Description of five new species of Schellencandona Meisch, 1996 (Ostracoda: Candoninae) from the southern French Alps, a highly diversified area for groundwater ostracods

85 European Journal of Taxonomy 1022: 85–133 https://doi.org/10.5852/ejt.2025.1022.3083 europeanjournaloftaxonomy.eu ISSN 2118-9773 2025 · Issartel C. & Marmonier P. This work is licensed under a Creative Commons Attribution License (CC BY 4.0) Received: 16 April 2025 • Accepted: 10 July 2025 • Published: 8 October 2025 Topic editor: Magalie Castelin • Section editor: Fabio Stoch • Desk editor: Eva-Maria Levermann Research article urn:lsid:zoobank.org:pub:84DE4613-0AD2-431B-9F33-1D75F04543CD Description of five new species of Schellencandona Meisch, 1996 (Ostracoda: Candoninae) from the southern French Alps, a highly diversified area for groundwater ostracods Colin ISSARTEL 1,*   & Pierre MARMONIER 2  1,2 Université Claude Bernard Lyon 1, LEHNA UMR 5023, CNRS, ENTPE, F-69622, Villeurbanne, France. * Corresponding author: [email protected] 2 Email: [email protected] Abstract. WedescribefivenewspeciesofthegenusSchellencandona Meisch, 1996 (Ostracoda, Candoninae) collected in the southern French Alps. Four of these species, S. danielopoli sp. nov., S. capderreyae sp. nov., S. mercantourensis sp. nov., and S. claretae sp. nov., are related to S. simililampadis(Danielopol,1978),aspeciespreviouslydescribedfromsouthernFrance.Thefifth species, S. malardi sp. nov., is related to the species of Schellencandona present in the Northern Alps.Thesefivenewspecieswerecollectedintheinterstitialhabitatsofrivers,generallydeepinside the bedsediment (i.e., at a depth of about 90 cm into the sediment), and show some morphological characteristics linked to a specialisation to live in groundwater (e.g., long aethetascs, large oocytes). Schellencandona danielopoli and S. claretae have a large geographic distribution and a wide altitudinal range. Schellencandona mercantourensis is present at high elevation in two different rivers. The last two species, S. capderreyae and S. malardi, occur at low-elevation sites in a single river. They can be considered vulnerable to future climatic changes in the Mediterranean region. Keywords. Stygobite species, hyporheic habitat, braided river, biodiversity, mountains. IssartelC&MarmonierP.2025.DescriptionoffivenewspeciesofSchellencandona Meisch, 1996 (Ostracoda: Candoninae)fromthesouthernFrenchAlps,ahighlydiversifiedareaforgroundwaterostracods.European Journal of Taxonomy 1022: 85–133. https://doi.org/10.5852/ejt.2025.1022.3083 Introduction The genus Schellencandona Meisch, 1996 belongs to the subfamily Candoninae Kaufmann, 1900, and currently contains 11 species. Three species were described from Asia: S. yakushimaensis Smith & Kamiya, 2006 in Southern Japan, S. tea Karanovic & Lee, 2012 in South Korea and S. dui Ma & Yu, 2018 in China. Seven other species of Schellencandona have been described from Western Europe. Schellencandona schellenbergi (Klie, 1934) occurs in Austria and Germany, S. triquetra (Klie, 1936) in Belgium and Germany, S. belgica (Klie, 1937) in Belgium, Germany, and France, S. insueta (Klie, European Journal of Taxonomy 1022: 85–133 (2025) 86 1938) in Germany, and S. mira (Sywula, 1976) in Poland. Schellencandona simililampadis (Danielopol, 1978) and S. rhodanensis Issartel & Marmonier, 2025 occur in France: the former is endemic to the Vidourle River, whereas the latter is widely distributed from North of the Saône River to the Cèze and Drôme rivers (Fig. 1; Issartel & Marmonier 2025). Another species of Schellencandona was collected in Northern Italy (noted hereafter as Schellencandona sp.), but it has not yet been described (Rossetti & Mazzini, pers. comm.). Very little information is available on Candoninae from the Southern Alps (between 45° latitude and the Mediterranean Sea), because most research on French ostracods has focused on species from lowland areas (Meisch et al. 1990; Marmonier & Creuzé des Châtelliers 1992; Issartel & Marmonier 2025). SpecimensofCandoninaecollectedinthesouthernAlpshaverarelybeenidentifiedtothespecies level (Capderrey et al. 2013; Dole-Olivier et al. 2015). However, Mediterranean mountains are known to have promoted speciation events (e.g., Martin-Bravo et al. 2010), resulting in the occurrence of several narrowly distributed species (for example, Rabitsch et al. 2016; Jardim-de-Queiroz et al. 2022). The description of S. simililampadis from a single site of the Vidourle River (Danielopol 1977, 1978; Fig. 1) and the collection of Schellencandona sp. in Northern Italy assume the presence of the genus Schellencandona in other rivers of the Southern French Alps, between the left bank of the Rhône River and the Italian border (Fig. 1). The present study focuses on the diversity of the genus Schellencandona in the rivers of the Southern FrenchAlps(Fig.1),usingalargesetofsamplescollectedduringfiveecologicalsurveys.Duringthese surveys,629sampleswerecollectedfromthebedsedimentsof17rivers.First,wedescribefivenew species of Schellencandona collected from rivers draining the southern French Alps. Second, we assessed thetaxonomicrelationshipsofthefivenewspeciesofSchellencandona with other species of the genus. Third, we discuss the ecological characteristics, geographic distribution, and conservation status of the fivenewspecies. Material and methods Inthepresentstudy,weusedmultiplesamplescollectedaspartoffiveecologicalresearchsurveyscarried out in 17 rivers of the southern French Alps, 12 of 17 rivers appeared to host the genus Schellencandona (Fig. 1, Table 1): the Drôme River (Marmonier et al. 2019), the Cèze River (Marmonier et al. 2020), the Lez, Eygues, Ouvèze, Buech, Jabron, and Duyes rivers (Capderrey et al. 2013), the Asse River (Claret, pers. comm.), the Verdon and Tinée rivers (Dole-Olivier et al. 2015), and a karstic system associated with the Vidourle River (Danielopol 1977). Faunal samples were collected from the riverbed sediment using the Bou-Rouch pumping method (Bou & Rouch1967).Specimenswererecoveredbyfilteringthepumpedwaterthrougha250µmmesh-sizenet. Seventeen rivers were sampled during ecological surveys, with different numbers of sampling sites and sampling depths within the riverbed sediment across rivers (Table 2). In addition to these 17 rivers, the karstic system associated with the Vidourle River was sampled at Sauve (Table 1), in the benthic layer of asubterraneanartificialgalleryusingahandnet(110µm),andinaclosespringbyfiltration,from1970 to 1972 (samples performed by members of the Laboratoire Souterrain de Moulis, CNRS, Danielopol 1977). All species occurrence data were previously included in the European Groundwater Crustacean Database as Schellencandona sp. (Zagmajster et al. 2014). Thecollectedanimalswerefixedinthefieldusingformaldehydeandstoredin96%ethanol(no information available for the Vidourle River). Dissected specimens were colored with methyl blue and mounted in glycerine on slides, and their valves were stored in ethanol. Undissected specimens werepreservedin96%ethanol.ThevalvesandlimbswereexaminedanddrawnusinganOlympus ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 87 BX51 microscope equipped with an Olympus DP23 camera. Complete animals and dissected valves were photographed using a camera with transmitted light or lateral light. The type material is deposited in the Muséum national d’Histoire naturelle (MNHN) in Paris, France and some paratypes are deposited in the zoological collection of the University Claude Bernard Lyon 1(UCBLZ)inVilleurbanne,France.Thetype(♂)andallotype(♀)ofSchellencandona schellenbergi were obtained from the Klie Collection located at the University of Hamburg, Germany (440b for the holotype♂,440cfortheallotype♀). Abbreviations for morphological terms used in text and figures The chaetotaxy of the limbs was coded according to the model of Broodbakker & Danielopol (1982), modifiedbyMartens(1987),Meisch(1996),Karanovic(2006)andScharfet al. (2020) for appendages and especially the male antenna, Danielopol (1977) for the description of the hemipenis. The abbreviations used are as follows: α = small seta of the 7th podomere of Mdp β = small seta of the 2nd podomere of Mdp γ = long distal seta of the 3rd podomere of Mdp A = anterior A1 = antennule (1st antenna) A2 = 2nd antenna a = outer lobe of the hemipenis a, b, d = protopodite setae of L5 b = inner lobe of the hemipenis C = hemipenis sclerotized strip linked to the M-process and the basis of e CR = caudal camus cs = serrated D = distal d = protopodite seta of L6 d1, d2, d3 and d4 = successive sections of the labyrinth d1, dp = protopodite setae of L7 EI to EIV = endopodite podomeres for A2, L6 and L7 e = bursa copulatrix e, f, g = setae of L6 EI, EII and EIII, respectively g = seta of EIV of the A2 g = EII+EIII seta of L7 G1, G2, G3 = claws of EIII of A2 Ga = anterior claw of CR GM = anterior claw of EIV of A2 Gm = posterior claw of EIV of A2 Gp = posterior claw of CR H = height h1, h2, h3 = setae of EIV of L7 L = length l = long seta L5 = maxilla (5th limb) L6 = walking leg (6th limb) L7 = cleaning leg (7th limb) LV = left valve European Journal of Taxonomy 1022: 85–133 (2025) 88 M = central chitinized process of the hemipenis m = medium seta Md = mandibula (3rd limb) Mdp = mandibular palp Mx1 = maxillula (4th limb) P = posterior pu = plumose seta s = small seta sa = anterior seta of CR S1 = long plumose seta of the 1st podomere of Mdp S2 = short plumose seta of the 1st podomere of Mdp sp = posterior seta of CR RV = right valve t1–4 = internal setae of EII of A2 (transformed in males) W = width ya = aesthetasc of the 8th podomere of A1 Y, y1, y2, y3 = aesthetascs of EI, EII, EIII and EIV of A2, respectively z1–3 = external setae of EIII of A2 Fig. 1. Geographic distribution of the species of Schellencandona Meisch, 1996 in the southern French Alps. Solid lines = rivers; X = study sites without Schellencandona; dotted lines = western extension of Alpine glaciers during the Last Glacial Maximum (based on Julian 1997; Bosq et al. 2018). ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 89 river station names municipalities latitude longitude altitude Drôme 1St 1 Crest 44.7336° N 4.9712° E 164 m a.s.l. Drôme 1St 2 Crest 44.7367° N 4.9568° E 158 m a.s.l. Drôme 1St 3 Crest 44.7423° N 4.9466° E 148 m a.s.l. Cèze 2St 4 Rochegude 44.2516° N 4.3216° E 99 m a.s.l. Vidourle 3Spring G Sauze 43.9394° N 3.9506° E 100 m a.s.l. Lez 4Montjoux Montjoux 44.5023°N 5.0889° E 446 m a.s.l. Lez 4Grignan Grignan 44.4195° N 4.9094° E 207 m a.s.l. Eygues 4Verclause Verclause 44.3810° N 5.4255° E 534 m a.s.l. Ouvèze 4Les Roches Entrechaux 44.2322° N 5.1397° E 256 m a.s.l. Grand Buech 4Col Croix haute Luce la Crx Haute 44.6567° N 5.7112° E 1018 m a.s.l. Petit Buech 4Montmaur Montmaur 44.5608° N 5.8952° E 879 m a.s.l. Buech 4Sisteron Sisteron 44.2013° N 5.9209° E 466 m a.s.l. Jabron 4Noyers Noyers sur Jabron 44.1668° N 5.9251° E 468 m a.s.l. Les Duyes Le Plan Pourri Mallemoisson 44.0412° N 6.1025° E 501 m a.s.l. Asse 5Pont d’Asse Oraison 43.8793° N 5.9051° E 335 m a.s.l. Verdon 6Pont de Colmars Colmars les Alpes 44.1789° N 6.6206° E 1225 m a.s.l. Tinée 6Plan de l’Ouort St Etienne de Tinée 44.2344° N 6.9492° E 1080 m a.s.l. References: 1 Marmonier et al. (2019); 2 Marmonier et al. (2020); 3 Danielopol (1977–78); 4 Capderrey et al. (2013); 5 Claret C. pers. com.; 6 Dole-Olivier et al. (2015). Table 1. Location of sampling stations where the species of Schellencandona Meisch, 1996 were collected in the Southern French Alps area. river nb sites nb samplessampling strategy reference Drôme 9 81 at each site, 3 stations (centre of the river, right and left banks), 3 replicate samples of 10 l at a depth of -50 cm inside the sediment, Apr. 2014 Marmonier et al. 2019 Cèze 17 51 at each site, 3 replicate samples of 10 l at – a depth of 50 cm, Jul. 2013 Marmonier et al. 2020 Ardèche 17 17 at each site, 3 replicate samples of at least 10 l at depths of -20, -50 and -80 cm, Jun. 2024 Malard pers. com. Lez 2 48 at each site (an alluvial plain), 2 stations, one in a losing section (upstream) and one in a gaining section (downstream of the alluvial plain); at each station, two local hydrological contexts (upwelling and downwelling zones), in each context 3 replicate samples of 10 l at -60 cm deep (in downwellings) and at depths of -30, -60, -90 cm (in upwellings), Jun. and Jul. 2010 Capderrey et al. 2013 Aigues 2 48 Ouvèze 2 48 Jabron 1 24 Buech 3 72 Duyes 1 24 Asse 1 72 at each site, 4 stations (2 main channels, 1 backwater and 1 phreatic pond), 3 replicate samples of 10 l at depths of -20, -50 and -80 cm, at 2 or 4 dates from Nov. 2005 and Jan. 2008 Claret pers. com. Durance 3 108 Verdon 6 6 at each site, 1–3 replicate samples of 10 l at a depth of -50 cm, Jul. 2009 or Sep. 2010 Dole-Olivier et al. 2015 Var 2 6 Tinée 3 7 Ubaye 6 9 Vésubie 3 3 Roya 2 5 17 80 629 Table 2. Details of the ecological research programs included in this study. For each of the 17 studied rivers, the number (nb) of sites, the number (nb) of samples, the sampling strategy and the reference is given. European Journal of Taxonomy 1022: 85–133 (2025) 90 Results Taxonomy Class Ostracoda Latreille, 1802 Order Podocopida Sars, 1866 Suborder Cypridocopina Baird, 1845 Superfamily Cypridoidea Baird, 1845 Family Candonidae Kaufmann, 1900 Subfamily Candoninae Kaufmann, 1900 Genus Schellencandona Meisch, 1996 Diagnosis of the genus Schellencandona Meisch, 1996 Meisch (1996) gave the following characteristics to the genus Schellencandona: (1) Carapace small (0.4 to 0.6 mm) with six muscle scars of almost equal size and simple hinge. (2) Surface of the carapace smooth or with shallow pits. (3) Eye absent. (4) A2 with a penultimate segment subdivided in males with male bristles. (5) Mdp with 2+3 setae and γ setae smooth. (6) L5 exopodite with 2 plates. (7) L7 protopodite with 2 setae. (8) EII of L7 fused with EIII bearing a g seta. (9) EIV of L7 with two long (h2-h3) and one short (h1) setae. (10) Zenker’s organ with 4+2 rings of spines. (11) Hemipenis with a veryflatM-process. List of the species: S. schellenbergi (Klie, 1934), S. triquetra (Klie, 1936), S. belgica (Klie, 1937), S. insueta (Klie, 1938), S. mira (Sywula, 1976), S. simililampadis (Danielopol 1978), S. yakushimaensis Smith & Kamiya, 2006, S. tea Karanovic & Lee, 2012, S. dui Ma & Yu, 2018 and S. rhodanensis Issartel & Marmonier (2025). Schellencandona danielopoli sp. nov. urn:lsid:zoobank.org:act:260AA59F-20E5-4AD0-AF4F-4D7EA84B2B17 Figs 2–4, 18, 20; Tables 1, 3 Diagnosis Small candonine (L = 0.6 mm) of the genus Schellencandona with a triangular carapace covered with pits and small fossae. Greatest H of LV located just mid-length (H/L = 0.55). For both valves, anterodorsal margin slightly concave. Anterior margin widely rounded and posterior margin more acute. The two valves are strongly asymmetrical: LV with a dorsal hump that overlaps the RV, RV with a dorsal margin straight and slightly inclined backwards. A1 with a reduced number of setae: absence of seta on EIII and only one anterior seta on EVI. A2 with a penultimate segment subdivided in males with male bristles. Only 3 t setae (in female) and 3 z setae, z2 transformed in a claw in male. Mdp with 2+3 setae and γ setae smooth. L5 protopodite with two a setae; exopodite with 2 plates and endopodite transformed in a pair of clasping hook-like organs highly asymmetrical, right one stocky and poorly arched, left one slender and curved. L6 without d and e setae, but with one f and one g setae. L7 protopodite with 2 setae, EII and EIII fused bearing a g seta, EIV with two long (h2–h3) and one medium-sized (h1) setae. Female genitalloberoundedwithaflatcentralpartandwithoutdorsalexpansion.Zenker’sorganwith6ringsof spines. Hemipenis with outer lobe a large, rounded, dorso-distally oriented, inner lobe b sub-rectangular with a rounded ventral side. Bursa copulatrix (e) rounded with a curved sclerotized distal strip and an internalconicalstructure.M-processveryflat.Ocularstructuresnotvisible. ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 91 Etymology The new species is named after Dan L. Danielopol for his very important contribution to the systematics of ostracods. Type material Holotype FRANCE • ♂,dissectedappendagesmountedinglycerine,valvesstoredinethanol;Alpes-de-HauteProvence district, Montmaur municipality; 44.5608° N, 5.8952° E; 879 m a.s.l.; Jun.–Jul. 2010; C. Capderrey leg.; interstitial habitat of the main channel of the Buech River in a large braided sector; MNHN-IU-2023-701. Allotype FRANCE•♀;samedataasforholotype;MNHN-IU-2023-702. Paratypes FRANCE•1♂,dissectedappendagesandvalvesstoredinethanol;samedataasforholotype;MNHNIU-2023-703•1♂;Drômedistrict,Verclausemunicipality;44.3810°N,5.4255°E;534ma.s.l.;Jun.– Jul. 2010; C. Capderrey leg.; interstitial habitat of the main channel of the Eygues River in a braided sector;UCBLZ2012-3-153-2•1♀;samedataasforholotype;MNHN-IU-2023-704•1juv.;same data as for the holotype; UCBLZ-2012-3-153-1 • 1 juv.; same locality as for holotype; undissected; UCBLZ-2012-3-207. Other material examined FRANCE • 23 specs of diverse stages; Lez River at Montjoux; UCBLZ-2012-3-207 • 1 juv.; Lez River at Grignan; UCBLZ-2012-3-207 • 10 specs of diverse stages; Eygues River at Verclause; UCBLZ-2012-3-207 • 2 juvs; Ouvèze River at Entrechaux; UCBLZ-2012-3-207 • 2 juvs; Grand Buech River at Luce la Croix Haute; UCBLZ-2012-3-207 • 60 specs of diverse stages; Petit Buech River at Montmaur; UCBLZ • 1 juv.; Buech River at Sisteron; UCBLZ-2012-3-207 • 5 specs of diverse stages; Les Duyes River at Mallemoisson; UCBLZ.2012.3.207. Description M easureMents . Holotype,♂(MNHN-2023-701):LV:L=600µm,H=330µm(H/L=0.55).RV= 588µm,H=290µm(H/L=0.49).W=210µm(W/L=0.35).Rangeformales(n=2):L=575–600µm, H=570–588µm,W=210–225µm.Allotype,♀(MNHN-2023-702):LV:L=560µm,H=310µm (H/L=0.55).RV:L=550µm,H=275µm(H/L=0.50).W=205µm(W/L=0.36).Rangeforfemales (n=2):L=560–565µm.H=310–320µm,W=200205µm. CarapaCe. Whitish with ornamentation consisting of pits (or small fossae) in central part that vanish progressively toward periphery. General shape of carapace triangular (Figs 2, 18A–B). Two valves strongly asymmetrical. LV overlaps RV with hump-like dorsal margin very variable (Fig. 2A–B) and without marked cardinal angles. Highest H located at middle of L. H slightly superior to ½ L: H/L = 0.55 for both male and female. Carapace viewed dorsally (Fig. 2C, I) moderately compressed, with greatest W at middle of L. Anterior and posterior ends weakly beak-shaped. Posterior end more pointed in female. ValVes. For both valves (Fig. 2), anterior margin widely rounded, while posterior margin more acute. Dorsal margin of LV hump-like