taxonID	type	description	language	source
536F827BFFA353122AE1FB7AF3B2F5FA.taxon	description	(Figs 5, 6) ZooBank registration: urn: lsid: zoobank. org: act: D 1 CEB 40 E- 0 C 7 F- 4 FC 1 - A 5 D 0 - 991 A 3 CCF 0 B 4 A	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFA353122AE1FB7AF3B2F5FA.taxon	etymology	Etymology Named after Dr Rafael Araujo, curator of Malacology at Museo Nacional de Ciencias Naturales (MNCN-CSIC) (2008 – 2021), who contributed greatly to the knowledge of freshwater molluscs, including those of Tunisia.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFA353122AE1FB7AF3B2F5FA.taxon	materials_examined	Type material Holotype (MNCN 15.05 / 200505 H) and three paratypes (MNCN 15.05 / 200505 P) in the MNCN collection and 20 paratypes in the UGSB collection (UGSB 17299). Type locality: Gnaa Spring, Jendouba, Tunisia. Material studied Gnaa Spring, Jendouba, Tunisia, 36.5653 ° N, 8.7895 ° E, leg. N. K., August 2015, MNCN 15.05 / 200505 and UGSB 17299 (80 % ethanol).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFA353122AE1FB7AF3B2F5FA.taxon	diagnosis	Diagnosis Shell small, ovate-conic; protoconch microsculpture pitted; central radular tooth formula 4 - C- 4 / 1 - 1; bursa copulatrix large, pyriform, with a duct longer than bursal length; SR 1 long, elongate, with a short duct; penis gradually tapering, with many folds over the entire surface and a small patch of pigmentation on its distal region; nervous system darkly pigmented, elongate (mean RPG ratio =. 60).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFA353122AE1FB7AF3B2F5FA.taxon	description	Description Shell ovate-conic, whorls 4 – 4.5, height 2.5 – 3 mm (Fig. 5 A – C; Supporting Information, Table S 3). Periostracum yellowish. Protoconch ~ 450 µm wide, whorls 1.5; nucleus ~ 150 µm wide; protoconch microsculpture pitted (Fig. 5 G). Teleoconch whorls moderately convex, with deep sutures; body whorl large, occupying about three-quarters of total shell length. Aperture longer than wide, slightly oval; inner lip thicker than outer lip; peristome margin simple, straight (Fig. 5 B). Umbilicus narrow, not covered by the inner lip. Holotype: SL = 2.87 mm, SW = 2.08 mm, AL = 1.61 mm, AW = 1.10 mm. Operculum oval, yellowish, about two and a half whorls; muscle attachment area oval and located near the nucleus (Fig. 5 E, F). Radular length intermediate, ~ 650 µm (~ 25 % of total shell length), with ~ 55 rows of teeth (Fig. 5 H). Central tooth formula 4 - C- 4 / 1 - 1 (Fig. 5 I); basal tongue V-shaped, length about equal to lateral margin. Lateral tooth formula 3 - C- 3. Inner marginal teeth having ~ 20 tapered cusps, shortening towards the base. Outer marginal teeth with ~ 25 sharp cusps (Fig. 5 J). Animal darkly pigmented, except for neck and tentacles (Fig. 6 F, G). Snout as long as wide, with medium distal lobation; foot size intermediate, with dorsal pigmentation. Ctenidium with 17 – 19 well-developed gill filaments, occupying ~ 50 % of pallial cavity length and posteriorly positioned. Osphradium of intermediate width and opposite middle of ctenidium (Fig. 6 A). Stomach slightly longer than wide, with two chambers almost equal in size and a medium-sized posterior caecum; style sac longer than wide, surrounded by an unpigmented intestine (Fig. 6 B; Supporting Information, Table S 4). Nervous system elongate (mean RPG ratio =. 