ribnik v Dragi (45,9379 lat, 14,5496 lon), on 20.V.2017. The species is widespread, occurring in the Palearctic, Nearctic and Oriental zoogeographical regions (Meisch et al. 2019). Dolerocypris fasciata is usually found in the littoral zone of lakes, (fish)ponds, swamps and similar water bodies where it is actively swimming within the subaquatic macrophyte and reed belts (Meisch 2000). Fabaeformiscandona fabaeformis (Fischer, 1851) The species was collected by the first author from the spring benthos connected to the Ledvica pond, near the village of Bobovek, Kranj (46,2759 lat, 14,3625 lon), during summer field sampling in 2021 (30.VIII.2021) (Mori et al. 2021). The species is common, occurring in the Palearctic and Oriental zoogeographical regions (Meisch et al. 2019). It can usually be found 14 Nataša MORI & Ali ŠALAMUN: An updated checklist of the extant freshwater ostracods … / SCIENTIFIC PAPER NATURA SLOVENIAE 24(2): 5-18 in muddy and swampy temporary small water bodies, while in lakes it dwells in the very shallow zone that dries up in the summer. It is also reported from drainage ditches and (fish)ponds (Meisch 2000). Metacypris cordata Brady & Robertson, 1870 The species was collected during Bioblitz in 2017 at Draga pri Igu (Bioportal 2022a). It was collected by the first author from the pond Rezani ribnik v Dragi (45,9364 lat, 14,5506 lon), which is densely overgrown by macrophyte vegetation, on 20.V.2017. The species is widespread in the Palearctic zoogeographical region (Meisch et al. 2019) and usually occurs in littoral vegetation in mesotrophic to eutrophic waters, from ditches, slow streams to ponds and lakes (Meisch 2000). Physocypria kraepelini G. W. Müller, 1903 The species was collected by the first author in two ponds, Krokodilnica (46,2727 lat, 14,3623 lon) and Ledvička (46,2727 lat, 14,3623 lon), near the village of Bobovek, Kranj, during the field sampling on 30.VIII.2021 (Mori et al. 2021). The species is widespread, occurring in the Palearctic, Nearctic and Oriental zoogeographical regions (Meisch et al. 2019). It is usually found in (fish)ponds, the littoral zone of lakes, stream, canals and ditches (Meisch 2000). Pseudocandona hartwigi (G. W. Müller, 1900) The species was collected by the first author during Bioblitz in 2018 in the Rački Ribniki- Požeg Landscape Park (Rače, Maribor) (Bioportal 2022b) from a temporary pool on the southern side of the Srednji Turnski ribnik pond (46,4346 lat, 15,6736 lon), on 16.VI.2018. The species is globally present in the Palearctic zoogeographical region (Meisch et al. 2019) and known from muddy small water bodies and the shallow zone of lakes (Meisch 2000). Pseudocandona rostrata (Brady & Norman, 1889) The species was collected in the Bohinj Lake littoral by A. Brancelj on 22.VI.2005 (46,2786 lat, 13,8863 lon). The species was erroneously quoted as »Pseudocandoma rostrata« in Mori & Meisch (2012) under New records for Slovenia and erroneously not listed in the 2012 species list. The species is globally present in the Palearctic and Nearctic zoogeographical regions (Meisch et al. 2019) and known from permanent and temporary small water bodies and lakes, springs, streams and interstitial groundwater (Meisch 2000). Sphaeromicola stammeri Klie, 1930 The species is reported from the cave Križna jama (46,2794 lat, 13,8868 lon) by Sket (2000) and