and variable in males: H/L varying from 0.55 to 0.59 (Fig. 2A–B). Dorsoposterior margin straight or slightly concave in both sexes. Dorso-anterior margin slightly concave in both sexes. Ventral margin slightly convex in both males and females. RV is smaller than LV, trapezoidal with cardinal angles well marked, dorsal margin straight and slightly inclined backward, and ventral European Journal of Taxonomy 1022: 85–133 (2025) 92 marginstraight.Innercalcifiedlamellarepresents11%ofbodylengthbothanteriorlyandposteriorlyin males and slightly larger anteriorly than posteriorly in females. Fused marginal valve zone moderately largerepresenting2.5%ofbodylength,withfewandstraightradialporecanals. antennule, a1 (Figs 3a, 4a). I+II: A-1l(Pu), P-2l(Pu) / III:0 / IV: A-1s / V: A-1l, P-1s / VI: A-1l / VII: A-2l-1s(α),P-1l/VIII:D-2l-ya-1l(cs).PosteriorsetaeofI+IIplumose.UsingIVpodomereasreference, ratios of podomeres in male 1-1-1.1-0.9-1.2-1.2 from III to VIII. ya aesthetasc long, 5–6.5 × as long as IV podomere. Fig. 2. Schellencandona danielopoli sp. nov. A, C–D, E–F.Holotype,♂(MNHN-IU-2023-701),right view of the undissected specimen. A. Right view of an undissected male. B.Paratype,♂(MNHNIU-2023-703), detail of dorsal margin. C. Dorsal view of whole carapace. D. Left valve, external view. E. Detail of anterior margin. F. Right valve, external view. G–J.Allotype,♀(MNHN-IU-2023-702). G. Right view of undissected female. H. Left valve, internal view. I. Dorsal view of whole carapace. J. Rightvalve,internalview.Scalebars=100µm.Arrowspointtoanteriormargin. ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 93 antenna, a2 (Figs 3B–D, 4B–D). Protopodite: coxa with 3 setae, 2 long and smooth, 1 short and plumose; basis with 1 long posterior seta; exopodite with 1 long and 2 short setae; EI with 1 posterior aesthetascY(equalling79%ofEIlength)anddistally2setae(1sand1l). Male a2 (Fig. 3B–D). EII and EIII segmented as two individuated podomeres; EII with 1 short aesthetasc (y1) and 4 t setae, t1 long and plumose, t4 short, t2 and t3 transformed in male bristles with length equal to63%ofEIlength.EIIIwith1shortaesthetascand3externalzsetae,z1andz3shorterthanEIV,z2 transformedinclaw(170%ofEIlength),G1reduced(65%ofEIlength),G2well-developed(170%of EIlength),G3reducedtobristle(47%ofEIlength).EIVwith2claws,posteriorly1long(Gm,160%of EIlength),anteriorly1reduced(GM,90%ofEIlength),1aesthetasc(y3,50%ofEIlength)associated with slightly shorter seta, g seta present. Fig. 3. Schellencandona danielopoli sp. nov., holotype,♂(MNHN-IU-2023-701). A. Antennule (A1). B. Antenna (A2). C. Detail of antenna, internal view. D. Detail of antenna, external view. E. Maxillula (Mx1) palp. F. Mandibular palp (Mdp). G. Walking leg (L6). H. Hemipenis, medial view. I. Right clasping organ. J. Left 5 th limb (with clasping organ). K. Zenker’s organ. L. Cleaning leg (L7). M. Caudal ramus.Abbreviations:seeMaterialandmethods.Scalebars=20µm. European Journal of Taxonomy 1022: 85–133 (2025) 100 ManDiBle. Consists of coxal plate and 4-segmented palp (Mdp). Coxa typically shaped, heavily chitinized with masticatory part. 1 st podomere of Mdp (Figs 6F, 7F) with externally exopodite plate and2longsetae,internallywith2longsetae(1plumoseS1)and2shortsetae(1smooth,α,1plumose, S2). 2nd podomere with externally 2 setae and internally group of 3 smooth setae and second group of 2setae(1longand1short,β).3rdpodomerewithexternally3setae,distally1longandsmoothseta(γ) and internally 3 small setae. 4thpodomerewith2serratedandlongclaws(190%of3rd podomere length) and 3 small setae. Maxillular palp (Mx1palp, Figs 6e, 7e). Two-segmented: 1st segment with 4 apical plumose setae on outer corner. 2nd segment with 2 claw-like setae (4 time as long as 2nd segment) and 4 thinner setae. Fig. 7. Schellencandona capderreyae sp. nov., allotype,♀(MNHN-IU-2023-706). A. Antennule (A1). B. Antenna (A2). C. Detail of antenna, internal view. D. Detail of antenna, external view. E. Maxillula (Mx1) palp. F. Mandibular palp (Mdp). G. Walking leg (L6). H. Maxilla (L5). I. Caudal ramus with genital lobe. J.Cleaningleg(L7).Abbreviations:seeMaterialandmethods.Scalebars=20µm. ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 101 Maxilla (l5, Figs 6i–J, 7H). With protopodite bearing 1 anterior seta (a) and 2 exterior setae (b and d),masticatoryprocess(endite)apicallywithgroupof11setae.Exopoditeplatewith2filaments.Male endopodites transformed in asymmetrical clasping organs (right one more developed, left one slender), slightly curved with 2 short but thick setae on ventral side and thin apical seta. In female, similar set of setaeobservedonprotopoditeand2filamentsonexopodite.Endopoditewith3shortapicalsetae. Walking leg (l6, Figs 6g, 7g). Five-segmented. Protopodite and EI without seta. EII with f seta and EIIIwith2gsetae.EIVwith2shortsetae(h1andh3)andlongclaw(h2)equalling160%ofEIlength. Cleaning leg (l7, Figs 6M, 7J). Four-segmented (with EII and EIII fused). Protopodite with 1 short (d1) and1longsetae(dp,130%ofEIlength).EIwithoutseta,EII+EIIIwithshortseta(g).EIVwith3long setae:h1(sub-equaltoEIlength),h2andh3(130%and200%ofEIlength,respectively). CauDal raMus (Cr, Figs 6l, 7i).Robustwithmedium-sizedspseta(22%–27%ofanteriormarginof CR, just reaching basis of Gp), short sa seta and 2 long and curved claws (Ga and Gp representing around 80–84%to64–67%ofanteriormarginofCR,respectively),bothclawsserrated. FeMale genital loBe (Fig.7I).Widelyroundedwithoutposteriorexpansion.Oocytelarge(12%ofvalve length). Male genital organs.Zenker’sorgan(Fig.6K)with6internalringsofspinesrepresenting20%oftotal length of carapace. Hemipenis (Fig. 6H) with distal outer lobe (a) large and rounded, dorso-distally oriented, inner lobe (b) sub-rectangular shaped with anterior and posterior angles rounded and small plication on ventral side. Lobe h not observed. Labyrinth well-sclerotized and divided in 4 sections, section d4 weakly reticulated. Copulatory tube thin located inside rounded bursa copulatrix (e) with well-sclerotizedcurveddistalstripandinternalconicalstructure.M-processflatwithbroadrounded dorso-distal part, linked to C strip, and thin basal part reaching d4 section of labyrinth. oCular struCtures. Not visible. Ecology and distribution Schellencandona capderreyae sp. nov. was collected from the interstitial habitat of a single river, the Jabron River, a tributary of the Durance River (Fig. 1), in a single sample at an elevation of 468 m a. s.l. It was sampled at the downstream end of a gravel bar (groundwater upwelling zone) at a depth of 90 cm intotheriverbedsediment.Waterhadatemperatureof18.7°C,anelectricalconductivityof382µS.cm -1 , a pH of 7.9 and a rather high dissolved oxygen concentration (i.e., 6.3 mg·L-1). Specialisation to groundwater: its very long aethetascs (ya on A1, Y and y3 on A2), the lack of visible eyesandthelargesizeoftheoocyte(12%ofthebodylength)suggestaspecialisationofthespecies to groundwater life. Schellencandona capderreyae sp. nov. can be considered, for the moment, as an endemic stygobiotic species. Taxonomic remarks The general shape of the carapace of the new species (trapezoid) is very similar to those of S. schellenbergi and S. simililampadis, but differs by the dorsal margin, which is parallel to the ventral margin in the new species (Figs 5, 18C), while it is inclined backwards in the two other species. The new species differs from the other European species. It is very close to S. simililampadis and S. schellenbergi, but differs in the three following characteristics: (1) A2 with a z2 seta transformed in a claw in males (see Fig. 19A for A2 of S. simililampadis); (2) stocky shape of the hemipenis, with the dorso-distal location of the outer a lobe, the small size of the h lobe (not visible) and the curved distal European Journal of Taxonomy 1022: 85–133 (2025) 102 sclerotized strip on the bursa copulatrix. In addition, Schellencandona capderreyae sp. nov. differs from the above-mentioned two species by (1) the A1 with a reduced number of setae, especially the lack of seta on podomere III in both males and females (seta present in S. schellenbergi), (2) the single anterior seta on podomere IV of A1 (two setae in the two other species), and (3) the lack of d and e setae on L6 (both present in S. simililampadis). The relationships between Schellencandona capderreyae sp. nov. and the four other species described in this work are detailed in the Discussion. Schellencandona mercantourensis sp. nov. urn:lsid:zoobank.org:act:EE6DF96A-2A5F-4345-9FA7-1D76CFB3FBD4 Figs 8–10, 18, 20; Tables 1, 3 Synonymy Candoninae sp. 3 – Dole-Olivier et al. 2015: 537, table 2. Diagnosis Small trapezoid candonine of the genus Schellencandona(L=545µm).Carapacethinwithout ornamentation. Anterior margin widely rounded, while posterior margin more pointed, dorsal margin straight in LV and slightly concave in RV, dorso-posterior margin slightly convex. Greatest H of LV located in the anterior third (H/L=0.50) in male. Strong asymmetry between the two valves: LV overlaps theRV,RV4%shorterinlengththanLV,resultinginaposteriorgapbetweenthetwovalves.Anterior andposteriorcalcifiedinnerlamellasamountingtoc.14%and9%ofL,respectively.A1withoutseta on the 3rd podomere and 2 setae on the 6th podomere. Male A2: EII and EIII separated with t2 and t3 transformed in male bristles, 3 z setae (z2 longer than z1 and z3), the longest claw (G2) represents 175%ofEIlength.FemaleA2:EII+IIIwith3tand2zsetae(z1longerthanz2).2nd podomere of the Mdp bears 3+2 setae. Endopodites of the maxilla (L5) developed in males into prehensile palps strongly asymmetrical, the right one hook-shaped with a ventro-distal angle marked by a sclerotized hump. Walking leg (L6) with d, e, f setae and one g seta. Cleaning leg (L7) 4-segmented, EII and EIII fused, with 2 setae (d1 and dp) on the protopodite. Zenker’s organ with 6 internal rings of spines. The outer lobe (a) of the hemipenis large and rectangular shaped, dorso-distally oriented. The inner lobe (b) is dorsally widely rounded. Lobe h short and ventrally rounded. Bursa copulatrix (e) rounded with a conical internal structure and a well-sclerotized dorsal strip. Female genital lobe anteriorly slightly rounded with a small posterior triangular expansion. Ocular structures not visible. Etymology The new species is named after the Mercantour National Park where the species was collected during a groundwater biodiversity survey. Type material Holotype FRANCE • ♂,dissectedappendagesmountedinglycerine,valvesstoredinethanol;AlpesdeHaute Provence district, Colmars les Alpes municipality; 44.1789° N, 6.6206° E; 1225 m a.s.l.; Sep. 2010; M.