60), darkly pigmented, darker on ganglia than on connectives and commissures; cerebral ganglia approximately equal in size (Fig. 6 C). Female glandular oviduct approximately three times as long as wide. Albumen gland shorter than capsule gland. Bursa copulatrix large, pyriform, almost as long as wide. Bursal duct longer than bursal length. Renal oviduct black-pigmented until the insertion of seminal receptacle, making one or two loops. Seminal receptacle elongate, with a short duct, joining renal oviduct at the insertion point with bursal duct (Fig. 6 D, E; Supporting Information, Table S 5). Male genitalia with a prostate gland approximately twice as long as wide, bean-shaped; seminal duct entering the middle-posterior region; pallial vas deferens emerging close to its anterior edge (Fig. 6 H). Penis as long as head, gradually tapering, with many folds over the entire surface and a small patch of pigmentation on its distal region (Fig. 6 F, G; Supporting Information, Table S 6); base medium wide; attached well behind the right eye; penial duct narrow, curved, coursing close to outer edge.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFA353122AE1FB7AF3B2F5FA.taxon	biology_ecology	Habitat Endemic to a small spring, in which the species lives in high abundance. The substrate is composed of silt and gravel. The average water temperature varies between 14 ° C in winter and 25 ° C in summer. The conductivity varies between 0.53 and 0.78 mS. Co-occurring mollusc species are Bullaregia tunisiensis Khalloufi, Béjaoui & Delicado, 2017, Pisidium sp., Galba truncatula (O. F. Müller, 1774), and Physella acuta (Draparnaud, 1805).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFA353122AE1FB7AF3B2F5FA.taxon	discussion	Remarks According to our DNA analyses, this species is more closely related to its congeners distributed in north-western Africa (Morocco) than those distributed in north-eastern Africa (Tunisia). It resembles Pseudamnicola conovula from Tunisia in shell and penis features (Supporting Information, Figs S 7 F – L, S 8 O – Q). Otherwise, it differs in having a larger bursa copulatrix and a COI average sequence divergence of 7.4 %. The shell and aperture shapes of P. araujoi are more similar to those of P. calamensis and P. linae (most probably a synonym of P. calamensis) than any of the 15 Pseudamnicola species described in Algeria (Glöer et al. 2010: figs 6 – 20), which are mostly known from their shells. The morphology and morphometry of its female genitalia are, however, different from the other two species (Glöer et al. 2010: figs 6 – 20, for comparison; Fig. 2).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFA0530C29E0FD6BF054F176.taxon	description	(Figs 7, 8)	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFA0530C29E0FD6BF054F176.taxon	etymology	Etymology	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFA0530C29E0FD6BF054F176.taxon	materials_examined	Referring to Monte Argentario (Italy), a municipality located near the type locality. Type material Holotype (MNCN 15.05 / 200500 H; dissected animal) and four paratypes (MNCN 15.05 / 200500 P) in the MNCN collection and ~ 50 paratypes in the UGSB collection (UGSB 11999). Type locality: a spring below the Fontana Carpina, Monte Argentario, Grosseto Province, Italy. Material studied A spring below the Fontana Carpina, Monte Argentario, Grosseto Province, Italy, 42.4242 ° N, 11.0908 ° E, leg. S. C. and M. C., September 2012, MNCN 15.05 / 200500 and UGSB 11999 (80 % ethanol).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFA0530C29E0FD6BF054F176.taxon	diagnosis	Diagnosis Shell relatively slender (SL / SW ratio> 1.5); protoconch microsculpture pitted; central radular tooth formula 4 - C- 4 / 1 - 1; bursa copulatrix large, pyriform, with a duct longer than bursal length; SR 1 elongate, with a short duct; penis gradually tapering, with many folds over the entire surface and a small patch of pigmentation on its distal region; nervous system slightly pigmented, elongate (mean RPG ratio =. 61).