later by Sket and Stoch (2014), and was not included in the previous checklists which reported only on free-living species. The species is recorded for the Palearctic zoogeographical region and lives as commensal (ectoparasite) on hypogean crustaceans (Meisch et al. 2019). Tonnacypris lutaria (Koch, 1838) The species was collected by the first author during Bioblitz 2021 in the karst intermittent Pivka River, under the bridge, west of the village Slovenska vas (45,7005 lat, 14,2078 lon), on 23.VI.2021 (Bioportal 2022c). The species is widespread, occurring in the Palearctic and Neotropical zoogeographical regions (Meisch et al. 2019) and usually inhabiting grassy seasonal Nataša MORI & Ali ŠALAMUN: An updated checklist of the extant freshwater ostracods … / SCIENTIFIC PAPER 15 NATURA SLOVENIAE 24(2): 5-18 pools and ditches, mainly in the open field, which dry up in late spring or early summer. It is sometimes found also in springs and water connected with springs (Meisch 2000). Discussion The total number of currently known extant freshwater ostracod species for Slovenia is 70. The species belong to families Candonidae, Cyprididae, Ilyocyprididae and Notodromadidae (superfamily Cypridoidea); families Cytheridae, Entocytheridae, Leptocytheridae, Limnocytheridae (superfamily Cytheroidea); and family Darwinulidae (superfamily Darwinuloidea). The species distribution among three main lineages (i.e., Cypridoidea, Cytheroidea, Darwinuloidea) is in accordance with global diversity patterns, where Cypridoidea is the largest group, comprising 4 families, followed by Cytheroidea, which are mostly marine, but have several non-marine incursions of which the Limnocytheridae are the commonest. The Darwinuloidea, with one extant family, are fully non-marine and containing only about 38 species (Martens et al. 2008; Meisch et al. 2019). However, the species distribution between families differs substantially from the global pattern, where the most diverse family in non- marine habitats is the Cyprididae, comprising 43.2% of all species, followed by the Candonidae (29.0%), Entocytheridae (9.1%) and Limnocytheridae (7.0%) (Meisch et al. 2019). The main reason is unbalanced ostracod sampling and research in Slovenia, focusing mostly on groundwater habitats, where highest species diversity belongs to Candonidae, while surface waters, where Cyprididae prevails, were sampled with much less effort. In comparison to other European countries, the current number of extant freshwater ostracod species in Slovenia is similar to Belgium (71 species) and the Czech Republic (70 species). The highest number of extant freshwater ostracod species is according to Pieri et al. (2015) known for Italy (152 species), Germany (126 species) and France (113 species), which is, most likely, connected with the size of the study areas, diversity of habitats and with the intensity of ostracod sampling and research. Due to the transitional nature of Slovenia by means of climate, hydrogeology and vegetation and due to turbulent geological history as well as connectivity with the Dinaric region and highly developed karstic region, the number of species currently known for Slovenia is most likely underestimated. Povzetek Dvoklopniki so ena izmed najstarejših skupin rakov, ki naseljujejo morje, celinske vode in semiterestrične habitate. Trenutno je opisanih