- J. Dole-Olivier leg.; interstitial habitat of the Verdon River; MNHN-IU-2023-708. Allotype FRANCE • ♀;samedataasforholotype;MNHN-IU-2023-709. ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 103 Paratype FRANCE • 1 ♀,dissectedappendagesmountedinglycerine,valvesstoredinethanol;AlpesMaritimes district, Saint Etienne de Tinée; 44.2344° N, 6.9492° E; 1080 m a.s.l.; Apr. 2009; M.-J. Dole-Olivier leg.; interstitial habitat of the Tinée River; MNHN-IU-2023-710. Other material examined FRANCE • 3 juvs, undissected; collected in the Verdon River; UCBLZ.2012-3-217. Description MeasureMents. Holotype,♂(MNHN-2023-708):LV:L=545µm,H=275µm(H/L=0.50).RV: L = 520µm,H=245µm(H/L=0.47).W=190µm(W/L=0.34).Allotype,♀(MNHN-2023-709):LV:L= 510µm,H=275µm(H/L=0.54).RV:L=485µm,H=250µm(H/L=0.52).W=185µm(W/L= 0.36).Paratype,♀(MNHN-2023-710):LV:L=520µm,H=260µm(H/L=0.50).RV:L=495µm, H=235µm(H/L=0.47).W=170µm(W/L=0.33). C arapaCe . Whitish and thin, without ornamentation. Carapace trapezoid with marked cardinal angles (Figs8,18E–F).HighestHfoundatanteriorthirdofanimal(i.e.,42%ofL).H/L=0.50formaleand 0.50–0.54 for females. Carapace (Fig. 8C, G) moderately compressed in dorsal view, with greatest W at 50%ofL,representing0.33–0.36ofL.Anteriorendweaklypointed.Posteriorendmoderatelyrounded. ValVes. For both valves (Fig. 8), anterior margin widely rounded, posterior margin more pointed, dorsoposteriormarginslightlyconvex.Bothvalvesarestronglyasymmetrical:LVoverlapsRV,RV4%shorter in length than LV, causing posterior gap between two valves (Fig. 8A, E). Dorsal margin straight in LV andslightlyconcaveinRV,representing28%ofL.VentralmarginstraightinLVandslightlyconcave inRVforbothmaleandfemale(Fig.8D,H).Anteriorcalcifiedinnerlamellalarger(14%and11%ofL formaleandfemalerespectively)thanposteriorone(9%ofLforbothsex).Fusedmarginalvalvezone narrow,representing2.5%ofLinbothmaleandfemale,withstraightanddenseradialporecanals,more numerous anteriorly. antennule, a1 (Figs 9a, 10a). I+II: A-1l(pu), P-2l(pu) / III: 0 / IV: A-1s / V: A-1l, P-1s / VI: A-2l / VII: A-2l-1s(α),P-1l/VIII:D-2l-ya-1l(cs).UsingIVpodomereasreference,lengthsofpodomeresareinthe ratios of 1.2-1-1.1-1-1-1.1 from III to VIII in male. ya aesthetasc very long, equal to 6 × as long as IV podomere. antenna, a2 (Figs 9B–D, 10B–D). Protopodite: coxa with 3 setae, 2 long and smooth, 1 short and plumose; basis with 1 long posterior seta; exopodite with 1 long and 2 short setae; EI with 1 posterior aesthetascY(equalling69%ofEIlength)anddistally2setae(1sand1m). Male a2 (Fig. 9B–D). EII and EIII segmented forming 2 distinct podomeres. EII with 1 short aesthetasc (y1)and4tsetae,t1medium,t4short,t2andt3transformedinmalebristleswithlengthequalto94%of EI length. EIII with 1 short aesthetasc (y2), 3 external z setae, z1 and z3 slightly longer than EIV length, z2ofmediumsize(40%ofEIlength).G1reduced(72%ofEIlength),G2well-developed(175%ofEI length),G3reducedtolongbristle(45%ofEIlength).EIVwith2claws,posteriorly1long(Gm,150% ofEIlength)andanteriorly1reduced(GM,55%ofEIlength),1aesthetasc(y3,58%ofEIlength) associated with subequal seta, g seta present. FeMale a2 (Fig. 10B–D). EII and EIII fused, with anteriorly 2 short aesthetacs (y1 and y2), 3 t setae, distally2zsetae(z1150%ofEIVlengthandz2short).G2clawreduced(45%ofEIlength).G1andG3 clawswell-developedandsub-equal(185and160%ofEIlength,respectively).EIVwithanteriorly1 European Journal of Taxonomy 1022: 85–133 (2025) 104 long(GM,147%ofEIlength)andposteriorly1reducedclaw(Gm,50%ofEIlength),1longaesthetasc (y3,70%ofEIlength)withsubequalseta,gsetapresent. ManDiBle. Consisting of coxal plate and 4-segmented palp (Mdp). Coxa typically shaped, heavily chitinized with masticatory part. 1 st podomere of Mdp (Figs 9F, 10F) with externally exopodite plate and 2 long setae, internally with 2 long setae (1 smooth and 1 plumose S1) and 2 short setae (1 smooth, α,and1plumose,S2).2nd podomere with externally 2 setae and internally group of 3 smooth setae and secondgroupof2setae(1longand1short,β).3rd podomere with externally 3 setae, distally 1 long smoothseta(γ)andinternally3smallsetae.4th podomere with 2 serrated and long claws (2.2 × as long as 3rd podomere) and 3 small setae. Fig. 8. Schellencandona mercantourensis sp. nov. A–D. Holotype,♂(MNHN-IU-2023-708)A. Right view of the undissected specimen. B. Left valve, internal view. C. Dorsal view of whole carapace. D. Right valve internal view. E–H. Allotype,♀(MNHN-IU-2023-709).E. Right view of the undissected specimen. F. Left valve, external view. G. Dorsal view of whole carapace. H. Right valve, external view. Scalebars=100µm.Arrowspointtoanteriormargin. ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 105 Maxillular palp (Mx1palp, Figs 9e, 10e). Two-segmented: 1 st segment with 4 apical plumose setae on outer corner. 2nd segment with 2 claw-like setae (4.7 × as long as 2nd segment) and 4 thinner setae. Maxilla (l5, Figs 9i–J, 10i). With protopodite bearing 1 anterior seta (a) and 2 exterior setae (b and d),masticatoryprocess(endite)apicallywithgroupof10setae.Exopoditeplatewith2filaments.Male endopodites transformed in clasping organs strongly asymmetrical. Right one strongly sclerotized, distal end hook-shaped, ventro-distal angle marked by sclerotized hump. Left one stocky and slightly curved. Two endopodites bear 2 short but thick setae on ventral side and thin apical seta. In female, similar set ofsetaeobservedonprotopoditeand2filamentsonexopodite.Endopoditewith3shortapicalsetae. Fig. 9. Schellencandona mercantourensis sp. nov., holotype,♂(MNHN-IU-2023-708). A. Antennule (A1) with a detail of the 7th and 8th podomeres. B. Antenna (A2). C. Detail of antenna, internal view. D. Detail of antenna, external view. E. Maxillula (Mx1) palp. F. Mandibular palp (Mdp) with details of the 2 nd podomere. G. Walking leg (L6). H. Hemipenis, outer view. I. Right 5 th limb (with clasping organ) J. Left clasping organ. K. Cleaning leg (L7). L. Zenker’s organ. M. Caudal ramus. Abbreviations: see Materialandmethods.Scalebars=20µm. European Journal of Taxonomy 1022: 85–133 (2025) 106 Walking leg (l6, Figs 9g, 10J). Five-segmented. Protopodite with one d seta, EI with one e seta (not observed in male holotype), EII with f seta and EIII with one g seta. EIV with 2 short setae (h1 and h3) andlongclaw(h2)serratedandequalling145%theEIlength. Cleaning leg (l7, Figs 9k, 10g). Four-segmented (with EII and EIII fused). Protopodite with 1 short (d1)and1longsetae(dp,125%ofEIlength).EIwithoutseta,EII+EIIIwithshortseta(g).EIVwith3 longsetae:h1,h2andh3(80%,110%and175%ofEIlength,respectively). Fig. 10. Schellencandona mercantourensis sp. nov., allotype,♀(MNHN-IU-2023-709). A. Antennule (A1). B. Antenna (A2). C. Detail of antenna, external view. D. Detail of antenna, internal view. E. Maxillula (Mx1) palp. F. Mandibular palp (Mdp) with details of the 2nd podomere. G. Cleaning leg (L7). H. Caudal ramus with genital lobe. I. Maxilla (L5). J. Walking leg (L6) with a detail of EIII and EIV.Abbreviations:seeMaterialandmethods.Scalebars=20µm. ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 107 CauDal raMus (Cr, Figs 9M, 10H).Robustwithmedium-sizedspseta(22%–29%ofanteriormarginof CR, not reaching basis of Gp), short sa seta and 2 long and curved claws (Ga and Gp representing around 69–71%and54–65%oftheanteriormarginofCR,respectively),bothclawsserrated. FeMale genital loBe (Fig. 10H). Anteriorly slightly rounded, with small posterior triangular expansion. Oocytemediumtolarge(9%ofvalvelength). Male genital organs.Zenker’sorgan(Fig.9L)with6internalringsofspinesrepresenting15%of total length of carapace. Hemipenis (Fig. 9H) with medium-sized distal outer lobe (a) and rectangular shaped, dorso-distally oriented. Inner lobe (b) dorsally widely rounded and small plication on ventral side. Lobe h short and ventrally rounded. Labyrinth well-sclerotized and divided in 4 sections, section d4 weakly reticulated. Copulatory tube thin located inside rounded bursa copulatrix (e) with marked dorsal sclerotizedstripandconicalinternalstructure.M-processflatwithnarrowroundeddorsalpart,linkedto C strip that joins base of e, and thin basal part reaching d4 section of labyrinth. oCular struCtures. Not visible. Ecology and distribution Schellencandona mercantourensis sp. nov. was sampled in the Mercantour National Park. It was collected in the interstitial habitat of two alpine rivers (i.e., the Verdon and Tinée rivers, Fig 1) at a depth of 50 cm into the riverbed sediment of two high-elevation sites (i.e., 1225 and 1080 m a.s.l., respectively). The species was not collected from the springs sampled in the same valleys and seems restricted to the interstitial habitat of the two rivers. Specialisation to groundwater: the very long aesthetascs (ya on A1, Y and y3 on A2), the medium to largeoocytesize(closeto9%ofthebodylength)andthelackofavisibleeyesuggestaspecialisation of the new species to groundwater. Schellencandona mercantourensis sp. nov. may be, for the moment, considered as a species specialized in riverbed sediment, with a narrow distribution area at high elevation in the Mercantour Mountains of the southern French Alps. Taxonomic remarks The general shape of Schellencandona mercantourensis sp. nov. is rather similar to the trapezoid S. schellenbergi and S. simililampadis, but the new species differs by its dorsal margin parallel to the ventral one (inclined backwards in the two other species), its convex dorso-posterior margin (straight in S. schellenbergi), and the asymmetry of the two valves (see below). The new species differs from the other European and Asiatic species by the following four characteristics: (1)thestrongasymmetrybetweenthetwovalves(RV4%shorterinlengththanLVinducingaposterior gap between the two valves), (2) by the shape of the L5 clasping organs (especially the strongly sclerotized hook-shaped right one) and (3) the shape of the hemipenis, rather thin, with a distally oriented a lobe and a very small but visible distal rounded h lobe. These three characteristics have never been observed in the genus Schellencandona before. Despite these differences, Schellencandona mercantourensis sp. nov. may be related to S. simililampadis because of two light similarities: (1) a rather similar A1 chaetotaxy, without seta on podomere III and the two setae on podomere VI, and (2) the A2 with a z2 seta very long compared to z1, but not transformed in a claw like in S. simililampadis and S. schellenbergi. The comparison between Schellencandona mercantourensis sp. nov. and the other species described here is detailed in the Discussion. European Journal of Taxonomy 1022: 85–133 (2025) 108 Schellencandona claretae sp. nov. urn:lsid:zoobank.org:act:8EE9955F-D3A9-4AAF-A5E9-943602D30B46 Figs 11–14, 18, 20; Tables 1, 3 Diagnosis Small trapezoid candonine of the genus Schellencandona(L=~545µmforthefemaleand~480µmfor the male). Carapace thin with poor ornamentation consisting of pits and a few fossae in the centre of the valves. Anterior margin widely rounded, posterior margin more pointed, dorsal margin slightly concave in both valves, dorso-posterior margin straight. Greatest H of LV located in the anterior third (H/L = 0.48).Strongasymmetrybetweenthetwovalves:LVoverlapstheRV,RV5%shorterinlengththanLV inducingaposteriorgapbetweenthetwovalves.Calcifiedinnerlamellaamountingtoca13%and12% of L for the anterior and the posterior ones, respectively. A1 without seta on the 3rd podomere. Male A2: EII and EIII separated with t2 and t3 transformed in male bristles, 2 z setae (z2 medium to long), the longestclaw(G2)represents180%ofEIlength.FemaleA2:EII+IIIwith3tand2zsetae.2nd podomere of the Mdp bears 3+2 setae. Endopodites of the maxilla (L5) developed in males into prehensile palps strongly asymmetrical, the right one hook-shaped with a ventro-distal angle marked by a sclerotized hump. Walking leg (L6) with e, f and 2 g setae. Cleaning leg (L7) 4-segmented, EII and EIII fused, with 2 setae (d1 and dp) on the protopodite. Zenker’s organ with 6 internal rings of spines. The outer lobe (a) of the hemipenis large and rectangular shaped, dorso-distally oriented. The inner lobe (b) widely rounded posteriorly and the lobe h with a sub-triangular distal expansion. Bursa copulatrix (e) conical with a ventral well-sclerotized strip. Female genital lobe rounded without posterior expansion. Ocular structures not visible. Etymology The new species is named after Cécile Claret who collected the species during an ecological study of the Asse River. Type material The only available male has an unusual shape and length of its carapace. A female is therefore chosen as the holotype. Holotype FRANCE • ♀,dissectedappendagesmountedinglycerine,valvesstoredinethanol;Hautes-Alpes district, Oraison municipality; 43.8793° N, 5.9051° E; 335 m a.s.l.; Jun. 2007; C. Claret leg.; interstitial habitat of the Asse River; MNHN-IU-2023-711. Allotype FRANCE • ♂;samedataasforholotype;MNHN-IU-2023-712. Paratype FRANCE • 1 ♀,dissectedappendagesmountedinglycerine,valvesstoredinethanol;AlpesdeHautes Provence district, Colmars les Alpes municipality; 44.1789° N, 6.6206° E; 1225 m a.s.l.; Sep. 2010; M.-J. Dole-Olivier leg.; interstitial habitat of the Verdon River; MNHN-IU-2023-713. Other material examined FRANCE • 5 juvs, undissected; collected in the Asse River; UCBLZ.2012-3-168; UCBLZ • 1 juv., undissected; collected in the Verdon River; UCBLZ.2012-3-217. ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 109 Description MeasureMents.Holotype,♀(MNHN-2023-711):LV:L=545µm.H=265µm(H/L=0.48).RVL= 515µm,H=250µm(H/L=0.48).W=210µm(W/L=0.38).Paratype,♀(MNHN-2022-713):LV:L= 545µm,H=270µm(H/L=0.49).RV:L=525µm,H=235µm(H/L=0.45).W=180µm(W/L= 0.33).Allotype,♂(MNHN-2023-712):LV:L=480µm,H=230µm(H/L=0.48).RVL=450µm,H= 215µm(H/L=0.47).W=185µm(W/L=0.38). CarapaCe. Whitish and thin, with poor ornamentation of rare pits and small fossae in centre of valves. General shape of carapace trapezoid with marked cardinal angles (Figs 11A, E, G, 18G–H). Highest Hlocatedatthirdanteriorpartofanimal(i.e.,at39%ofL)withH/L=0.48forbothmaleandfemale. Carapacevieweddorsally(Fig.11D,F,H)moderatelycompressed,withgreatestWat50%ofLin female,representing38%ofL.CarapaceofmalewithgreatestWatlastthird,representing38%ofL. Anterior end weakly beak-shaped in both sexes. Posterior end moderately rounded in female (Fig 11D) and more pointed in male (Fig. 11H). In female collected in Verdon River, similar general shape of carapace in lateral view (Fig. 11E; H/L = 0.49), but slenderer than holotype in dorsal view (Fig. 11F), withWrepresenting33%ofL. ValVes.Twovalvesstronglyasymmetrical:LVoverlapsRV,RV5%shorterinlengththanLVinducing posterior gap between two valves (Fig. 11A, E, G). For both valves, anterior margin widely rounded, while posterior margin more pointed, dorso-posterior margin straight. Dorsal margin slightly concave, representing34%ofL.VentralmarginslightlyconvexinLV(Fig.11C,J)andslightlyconcaveinRVfor bothmaleandfemale(Fig.11B,I).Anteriorcalcifiedinnerlamellalarger(13%and14%ofLforfemale andmalerespectively)thanposteriorone(12%ofLforfemaleand10%formale).Fusedmarginalvalve zonenarrow,representing2%ofLforbothmaleandfemale,withstraightanddenseradialporecanals, morenumerousanteriorly.Strongdifferencebetweenmaleandfemale,insize(12%difference,see below)andinshapeofthecarapace,especiallyindorsalview.Greatestwidthat50%oflengthinfemale and at last third in male. Posterior end gently rounded in female, pointed and triangular-shaped in male. a ntennule , a1 (Figs 12a, 13a, 14a). I+II: A-1l(pu), P-2l(pu) / III: 0 / IV: A-1s / V: A-1l, P-1s / VI: A-2l / VII:A-2l-1s(α),P-1l/VIII:D-2l-ya-1l(cs).UsingIVpodomereasreference,ratiosofpodomeresare 1.4-1-1.3-1.4-1.4-1.2 from III to VIII. ya aesthetasc very long, equalling 7.1 × as long as IV podomere. Female of Verdon River with similar set of setae on A1 and similarly long ya (Fig. 14A). Using IV podomere as reference, ratios of podomeres are 1.6-1-1.3-1.2-1.5-1.6 from III to VIII. antenna, a2 (Figs 12B–D, 13B–D, 14B–D). Protopodite: coxa with 2 setae, only 1 long and smooth seta observed, and 1 short and plumose; basis with 1 long posterior seta; exopodite with 1 long and 2 short setae;EIwith1posterioraesthetascY(equalling68%ofEIlength)anddistally2setae(1sand1m). Male a2 (Fig. 12B–D). EII and EIII forming 2 distinct podomeres. EII with 1 short aesthetasc (y1) and 4 tsetae,t1andt4short,t2andt3transformedinmalebristleswithlengthequalto70%ofEIlength.EIII with 1 short aesthetasc (y2), 2 external z setae, z1 slightly shorter than EIV length, z2 of medium size (45%ofEIlength).G1reduced(60%ofEIlength),G2well-developed(180%ofEIlength),G3reduced toshortbristle(20%ofEIlength).EIVwith2claws,1longposteriorly(Gm,150%ofEIlength)and1 reducedanteriorly(GM,57%ofEIlength),1medium-sizedaesthetasc(y3,42%ofEIlength)associated with subequal seta, g seta not observed. FeMale a2 (Fig. 13B–D). EII and EIII fused, with anteriorly 2 short aesthetascs (y1 and y2), 3 t setae, distally2zsetae(bothshort).G2clawreduced(63%ofEIlength).G1andG3clawswell-developed (205%and180%ofEIlength,respectively).EIVwithanteriorly1long(GM,170%ofEIlength) andposteriorly1reducedclaw(Gm,80%ofEIlength),1longaesthetasc(y3,83%ofEIlength)with European Journal of Taxonomy 1022: 85–133 (2025) 116 0.49).Indorsalview,carapaceswallen(Wrepresents50%–55%ofL),pyriformandtriangularshaped bothanteriorlyandposteriorly,withslightlybeak-shapedends.Calcifiedinnerlamellaamountingtoc. 