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFA0530C29E0FD6BF054F176.taxon	description	Description Shell ovate-conic, whorls 4 – 5, height 2.5 – 3.5 mm (Fig. 7 A – C; Supporting Information, Table S 3). Periostracum yellowish. Protoconch ~ 450 µm wide, whorls 1.5; nucleus ~ 125 µm wide; protoconch microsculpture pitted (Fig. 7 G). Teleoconch whorls moderately convex, with deep sutures; body whorl large, occupying about two-thirds of total shell length. Aperture slightly oval; inner lip thicker than outer lip; peristome margin simple, straight (Fig. 7 D). Umbilicus narrow, not covered by the inner lip. Holotype: SL = 3.46 mm, SW = 2.01 mm, AL = 1.69 mm, and AW = 1.24 mm. Operculum oval, brownish, about two and a half whorls; muscle attachment area oval and located near the nucleus (Fig. 7 E, F). Radular length intermediate, ~ 675 µm (~ 25 % of total shell length), with ~ 65 rows of teeth (Fig. 7 H). Central tooth formula 4 - C- 4 / 1 - 1 (Fig. 7 I); basal tongue V-shaped, length about equal to lateral margin. Lateral tooth formula 3 - C- 3. Inner marginal teeth having 20 – 23 tapered cusps, shortening towards the base. Outer marginal teeth with ~ 25 sharp cusps (Fig. 7 J). Animal darkly pigmented, except for neck and tentacles (Fig. 8 F). Snout as long as wide, with medium distal lobation; foot size intermediate, with dorsal pigmentation. Ctenidium with 17 – 19 well-developed gill filaments, occupying ~ 50 % of pallial cavity length and posteriorly positioned. Osphradium of intermediate width and opposite middle of ctenidium (Fig. 8 A). Stomach slightly longer than wide, with two chambers almost equal in size and a medium-sized posterior caecum; style sac longer than wide, surrounded by an unpigmented intestine (Fig. 8 B; Supporting Information, Table S 4). Nervous system elongate (mean RPG ratio =. 61), slightly pigmented, darker on ganglia than on connectives and commissures; cerebral ganglia approximately equal in size (Fig. 8 C). Female glandular oviduct approximately four times longer than wide. Albumen gland shorter than capsule gland. Bursa copulatrix pyriform, slightly longer than wide. Bursal duct longer than bursal length. Renal oviduct black-pigmented until the area above the insertion of seminal receptacle, coiled. Seminal receptacle elongate, with a short duct, joining renal oviduct slightly above the insertion point with bursal duct (Fig. 8 D, E; Supporting Information, Table S 5). Male genitalia with a prostate gland approximately twice as long as wide, bean-shaped; seminal duct entering the middle-posterior region; pallial vas deferens emerging close to its anterior edge (Fig. 8 H). Penis almost as long as head, gradually tapering, with many folds over the entire surface and a small patch of pigmentation on its distal region (Fig. 8 F, G; Supporting Information, Table S 6); base moderately wide; attached well behind the right eye; penial duct narrow, curved, coursing close to outer edge.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFA0530C29E0FD6BF054F176.taxon	biology_ecology	Habitat Endemic to a coastal spring on the Monte Argentario Peninsula.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFA0530C29E0FD6BF054F176.taxon	discussion	Remarks Two hydrobiid populations occurring in Monte Argentario at the Fonte delle tre Viti Spring and Romito Spring were identified as Amnicola moussoni (Calcara 1841) (= Pseudamnicola moussonii) and Amnicola vestita (Benoit, 1875), respectively, by Paulucci (1886). Our studied population near Fontana Caprina is here considered a distinct species because: (i) the two cited species by Paulucci (1886) were originally described from Sicily, and our integrative evidence suggested that the Pseudamnicola species from Sicily have more restricted ranges than previously thought; (ii) according to Giusti (1976), A. vestita is a synonym of P. moussonii; and (iii) there are clear genetic (6.2 % average sequence divergence for COI) and morphological differences (e. g. in shell or female genitalia features) between P. argentariensis