približno 8000 recentnih vrst, kar je približno 12 % vseh opisanih vrst rakov na svetu. Nemorske, prostoživeče in komenzalne vrste iz redu Podocopida sestavljajo več kot 25 % vseh znanih obstoječih vrst dvoklopnikov. Prvi zaenkrat znani zapis veljavne vrste dvoklopnika iz Slovenije je iz leta 1920, ko je francoski zoolog Paul Paris poročal o vrsti Typhlocypris eremita (Veydovský, 1882) iz Podpeške jame pri vasi Podpeč (Videm-Dobrepolje). V prispevku predstavljamo posodobljen seznam dvoklopnikov iz Slovenije. Zadnji objavljeni seznam iz leta 2012 poroča o 61 prostoživečih vrstah 16 Nataša MORI & Ali ŠALAMUN: An updated checklist of the extant freshwater ostracods … / SCIENTIFIC PAPER NATURA SLOVENIAE 24(2): 5-18 dvoklopnikov. Posodobljeni seznam, predstavljen v tej publikaciji, vsebuje 70 veljavnih vrst. Vrstno najbolj bogata je naddružina Cypridoidea, ki vsebuje 36 vrst iz družine Candonidae, 22 vrst iz družine Cyprididae ter 3 oziroma 2 vrsti iz družine Ilyocyprididae in Notodromadidae. Samo 6 vrst pripada naddružini Cytheroidea in ena naddružini Darwinuloidea. V primerjavi z drugimi evropskimi državami je trenutno število znanih vrst dvoklopnikov v Sloveniji podobno kot v Belgiji (71 vrst) in na Češkem (70 vrst). Največja vrstna pestrost je trenutno zabeležena za Italijo (152 vrst), Nemčijo (126 vrst) in Francijo (113 vrst), kar je najverjetneje povezano z velikostjo preučevanih območij, pestrostjo habitatov in z intenzivnost vzorčenja in raziskovanja. Zaradi podnebno, hidrogeološko in vegetacijsko prehodne narave Slovenije, zaradi burne geološke zgodovine ter povezanosti z dinarskimi predeli in dobro razvitim krasom predvidevamo, da je trenutno število vrst dvoklopnikov podcenjeno. Za dopolnitev seznama vrst so potrebna nadaljnja terenska vzorčenja, s poudarkom na vzhodnem in jugovzhodnem delu Slovenije ter na vzorčenju površinskih voda. Poleg tega je treba za pridobitev vseh obstoječih podatkov opraviti še bolj poglobljeno raziskavo literature in starih muzejskih zbirk po Evropi, pa tudi opisati številne stigobiontske vrste, nove za znanost, najdene v zadnjih 20 letih. Nenazadnje je nujna posodobitev nacionalnega rdečega seznama dvoklopnikov. Acknowledgements The work was partly funded by the Slovenian Research Agency (Z1-2213, P1-0255). Taxonomy was in part checked and organized in LIFE project NAtuRe Conservation Information System – LIFE NarcIS (LIFE19 GIE/SI/000161). The authors are grateful to organizers of Slovenian BioBlitz events that stimulated additional field collections of ostracods and CKFF as a technical support to build a Slovenian Ostracoda Database (ODS). Special thanks go to colleagues: Grega Bračko, Anton Brancelj, Barbara Debeljak, Teo Delić, Cene Fišer, Andrej Kapla, Žiga Ogorelec, Maja Opalički Slabe, Boris Sket, Maja Zagmajster and Uroš Žibrat, for collecting samples during various field campaigns and passing the ostracods specimens to the first author for identification. References Bioportal (2022a): BioBlitz Slovenija 2017 - dolina Drage pri Igu 2017 - Natura v 24 urah. Bioportal, Center za kartografijo favne in flore. https://www.bioportal.si/projekti_podatki.php [accessed on 14.11.2022] Bioportal (2022b): BioBlitz Slovenija 2018 – Rače, Bioportal, Center za kartografijo favne in flore. https://www.bioportal.si/projekti_podatki.php [accessed on 14.11.2022] Bioportal (2022c): BioBlitz