NATURA SLOVENIAE 25(2): 27-52 Prejeto / Received: 29. 10. 2023 SCIENTIFIC PAPER Sprejeto / Accepted: 13. 12. 2023 DOI: 10.14720/ns.25.2.27-52 Biotehniška fakulteta Univerze v Ljubljani in Nacionalni inštitut za biologijo, Ljubljana, 2023 A checklist of isopods (Crustacea: Isopoda) in Slovenia Miloš VITTORI 1 , Borut MAVRIČ 2 , Anja PEKOLJ 1 , Marijan GOVEDIČ 3 , Maja ZAGMAJSTER 1 1 University of Ljubljana, Biotechnical Faculty, Department of Biology, Večna pot 111, SI-1000 Ljubljana, Slovenia; E-mails: milos.vittori@bf.uni-lj.si, anja.pekolj@bf.uni-lj.si, maja.zagmajster@bf.uni-lj.si 2 Marine Biological Station, National Institute of Biology, Fornače 41, SI-6339 Piran, Slovenia; E-mail: borut.mavric@nib.si 3 Center za kartografijo favne in flore, pisarna Ljubljana, Tacenska 20, SI-1000 Ljubljana, Slovenia; E-mail: marijan.govedic@ckff.si Abstract. Isopods are a diverse peracarid crustacean group with marine, freshwater and terrestrial representatives. Isopod species lists were typically prepared according to different habitats, which was also the case for Slovenia. Here, we prepared the first unified overview of isopod species of Slovenia, which is also the first list of marine isopods in the country. We examined scientific publications, research reports and institutional databases. A total of 125 species have been recorded in Slovenia, of which 30 are marine, 21 are found in inland waters, and 74 are terrestrial. Of these, we report seven marine and one terrestrial species for the first time. A major part of freshwater isopod richness is linked to the subterranean environment, where most endemic species for the country can be found. Among marine species, many are parasites, with potential economic impact, and two species are considered introduced. When the new species list was compared to the valid national Red List of endangered species from 2002 and the Decree on Protected Wild Animal Species from 2004, only 41 species retained the same taxonomic status. Taking into consideration the recent taxonomic insights, many synonyms and invalid taxa call for a revison of the national Red List of Malacostraca and other nature protection acts. Key words: Peracarida, marine, freshwater, terrestrial, subterranean, fauna Izvleček. Pregled vrst rakov enakonožcev (Crustacea: Isopoda) Slovenije – Enakonožci so pestra skupina rakov valilničarjev z morskimi, sladkovodnimi in kopenskimi predstavniki. Seznami vrst enakonožcev običajno predstavljajo posamezne habitate, kar drži tudi za Slovenske. V tem prispevku smo pripravili prvi skupni pregled vrst enakonožcev v Sloveniji, ki je tudi prvi pregled morskih vrst enakonožcev v državi. Nekateri, zlasti morski paraziti imajo lahko tudi negativen ekonomski učinek. Pregledali smo predhodno zbrane podatke o pojavljanju enakonožcev na ozemlju Slovenije v znanstvenih in strokovnih prispevkih, poročilih raziskav ter podatkovnih bazah sodelujočih ustanov. Skupno je bilo v Sloveniji zaznanih 125 vrst, od tega 30 morskih, 21 v celinskih vodah in 74 kopenskih. V tem prispevku prvič poročamo o pojavljanju sedmih morskih in ene kopenske vrste. Velik delež vrstnega bogastva enakonožcev je vezan na podzemlje, kjer lahko najdemo tudi večino slovenskih endemitov v celinskih vodah in na kopnem. Med morskimi vrstami je mnogo parazitov, ki imajo lahko ekonomski vpliv, ter dve tujerodni vrsti. Če prenovljeni seznam vrst primerjamo z veljavnim Rdečim seznamom ter Uredbo o zavarovanih prosto živečih živalskih vrstah, zgolj 41 vrst ohrani enake taksonomske statuse. Številni sinonimi in neveljavni taksoni glede na trenutno taksonomijo skupine kažejo na potrebo po reviziji nacionalnega Rdečega seznama višjih rakov ter drugih varstvenih aktov. Ključne besede: Peracarida, morski, celinske vode, kopenski, podzemni, favna 28 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER NATURA SLOVENIAE 25(2): 27-52 Introduction Isopods are a diverse order of peracarid crustaceans, with over 10,000 described species worldwide (Boyko et al. 2008). They inhabit almost all marine, freshwater, and terrestrial environments, from the deep sea to deserts (Sfenthourakis & Taiti 2015). Most species of the order are marine, while among non-marine ones, the suborder Oniscidea represents more than three quarters of known species (Boyko et al. 2008). This suborder is one of the few crustacean groups successful in terrestrial habitats, being an order of magnitude richer in terrestrial species than terrestrial decapods or amphipods (Broly et al. 2013). Isopods are important decomposers of plant matter both in aquatic (Wilson 2008) and terrestrial environments (David 2014; Sfenthourakis & Taiti 2015); on land, they may contribute greatly to soil formation (Zimmer 2002; David 2014). Numerous marine isopods live in close association with other benthic organisms and many are parasites, often on fish (Poore & Bruce 2012). Parasitic and wood-boring marine isopods can have a considerable negative economic impact (Borges et al. 2014; Čolak et al. 2018). Isopods are also a very successful arthropod group in subterranean freshwater and terrestrial environments (Coineau & Boutin 2004; Hobbs 2012; Sfenthourakis & Hornung 2018). As decomposers that tend to accumulate metals in their tissues, isopods are important experimental organisms in ecotoxicology, particularly in studies dealing with metal and nanoparticle toxicity. Terrestrial species are particularly well studied in this respect (van Gestel et al. 2018), but ecotoxicological studies have also been performed on aquatic species (Lukančič et al. 2010; Plahuta et al. 2017). This has been one of the most flourishing research topics concerning this group in the past few decades (Vittori & Dominko 2022). Isopods are also important in basic research, particularly in developmental biology, studies of microbe-host interactions and, as their representatives span various degrees of adaptation to terrestrial life, the study of the transition from water to land (Hornung 2011; Vittori & Dominko 2022). Isopods, particularly representatives of the genus Asellus, are also some of the best studied subterranean invertebrates and serve as models for studying adaptations to the subterranean environment (Konec et al. 2015; Re et al. 2018; Balázs et al. 2021). Due to the success of isopods in the sea, in inland waters, and on land, studies of their diversity are generally in the domains of four categories of biologists: marine zoologists, limnologists, speleobiologists, and researchers dealing with the edaphic fauna. As a result, it is challenging to bring lists of species records together. Additionally, many isopods inhabit different subterranean habitats, aquatic as well as terrestrial. Caves harbour isopods that are amphibious or secondarily aquatic, particularly among Oniscidea (Sfenthourakis & Taiti 2015). In Slovenia, overviews of species occurrence were made separately according to different habitats. For terrestrial species, Karaman (1966) and Potočnik (1989) assembled checklists for the former state of Yugoslavia in the Western Balkans, with species listed separately for each federal republic (now countries), including the territory of Slovenia. Potočnik published several works on the terrestrial isopods of Slovenia (Potočnik 1979, 1980, 1981, 1984, 1992; Potočnik & Novak 1980). As for aquatic isopods, a checklist with descriptions of known distributions was published in the overview of all aquatic crustaceans for the former state of Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER 29 NATURA SLOVENIAE 25(2): 27-52 Yugoslavia (Sket 1967). The Asellidae, in particular, are well studied, with integrated occurrence, habitat, and molecular data now available in the World Asellidae Database, including data from Slovenia (Saclier et al. 2024). Only a few publications are available on the occurrence of marine isopods in Slovenia (Sket 2008; Tratar 2010). A checklist of crustaceans occurring in the Gulf of Trieste was compiled more than a century ago by Graeffe (1902), with many of the species likely occurring also in the Slovenian part of the Gulf. T h e a i m o f t h i s c o n t r i b u t i o n i s t o p r o v i d e a n u p d a t e d c h e c k l i s t o f i s o p o d s i n S l o v e n i a th a t considers taxonomic revisions and data acquired after the 1980s. It represents a reference point regarding the present state of knowledge and can form the basis for planning much needed systematic studies of the isopod fauna in marine, freshwater, and terrestrial environments. An overview of species was needed also to evaluate the current species richness of isopods, identify newly introduced species and provide a reference for a revision of protective legislation. Materials and methods Data were mostly collected from published species checklists that either focus on or include isopods and other references that report on the occurrence of isopods in Slovenia. The information from such literature sources that refer to subterranean taxa and/or subterranean habitats were extracted from the database SubBioDB (a taxonomic distributional database, established and managed by the Subterranean Biology Laboratory (SubBioLab) at the Department of Biology, Biotechnical Faculty, University of Ljubljana). The overview of marine taxa was based mostly on records from specimen collections of the Marine Biology Station Piran ( M B P ) , w h i c h i s a p a r t o f t h e N a t i o n a l I n s t i t u t e o f B i o l o g y i n S l o v e n i a . F i n a l l y , d a t a w e r e supplemented with those from the database of the Center of Cartography of Fauna and Flora in Slovenia. In addition to reviewing existing literature, we also checked the extensive terrestrial isopod collection in the Slovenian Museum of Natural History in Ljubljana (SMNH), deposited there by Franc Potočnik. In the collection, we focused on species with a sin gle record to confirm their identifications and presence in the country. We were able to successfully identify previously reported and deposited material of Philoscia muscorum, Porcellio marginalis (Potočnik 1984), and Oniscus asellus (Potočnik 1980). We also consulted publicly accessible databases, the World Register of Marine Species (WoRMS Editorial Board 2023), the Global Biodiversity Information Facility (GBIF 2023), and the Pan-European Species Directories Infrastructure (PESI 2023). As subspecies were often not reported and their statuses are in need of reassessment, the list is limited to species and the current statuses of subspecies are only discussed regarding protective legislation. The presence of each species is referenced by listing a single published reference, which in most cases represents the most recent publication that includes the species. The previous checklists we refer to should be used to identify primary sources of the records. For species previously not included in checklists, we provide the source publications reporting on their occurrence. In the case of unpublished records, we provide detailed localities where the species in question were recorded. 30 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER NATURA SLOVENIAE 25(2): 27-52 Even though we acknowledge that some isopods cannot be placed in a single habitat category, we add information on the preferred habitat (terrestrial, freshwater, or marine), and mark obligate subterranean species separately as well as information on whether a species is introduced, endemic, or parasitic. We also point out species that were scientifically described from the territory of Slovenia. In a special section, we list the species that have been reported in the literature, but there is reasonable doubt that they occur in Slovenia. Changing taxonomy and improved knowledge results in changes in taxonomic statuses and new species descriptions. Considering the time lag since the publication of the last checklists of isopods and since the acceptance of the national Red List of Malacostraca (Ur. l. RS 2002), taxonomic and status changes could be expected. We prepared an overview of the current national Red List and an overview of changed statuses due to changes in taxonomy. Statuses of subspecies included in the Red List were checked in the World Register of Marine Species (WoRMS Editorial Board 2023). While we discuss the current taxonomic validity of the species in these lists, this is to spur the revision of legislation documents and not to determine or change the protection statuses of recorded species. Results Overview of the species checklist A total of 125 species of isopods, belonging to seven suborders, 31 families and 62 different genera, can be confirmed for Slovenia (Tab. 1). For eight species, the presence in the country had not been published before, hence we provide the first data on their occurrence in Tab. 2. Eight species that have been reported for the country in past publications cannot reliably be considered as part of the Slovenian fauna. We comment on this in Tab. 3. Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER 31 NATURA SLOVENIAE 25(2): 27-52 Table 1. An overview of isopod species confirmed to be present in Slovenia, listed in alphabetical order and according to suborders and families. A published reference for their occurrence in the country is provided, while detailed locality data on species reported for the first time are given in Tab. 2. The main habitat of each species is given in a separate column. The addition of the letter T marks obligate subterranean (or troglobiotic) species. Species marked with asterisks were scientifically described from Slovenia. Endemic, introduced, and ectoparasitic species are marked in the Remarks column. Tabela 1. Pregled vrst enakonožcev, potrjenih v Sloveniji. Razporejeni so v abecednem vrstnem redu po podredovih in družinah. Dodane so objavljene reference pojavljajočih se vrst, natančni podatki o lokalitetah vrst, o katerih poročamo prvič, pa so podane v tabeli 2. Glavni habitat vsake vrste je podan v ločenem stolpcu. Črka T označuje obligatno podzemeljske (troglobiotske) vrste. Vrste, ki so označene z zvezdicami, so bile opisane iz Slovenije. Endemične, tujerodne in ektoparazitske vrste so označene v predzadnjem stolpcu. Higher taxon Species Habitat Remarks Reference Asellota Asellidae Asellus aquaticus (Linnaeus, 1758) freshwater Sket 1967 Asellus kosswigi Verovnik, Prevorčnik & Jugovic 2009 freshwater - T Konec et al. 2015 Proasellus coxalis (Dollfus, 1892) freshwater Sket 1967 Proasellus deminutus (Sket, 1959) * freshwater - T endemic Sket 1972 Proasellus intermedius (Sket, 1965) freshwater - T Sket 1967 Proasellus istrianus (Stammer, 1932) freshwater Sket 1967 Proasellus orientalis Sket, 1965 * freshwater - T endemic Sket 1971 Proasellus parvulus (Sket, 1960) * freshwater - T endemic Sket 1967 Proasellus slavus (Remy, 1948) freshwater - T Sket 1972 Proasellus slovenicus (Sket, 1957) * freshwater - T endemic Sket 1967 Proasellus vulgaris (Sket, 1965) * freshwater - T endemic Sket 1967 Janiridae Jaera nordmanni (Rathke, 1836) marine Tratar 2010 Janira maculosa Leach, 1814 marine new (MBP) Munnidae Uromunna petiti (Amar, 1948) marine Tratar 2010 Stenasellidae Balkanostenasellus skopljensis (Karaman, 1937) freshwater - T Sket & Velkovrh 1981 Cymothoida Anthuridae Anthura gracilis (Montagu, 1808) marine Sket 2003 Cyathura carinata (Krøyer, 1847) marine Vrišer 2003 Cirolanidae Natatolana borealis (Lilljeborg, 1851) marine ectoparasite Vrišer 2003 Sphaeromides virei (Brian, 1923) freshwater - T Sket 1964 Cymothoidae Anilocra physodes (Linnaeus, 1758) marine ectoparasite Vrišer 2003 Ceratothoa parallela (Otto, 1828) marine Sket 2003 Nerocila bivittata (Risso, 1816) marine Sket 2003 Expanathuridae Eisothistos macrurus Wägele, 1979 marine Lipej et al. 2016 Gnathiidae Gnathia dentata (G. O. Sars, 1872) marine ectoparasite Tratar 2010 Gnathia oxyuraea (Lilljeborg, 1855) marine ectoparasite new (MBP) Gnathia vorax (Lucas, 1849) marine ectoparasite Tratar 2010 Paranthuridae Paranthura japonica Richardson, 1909 marine introduced Ragkousis et al. 2020 Epicaridea Bopyridae Bopyrus squillarum Latreille, 1804 marine ectoparasite Vrišer 2003 Limnoriidea Limnoriidae Limnoria tripunctata Menzies, 1951 marine Sket 2003 Oniscidea Agnaridae Orthometopon dalmatinum (Verhoeff, 1901) terrestrial Vilisics & Lapanje 2005 32 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER NATURA SLOVENIAE 25(2): 27-52 Higher taxon Species Habitat Remarks Reference Orthometopon planum (Budde-Lund, 1885) terrestrial Potočnik 1990 Protracheoniscus hermagorensis Verhoeff, 1927 terrestrial Potočnik 1989 Protracheoniscus politus (C. Koch, 1841) terrestrial Potočnik 1989 Armadillidae Armadillo officinalis Duméril, 1816 terrestrial Potočnik 1989 Armadillidiidae Armadillidium opacum (C. Koch, 1841) terrestrial Potočnik 1989 Armadillidium carniolense Verhoeff, 1901 terrestrial Potočnik 1989 Armadillidium klugii Brandt, 1833 terrestrial Potočnik 1989 Armadillidium nasatum Budde-Lund, 1885 terrestrial Vilisics & Lapanje 2005 Armadillidium pallasii Brandt, 1833 terrestrial Potočnik 1989 Armadillidium scaberrimum Stein, 1859 terrestrial Potočnik 1989 Armadillidium versicolor Stein, 1859 terrestrial Potočnik 1989 Armadillidium vulgare (Latreille, 1804) terrestrial Potočnik 1989 Cylisticidae Cylisticus convexus (De Geer, 1778) terrestrial Potočnik 1989 Detonidae Armadilloniscus ellipticus (Harger, 1878) terrestrial Potočnik 1989 Halophilosciidae Halophiloscia couchii (Kinahan, 1858) terrestrial Potočnik 1989 Halophiloscia hirsuta Verhoeff, 1928 terrestrial Potočnik 1989 Ligiidae Ligia italica Fabricius, 1798 terrestrial Potočnik 1989 Ligidium germanicum Verhoeff, 1901 terrestrial Potočnik 1989 Ligidium hypnorum (Cuvier, 1792) terrestrial Potočnik 1989 Mesoniscidae Mesoniscus graniger (Frivaldszky, 1865) terrestrial Potočnik & Novak 1980 Oniscidae Oniscus asellus Linnaeus, 1758 terrestrial Potočnik 1989 Oroniscus calcivagus Verhoeff, 1908 * terrestrial Potočnik 1989 Philosciidae Chaetophiloscia cellaria (Dollfus, 1884) terrestrial Potočnik 1989 Chaetophiloscia elongata (Dollfus, 1884) terrestrial Potočnik 1989 Chaetophiloscia hastata Verhoeff, 1929 terrestrial Potočnik 1989 Chaetophiloscia splitensis Verhoeff, 1930 terrestrial Potočnik 1989 Lepidoniscus minutus (C. Koch, 1838) terrestrial Potočnik 1989 Philoscia affinis