and P. moussonii. Manganelli et al. (2017) reported several Pseudamnicola populations in Monte Argentario, one from the same area as our studied snails, and tentatively classified them into P. moussonii. Based on our species delimitation results, we recommend further genetic verification of this species identification, because P. argentariensis can potentially occur in other localities in the region. Pseudamnicola argentariensis is one of the few slender-shelled representatives of the genus. In comparison to other slender-shelled species, it can be distinguished by: its wider spire and larger aperture from Pseudamnicola luteolus (Küster 1852 - 1853) from Algeria (Glöer et al. 2010: fig. 21); its smaller shell, larger aperture, less convex spire whorls, longer bursal duct, and wider penis from P. granjaensis from Majorca (Delicado et al. 2014: figs 4, 8); and its more globous shell, wider spire, and larger aperture from Pseudamnicola sciaccaensis Glöer & Beckmann, 2007 from Sicily (Glöer and Beckmann 2007: fig. 1). Snails were found in high abundance at the type locality, with the great majority being juveniles. Adult shells differed from the ones of the closely related P. lucensis according to their generally higher spire and larger aperture (Supporting Information, Fig. S 9). Pseudamnicola argentariensis differs anatomically by having a larger bursa copulatrix, more slender penis, longer radula, and fewer cusps on the lateral radular teeth (Giusti 1976; Supporting Information, Fig. S 10). Based on these morphological differences, previous studies identified these snails as a 18 • Delicado et al. different species of Pseudamnicola, not belonging to P. lucensis, and referred to as Pseudamnicola sp. 1 (Delicado et al. 2018, Boulaassafer et al. 2020).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBE53092866F9EAF0E1F494.taxon	description	ZooBank registration: urn: lsid: zoobank. org: act: 536 D 395 B- 2699 - 420 F-B 2 A 6 - 8020 BC 0 BC 931	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBE53092866F9EAF0E1F494.taxon	etymology	Etymology Named after Marco Bodon, collector of the species, in recognition of his valuable contribution to the knowledge of the molluscan fauna of Italy.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBE53092866F9EAF0E1F494.taxon	materials_examined	Type material Holotype (MNCN 15.05 / 200502 H) in the MNCN collection and five paratypes in the UGSB collection (UGSB 988). Type locality: a spring on the left bank of the Biedano Stream, Blera, Latium, Italy. Material studied A spring on the left bank of the Biedano Stream, Blera, Latium, Italy, 42.2680 ° N, 12.0256 ° E, leg. M. B., November 2007, MNCN 15.05 / 200502 H and UGSB 988 (80 % ethanol). A spring in Via Marrucella, Capri Island, Italy, 40.5492 ° N, 14.2323 ° E, leg. M. B., March 2004, UGSB 5967 (80 % ethanol). A stream near Sperlonga, Latium, Italy, 41.2579 ° N, 13.4348 ° E, leg. M. B. and S. C., January 2014, UGSB 16628 (80 % ethanol).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBE53092866F9EAF0E1F494.taxon	diagnosis	Diagnosis Shell small, ovate-conic, with a short spire; protoconch microsculpture pitted; central radular tooth formula 4 - C- 4 / 1 - 1; bursa copulatrix small, pyriform, with a duct slightly longer than bursal length; SR 1 elongate, with a short duct; penis gradually tapering, unpigmented, with many folds over the entire surface and a wide base; nervous system darkly pigmented, elongate (mean RPG ratio =. 50).