Slovenija 2021 - Petelinjsko jezero, Bioportal, Center za kartografijo favne in flore. https://www.bioportal.si/projekti_podatki.php [accessed on 14.11.2022] Bole J., Drovenik B., Mršić N., Sket B. (1993): Endemic animals in hypogean habitats in Slovenia. Naše jame 35(1): 43-55. Brancelj A. (1996): Raki dvoklopniki (Crustacea: Ostracoda) v celinskih vodah. In: Gregori J., Martinčič A., Tarman K., Urbanc-Berčič O., Tome D., Zupančič M. (Eds.), Narava Slovenije, stanje in perspektive. Društvo ekologov Slovenije, Ljubljana, pp. 236-237. Brancelj A., Urbanc-Berčič O., Krušnik C., Kosi G., Povž M., Dobravec J. (1995): Življenje v vodah Triglavskega Narodnega Parka. Razprave in raziskave: strokovna knjižnica Triglavskega narodnega parka 4. Triglavski Narodni Park, Bled, 101 pp. Nataša MORI & Ali ŠALAMUN: An updated checklist of the extant freshwater ostracods … / SCIENTIFIC PAPER 17 NATURA SLOVENIAE 24(2): 5-18 Dole-Olivier M.J., Castellarini F., Coineau N., Galassi D.M.P., Martin P., Mori N., Valdecasas A., Gibert J. (2009): Towards an optimal sampling strategy to assess groundwater biodiversity: comparison across six European regions. Freshw. Biol. 54(4): 777-796. Griffiths H.I., Brancelj A. (1996): Preliminary list of freshwater Ostracoda (Crustacea) from Slovenia. Ann. Istrian Mediterr. Stud. 9: 201-210. Horne D.J. (2003): Key events in the ecological radiation of the Ostracoda. In: Park L.E., Smith A.J. (Eds.), Bridging the gap: trends in the ostracode biological and geological sciences. Paleontology Society Paper 9, Yale University Press, New Haven, pp. 181-201. Horne D.J., Cohen A., Martens K. (2002): Taxonomy, morhology and biology of Quaternary and living Ostracoda. In: Holmes J.A., Chivas A.R. (Eds.), The Ostracoda. Applications in Quaternary Research. Geophysical Monograph 131, American Geophysical Union, Washington, DC, pp. 5-36. Joseph G. (1882): Systematisches Verzeichniss der in den Tropfstein-Grotten von Krain einheimischen Arthropoden nebst Diagnosen der vom Verfasser entdeckten und bisher noch nicht beschriebenen Arten. Berliner Entomol. Z. 56(1): 1-50. Karanovic I. (2012): Recent freshwater ostracods of the world. Springer-Verlag, Berlin Heidelberg, 608 pp. Klie W. (1931): Zwei neue Arten der ostracoden-Gattung Candona aus unterirdischen Gewassern im sudostlichen Europa. Zool. Anz. 96(7/8): 161-169. Klie W. (1935): Drei neue Hohlenostracoden aus der Umgebung von Laibach. Zool. Anz. 111: 189-198. Klie W. (1938): Ostracoden aus unterindirchen Gewassern in Suditalien. Zool. Anz. 123(5/6): 148-155. Klie W. (1939): Studien über Ostracoden aus dem Ohridsee. II: Limnocytherinae und Cytherinae. Arch. Hydrobiol. 25: 631-646. Martens K., Schön I., Meisch C., Horne D.J. (2008): Global diversity of ostracods (Ostracoda, Crustacea) in freshwater. Hydrobiologia 595: 185-193. Meisch C. (2000): Freshwater Ostracoda of Western and Central Europe. Spektrum Akademischer Verlag GmbH, Heidelberg, Berlin, 522 pp. Meisch C., Smith R.J., Martens K. (2019): A subjective global checklist of the extant non-marine Ostracoda (Crustacea). Eur. J. Taxon 492: 1-135. Mesquita-Joanes F., Aguilar-Alberola J., Palero F., Rueda J. (2020): A new species of Cypris (Crustacea: Ostracoda) from the Iberian Peninsula and the Balearic Islands, with comments on the first ostracod named using the Linnean system. Zootaxa 4759: 113-131. Mori