Verhoeff, 1908 terrestrial Potočnik 1989 Philoscia muscorum (Scopoli, 1763) * terrestrial Potočnik 1989 Platyarthridae Platyarthrus hoffmannseggii Brandt, 1833 terrestrial Potočnik 1989 Porcellionidae Porcellio dilatatus Brandt, 1831 terrestrial Potočnik 1989 Porcellio laevis Latreille, 1804 terrestrial Potočnik 1989 Porcellio longicornis Stein, 1859 terrestrial Potočnik 1990 Porcellio marginalis Budde-Lund, 1885 terrestrial Potočnik 1989 Porcellio scaber Latreille, 1804 terrestrial Potočnik 1989 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER 33 NATURA SLOVENIAE 25(2): 27-52 Higher taxon Species Habitat Remarks Reference Porcellio spinicornis Say 1818 terrestrial Potočnik 1989 Porcellionides pruinosus (Brandt, 1833) terrestrial Potočnik 1989 Trachelipodidae Porcellium conspersum (C. Koch, 1841) terrestrial Potočnik 1981 Porcellium fiumanum (Verhoeff, 1901) terrestrial Potočnik 1989 Trachelipus arcuatus (Budde-Lund, 1885) terrestrial Potočnik 1989 Trachelipus camerani (Tua, 1900) terrestrial Vilisics & Lapanje 2005 Trachelipus nodulosus (C. Koch, 1838) terrestrial Potočnik 1989 Trachelipus rathkii (Brandt, 1833) terrestrial Potočnik 1989 Trachelipus ratzeburgii (Brandt, 1833) terrestrial Potočnik 1989 Trachelipus razzautii (Arcangeli, 1913) terrestrial Potočnik 1989 Trachelipus vespertilio (Budde-Lund, 1896) terrestrial Vittori 2022 Trichoniscidae Alpioniscus strasseri (Verhoeff, 1927) terrestrial - T Potočnik 1989 Androniscus degener Brian, 1927 terrestrial - T Potočnik & Novak 1981 Androniscus dentiger Verhoeff, 1908 terrestrial Potočnik 1989 Androniscus roseus (C. Koch, 1838) terrestrial Potočnik 1989 Androniscus stygius (Nemec, 1897) terrestrial - T Potočnik 1989 Androniscus subterraneus (Carl, 1906) terrestrial - T Potočnik 1989 Buddelundiella cataractae Verhoeff, 1930 terrestrial Potočnik 1989 Calconiscellus gottscheensis (Verhoeff, 1927) * terrestrial Potočnik 1989 Calconiscellus karawankianus (Verhoeff, 1908) * terrestrial Potočnik 1989 Haplophthalmus abbreviatus Verhoeff, 1928 * terrestrial Potočnik 1989 Haplophthalmus danicus Budde-Lund, 1880 terrestrial Potočnik 1989 Haplophthalmus fiumaranus Verhoeff, 1908 terrestrial Potočnik 1989 Haplophthalmus mengii (Zaddach, 1844) terrestrial Potočnik 1989 Haplophthalmus rhinoceros Verhoeff, 1930 terrestrial Potočnik 1989 Hyloniscus adonis Verhoeff, 1927 * terrestrial Potočnik 1989 Hyloniscus riparius (C. Koch, 1838) terrestrial Potočnik 1989 Hyloniscus vividus (C. Koch, 1841) terrestrial Potočnik 1989 Moserius percoi Strouhal, 1940 * terrestrial - T Potočnik 1989 Tachysoniscus austriacus (Verhoeff, 1908) terrestrial Potočnik 1989 34 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER NATURA SLOVENIAE 25(2): 27-52 Higher taxon Species Habitat Remarks Reference Thaumatoniscellus speluncae Karaman, Bedek & Horvatović, 2009 terrestrial - T Polak et al. 2012 Titanethes albus (C. Koch, 1841) * terrestrial - T Potočnik 1989 Trichoniscus carniolicus Strouhal, 1939 * terrestrial Potočnik 1989 Trichoniscus illyricus Verhoeff, 1931 terrestrial Potočnik 1989 Trichoniscus matulici Verhoeff, 1901 terrestrial Potočnik 1989 Trichoniscus provisorius Racovitza, 1908 terrestrial new Trichoniscus stammeri Verhoeff, 1932 * terrestrial - T endemic Potočnik 1989 Tylidae Tylos europaeus Arcangeli, 1938 terrestrial Potočnik 1989 Sphaeromatidea Sphaeromatidae Campecopea hirsuta (Montagu, 1804) marine new (MBP) Cymodoce truncata Leach, 1814 marine Vrišer 2003 Dynamene bicolor (Rathke, 1836) marine Tratar 2010 Dynamene edwardsi (Lucas, 1849) marine Tratar 2010 Lekanesphaera hookeri (Leach, 1814) marine Sket 1967 Monolistra bericum (Fabiani, 1901) freshwater - T Sket 1967 Monolistra bolei (Sket, 1960) * freshwater - T endemic Sket 1967 Monolistra calopyge Sket, 1982 * freshwater - T endemic Sket 1982 Monolistra caeca Gerstaecker, 1856 * freshwater - T Sket 1967 Monolistra racovitzai Strouhal, 1928 * freshwater - T Sket 1967 Monolistra spinosa (Racovitza, 1929) * freshwater - T endemic Sket 1967 Monolistra spinosissima (Racovitza, 1929) * freshwater - T endemic Sket 1967 Monolistra velkovrhi Sket, 1960 * freshwater - T Sket 1967 Paracerceis sculpta (Holmes, 1904) marine introduced Ferrario et al. 2018 Sphaeroma serratum (J. C. Fabricius, 1787) marine Vittori 2021 Valvifera Arcturidae Astacilla longicornis (Sowerby, 1806) marine new (MBP) Astacilla dilatata G. O. Sars, 1883 marine Sket 2003 Holognathidae Cleantis prismatica (Risso, 1826) marine new (MBP) Idoteidae Idotea balthica (Pallas, 1772) marine Vrišer 2003 Stenosoma appendiculatum (Risso, 1826) marine new (MBP) Stenosoma lancifer (Miers, 1881) marine new (MBP) Synischia hectica (Pallas, 1772) marine Lipej et al. 2013 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER 35 NATURA SLOVENIAE 25(2): 27-52 The highest proportion of species, 74 (nearly 60%), are terrestrial (suborder Oniscidea), with the greatest richness found in the family Trichoniscidae with 26 species (Fig. 1). It is only in this family that terrestrial obligate subterranean species can be found (eight species). Other terrestrial families with more than five species are Armadillidiidae, Philosciidae, Porcellionidae and Trachelipodidae. There is only one terrestrial species endemic to Slovenia: Trichoniscus stammeri (Tab. 1 and Fig. 2). While it is difficult to be certain which of the currently cosmopolitan species present in Slovenia are native, no demonstrably introduced terrestrial species have been recorded so far. Figure 1. Proportions of freshwater, marine and terrestrial isopods in Slovenia (inner level) and proportions of different families in each of these categories (outer level). Families represented by a single species are grouped under »Other«. Slika 1. Razmerja enakonožcev celinskih vod ter morskih in kopenskih enakonožcev v Sloveniji (notranji nivo) ter razmerja med družinami v vsaki kategoriji (zunanji nivo). Zaradi preglednosti družine, zastopane z zgolj eno vrsto, niso prikazane ločeno. 36 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER NATURA SLOVENIAE 25(2): 27-52 Figure 2. Proportions of freshwater, marine and terrestrial isopods (inner level) and corresponding proportions of parasitic species for marine isopods and troglobiotic species for the remaining two categories (second level). The proportion of endemic species is presented separately (outer level). There are no known endemic marine species. Slika 2. Razmerja enakonožcev celinskih vod, morskih in kopenskih enakonožcev (notranji nivo) ter pripadajoči deleži parazitov pri morskih enakonožcih in troglobiontov pri ostalih dveh kategorijah (drugi nivo). Delež endemitov je podan ločeno (zunanji nivo). Morski endemiti niso znani. The second group richest in species are marine isopods, with 30 species (approximately 25% of all species). Sphaeromatidae are the most diverse family with eight species, followed by Gnathiidae and Idoteidae (Fig. 1). The list contains two non -indigenous species: Paracerceis sculpta and Paranthura japonica. Both can be considered as established non-indigenous species in the Slovenian Sea. Eight species can be categorised as parasites (Fig. 2), predominantly with fish hosts. An exception is Bopyrus squillarum, which is hosted by Palaemon decapods. Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER 37 NATURA SLOVENIAE 25(2): 27-52 The freshwater harbours a total of 21 species (about 15% of all), of which only three are not considered to be bound to subterranean habitats (Tab. 1 and Fig. 2). The most representatives in freshwater belong to Asellidae, followed by Sphaeromatidae (Fig. 1). The most species-rich genera in both families, Proasellus and Monolistra, respectively, are represented with nine species each. Many species in these genera are endemic to Slovenia. Specimens from the genus Microcharon were reported but were not identified to species level in the publication that lists this record (Brancelj et al. 2016). As a result, we only list the genus at this point. There are eight marine and one terrestrial species for which no data have been published (Tab. 1). In Table 2 we prov ide information on records that confirm the presence of these species in Slovenia. New marine species for the Slovenian fauna were collected during sampling procedures of the marine benthic communities, conducted during various projects of the Marine Biological Station from 2008 onward. The new terrestrial species was recorded in synanthropic habitats, but it is widespread in Europe and has been reported from the Balkans before (Schmalfuss 2003). It is therefore difficult to assess whether it has been introduced or not. Table 2. Details of records confirming the presence of eight marine and one terrestrial isopod species in Slovenia. The abbreviation MBP refers to Marine Biological Station of the National Institute of Biology. Tabela 2. Podrobnosti novih najdb, ki potrjujejo pojavljanje osmih morskih in enega kopenskega enakonožca v Sloveniji. Kratica MBP označuje Morsko biološko postajo Nacionalnega inštituta za biologijo. Family Species Locality Lat, Lon (WGS84) Date Leg./ Det. Remarks Arcturidae Astacilla longicornis Sea at Strunjan 45.535900, 13.601967 