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBE53092866F9EAF0E1F494.taxon	description	Description Shell ovate-conic, whorls 3 – 3.5, height 2 – 2.5 mm (Fig. 9 A – C; Supporting Information, Table S 3). Periostracum yellowish. Protoconch ~ 400 µm wide, whorls 1.5; nucleus ~ 125 µm wide; protoconch microsculpture pitted (Fig. 9 G). Teleoconch whorls moderately convex, with deep sutures; body whorl large, occupying about three-quarters of total shell length. Aperture longer than wide, slightly oval; inner lip thicker than outer lip; peristome margin simple, straight (Fig. 9 D). Umbilicus narrow, not covered by the inner lip. Holotype: SL = 2.21 mm, SW = 1.81 mm, AL = 1.26 mm, and AW = 0.86 mm. Operculum oval, brownish, about two and a half whorls; muscle attachment area oval and located near the nucleus (Fig. 9 E, F). Radular length intermediate, ~ 600 µm (~ 25 % of total shell length), with ~ 60 rows of teeth (Fig. 9 H). Central tooth formula 4 - C- 4 / 1 - 1 (Fig. 9 I); basal tongue V-shaped, length about equal to lateral margin. Lateral tooth formula 3 - C- 3. Inner marginal teeth having ~ 25 tapered cusps, shortening towards the base. Outer marginal teeth with ~ 20 sharp cusps (Fig. 9 J). Animal darkly pigmented except for neck and tentacles (Fig. 10 F). Snout as long as wide, with medium distal lobation; foot size intermediate, with dorsal pigmentation. Ctenidium with 17 – 19 well-developed gill filaments, occupying ~ 50 % of pallial cavity length and posteriorly positioned. Osphradium of intermediate width and opposite middle of ctenidium (Fig. 10 A). Stomach as long as wide, with two chambers almost equal in size and a medium-sized posterior caecum; style sac longer than wide, surrounded by an unpigmented intestine (Fig. 10 B; Supporting Information, Table S 4). Nervous system elongate (mean RPG ratio =. 50), darkly pigmented, darker on ganglia than on connectives and commissures; cerebral ganglia approximately equal in size (Fig. 10 C). Female glandular oviduct approximately four times as long as wide. Albumen gland shorter than capsule gland. Bursa copulatrix small, pyriform, longer than wide. Bursal duct longer than bursal length. Renal oviduct black-pigmented until the area above the insertion of seminal receptacle, making one or two loops. Seminal receptacle elongate, with a short duct, joining renal oviduct at the insertion point with bursal duct (Fig. 10 D, E; Supporting Information, Table S 5). Male genitalia with a prostate gland approximately three times as long as wide, bean-shaped; seminal duct entering the middle-posterior region; pallial vas deferens emerging close to its anterior edge (Fig. 10 H). Penis shorter than head, gradually tapering, unpigmented, with many folds over the entire surface (Fig. 10 F, G; Supporting Information, Table S 6); base wide; attached well behind the right eye; penial duct narrow, curved, coursing close to outer edge.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBE53092866F9EAF0E1F494.taxon	biology_ecology	Habitat The species lives in coastal running waters, mainly in small springs.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBE53092866F9EAF0E1F494.taxon	discussion	Remarks The few individuals available for the study showed little variation in shell features (Fig. 9 A – C). The species was first discovered by DNA-based phylogenetic analyses (Delicado et al. 2015), but the comprising populations could not be assigned to any of the nominal species owing to a lack of morphological information. In our study, all DNA-based species delimitation methods (except the ABGD for 16 S) recovered this species as distinct from P. lucensis, P. orsinii, and P. argentariensis, which also occur on the Apennine Peninsula and adjacent islands (Issel 1866, Giusti 1976, Falkner and Boeters 2003). Pseudamnicola bodoni differs from these geographically proximate species in the combination of a short spire, short seminal receptacle, short penis, and average sequence divergence of 4.8 % – 7.8 % for COI. It differs from the Sicilian populations of P. moussonii and P. reticulatus in having a more globose shell, a larger number of cusps on the marginal radular teeth, a shorter penis, and an average sequence divergence of 6.1 % – 7.6 % for COI.