10%and7%ofLfortheanteriorandtheposteriorparts,respectively.A1withasetaontheanteriorside of the 3rd podomere. Male A2: EII and EIII separated with t2 and t3 transformed in male bristles, 2 short zsetae(z1longerthanz2),thelongestclaw(G2)represents170%ofEIlength.FemaleA2:EII+IIIwith 3 t and 2 z setae. 2 nd podomere of the Mdp bears 3+2 setae. Endopodites of the maxilla (L5) developed in males into prehensile palps, poorly asymmetrical, both elongated and slightly curved. Walking leg (L6) with f and 2 g setae. Cleaning leg (L7) 4-segmented, EII and EIII fused, with 2 setae (d1 and dp) on the protopodite. Zenker’s organ with 6 internal rings of spines. Hemipenis with an outer lobe (a) large and sub-rectangular, dorso-distally oriented. The inner lobe (b) dorsally pointed (close to a 90° angle). Bursa copulatrix (e) rounded with a curved distal strip and an internal sub-conical structure. Female genital lobe rounded anteriorly without posterior expansion. Ocular structures not visible. Etymology The new species is named after Florian Malard who collected the species during an ecological study of the braided rivers of the southern French Alps. Type material Holotype FRANCE • ♂,dissectedappendagesmountedinglycerine,valvesstoredinethanol;Drômedistrict, Monjoux municipality; 44.5023° N, 5.0889° E; 446 m a.s.l.; Jun.–Jul. 2010; C. Capderrey leg.; interstitial habitat of the Lez River; MNHN-IU-2023-714. Allotype FRANCE • ♀;samedataasforholotype;MNHN-IU-2023-715. Paratypes FRANCE • 1 ♂;samedataasforholotype;MNHN-IU-2023-716;MNHN•1 ♂;samedataasfor holotype;UCBLZ.2012-3-153-5;UCBLZ•1♀;samedataasforholotype;MNHN-IU-2023-717; MNHN • 1 juv.; same data as for holotype; UCBLZ.2012-3-153-6. Other material examined FRANCE • several juvs, undissected; same data as for holotype; UCBLZ.2012-3-210. Description MeasureMents. Holotype,♂ (MNHN-2023-714): LV:L=485µm,H=240µm(H/L= 0.49). RV=470µm,H=230µm(H/L=0.49).W=245µm(W/L=0.50).Rangeformales(n=2):L=485to500µm, H=240to245µm,W=245to250µm.Allotype, ♀(MNHN-2023-715):LV:L=465µm,H=240µm(H/ L=0.51).RV:L=455µm,H=230µm(H/L=0.50).W=255µm(W/L=0.55).Rangeforfemales(n=2): L=465to490µm,H=230to240µm,W=255to260µm. CarapaCe. Whitish, with strong ornamentation (fossae) on entire carapace surface. General shape of carapace trapezoid with marked cardinal angles (Figs 15, 18I–J). Highest H located at anterior third with H/L = 0.49 and 0.51 for male and female, respectively. Carapace viewed laterally with anterior margin widely rounded, posterior margin and ventral margin straight and dorsal margin inclined backwards (5.5%decreaseofHbetweenanteriorandposteriorcardinalangle).Carapacevieweddorsally(Fig.15C, F) very enlarged, pyriform and triangular-shaped both anteriorly and posteriorly, with greatest W located atlastthirdofanimal(at60%ofLinbothmaleandfemale),representing50%and55%ofLformale and female, respectively. Anterior and posterior ends slightly beak-shaped. ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 117 V alVes . LV overlaps the RV on all sides (Fig. 15A, G). Dorsal margin of LV and RV slightly concave in themale.Dorsalmarginrepresenting37%ofLVlengthand33%ofRVlength.Dorso-posteriormargin straight on both valves. Ventral margin straight in LV and RV, slightly convex near oral area (Fig. 15B, E).Anteriorcalcifiedinnerlamellalarger(around10%ofL)thanposteriorone(7%ofLforbothsexes). Fusedmarginalvalvezonenarrow,representing2.5%ofLforbothmaleandfemale,withstraightand dense radial pore canals, more numerous anteriorly (Fig. 15D). antennule, a1 (Figs 16a, 17a). I+II: A-1l(pu), P-2l(pu) / III: A-1s / IV: A-1s / V: A-1l, P-1s / VI: A-2l/VII:A-2l-1s(α),P-1l/VIII:D-2l-ya-1l(cs).UsingIVpodomereasreference,podomeresarein ratios of 1.8-1-1.5-1-1.5-1.6 from III to VIII. ya aesthetasc very long, 10.7 × as long as IV podomere. antenna, a2 (Figs 16B–D, 17B–D). Protopodite: coxa with 3 setae, 2 long and smooth, 1 short and plumose; basis with 1 long posterior seta; exopodite with 1 long and 2 short setae; EI with 1 posterior aesthetascY(equalling55%to73%ofEIlengthinmaleandfemale,respectively)anddistally2setae (1s and 1m). Male a2 (Fig. 16B–D). EII and EIII segmented, forming 2 distinct podomeres. EII with 1 short aesthetasc (y1) and 4 t setae, t1 and t4 short, t2 and t3 transformed in male bristles having length equal Fig. 15. Schellencandona malardi sp. nov. A–E. Holotype,♂(MNHN-IU-2023-714).A. Right view of the undissected specimen. B. Left valve, external view. C. Dorsal view of whole carapace. D. Detail of anterior margin. E. Right valve, external view. F–G. Allotype,♀(MNHN-IU-2023-715).F. Ventral view of whole carapace. G.Rightviewoftheundissectedspecimen.Scalebars=100µm.Arrows point to anterior margin. European Journal of Taxonomy 1022: 85–133 (2025) 118 to90%ofthatofEI.EIIIwith1shortaesthetasc(y2),2externalzsetae,z1slightlylongerthanEIV length,z2short(15%ofEIlength).G1reduced(96%ofEIlength),G2well-developed(170%ofEI length),G3reducedtoshortbristle(45%ofEIlength).EIVwith2claws,posteriorly1long(Gm,165% ofEIlength)andanteriorly1reduced(GM,69%ofEIlength),1smallaesthetasc(y3,39%ofEIlength) associated with subequal seta, g seta present. FeMale a2 (Fig. 17B–D). EII and EIII fused, with anteriorly 2 short aesthetacs (y1 and y2), 3 t setae, distally2zsetae(bothshort).G2clawreduced(85%ofEIlength).G1andG3clawswell-developed andsub-equal(196%EIlength).EIVwithanteriorly1long(GM,163%ofEIlength)andposteriorly 1medium-sizedclaw(Gm,129%ofEIlength),1medium-sizedaesthetasc(y3,79%ofEIlength)with subequal seta, g seta present. Fig. 16. Schellencandona malardi sp. nov., holotype,♂(MNHN-IU-2023-714). A. Antennule (A1). B. Antenna (A2). C. Detail of antenna, internal view. D. Detail of antenna, external view. E. Mandibular palp (Mdp). F. Maxillula (Mx1) palp. G. Walking leg (L6) with details of EIII and EIV. H. Hemipenis, inner view. I. Left 5th limb (with clasping organ). J. Right 5th limb (with clasping organ). K. Cleaning leg (L7). L. Zenker’s organ. M. Caudal ramus. Abbreviations: see Material and methods. Scale bars = 20µm. ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 119 ManDiBle. Consisting of coxal plate and 4-segmented palp (Mdp). Coxa typically shaped, heavily chitinized with masticatory part. 1st podomere of Mdp (Figs 16E, 17F) with externally exopodite plate, internallywith2longsetae(1smoothand1plumoseS1)and2shortsetae(1smooth(α),1plumose, S2). 2nd podomere with externally 2 setae and internally group of 3 smooth setae and second group of 2setae(1longand1short,β,seedetailinFig.16E).3 rd podomere with externally 3 setae, distally 1 longseta(γ)andinternally3smallsetae.4thpodomerewith2serratedandlongclaws(160%ofthe3rd podomere length) and 3 small setae. Maxillular palp (Mx1palp, Figs 16F, 17e). Two-segmented: 1 st segment with 4 apical plumose setae on outer corner. 2nd segment with 2 claw-like setae (4.7 × as long as 2nd segment) and 4 thinner setae. Fig. 17. Schellencandona malardi sp. nov., allotype,♀(MNHN-IU-2023-715). A. Antennule (A1). B. Antenna (A2). C. Detail of antenna internal view. D. Detail of antenna external view. E. Maxillula (Mx1) palp. F. Mandibular palp (Mdp) with details of the 2 nd podomere. G. Maxilla (L5). H. Caudal ramus with genital lobe. I. Cleaning leg (L7). J. Walking leg (L6) with a detail of EIII and EIV. Abbreviations: see Material and methods. Scalebars=20µm. European Journal of Taxonomy 1022: 85–133 (2025) 120 Fig. 18. A–B. Schellencandona danielopoli sp. nov., holotype,♂(MNHN-IU-2023-701). A. Entire animal, right view. B. Dorsal view. C–D. Schellencandona capderreyae sp. nov., holotype, ♂ (MNHN-IU-2023-705). C. Entire animal, right view. D. Dorsal view. E–F. Schellencandona mercantourensis sp. nov., holotype,♂(MNHN-IU-2023-708).E. Entire animal, left view. F. Dorsal view. G–H. Schellencandona claretae sp. nov., holotype,♀(MNHN-IU-2023-711).G. Entire animal, right view. H. Dorsal view. I–J. Schellencandona malardi sp. nov. male (MNHN-IU-2023-714). I. Entire animal, right view. J.Dorsalview.Scalebars=100µm.Arrows point to anterior margin. ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 121 Maxilla (l5, Figs 16i–J, 17g). With protopodite bearing 1 anterior seta (a) and 2 exterior setae (b and d),masticatoryprocess(endite)apicallywithgroupof10setae.Exopoditeplatewith2filaments.Male endopodites transformed in clasping organs weakly asymmetrical, both elongated and slightly curved; right one thicker than left one. Two endopodites bear 2 short but thick setae on ventral side and thin apical seta. In female, similar set of setae observed on protopodite (a, b, d). Exopodite plate with two filaments.Endopoditeendingwiththreeshortsetae. Walking leg (l6, Figs 16g, 17J). Five-segmented. Protopodite without d seta, EI without e seta, EII with f seta and EIII with 2 g setae. EIV with 2 short setae (h1 and h3) and long claw (h2) serrated and equalto250%oflengthofEII. Cleaning leg (l7, Figs 16k, 17i). Four-segmented (with EII and EIII fused). Protopodite with 1 short (d1)and1longsetae(dp,140%ofEIlength).EIwithoutseta,EII+EIIIwithgseta(shortinmaleand longerinfemale,45%ofEIlength).EIVwith1mediumsetah1(62to69%ofEIlength)andtwolong setae,h2andh3(118%and195%ofEIlength,respectively). CauDal raMus (Cr, Figs 16M, 17H).Slender,withrelativelyshortspseta(22%–25%ofanteriormargin of CR, not reaching basis of Gp), short sa seta and 2 relatively short and curved claws (Ga and Gp representingaround64–66%and47–60%ofanteriormarginofCR,respectively),bothclawsserrated. FeMale