10.06.2008 MBP/B. Mavrič Sphaeromatidae Campecopea hirsuta Piran, sea under medieval wall 45.529000, 13.573067 10.06.2008 MBP/B. Mavrič Sea at Cape of Piran 45.530567, 13.565100 18.06.2008 MBP/B. Mavrič Sea near the coastal road between Koper and Izola 45.548150, 13.700650 26.06.2008 MBP/B. Mavrič Sea at Debeli Rtič 45.592617, 13.714683 17.06.2008 MBP/B. Mavrič Sea at the youth rehabilitation centre at Debeli Rtič 45.587583, 13.706983 17.06.2008 MBP/B. Mavrič Laguna Bernardin 45.514833, 13.573117 12.06.2008 MBP/B. Mavrič Port of Piran 45.526583, 13.566733 12.06.2008 MBP/B. Mavrič Sea at Jadranka Izola 45.539167, 13.670000 18.05.2009 MBP/B. Mavrič Sea under the wall in front of Marina Portorož 45.504167, 13.594167 19.05.2009 MBP/B. Mavrič Portorož beach 45.512778, 13.593611 19.05.2009 MBP/B. Mavrič Holognathidae Cleantis prismatica Sea soft bottom sample, Sv Nikolaj 45.574167, 13.740000 10.06.2009 MBP/B. Mavrič 38 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER NATURA SLOVENIAE 25(2): 27-52 Family Species Locality Lat, Lon (WGS84) Date Leg./ Det. Remarks Sea soft bottom sample, Koper at the end of Semedelska road 45.543333, 13.720278 29.5.2009 MBP/B. Mavrič Sea soft bottom sample, Strunjan, in front of Salina 45.526111, 13.601667 18.5.2009 MBP/B. Mavrič Sea soft bottom sample, wall in front of Marina Portorož 45.504167, 13.594167 19.5.2009 MBP/B. Mavrič Seagrass meadow in front of Strunjan 45.527594, 13.600892 21.5.2018 MBP/B. Mavrič Gnathiidae Gnathia oxyuraea Soft bottom taken with Van Veen grab, Bay of Sv. Jernej 45.594983, 13.709600 8.9.2021 MBP/B. Mavrič National monitoring location VT2P2 Janiridae Janira maculosa Pacug 45.526186, 13.589369 10.8.2012 MBP/B. Mavrič Within colonies of Mediterranean stony coral (Cladocora caespitosa) from the depth of 3–6 m Cape Strunjanček, Strunjan 45.537217, 13.601753 22.8.2012 MBP/B. Mavrič Several invidivudals, within the colonies of Mediterranean stony coral (Cladocora caespitosa) from the depth of 3–6 m Idoteidae Stenosoma appendiculatum Sample of muddy bottom taken with Van Veen grab at cape Ronek 45.542750, 13.624000 10.6.2019 MBP/B. Mavrič National monitoring location VT4P12 Stenosoma lancifer Sea at Sv. Nikolaj 1 45.574167, 13.740000 10.6.2009 MBP/B. Mavrič Sv. Nikolaj 2 45.574444, 13.737222 10.6.2009 MBP/B. Mavrič Lazaret 45.590833, 13.719444 26.5.2009 MBP/B. Mavrič Trichoniscidae Trichoniscus provisorius Garden in Središče ob Dravi 46.395278, 16.266944 29.9.2019, 29.8.2021 M. Vittori/ M. Vittori Fallen tree in front the Biotechnical Faculty main building, Ljubljana 46.048972, 14.475583 14.6.2023, 2.8.2023 U. Bogataj, K. Kunčič, M. Vittori/ M. Vittori Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER 39 NATURA SLOVENIAE 25(2): 27-52 There are eight species that were reported in some sources but cannot be considered as part of the Slovenian fauna due to different reasons (Tab. 3). They should be excluded from the list until a documented confirmation of their presence in the country is available. Table 3. Excluded isopod species and species the presence of which cannot be currently confirmed and are therefore removed from the checklist of Slovenian isopod fauna. Tabela 3. Izločene vrste enakonožcev in vrste, ki jih trenutno ne moremo potrditi, zato so izvzete iz seznama vrst enakonožcev Slovenije. Family Species Source of record Explanation Asellidae Proasellus pavani (Arcangeli, 1942) PESI 2023 This species is mentioned in the PESI database. However, there are no other records, a primary source, or GBIF data that would support its occurrence in Slovenia. Armadillidae Armadillidium dollfusi Verhoeff, 1902 Potočnik 1979 According to Schmalfuss (2003), the record of this species from Slovenia might be a misidentification. Its known distribution is in northwest Italy (Schmalfuss 2003). We were able to locate one lot in SMNH that matches one of the published records of A. dollfusi in terms of year and locality (»Pred Planinsko jamo 1970«), but the Armadillidium specimens in this vial appear identical with Armadillidium carniolense. The presence of this species should be confirmed before considering it a part of Slovenian fauna. Armadillidium granulatum Brandt, 1833 PESI 2023 Mentioned in the PESI database, but not documented otherwise. Armadillidium quinquepustulatum Budde-Lund, 1885 Potočnik 1979 According to Schmalfuss (2003), the record of the species from Slovenia is likely a misidentification. Its known distribution is in southeast France (Schmalfuss 2003). This species was reported from a single locality (Potočnik 1979), but we were not able to find the corresponding material in SMNH at this point. Its presence should be confirmed. Gnathiidae Paragnathia formica (Hesse, 1864) Lipej et al. 2013 The collected individuals of this species were in larval stages (pranizae) and their determination uncertain. Idoteidae Stenosoma viridula Avčin et al. 1973; Lipej et al. 2013 This species is currently considered a synonym of Synischia hectica (Charfi- Cheikhrouha 2000) and is excluded from the list under this name. 40 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER NATURA SLOVENIAE 25(2): 27-52 Family Species Source of record Explanation Ligiidae Ligia oceanica (Linnaeus, 1767) Avčin et al. 1973 This species is found along the coasts of the North Atlantic and the Baltic Sea (Schmalfuss 2003), very far from Slovenia. The source of the record lists this species as being abundant in Strunjan Bay (Avčin et al. 1973), but the species that is indeed abundant is Ligia italica. Ligia oceanica has never been reported by other researchers in Slovenia, despite extensive work in the area (Potočnik 1984). It is therefore most likely that this report was a misidentification. Porcellionidae Leptotrichus panzerii (Audouin, 1826) PESI 2023 Mentioned in the PESI database, but not documented otherwise. Sphaeromatidae Dynamene bidentata (Adams, 1800) Sket 2003 The species D. bidentata, mentioned by Sket (2003), is not present in the Mediterranean Sea according to Vieira et al. (2016), hence the records should be regarded as D. bicolor. Trichoniscidae Hyloniscus mariae Verhoeff, 1908 PESI 2023 Mentioned in the PESI database, but not documented otherwise. Titanethes dahli Verhoeff, 1926 Polak et al. 2012 This species is currently considered as a form of T. albus and not a separate species (Karaman & Horvatović 2018). Trichoniscus strasseri Schmalfuss 2003 This species was described from the Croatian island of Cres (Verhoeff 1938; Schmölzer 1965; Karaman 1966) and has not been recorded in Slovenia to our knowledge, nor has its presence in Slovenia been reported in the literature listed for this species in the World Catalogue (Schmalfuss 2003). The listing of Slovenia as its distribution range is likely an error. Overview of isopod taxa in Slovenian legislation and comments on their validity There are 72 different isopod taxa included in Slovenian nature protection legislation, although only 41 of the species bear the same name and the same protection status after considering taxonomic changes (Tab. 4). Four species names have become synonymous with other valid names, where the taxonomic status can simply be transferred to the new name (Armadillidium albanicum, Armadilloniscus litoralis, Trichoniscus turgidus, Tylos latreillei; Tab. 4). One species of the genus Monolistra is no longer accepted as a species. As a result, its status is transferred to the valid subspecies (Tab. 4). Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER 41 NATURA SLOVENIAE 25(2): 27-52 Table 4. An overview of isopod taxa listed in the Slovenian Red Data List (Ur. l. RS. 2002) and the Decree on Protected Wild Animal Species (Ur. l. RS. 2004). The column RL (Red List) marks the status of the species in the Slovenian Red Data list: E - endangered, V- vulnerable, R - rare, K - data deficient, I – not evaluated. The column Decree marks whether the species is listed in the Appendix 1A (species protected) or 2A (species’ habitat protected) in the Decree on Protected Wild Animal Species. Tabela 4. Pregled taksonov enakonožcev, naštetih v Rdečem seznamu višjih rakov (Ur. l. RS. 2002) in Uredbi o zavarovanih prosto živečih živalskih vrstah (Ur. l. RS. 2004). V stolpcu RL so označeni statusi vrst v Rdečem seznamu: E – ogrožena, V – ranljiva, R – redka, K - premalo znana, I – neopredeljena vrsta. Zadnji stolpec označuje, ali je vrsta našteta v Prilogi 1A (vrste, katerih živali so zavarovane) oz. Prilogi 2A (vrste, katerih habitat je varovan) Uredbe o zavarovanih prosto živečih živalskih vrstah. Taxon Valid taxon Status RL Decree Androniscus dentiger croaticus Subspecies not valid not transferred R Androniscus roseus buccarensis Subspecies not valid not transferred K Androniscus roseus dolinensis Subspecies not valid not transferred R Androniscus roseus hamuligerus Androniscus roseus hamuligerus valid R Androniscus stygius cavernarum Subspecies not valid not transferred K Androniscus stygius dentatus Androniscus stygius dentatus valid R Androniscus stygius scabridus Androniscus stygius scabridus valid R Androniscus stygius strasseri Androniscus stygius strasseri valid K Androniscus stygius stygius Androniscus