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBB530B2995FC42F3CBF145.taxon	description	(Figs 11, 12) Pseudamnicola sp. 2 — Delicado et al. 2015 [in part] Pseudamnicola sp. 2 — Delicado et al. 2018 Pseudamnicola sp. 2 — Boulaassafer et al. 2020 ZooBank registration: urn: lsid: zoobank. org: act: 0 DD 397 BA- 5997 - 4 FF 8 - 8 E 42 - A 3 A 4 EB 495 D 83	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBB530B2995FC42F3CBF145.taxon	etymology	Etymology From Greek megastome, referring to the large shell aperture of this species.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBB530B2995FC42F3CBF145.taxon	materials_examined	Type material Holotype (MNCN 15.05 / 200501 H) and ~ 30 paratypes (MNCN 15.05 / 200501 P) in the MNCN collection. Type locality: Wedi El Garâa Stream, Bizerte, Tunisia. Material studied Wedi El Garâa Stream, Bizerte, Tunisia, 37.2426 ° N, 9.7185 ° E, leg. N. K. and D. D., May 2009, MNCN 15.05 / 200501 (70 % ethanol). A well in the Ennkhilet region, north of Ichkeul, Tunisia, 37.2055 ° N, 9.6677 ° E, leg. N. K. and D. D., May 2009, MNCN 15.05 / 95107 (70 % ethanol).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBB530B2995FC42F3CBF145.taxon	diagnosis	Diagnosis Shell ovate-conic, with a relatively wide aperture (AW / AL ratio>. 75); protoconch microsculpture pitted; central radular tooth formula (4) 3 - C- 3 (4) / 1 - 1; bursa copulatrix large, pyriform, with a duct slightly longer than bursal length; SR 1 elongate, with a short duct; penis large, gradually tapering, unpigmented, with many folds over the entire surface and a moderately wide base; nervous system darkly pigmented, elongate (mean RPG ratio =. 52).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBB530B2995FC42F3CBF145.taxon	description	Description Shell ovate-conic, whorls 4 – 4.5, height 3 – 4 mm (Fig. 11 A, C, D; Supporting Information, Table S 3). Periostracum yellowish. Protoconch ~ 450 µm wide, whorls 1.5; nucleus ~ 120 µm wide; protoconch microsculpture pitted (Fig. 11 F). Teleoconch whorls moderately convex, with deep sutures; body whorl large, occupying about three-quarters of total shell length. Aperture almost as wide as long, slightly oval; inner lip thicker than outer lip; peristome margin simple, straight (Fig. 11 B). Umbilicus narrow, not covered by the inner lip. Holotype: SL = 3.75 mm, SW = 2.75 mm, AL = 2.04 mm, and AW = 1.62 mm. Operculum oval, brownish, about two and a half whorls; muscle attachment area oval and located near the nucleus (Fig. 11 E). Radular length intermediate, ~ 750 µm (~ 25 % of total shell length), with ~ 55 rows of teeth (Fig. 11 G). Central tooth formula (4) 3 - C- 3 (4) / 1 - 1 (Fig. 11 H); basal tongue V-shaped, length about equal to lateral margin. Lateral tooth formula 2 - C- 2 (rarely with three lateral cusps). Inner marginal teeth having 16 – 17 tapered cusps, shortening towards the base. Outer marginal teeth with ~ 22 sharp cusps (Fig. 11 I). Animal black-pigmented except for neck and tentacles (Fig. 12 F). Snout as long as wide, with medium distal lobation; foot size intermediate, with dorsal pigmentation. Ctenidium with 16 – 19 well-developed gill filaments, occupying ~ 50 % of pallial cavity length and posteriorly positioned. Osphradium of intermediate width and opposite middle of ctenidium (Fig. 12 A). Stomach as long as wide, with two chambers almost equal in size and a medium-sized posterior caecum; style sac longer than wide, surrounded by an unpigmented intestine (Fig. 12 B; Supporting Information, Table S 4). Nervous system elongate (mean RPG ratio =. 