genital loBe. Simple (Fig. 17H) widely rounded anteriorly without posterior expansion. Oocytes large(10%ofvalvelength). Male genital organs.Zenker’sorgan(male,Fig.16L)ith6internalringsofspinesrepresenting23% of total length of carapace. Hemipenis (Fig. 16H) with distal outer lobe (a) dorso-distally oriented, large and sub-rectangular (with dorsal angle well marked in most individuals, but not all). Inner lobe (b) dorsally pointed, close to 90° angle, and small plication on ventral side. Lobe h not visible. Labyrinth well-sclerotized and divided in 4 sections, section d4 weakly reticulated. Copulatory tube thin located inside rounded bursa copulatrix (e) with well-sclerotized and curved distal strip and internal sub-conical structure.M-processflatwithnarrowandwidelyroundeddorsalpart,linkedtoCstripjoiningbaseofe and thin basal part reaching d4 section of labyrinth. oCular struCtures. Not visible. Ecology and distribution Schellencandona malardi sp. nov. was sampled in the interstitial habitat of a single river, the Lez River, an east-side tributary of the Rhône River (Fig. 1, Table 1), at low elevation (i.e., 446 m a.s.l.). The species was exclusively sampled in groundwater upwelling zones (at the downstream end of gravel bars), never atadepthof30cm,rarelyatadepthof60cm(10%)andmostlyatadepthof90cmintotheriverbed sediment(90%oftheindividuals).Thewatercollectedatadepthof90cmhadatemperatureranging from15.5to17.2°C,anelectricalconductivityrangingfrom407to452µS.cm-1, a near-neutrality pH (7.4–7.7) and a wide range of dissolved oxygen concentration (2.15–7.3 mg·L-1). Specialisation to groundwater: the well-developed aesthetascs (especially ya on A1 and Y on A2), thelargesizeoftheoocytes(10%ofcarapacelength)andthelackofdevelopedeyessuggestthat Schellencandona malardi sp. nov. is specialized to groundwater life. Schellencandona malardi may thus be considered as a stygobiotic species endemic to the Lez River, living deep in the river bottom sediment and in a wide range of dissolved oxygen concentrations. European Journal of Taxonomy 1022: 85–133 (2025) 122 Taxonomic remarks ThenewspeciesfitswithallthecharacteristicslistedbyMeisch(1996)forSchellencandona (see above) except for the surface of the carapace that is strongly ornamented with fossae on its entire surface. In the genus Schellencandona, the new species differs from all the species described in Europe and in Asia by the pyriform shape of the carapace in dorsal view. This shape is, for the moment, unique in the genus Schellencandona. Schellencandona malardi sp. nov. has a hemipenis very similar to those of S. simililampadis and S. schellenbergi (stocky shape, with a large a lobe dorso-distally oriented, the h lobe not visible and a curved distal sclerotized strip on the bursa copulatrix), but differs from those of the above-mentioned species in (1) the presence of one seta in the 3rd podomere of A1 (absent in the two other species) and (2) the size of the z2 seta on A2 not transformed in a claw and smaller than z1 (claw-like in the two other species). To our knowledge, the most closely related species are two unpublished species of Schellencandona collected in the Jura Mountains (Northern French Alps, noted Schellencandona sp. J1 and sp. J3 in Dole-Olivier et al. 2009). These two undescribed species exhibit markedly different carapace shapes compared to those of Schellencandona malardi sp. nov., yet share a striking similarity in hemipenis shape as well as A1 and A2 chaetotaxy (for example, see A2 of Schellencandona sp. J1 in Fig 19B). At present, Schellencandona malardi can be regarded as related to this group of Jura Mountain species; however, thisclassificationrequiresathoroughevaluationfollowingthecompletedescriptionofthegroup. The similarity of Schellencandona malardi sp. nov. with the other species described here is detailed in the Discussion. Discussion Morphological variabilities within the five new species Differences in chaetotaxy between males and females Some differences in the chaetotaxy of males and females of the same species are observed in limbs not directly associated with reproduction (e.g., the caudal ramus in Schellencandona danielopoli sp. nov.), but these weak differences between males and females are frequent in the Candoninae (e.g., Namiotko et al. 2004). Other observed differences consist of the lack of some setae: the e seta on the L6 of the male of Schellencandona mercantourensis sp. nov., and the g seta on the EIV of A2, one of the two g setae and the d seta on L6 of the male of Schellencandona claretae sp. nov. In both species, only one male was available, that may limit the quality of the observations. Another surprising difference is observed in the only available male of Schellencandona mercantourensis sp.nov.thatisconsistentlysmallerthantheadultfemales(12%smaller)andthatshowsaratherdifferent posterior carapace shape (i.e., pointed and triangular in the male versus rounded in the females). It is, for the moment, not possible to be certain that these differences in size and carapace shape between the male and the females are a characteristic of the species or may be due to a teratologic development of this male. Differences among populations of the same species Inmanycases,specieswithalargedistributionalareaandlimiteddispersalefficiencyshowahigh morphological variability justifying splitting the species into different sub-species (e.g., Cryptocandona kieferi was divided in three subspecies by Namiotko et al. 2005) or different species (e.g., Schellencandona triquetra and S. rhodanensis, see Issartel & Marmonier 2025). In this study, three ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 123 species showed medium to large distribution areas at the scale of the Southern French Alps, but when comparing distant populations for each of these species, we found a weak inter-population variability. First, Schellencandona danielopolisp.nov.hadthewidestdistributionarea,witheightsitesinfive different rivers. It was collected from Les Duyes River, at the eastern end of its distribution area to the Lez River, at the western end of its distribution (Fig. 1). These two most distant rivers were separated by a straight distance of 100 km, but by a hydrological distance of 220 km along the river course. Despite thisdistance,nosignificantdifferencewasobservedinthecarapaceshape,soft-partmorphology,or hemipenis shape of the two males collected from the Eygues and Buech rivers (Fig. 1). However, the different populations of this species are all located in the Rhône River watershed and may have recently exchanged individuals through dispersal along hyporheic corridors or direct groundwater pathways between the left tributaries of the Rhône River. Several stygobiotic species, including the asellid isopods Proasellus walteri (Chappuis, 1948) and P. synaselloides (Henry, 1963), were found to have a wide geographic distribution across several tributaries of the Rhône River (Eme et al. 2013; Malard et al. 2017). Second, Schellencandona mercantourensis sp. nov. was collected in the upstream part of the Verdon and the Tinée rivers (i.e., 25 km away from each other in a direct way, Fig. 1), two rivers that do not showanydownstreamconnection(theVerdonRiverflowingtowardstheRhôneRiverandtheTinée RiverflowingdirectlytowardstheMediterraneanSea;Fig.1).Veryfewadultswerecollectedatthetwo stations, but the two dissected females did not show any consistent morphological differences, suggesting the existence of hydrological connections between the upstream reaches of these two alpine rivers (e.g., either via surface or groundwater pathways; Agence de l’Eau Rhône-Méditerranée 2021), or recent and rapid colonisation of subterranean habitats. Finally, Schellencandona claretae sp. nov. was sampled downstream of the Asse River and upstream of the Verdon River (i.e., 70 km between the two stations; Fig. 1). These rivers are hydrologically connected downstream of the Durance River (Fig. 1) and may exchange organisms through hyporheic corridors. In addition, groundwater systems belonging to two rivers are hydrologically connected (Agence de l’Eau Rhône-Méditerranée 2014), potentially allowing faunal exchanges across catchment boundaries. At each station, one adult female was collected and dissected (Figs 11, 13–14). It is not clear for the moment if the differences in the shape of the carapace and the chaetotaxy of the limbs between the two females may represent a difference between two individuals or between the two populations. Future research must include more mature individuals to examine the morphological variability inside each population, togetherwithmolecularaffinitiesbetweenthetwopopulations. Taxonomic relationships with the other species of Schellencandona In Asia, three species of Schellencandona have been described from South Korea (S. tea), Japan (S. yakushimaensis), and China (S. dui). Their carapace shapes are similar (i.e., elongated, with anterior and posterior margins rather similarly rounded, dorsal margin convex, and ventral margin concave), andthusverydifferentfromthefivenewspeciesdescribedhere(i.e.,triangularortrapezoidshapes, asymmetrical anterior and posterior margins). Similarly, the claws of A2 (especially G1, G3, GM) are rathershortintheAsiaticspeciescomparedtothelongclawsofthefivenewspeciesdescribedhere.The males of