stygius stygius valid R Androniscus subterraneus degener Androniscus degener transferred to species R Androniscus subterraneus nodosus Subspecies not valid not transferred R Armadillidium albanicum Armadillidium klugii synonym; transferred to valid species R Armadillidium carniolense schoebli Armadillidium carniolense transferred to species R Armadillidium dollfusi Armadillidium dollfusi valid K Armadillidium opacum Armadillidium opacum valid K Armadillidium pallasii Armadillidium pallasii valid K Armadillidium scaberrimum Armadillidium scaberrimum valid K Armadilloniscus litoralis Armadilloniscus ellipticus synonym; transferred to valid species E Asellus aquaticus Asellus aquaticus valid V Asellus aquaticus cavernicolus Asellus aquaticus cavernicolus valid 2A Balkanostenasellus skopljensis Balkanostenasellus skopljensis valid R 2A Buddelundiella cataractae Buddelundiella cataractae valid R Calconiscellus gottscheensis Calconiscellus gottscheensis valid K Calconiscellus karawankianus Calconiscellus karawankianus valid K Chaetophiloscia cellaria Chaetophiloscia cellaria valid E Chaetophiloscia splitensis Chaetophiloscia splitensis valid E Halophiloscia aristotelis Halophiloscia couchii synonym; transferred to valid species E Halophiloscia couchii Halophiloscia couchii valid E Halophiloscia hirsuta Halophiloscia hirsuta valid E Haplophthalmus abbreviatus Haplophthalmus abbreviatus valid K Haplophthalmus fiumaranus dolinensis Haplophthalmus fiumaranus dolinensis valid R Haplophthalmus fiumaranus fiumaranus Haplophthalmus fiumaranus fiumaranus valid K 42 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER NATURA SLOVENIAE 25(2): 27-52 Taxon Valid taxon Status RL Decree Haplophthalmus fiumaranus dolinensis, fiumaranus Haplophthalmus fiumaranus transferred also to species R, K Haplophthalmus mengii Haplophthalmus mengii valid K Haplophthalmus rhinoceros Haplophthalmus rhinoceros valid R Hyloniscus vividus Hyloniscus vividus valid K Lekanesphaera hookeri Lekanesphaera hookeri valid V 2A Lepidoniscus minutus carniolensis Lepidoniscus minutus carniolensis valid R Lepidoniscus minutus carniolensis Lepidoniscus minutus transferred also to species R Lepidoniscus minutus pannonicus Subspecies not accepted not transferred K Monolistra bolei Monolistra bolei valid R 2A Monolistra brevispinosa Monolistra bolei brevispinosa transferred to subspecies R 2A Monolistra caeca Monolistra caeca valid 2A Monolistra calopyge Monolistra calopyge valid R 2A Monolistra racovitzai Monolistra racovitzai valid 2A Monolistra racovitzai conopyge Monolistra racovitzai conopyge valid R Monolistra schottlaenderi Monolistra schottlaenderi valid 2A Monolistra spinosa Monolistra spinosa valid 2A Monolistra spinosissima Monolistra spinosissima valid R 2A Monolistra velkovrhi Monolistra velkovrhi valid V 2A Moserius percoi Moserius percoi valid R Oroniscus calcivagus Oroniscus calcivagus valid R Philoscia affinis Philoscia affinis valid K Porcellio dilatatus Porcellio dilatatus valid K Porcellio marginalis Porcellio marginalis valid R Porcellium conspersum Porcellium conspersum valid R Proasellus parvulus Proasellus parvulus valid R Proasellus pavani orientalis Proasellus orientalis transferred to species R Proasellus slavus histriae Proasellus slavus histriae valid R Proasellus slavus variabilis nomen nudum not transferred K Proasellus slovenicus Proasellus slovenicus valid R Protracheoniscus hermagorensis Protracheoniscus hermagorensis valid K Sphaeromides virei Sphaeromides virei valid 2A Sphaeromides virei virei Sphaeromides virei virei transferred to species R Trachelipus arcuatus Trachelipus arcuatus valid K Trachelipus nodulosus Trachelipus nodulosus valid K Trachelipus pseudoratzeburgi apenninorum Subspecies not accepted not transferred K Trachelipus razzautii Trachelipus razzautii valid K Trichoniscus carniolicus Trichoniscus carniolicus valid R Trichoniscus stammeri Trichoniscus stammeri valid R Trichoniscus turgidus Trichoniscus matulici synonym; transferred to new species I Tylos latreillei Tylos europaeus synonym; transferred to new species E Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER 43 NATURA SLOVENIAE 25(2): 27-52 For three subspecies that are no longer considered valid, the protection status can be transferred to the species level (Tab. 4). This does not apply for seven other invalid subspecies where the species had more subspecies without protection statuses present in the country. The species therefore cannot assume the status determined for a single (invalid) subspecies without a re-evaluation of the whole species status. Interestingly, the national Red List also mentions a subspecies that is a nomen nudum. The subspecies was listed, with an explanation that it had not yet been described, in the publication that proposed Red List statuses for freshwater Malacostraca (Sket 1992). However, it was never formally described. The new status of the currently valid species Haplophthalmus fiumaranus could be taken from both subspecies that had protection statuses determined, i.e. H. f. dolinensis and H. f. fiumaranus. In such cases, both statuses are being transferred. According to the Red List (Ur. l. RS 2002), the highest protection status would be favoured, in this case rare instead of data deficient species. But as a status re-evaluation for the new taxon could reveal that a more suitable status would be »vulnerable«, we consider it safer to suggest both statuses, while ultimately a re-evaluation can determine the most suitable status. Discussion The present work provides the first complete checklist of all isopods from different habitats in Slovenia, and a list of species that cannot be considered as part of Slovenian fauna even though listed in some literature sources. The number of terrestrial species has remained roughly the same as in the most recent checklist (Potočnik 1992), but some species have been removed (mostly synonyms) and others added: one that we report in this work and five reported in recent publications (Vilisics & Lapanje 2005; Polak et al. 2012; Vittori 2022). In freshwater, there is a greater increase in the number of species as compared to Sket (1967), as new species have been described and certain subspecies elevated to species status. The list for marine isopods is the first comprehensive overview of the group for the country. The species richness of terrestrial isopods is greatest in the Mediterranean region of Europe and decreases northward (Hornung 2011). The richness of terrestrial isopods in Slovenia is high for its size, as it is comparable to larger countries in the Balkans (Sfenthourakis & Hornung 2018). This is very likely related to the geographic diversity within the country, which includes the coast with suitable habitats for littoral species, numerous caves with troglobionts, as well as diverse surface habitats for widespread species of the Balkans and Central Europe. We should also consider that the terrestrial isopod fauna in Slovenia has been well studied in the past (Karaman 1966; Potočnik 1989) which, however, does not apply for all countries in Southeast Europe. Although terrestrial isopods generally have limited dispersal abilities (Hornung 2011), there is only one terrestrial species endemic to Slovenia (T. stammeri). A species until recently considered endemic for Slovenia is Calconiscellus gottscheensis. However, this species has also been found in caves in nearby regions of Croatia (Jana Bedek, personal communication). Trichoniscus carniolicus, another species that used to be considered endemic (Potočnik 1992), has also been reported in Austria (Strouhal 1968) , while Oroniscus calcivagus has been recorded 44 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER NATURA SLOVENIAE 25(2): 27-52 in Italy according to GBIF data supported by a deposited museum specimen (GBIF 2023). Moserius percoi was first described from a single female collected in 1885 (Strouhal 1940) from a cave near the border between Slovenia and Italy. The species was later discovered also in Tuscany in Italy (Taiti & Ferrara 1995), at a large geographical distance from its type locality. An examination of further specimens, especially males, from Slovenia would be welcome, as it could offer additional confirmation that both known populations of M. percoi belong to the same species. There are some terrestrial isopod species that are expanding their ranges in Europe, particularly in synanthropic environments. These are predominantly Mediterranean species that have become cosmopolitans due to human introduction (Szlavecz et al. 2018). The ten most common woodlice in urban environments (Szlavecz et al. 2018) have already been recorded in synanthropic habitats in Slovenia, although some of these species have only been reported on single occasions (Porcellio dilatatus, Porcellio laevis), which makes it difficult to assess how common and widespread they are and whether or not they are permanently present. None of these species can be considered introduced. A note must be made regarding the records of Trachelipus illyricus. Although the World catalogue of terrestrial isopods (Schmalfuss 2003) considers