52), darkly pigmented, darker on ganglia than on connectives and commissures; cerebral ganglia approximately equal in size (Fig. 12 C). Female glandular oviduct approximately three times as long as wide. Albumen gland shorter than capsule gland. Bursa copulatrix pyriform, longer than wide. Bursal duct longer than bursal length. Renal oviduct black-pigmented until the insertion of seminal receptacle or the area above, relatively straight. Seminal receptacle elongate, with a short duct, joining renal oviduct at the insertion point with bursal duct (Fig. 12 D, E; Supporting Information, Table S 5). Male genitalia with a prostate gland approximately three times as long as wide, bean-shaped; seminal duct entering the middle-posterior region; pallial vas deferens emerging close to its anterior edge (Fig. 12 H). Penis longer than head, gradually tapering, unpigmented, with many folds over the entire surface (Fig. 12 F, G; Supporting Information, Table S 6); base narrower than central area of penis; attached well behind the right eye; penial duct narrow, curved, coursing close to outer edge.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBB530B2995FC42F3CBF145.taxon	biology_ecology	Habitat Known from two different habitat types in southern Bizerte. The species was found in the muddy bottom of a stream (Wedi El Garâa) near Bizerte and attached to the walls of a well in the Ennkhilet region north of Ichkeul. In the first locality, aquatic plants are sparse, and the water temperature and conductivity are 22 ° C and 2.6 – 2.9 mS, respectively. In the second locality, aquatic plants (Ranunculus sp. and Lemna minor Linn.) and filamentous algae (Spirogyra sp.) are dense. The temperature and conductivity of the water are high (24 ° C and 1.6 – 2.4 mS, respectively). Snails were found in low abundance at the two localities. Co-occurring mollusc species are Galba truncatula, Physella acuta, Gyraulus parvus (Say, 1817), and Pisidium sp.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFBB530B2995FC42F3CBF145.taxon	discussion	Remarks Pseudamnicola megastomus has an unusually large shell aperture, comparable to that of Pseudamnicola algeriensis Glöer, Bouzid & Boeters, 2010 (Glöer et al. 2010: fig. 14). However, specimens of P. megastomus are slightly smaller and have a narrower last body whorl and a wider aperture than in the latter species. Its shell morphology is similar to that of a paratype of Pseudamnicola ghamizii Glöer, Bouzid & Boeters, 2010 (Glöer et al. 2010: fig. 39), but differs in its higher shell and larger aperture. The species was recorded from north-eastern Tunisia, where another accepted species of Pseudamnicola, P. meluzzii, is distributed. The former can be distinguished easily by having a larger shell, a wider aperture, fewer cusps on the lateral and central radular teeth, and a longer bursa copulatrix. The features of the penis of both species are very similar. The newly discovered species in north-western Tunisia, P. araujoi, differs from P. megastomus in having a smaller and more globose shell, a shorter penis, and a less concentrated nervous system. Pseudamnicola megastomus and P. conovula were depicted as closely related species in previous studies (Delicado et al. 2015, 2018, Boulaassafer et al. 2020) and by all our phylogenetic analyses (Fig. 2; Supporting Information, Figs S 4 – S 6). However, this relationship has always Gastropod species delimitation • 23 been poorly supported. A population of P. conovula living at Toute Stream (Bizerte Region) and its conspecific populations differ from P. megastomus according to their different shell features and female reproductive anatomy. The average sequence divergence among these four species was 2.5 % – 7.4 % for COI.