N., Brancelj A. (2011): Spatial and temporal variability of hyporheic invertebrate community within a stream reach of the River Bača (W Slovenia). Nat. Slov. 13(1): 25-38. Mori N., Meisch C. (2012): Contribution to the knowledge on the distribution of recent free-living freshwater ostracods (Podocopida, Ostracoda, Crustacea) in Slovenia. Nat. Slov. 14(2): 5-22. Mori N., Oz B., Kanduč T., Kocman D. (2011): Ostracoda in South-eastern Alps (Slovenia): assemblages in ground waters, springs and adjacent spring brooks. 7th European Ostracodologists Meeting, Universalmuseum Joanneum GmbH, Graz, pp. 147-150. Mori N., Bedjanič M., Brancelj A., Ambrožič Ergaver Š., Ratajc U., Plut M. (2021): Inventarizacija vodnih nevretenčarjev na območju Naravnega rezervata Glinokopnih bajerjev z okolico v Bobovku pri Kranju. Končno poročilo - Nacionalni inštitut za biologijo, Ljubljana, 40 pp. 18 Nataša MORI & Ali ŠALAMUN: An updated checklist of the extant freshwater ostracods … / SCIENTIFIC PAPER NATURA SLOVENIAE 24(2): 5-18 Namiotko T., Danielopol D.L., Meisch C., Gross M., Mori N. (2014): Redefinition of the genus Typhlocypris Vejdovský, 1882 (Ostracoda, Candonidae). Crustaceana 87: 952-984. Paris P. (1920): Ostracods (première série). Arch. zool. exp. gen. 58: 475-487. Petkovski T.K. (1958): Süsswasser Ostracoden aus Jugoslawien. II. Subfam. Ilyocyprinae. Fragm. Balc. 2(8): 53-58. Petkovski T.K. (1959): Süsswasserostracoden aus Jugoslawien VI. Acta Mus. Maced. Sci. Nat. 6(3): 53-75 Petkovski T.K. (1960a): Susswasserostracoden aus Jugoslavien VII. Fragm. Balc. 3(12): 100-106. Petkovski T.K. (1960b): Zur Kenntnis der Crustaceen des Prespasees. Fragm. Balc. 3(15): 117-131. Petkovski T.K. (1964): Bemerkenswerte Entomostraken aus Jugoslavien. Acta Mus. Maced. Sci. Nat. 9(7): 147-182. Petkovski T.K. (1969): Einige neue und Bemerkenswerte Candoninae aus dem Ohridsee und einigen andered Fundorten in Europa. Acta Mus. Maced. Sci. Nat. 11(5): 81-111. Petkovski T.K. (1976): Zwei neue und eine seltene Ostracoden-Art der Gattung Cypria ZENKER aus Jugoslawien (Nebst einer Bestimmunstabelle der europäischen Arten). Acta Mus. Maced. Sci. Nat. 14(7): 174-192. Petkovski T.K., Meisch C. (1994): Cypria bicolor n. sp., a new crenobiont freshwater ostracod (Crustacea, Ostracoda) from Slovenia. Bull. Soc. Nat. luxemb. 95: 229-236. Pieri V., Martens K., Meisch C., Rossetti G. (2015): An annotated checklist of the Recent non-marine ostracods (Ostracoda: Crustacea) from Italy. Zootaxa 3919: 271-305. Salas M.J., Vannier J., Williams M. (2007): Early Ordovician ostracods from Argentina: their bearing on the origin of the binodicope and palaeocope clades. J. Paleontol. 81: 1384-1395. Schmeil O. (1893): Zur Hohlenfauna des Karstes. Z. Nat. wiss. 66: 339-353. Sket B. (2000): Pregled in izbor jam v Republiki Sloveniji, ki so pomembne za ohranjanje podzemske favne. Ljubljana, 36 pp. Sket B., Brancelj A. (1992): Rdeči seznam ogroženih sladkovodnih nižjih rakov (Entomostraca: Anostraca, Cladocera, Copepoda, Ostracoda) v Sloveniji. Varstvo narave 17: 165-172. Sket B., Stoch F. (2014): Recent Fauna of the Cave Križna jama in Slovenia. — Mitt. Komm. Quartärforsch. Österr. Akad. Wiss. 21: 45-55. Ur. l. RS (2002): Pravilnik o uvrstitvi ogroženih rastlinskih in živalskih vrst v rdeči seznam. Uradni list Republike Slovenije, Ljubljana 12(82): 8994–8975 (24.9.2002).