the three Asiatic species are unknown; thus, no comparison with the hemipenis morphology is currently possible. In Europe, seven species have been described in the genus Schellencandona (S. triquetra, S. belgica, S. insueta, S. mira, S. rhodanensis, S. schellenbergi and S. simililampadis; Meisch 2000; Meisch et al. 2024; Issartel & Marmonier 2025) and an additional one has been communicated from Italy (Rossetti pers. com.). Despite some convergence in the carapace shape (like for the triangular shapes European Journal of Taxonomy 1022: 85–133 (2025) 124 of Schellencandona danielopoli sp. nov., S. triquetra and S. rhodanensis),thefivenewspecieshave carapace shapes that differ from those of S. belgica and S. mira (both dorsally rounded) and S. insueta (widely rounded posterior margin), but seem related to a group formed by the trapezoidal S. schellenbergi and S. simililampadis, as highlighted by Danielopol (1978). However, several differences, especially in the hemipenis shape, the A1 and A2 chaetotaxy, and the L5 clasping organs, allowed us to separate the fivenewspeciesintothreemorphologicalgroups(Table3,Fig.20). First group: Schellencandona mercantourensis sp. nov. and Schellencandona claretae sp. nov. Thisfirstmorphologicalgroupisbasedonfiveoriginalmorphologicalcharacteristics(Table3,Fig.20). (1)Astrongasymmetrybetweentheleftandrightvalves(RVis5%shorterinlengththanLV,inducing a posterior gap between the two valves). (2) A rather thin and elongated hemipenis (see Fig. 20), with a distally oriented outer lobe (a), a small but visible lobe h, and a simple bursa copulatrix without distal curved strip as in the three other species. (3) The lack of setae on the A1 3rd podomere and two setae on the A1 6th podomere. (4) A long z2 seta on male A2, longer than z1, but not transformed into a claw. (5) Unusually shaped L5 clasping organs (strongly asymmetrical, with a well-sclerotized right one, hookFig. 19. A. Schellencandona simililampadis (Danielopol, 1978), detail of male A2, external view (redrawn after Danielopol 1978). B. Schellencandona sp. J1 (UCBLZ 2012-3-14-36), detail of male A2, external view. Abbreviations: see Material and methods. Scalebars=20µm. ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 125 shaped, and with a sclerotized ventro-distal angle). This group may be related to S. simililampadis and S. schellenbergi,evenifthefirstandlastcharacteristicswerenotobservedinthesetwospecies. Inthisfirstgroup,thetwospeciesdifferinseveralcharacteristics(Table3,Figs18,20):(1)theshape of the carapace, especially the postero-dorsal margin, which is slightly convex in Schellencandona mercantourensis sp. nov., but straight in Schellencandona claretae sp. nov., resulting in a pointed posterior end. (2)The lack of ornamentation on the carapace of the first species and reduced ornamentation of pits and small fossae in Schellencandona claretae. (3) Three z setae in Schellencandona mercantourensis, but two in Schellencandona claretae. (4) The medium size of Sp seta that does not reach the basis of Gp in Schellencandona mercantourensis, whereas it is long in Schellencandona claretae. (5) The h lobe of the hemipenis rounded in Schellencandona mercantourensis, whereas it is triangular in Schellencandona claretae. (6) The shape of the bursa copulatrix which is conical with a thin dorsal sclerotized fold in Schellencandona mercantourensis, whereas it is ventrally well-sclerotized in Schellencandona claretae. Finally, (7) the female genital lobe, which is anteriorly rounded with a small posterior triangular expansion in Schellencandona mercantourensis, while it is without posterior expansion in Schellencandona claretae. Second group: Schellencandona danielopoli sp. nov. and Schellencandona capderreyae sp. nov. The second morphological group is based on four distinctive morphological characteristics (Table 3, Fig. 20). (1) A rather stocky hemipenis, with a dorso-distally oriented outer lobe (a), without a visible h lobe, a curved distal sclerotized strip on the bursa copulatrix. (2) Lack of seta on the A1 3rd podomere and only one seta on the 6th one. (3) The z2 seta transformed in a claw. (4) The L5 clasping organs nearly similar and regularly curved. These four characteristics make these two species close to S. simililampadis (see A2 in Fig. 19A) and, to a lesser extent, to S. schellenbergi (except point 2). The transformation of the seta z2 in a claw, while z1 remains a seta, was observed, for example, in the genus Latinopsis (Karanovic & Datry 2009) or the African genus Benincandona (Hotèkpo et al. 2024), while it is generally the z1 seta that is transformed into a claw in European species (e.g., in Typhlocypris, Namiotko & Danielopol 2004, or in Pseudocandona, Smith & Kamiya 2015). Fig. 20.Hemipenis(top)andL5claspingorgans(bottom)ofthefivenewspeciesofSchellencandona Meisch, 1996. Scale bars = 20µm. European Journal of Taxonomy 1022: 85–133 (2025) 132 Namiotko T. & Danielopol D.L. 2004. Review of the eremita species-group of the Pseudocandona Kaufmann (Ostracoda, Crustacea), with the description of a new species. Revista Española de Micropaleontología 36: 109–125. Namiotko T. Danielopol D.L., & Raða T. 2004. Pseudocandona sywulai sp. nov., a new stygobitic ostracode (Ostracoda, Candonidae) from Croatia. Crustaceana 77: 311–331. https://doi.org/10.1163/1568540041181501 Namiotko T., Marmonier P. & Danielopol D.L. 2005. Cryptocandona kieferi (Crustacea, Ostracoda): redescription, morphological variability, geographical distribution. Vie et Milieu 55: 91–108. https://hal.sorbonne-universite.fr/hal-03219029v1 Pauls S. U., Lumbsch H. T. & Haase P. 2006. PhylogeographyofthemontanecaddisflyDrusus discolor: evidence for multiple refugia and periglacial survival. Molecular Ecology 15: 2153–2169. https://doi.org/10.1111/j.1365-294X.2006.02916.x Piegay H., Alber A., Slater L. & Bourdin L. 2009. Census and typology of braided rivers in the French Alps. Aquatic Sciences 71: 371–388. https://doi.org/10.1007/s00027-009-9220-4 Rabitsch W., Graf W., Huemer P., Kahlen M., Komposch C., Paill W., Reischütz A., Reischütz P., Moser D. & Essl F. 2016. Biogeography and ecology of endemic invertebrate species in Austria: a cross-taxon analysis. Basic and Applied Ecology 17: 95–105. https://doi.org/10.1016/j.baae.2015.11.002 Rangwala I. & Miller J.R. 2012. Climate change in mountains: a review of elevation-dependent warming and its possible causes. Climatic change 114: 527–547. https://doi.org/10.1007/s10584-012-0419-3 Rossetti G. & Martens K. 1996. Redescription and morphological variability of Darwinula stevensoni (Brady & Robertson, 1870) (Crustacea, Ostracoda). Bulletin de l’Institut royal des Sciences naturelles de Belgique 66: 73–92. ScharfB.,MeischC.,KülköylüoğluO.&YavuzatmacaM.2020.Stenocypria fischeri (Lilljeborg, 1883), a poorly known freshwater ostracod (Crustacea, Ostracoda). Bulletin de la Société des naturalistes luxembourgeois 122: 217–238. Smith R.J. & Kamiya T. 2006. Six new species of fresh and brackish water ostracods (Crustacea) from Yakushima, Southern Japan. Hydrobiologia 559: 331–355. https://doi.org/10.1007/s10750-005-0946-2 Smith R.J. & Kamiya T. 2015. Four new species of the subfamily Candoninae (Crustacea, Ostracoda) from freshwater habitats in Japan. European Journal of Taxonomy 136: 1–34. https://doi.org/10.5852/ejt.2015.136 Sywula T. 1976. Notes on Ostracoda 16. New species of Ostracoda (Crustacea) from subterranean waters of Poland. Bulletin of the Polish Academy of Sciences Biological Sciences 24: 271–278. UICN 2012. Catégories et Critères de la Liste Rouge de l’UIC : Version 3.1. Deuxième Edition. UICN, Gland (Suisse) / Cambridge. https://www.uicn.fr/listes-rouges-regionales Wallis G.P., Waters J.M., Upton P. & Craw D. 2016. Transverse alpine speciation driven by glaciation. Trends in Ecology & Evolution 31: 916–926. https://doi.org/10.1016/j.tree.2016.08.009 Ward J.V., Tockner K., Arscott D.B. & Claret C. 2002. Riverine landscape diversity. Freshwater biology 47: 517–539. https://doi.org/10.1046/j.1365-2427.2002.00893.x Zagmajster M., Eme D., Fišer C., Galassi D., Marmonier P., Stoch F., Cornu J.-F. & Malard F. 2014. Geographic variation in range size and beta diversity of groundwater crustaceans: insights from habitats with low thermal seasonality. Global Ecology and Biogeography 23: 1135–1145. https://doi.org/10.1111/geb.12200 ISSARTEL C. & MARMONIER P., Five new Schellencandona from the French Alps (Ostracoda) 133 Zierl B. & Bugmann H. 2005. Global change impacts on hydrological processes in Alpine catchments. Water Resources Research 41: 2. https://doi.org/10.1029/2004WR003447 Printed versions of all papers are deposited in the libraries of four of the institutes that are members of the EJTconsortium:MuséumnationaldʼHistoirenaturelle,Paris,France;MeiseBotanicGarden,Belgium; Royal Museum for Central Africa, Tervuren, Belgium; Royal Belgian Institute of Natural Sciences, Brussels, Belgium. The other members of the consortium are: Natural History Museum of Denmark, Copenhagen, Denmark; Naturalis Biodiversity Center, Leiden, the Netherlands; Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain; Leibniz Institute for the Analysis of Biodiversity Change, Bonn – Hamburg, Germany; National Museum of the Czech Republic, Prague, Czech Republic; The Steinhardt Museum of Natural History, Tel Aviv, Israël.