T. illyricus a synonym of Trachelipus camerani and one of its subspecies, T. illyricus lasiorum, a synonym of Trachelipus ratzeburgii, Schmidt (1997) synonymised T. illyricus exclusively with T. ratzeburgii and not T. camerani in his revision of the genus. While this synonymization was based only on the examination of male pereopod 7 and pleopod 1, these characters should be sufficient to distinguish T. ratzeburgii from T. camerani. Based on these considerations, it is best to regard past records of T. illyricus as T. ratzeburgii. The richness of freshwater species is remarkable considering the size of Slovenia. Most of this richness is found in subterranean waters, which are also home to the greatest number of Slovenian endemic isopods. Parallels with this can be found in the freshwater fauna of amphipods in Slovenia, the great majority of which inhabit groundwater (Fišer et al. 2021). However, even groundwater species with distributions reaching into neighbouring countries have small distribution ranges (Stoch 1989; Prevorčnik et al. 2010; Konec et al. 2016). The recorded isopod richness in the Slovenian Sea is relatively high compared to regions of similar size elsewhere in the Adriatic (Zavodnik & Kovačić 2000; Zavodnik et al. 2006). Thirty recorded species in the Slovenian Sea represent almost 40% of all species listed for the Adriatic Sea (Castelló et al. 2020). Among new species for the country, the records of Campecopea hirsuta in samples from hard bottom upper mediolittoral taken at different locations along the Slovenian coast and identified on the basis of well-defined characters (Bruce & Holdich 2002) are, to our knowledge, the first records of this species for the Adriatic Sea. S l o v e n i a n c o a s t a l w a t e r s a r e c o n t i n u o u s l y m o n i t o r e d b y t h e M a r i n e B i o l o g y S t a t i o n o f t h e National Institute of Biology, generally providing good insight into the benthic fauna. Nevertheless, dedicated publications dealing with isopods are scarce. Several specimens await determination to species level, such as those from the genus Eurydice (Pitacco et al. 2013) and Arcturus (Vrišer 2003). An additional problem with marine isopod taxonomy is that species descriptions, especially those from the late 19 th and early 20 th centuries, are vague and incomplete, calling for species redescriptions (Rincón et al. 2018). More systematic studies of Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER 45 NATURA SLOVENIAE 25(2): 27-52 marine species are needed to improve our knowledge of the richness and the distribution of native isopods and to detect potential invasive species. The latter is important as numerous marine isopods can have considerable economic impact. Wood boring isopods, such as Limnoria tripunctata, can damage infrastructure (Borges et al. 2014), whereas parasitic taxa, such as representatives of Gnathiidae and Cymothoidae, can affect fisheries. Even though research in some isopods, for example those in terrestrial habitats, has a long history in Slovenia, very little information is available on their distribution patterns. In the future, systematic distribution studies of the isopod fauna can fill this gap, resulting in distribution maps as prepared for ants in the territory of Slovenia by Bračko (2023), or for the terrestrial isopod fauna of Belgium, a country of similar size (Boeraeve et al. 2022). In addition, we can expect the detection of further terrestrial isopod species. Some species have likely been missed either by chance due to limited sampling or due to species not yet described at the time of collection. There is considerable likelihood that further species remain to be discovered in subterranean habitats. The use of molecular methods will further help identify species, as large genetic diversity has been confirmed within freshwater isopods and new species descriptions may follow. In the Slovenian Sea, the marine isopod fauna is also likely richer than is currently known and more studies are needed. Further studies in different habitats are important also to detect introductions of alien species. Changes in land use and climate as well as transport of alien species due to increased traffic of goods provides opportunities for the introduction or natural expansion of species currently not found in Slovenia. In this way, several terrestrial isopod species have been spreading across Europe in recent years, such as Armadillidium arcangelii (Noél et al. 2022), A. nasatum and Agabiformius lentus (Cochard et al. 2010). In the Slovenian Sea, several introduced species have been identified, and emphasis should be put on detecting new ones, as they can have ecological and economic consequences. If we compare the Decree on Protected Wild Animal Species (Ur. l. RS. 2004), listing twelve species and one subspecies as protected, and the national Red List with 45 species and 9 subspecies with determined statuses (Ur. l. RS. 2002), there are some inconsistencies between the two documents. According to the Decree, all taxa with protection statuses should be listed in the Red List, but this is not always the case, as the Red List has not been updated since its publication in 2002. For example, there is only one subspecies of Monolistra, M. racovitzai conopyge, included in the Red List, but M. racovitzai is protected according to the Decree. In another case, it is vice versa. The subspecies Asellus aquaticus cavernicolus is listed in the Decree, while the species A. aquaticus has vulnerable status in the Red List. In such cases, the status is valid also for the subspecies. These examples point out the need for a review of the current national Red List of endangered species, as taxonomy and knowledge of the distribution of species have changed. Importantly, more data on species distribution, habitat requirements and temporal changes in distribution would help improve the assignment of conservation statuses. The acquisition of such data has been performed on a scale comparable to the size of Slov enia in Fla nd ers (De Smed t et a l. 2022). The la ck of d a ta wa s a lso p ointed out a s an important issue by researchers who prepared the initial publications proposing Red List statuses for isopod taxa in Slovenia (Potočnik 1992; Sket 1992). In these publications, endemism, small documented distribution ranges, threats to habitats and type localities in Slovenia were major criteria for the proposal of Red List statuses and protective measures. Even though we provide comments on the potential transfer of statuses in the current situation, this should not be treated 46 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER NATURA SLOVENIAE 25(2): 27-52 as a suggestion on species/subspecies statuses in the reviewed Red List. The latter should be made by expert work considering all relevant taxonomic and distributional data on each taxon and an evaluation of its conservation status in the country. Povzetek Enakonožci so skupina višjih rakov z več kot 10.000 vrstami, od katerih nekatere živijo v morju, druge v sladkih vodah, številne pa so kopenske (Boyko et al. 2008). So pomembni razkrojevalci tako v vodnih kot kopenskih okoljih. Med vodnimi predstavniki je precej parazitov, najpogosteje na ribah, in ti so lahko ekonomsko pomembni (Čolak et al. 2018). Številni so pomembni razkrojevalci v vodnih in kopenskih okoljih (Wilson 2008; David 1012). Enakonožci so uspešna skupina tudi v podzemlju (Coineau & Boutin 2004; Sfenthourakis & Hornung 2018). Zaradi njihove ekološke pestrosti so pregledi njihovega vrstnega bogastva razdrobljeni in običajno ločeni po habitatih. Za ozemlje Slovenije obstajajo starejši seznami vrst, ki obravnavajo bodisi vrste celinskih vod (Sket 1967) bodisi kopenske vrste (Potočnik 1989), za morske pa takšnega seznama še ni bilo. V tem prispevku smo pripravili prvi skupni pregled vrst enakonožcev v Sloveniji. Pregled upošteva spremembe taksonomije ter vrste, zaznane v zadnjih treh desetletjih. Podatke o pojavljanju vrst smo zbrali iz objavljene literature ter podatkovnih baz Nacionalnega inštituta za biologijo, Oddelka za biologijo Biotehniške fakultete Univerze v Ljubljani ter Centra za kartografijo favne in flore. Skupno smo v Sloveniji zaznali 125 vrst enakonožcev, od tega 30 morskih vrst, 21 vrst v celinskih vodah in 74 kopenskih vrst. Med morskimi po pestrosti prevladuje družina Sphaeromatidae, ki je na račun rodu Monolistra močno zastopana tudi v podzemeljskih celinskih vodah. V slednjih je najpestrejša družina Asellidae, na kopnem pa prednjači družina Trichoniscidae. V tem prispevku prvič poročamo o pojavljanju sedmih morskih in ene kopenske vrste. Velik delež vrstnega bogastva enakonožcev celinskih vod in na kopnem sestavljajo vrste, živeče v podzemlju, med katerimi je tudi večina (10) slovenskih endemitov. V površinskih celinskih vodah ter na kopnem najdemo zgolj po eno endemično vrsto. Med morskimi vrstami je šest parazitov ter dve tujerodni vrsti, medtem ko tujerodnih vrst v ostalih dveh kategorijah nismo zasledili. Zgolj 41 vrst, navedenih v Pravilniku o uvrstitvi ogroženih rastlinskih in živalskih vrst v rdeči seznam (Ur. l. RS 2002) ter v Uredbi o zavarovanih prosto živečih živalskih vrstah (Ur. l. RS 2004), je v trenutni taksonomiji ohranilo svoje taksonomske statuse, medtem ko so številne v zakonodaji navedene vrste in podvrste bodisi neveljavni taksoni bodisi sinonimi drugih vrst enakonožcev. To kaže na potrebo po reviziji varstvenih aktov. Za vzpostavitev ustreznega varstva enakonožcev bi bilo nujno pridobivanje podatkov o njihovi razširjenosti in njenem spreminjanju, ki trenutno manjkajo. Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER 47 NATURA SLOVENIAE 25(2): 27-52 Acknowledgements The authors would like to thank Dr Tomi Trilar and Tea Knapič from the Slovenian Museum of Natural History for the possibility to examine deposited isopod material. Dr Pallieter De Smedt kindly provided helpful advice on the determination of Trichoniscus provisorius. The preparation of this checklist has been encouraged by the need for a national checklist of taxa in Slovenia, as a necessary backbone of taxa to be included in the NarcIS - Nature Conservation Information System, established within the scope of the EU-funded project LIFE NarcIS (LIFE19 GIE/SI/000161). The past field work and research of isopods was funded by the Slovenian Research and Innovation Agency through core programme P1-0184. References Avčin A, Keržan I, Kubik L, Meith-Avčin N, Štirn J, Tušnik P, Valentinčič T, Vrišer B, Vukovič S. 1973. Aquatic ecosystems in the Bay of Strunjan I. Prispevki k znanosti o morju. 5: 168-215. Balázs G, Biró A, Fišer Ž, Fišer C, Herczeg G. 2021. Parallel morphological evolution and habitat‐ dependent sexual dimorphism in cave‐ vs. surface populations of the Asellus aquaticus (Crustacea: Isopoda: Asellidae) species complex. Ecology and Evolution. 11: 15389-15403. https://doi.org/10.1002/ece3.8233 Boeraeve P, Arijs G, Segers S, Brosens D, Desmet P, Swinnen K, Lambrechts J, De Smedt P. 2022. Inventory of the terrestrial isopods in Belgium (2011–2020). ZooKeys. 1101: 57-69. https://doi.org/10.3897/zookeys.1101.65810 Borges LM, Merckelbach LM, Cragg SM. 2014. Biogeography of wood-boring crustaceans (Isopoda: Limnoriidae) established in European coastal waters. PloS One. 9(10): e109593. https://doi.org/10.1371/journal.pone.0109593 Boyko CB, Bruce NL, Hadfield KA, Merrin KL, Ota Y, Poore GCB, Taiti S, editors. 2008 onwards. World marine, freshwater and terrestrial isopod crustaceans database; [accessed 9.1.2023]. https://www.marinespecies.org/isopoda, https://doi.org/10.14284/365 Bračko G. 2023. Atlas of the ants of Slovenia. Ljubljana: Biotechnical Faculty. Brancelj A, Žibrat U, Jamnik B. 2016. Differences between groundwater fauna in shallow and in deep intergranular aquifers as an indication of different characteristics of habitats and hydraulic connections. Journal of limnology. 75: 2. https://doi.org/10.4081/jlimnol.2016.1294 Broly P, Deville P, Maillet S. 2013. The origin of terrestrial isopods (Crustacea: Isopoda: Oniscidea). Evolutionary Ecology. 27(3): 461-476. https://doi.org/10.1007/s10682-012-9625-8 Bruce NL, Holdich DM. 2002. Revision of the isopod crustacean genus Campecopea (Flabellifera: Sphaeromatidae) with discussion of dorsal processes as characters of phylogenetic significance. Journal of the Marine Biological Association of the United Kingdom. 82(1): 51-68. https://doi.org/10.1017/S0025315402005179 Castelló J, Bitar G, Zibrowius H. 2020. Isopoda (Crustacea) from the Levantine sea with comments on the biogeography of mediterranean isopods. Mediterranean Marine Science. 21(2): 308-339. https://doi.org/10.12681/mms.20329 48 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER NATURA SLOVENIAE 25(2): 27-52 Charfi-Cheikhrouha F. 2000. Description d'Idotea hectica (Pallas, 1772) des côtes tunisiennes (Isopode Valvifère). Crustaceana. 73(2): 153-161. https://doi.org/10.1163/156854000504228 Cochard P-O, Vilisics F, Sechet E. 2010. Alien terrestrial crustaceans (Isopods and Amphipods). In: Roques A, Kenis M, Lees D, Lopez-Vaamonde C, Rabitsch W, Rasplus J-Y, Roy D, editors. Alien terrestrial arthropods of Europe. BioRisk. 4(1): 81-96. Coineau N., Boutin C. (2004): Isopoda (aquatic). In: Gunn J, editor. Encyclopedia of Caves and Karst Science. London: Fitzroy Dearborn. p. 540-547. Čolak S, Kolega M, Mejdandžić D, Župan I, Šarić T, Piplović E, Mustać B. 2018. Prevalence and effects of the cymothoid isopod (Ceratothoa oestroides, Risso 1816) on cultured meagre (Argyrosomus regius, A s s o 1 8 0 1 ) i n t h e E a s t e r n A d r i a t i c S e a . Aquaculture Research. 49(2): 1001-1007. https://doi.org/10.1111/are.13547 David JF. 2014. The role of litter-feeding macroarthropods in decomposition processes: a reappraisal of common views. Soil Biology and Biochemistry. 76: 109-118. https://doi.org/10.1016/j.soilbio.2014.05.009 De Smedt P, Boeraeve P, Arijs G, Segers S, Lambrechts J, Maes D. 2022. A Red List of terrestrial isopods (Isopoda: Oniscidea) in Flanders (northern Belgium) and its implications for conservation. Journal of insect conservation. 26(4): 525-535. https://doi.org/10.1007/s10841-022-00390-7 Ferrario J, Bogi C, Cardeccia A, Langeneck J, Marchini A, Ulman A, Occhipinti Ambrogi A. 2018. Fouling community in the harbour of Piran (Slovenia). Biologia Marina Mediterranea. 25(1): 147-151. Fišer C, Mavrič B, Govedič M, Pekolj A, Zagmajster M. 2021. Checklist of amphipod crustaceans (Crustacea: Amphipoda) in Slovenia. Natura Sloveniae. 23(2): 5-24. https://doi.org/10.14720/ns.23.2.5-24 GBIF. 2023. Oroniscus calcivagus Verhoeff, 1908. In: GBIF Secretariat. GBIF Backbone Taxonomy; [accessed 27.10.2023]. https://www.gbif.org. Checklist dataset: https://doi.org/10.15468/39omei Graeffe E. 1902. Uebersicht der Fauna des Golfes von Trieste V. Crustacea. Arbeiten aus dem Zoologischen Instituten der Universität Wien und der Zoologischen Station in Triest. 13(1): 1-48. H o b b s H H . 2 0 1 2 . C r u s t a c e a . I n : W h i t e W B , C u l v e r D C , e d i t o r s . E n c y c l o p e d i a o f C a v e s . 2 nd ed. Waltham (MA): Academic Press. p. 177-194. Hornung E. 2011. Evolutionary adaptation of oniscidean isopods to terrestrial life: structure, physiology and behavior. Terrestrial Arthropod Reviews. 4: 95-130. https://doi.org/10.1163/187498311X576262 Karaman IM, Horvatović M. 2018. Revision of the genera Cyphonethes Verhoeff, 1926 and Titanethes Schioedte, 1849 (Isopoda: Oniscoidea: Trichoniscidae) with a description of a new genus and three new taxa. Zootaxa. 4459(2): 261-284. https://doi.org/10.11646/zootaxa.4459.2.3 Karaman M. 1966. Kopnezi izopodi (Isopoda terrestria) Jugoslavije. Zbornik filozofskog fakulteta u Prištini. 3: 371-404. Konec M, Delić T, Trontelj P. 2016. DNA barcoding sheds light on hidden subterranean boundary between Adriatic and Danubian drainage basins. Ecohydrology. 9(7): 1304-1312. https://doi.org/10.1002/eco.1727 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER 49 NATURA SLOVENIAE 25(2): 27-52 Konec M, Prevorčnik S, Sarbu SM, Verovnik R, Trontelj P. 2015. Parallels between two geographically and ecologically disparate cave invasions by the same species, Asellus aquaticus (Isopoda, Crustacea). Journal of Evolutionary Biology. 28(4): 864-875. https://doi.org/10.1111/jeb.12610 Lipej L, Orlando-Bonaca M, Mavrič B. 2016. Biogenic formations in the Slovenian Sea. Piran: National Institute of Biology, Marine Biology Station Piran. Lipej L, Mavrič B, Vodopivec M, Orlando Bonaca M. 2013. Monitoring habitatov, flore in favne v Krajinskem parku Strunjan. Poročilo MBP. Piran: National Institute of Biology, Marine Biology Station Piran. Lukančič S, Žibrat U, Mezek T, Jerebic A, Simčič T, Brancelj A. 2010. Effects of exposing two non- target crustacean species, Asellus aquaticus L., and Gammarus fossarum Koch., to atrazine and imidacloprid. Bulletin of environmental contamination and toxicology. 84(1): 85-90. https://doi.org/10.1007/s00128-009-9854-x Noël F, Gregory SJ, Agapakis G. 2022. Armadillidium arcangelii Strouhal, 1929 (Isopoda: Oniscidea): a step towards the conquest of Europe? Bulletin of the British Myriapod & Isopod Group. 34: 72-82. PESI 2023. Pan-European Species directories Infrastructure; [accessed 25.10.2023]. http://www.eu- nomen.eu/portal/ Pitacco V, Mavrič B, Orlando Bonaca M, Lipej L. 2013. Rocky macrozoobenthos mediolittoral community in the Gulf of Trieste (North Adriatic) along a gradient of hydromorphological modifications. Acta Adriatica. 54(1): 67-86. Plahuta M, Tišler T, Toman MJ, Pintar A. 2017. Toxic and endocrine disrupting effects of wastewater treatment plant influents and effluents on a freshwater isopod Asellus aquaticus (Isopoda, Crustacea). Chemosphere. 174: 342-353. https://doi.org/10.1016/j.chemosphere.2017.01.137 Polak S, Bedek J, Ozimec R., Zakšek V. 2012. Subterranean fauna of twelve Istrian caves. Annales: Series Historia Naturalis. 22(1): 7-24. Poore GC, Bruce NL. 2012. Global diversity of marine isopods (except Asellota and crustacean symbionts). PLoS One. 7: e43529. https://doi.org/10.1371/annotation/3260cd00-89cf-4e08- ab25-07e0be598ab4 Potočnik F. 1979. Prispevek k poznavanju mokric (Isopoda terrestria) Slovenije. Biološki vestnik. 27: 63-70. Potočnik F. 1980. Prispevek k poznavanju mokric (Isopoda terrestria) v Sloveniji II - Nove vrste za favno Slovenije. Biološki vestnik. 28(2): 21-26. Potočnik F. 1981. Mokrice (Isopoda terrestria) Triglavskega narodnega parka. Preliminarno poročilo. Biološki vestnik. 29(2): 57-66. Potočnik F. 1984. Mokrice (Isopoda terrestria) slovenske obale Jadrana. Biološki vestnik. 32(1): 77-86. Potočnik F. 1989. The survey of the fauna of Woodlices (Isopoda terrestria) of Yugoslavia. Biološki vestnik. 37(2): 61-82. Potočnik F. 1990. Mokrice (Isopoda terrestria). In: Bole J, Brancelj A, Carnelutti J, Devetak D, Drovenik B, Gogala A, Horvat B, Kos I, Krušnik C, Kryštufek B et al., editors. Inventarizacija in topografija favne na območju kraškega roba in območju Veli Badanj-Krog (končno poročilo). Ljubljana: Inštitut za biologijo Univerze v Ljubljani. p. 25-29. 50 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER NATURA SLOVENIAE 25(2): 27-52 Potočnik F. 1992. The red list of endangered Isopoda terrestria (Crustacea) in Slovenia. Varstvo narave. 17: 157-164. Potočnik F, Novak T. 1980. Über Landasseln (Isopoda terrestria) aus Höhlen Sloweniens. Anzeiger der math.-naturw. Klasse Österreichischen Akademie der Wissenschaften. 1980(5): 75-81. Prevorčnik S, Verovnik R, Zagmajster M, Sket B. 2010. Biogeography and phylogenetic relations within the Dinaric subgenus Monolistra (Microlistra) (Crustacea: Isopoda: Sphaeromatidae), with a description of two new species. Zoological Journal of the Linnean Society. 159(1): 1-21. https://doi.org/10.1111/j.1096-3642.2009.00593.x Ragkousis M, Abdelali N, Azzurro E, Badreddine A, Bariche M, Bitar G, Crocetta F, Denitto F, Digenis M, El Zrelli R et al. 2020. New alien Mediterranean biodiversity records (October 2020). Mediterranean Marine Science. 21 (3): 631-652. Re C, Fišer Ž, Perez J, Tacdol A, Trontelj P, Protas ME. 2018. Common genetic basis of eye and pigment loss in two distinct cave populations of the isopod crustacean Asellus aquaticus. Integrative and comparative biology. 58(3): 421-430. https://doi.org/10.1093/icb/icy028 Rincón B, Arranz S, Junoy J. 2018. Isopods of the genus Astacilla (Valvifera, Arcturidae) from the LIFE +INDEMARES project off Alborán Island (S Spain), with the description of a rare species A. carlosoteroi (Reboreda,Wägele & Garmendia, 1994). Mediterranean Marine Science. 19(3): 504-512. https://doi.org/10.12681/mms.15594 Schmalfuss H. 2003. World catalog of terrestrial isopods (Isopoda: Oniscidea). Stuttgarter Beiträge zur Naturkunde. Serie A, 654. Stuttgart: Staatliches Museum für Naturkunde. Schmidt C. 1997. Revision of the European species of the genus Trachelipus Budde-Lund, 1908 (Crustacea: Isopoda: Oniscidea). Zoological Journal of the Linnean Society. 121: 129-244. https://doi.org/10.1111/j.1096-3642.1997.tb00337.x Schmölzer K. 1965. Bestimmungsbücher zur Bodenfauna Europas. Lieferung 4 and 5. Ordnung Isopoda (Landasseln). Berlin: Akademie-Verlag. Saclier N, Duchemin L, Konecny-Dupré L, Grison P, Eme D, Martin C, Callou C, Lefébure T, François C, Issartel C et al. 2024. A collaborative backbone resource for comparative studies of subterranean evolution: The World Asellidae database. Molecular Ecology Resources. 24(1): 1-19. https://doi.org/10.1111/1755-0998.13882 Sfenthourakis S, Hornung E. 2018. Isopod distribution and climate change. ZooKeys. 801: 25-61. https://doi.org/10.3897/zookeys.801.23533 Sfenthourakis S, Taiti S. 2015. Patterns of taxonomic diversity among terrestrial isopods. ZooKeys. 515: 13-25. https://doi.org/10.3897/zookeys.515.9332 Sket B. 1964. Genus Sphaeromides Dollfus 1897 (Crust., Isopoda, Cirolanidae) in Jugoslawien. Biološki vestnik. 12(1): 153-168. Sket B. 1967. Crustacea. Isopoda (aquatica). Catalogus faunae Yugoslaviae III/3. Ljubljana: Slovenska akademija znanosti in umetnosti. Sket B. 1971. Vier neue aberrante Niphargus-Arten (Amphipoda, Gammaridae) und einige Bemerkungen zur Taxonomie der Niphargus-ähnlichen Gruppen. Ljubljana: Slovenska akademija znanosti in umetnosti. Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER 51 NATURA SLOVENIAE 25(2): 27-52 Sket B. 1972. Die Niphargus jovanovici-Gruppe (Amphipoda, Gammaridae) in Jugoslawien und NO-Italien, taxonomisch, zoogeographisch und phylogenetisch betrachtet. Ljubljana: Slovenska akademija znanosti in umetnosti. Sket B. 1982. Some news about the subgenus Microlistra (Isopoda, Sphaeromatidae) in the subterranean waters of Yugoslavia. Biološki vestnik. 30(1): 143-154. Sket B. 1992. The red data list of endangered freshwater Malacostraca: (Isopoda aquatica, Amphipoda, Decapoda) in Slovenia. Varstvo narave. 17: 147-155. Sket B. 2003. Raki – Crustacea. In: Sket B, Gogala M, Kuštor V, editors. Živalstvo Slovenije. Ljubljana: Tehniška založba Slovenije. p. 188-224. Sket B. 2008. A contribution to the history of biodiversity research in Slovenia – lower invertebrates mainly. Acta Biologica Slovenica. 51(2): 5-19. https://doi.org/10.14720/abs.51.2 Sket B, Velkovrh F. 1981. Podzemeljske živali v termalnih vodah. Biološki vestnik. 29(2): 91-120. Stoch F. 1989. Considerazioni biogeografiche sugli Isopodi (Crustacea, Peracarida) delle acque interne dell’Italia nordoriental. Biogeographia. 13: 595-603. https://doi.org/10.21426/B613110247 Strouhal H. 1940. Moserius percoi nov. gen., nov. spec., eine neue Höhlen-Höckerassel, nebst einer Übersicht über die Haplophthalminen. Zoologischer Anzeiger. 129: 13-20. Strouhal H. 1968. Drei fur Österreich neue Landasseln (Isop. terr.). Sitzungsberichte der osterreichischen Akademie der Wissenschaften, mathematisch-naturwissenschaftliche Klasse, Abteilung I. 177: 354-360. Szlavecz K, Vilisics F, Tóth Z, Hornung E. 2018. Terrestrial isopods in urban environments: an overview. ZooKeys. 801: 97-126. https://doi.org/10.3897/zookeys.801.29580 Taiti S, Ferrara F. 1995. Isopodi terrestri (Crustacea, Oniscidea) delle grotte della Toscana (Italia centrale). Mémoires de biospéologie. 22: 169-196. Tratar D. 2010. Fauna of certain marine crustacean groups (Crustacea) in mediolittoral and upper infralittoral belts of Slovenian sea. Graduation thesis. Ljubljana: University of Ljubljana, Biotechnical Faculty. Ur. l. RS. 2002. Pravilnik o uvrstitvi ogroženih rastlinskih in živalskih vrst v rdeči seznam. Uradni list RS, no. 82/02, 42/10. Ur. l. RS. 2004. Uredba o zavarovanih prosto živečih živalskih vrstah. Uradni list RS, no. 46/04, 109/04, 84/05, 115/07, 32/08 – odl. US, 96/08, 36/09, 102/11, 15/14, 64/16, 62/19. Van Gestel CA, Loureiro S, Zidar P. 2018. Terrestrial isopods as model organisms in soil ecotoxicology: a review. ZooKeys. 801: 127-162. https://doi.org/10.3897/zookeys.801.21970 Verhoeff K. 1938. Zur Kenntnis der Gattung Porcellio und uber Isopoda Oniscoidea der Insel Cherso. Archiv fur Naturgeschichte, Neue Folge. 7: 97-136. Vieira PE, Queiroga H, Costa FO, Holdich DM. 2016. Distribution and species identification in the crustacean isopod genus Dynamene Leach, 1814 along the North East Atlantic-Black Sea axis. ZooKeys. 635: 1-29. https://doi.org/10.3897/zookeys.635.10240 Vilisics F, Lapanje A. 2005. Terrestrial Isopods (Isopoda: Oniscidea) from the Slovenian Karst. Natura Sloveniae. 7(1): 13-21. https://doi.org/10.14720/ns.7.1.13-21 52 Miloš VITTORI et al.: A checklist of isopods (Crustacea: Isopoda) in Slovenia / SCIENTIFIC PAPER NATURA SLOVENIAE 25(2): 27-52 Vittori M. 2021. Structure of a hinge joint with textured sliding surfaces in terrestrial isopods (Crustacea: Isopoda: Oniscidea). Zoological Letters. 7: 7. https://doi.org/10.1186/s40851-021- 00177-9 Vittori M. 2022. New records of Trachelipus vespertilio (Budde- Lund, 1896) (Isopoda, Oniscidea) with a description of the male. Biodiversity Data Journal. 10: e91063. https://doi.org/10.3897/BDJ.10.e91063 Vittori M, Dominko M. 2022. A bibliometric analysis of research on terrestrial isopods. ZooKeys. 1101: 13-34. https://doi.org/10.3897/zookeys.1101.81016 Vrišer B. 2003. Meiobenthic fauna (without Harpacticoida) in the southern part of Gulf of Trieste. Annales: Series Historia Naturalis. 13(1): 33-42. Wilson GD. 2008. Global diversity of Isopod crustaceans (Crustacea; Isopoda) in freshwater. Hydrobiologia. 595: 231-240. https://doi.org/10.1007/s10750-007-9019-z WoRMS Editorial Board. 2023. World Register of Marine Species; [accessed 24.10.2023]. https://www.marinespecies.org, https://doi.org/10.14284/170 Zavodnik D, Kovačić M. 2000. Index of marine fauna in Rijeka bay (Adriatic Sea, Croatia). Natura Croatica. 9(4): 297-379. Zavodnik D, Legac M, Gluhak T. 2006. An account of the marine fauna of Pag Island (Adriatic Sea, Croatia). Natura Croatica. 15(3): 65-107. Zimmer M. 2002. Nutrition in terrestrial isopods (Isopoda: Oniscidea): an evolutionary-ecological approach. Biological Reviews. 77(4): 455-493. https://doi.org/10.1017/S1464793102005912 © 2023 Miloš Vittori, Borut Mavrič, Anja Pekolj, Marijan Govedič, Maja Zagmajster To je prostodostopen članek, objavljen pod določili licence Creative Commons Priznanje avtorstva 4.0 Mednarodna, ki dovoljuje neomejeno rabo, razširjanje in kopiranje v kakršnemkoli mediju ter obliki, pod pogojem, da sta navedena avtor in vir. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.