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB95304299BF913F372F1D0.taxon	description	(Figs 13, 14) Pseudamnicola orsinii (Küster, 1852) — Delicado et al. 2015 Pseudamnicola sp. 5 — Delicado et al. 2018 Pseudamnicola sp. 5 — Boulaassafer et al. 2020 ZooBank registration: urn: lsid: zoobank. org: act: CD 01 E 3 A 2 - 61 DA- 4003 - 8950 - F 6743 F 7 FCB 01	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB95304299BF913F372F1D0.taxon	etymology	Etymology In Latin, reticulatus means reticulated, describing the net-like shell sculptures found in the type population.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB95304299BF913F372F1D0.taxon	materials_examined	Type material Holotype (MNCN 15.05 / 200503 H; dissected animal) and one paratype (MNCN 15.05 / 200503 P) in the MNCN collection and six paratypes in the UGSB collection (UGSB 5971). Type locality: a spring discharging to the Fiumefreddo River, Fiumefreddo di Sicilia, Sicily, Italy. Material studied A spring discharging to the Fiumefreddo River, Fiumefreddo Sicilia, Sicily, Italy, 37.7851 ° N, 15.2271 ° E, leg. M. B., January 2008, MNCN 15.05 / 200503 and UGSB 5971 (80 % ethanol).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB95304299BF913F372F1D0.taxon	diagnosis	Diagnosis Shell small, ovate-conic, with a fine net-like surface sculpture (in the type population); protoconch microsculpture pitted; central radular tooth formula (4) 3 - C- 3 (4) / 1 - 1; bursa copulatrix medium-sized, pyriform, with a duct longer than bursal length; SR 1 long, elongate, with a short duct; penis gradually tapering, with many folds over the entire surface, a moderately wide base, and a small patch of pigmentation on its distal region; nervous system darkly pigmented, elongate (mean RPG ratio =. 52).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB95304299BF913F372F1D0.taxon	description	Description Shell ovate-conic, whorls 3.5 – 4, height 2.00 – 3.25 mm, with a fine net-like surface sculpture (in the type population) (Fig. 13 A – C; Supporting Information, Table S 3). Periostracum yellowish to whitish. Protoconch ~ 500 µm wide, eroded in the type population, whorls 1.5; nucleus ~ 150 µm wide; protoconch microsculpture pitted (Fig. 13 G). Teleoconch whorls moderately convex, with deep sutures; body whorl large, occupying about three-quarters of total shell length. Aperture longer than wide, slightly oval; inner lip thicker than outer lip; peristome margin simple, straight (Fig. 13 D). Umbilicus narrow, not covered by the inner lip. Holotype: SL = 3.28 mm, SW = 2.23 mm, AL = 1.85 mm, and AW = 1.40 mm. Operculum oval, yellowish, about two and a half whorls; muscle attachment area oval and located near the nucleus (Fig. 13 E, F). Radular length intermediate, ~ 600 µm (~ 25 % of total shell length), with ~ 55 rows of teeth (Fig. 13 H). Central tooth formula (4) 3 - C- 3 (4) / 1 - 1 (Fig. 13 I); basal tongue V-shaped, length about equal to lateral margin. Lateral tooth formula 3 - C- 3. Inner marginal teeth having 15 – 20 tapered cusps, shortening towards the base. Outer marginal teeth with ~ 20 sharp cusps (Fig. 13 J). Animal darkly pigmented, with pigmentation lighter on neck and tentacles (Fig. 14 F). Snout as long as wide, with medium distal lobation; foot size intermediate, with dorsal pigmentation. Ctenidium with ~ 20 well-developed gill filaments, occupying ~ 50 % of pallial cavity length and posteriorly positioned. Osphradium of intermediate width and opposite middle of ctenidium (Fig. 14 A). Stomach slightly longer than wide, with two chambers almost equal in size and a medium-sized posterior caecum; style sac longer than wide, surrounded by an unpigmented intestine (Fig. 14 B; Supporting Information, Table S 4). Nervous system elongate (mean RPG ratio =. 52), darkly pigmented, darker on ganglia than on connectives and commissures; cerebral ganglia approximately equal in size (Fig. 14 C). Female glandular oviduct approximately three times as long as wide. Albumen gland shorter than capsule gland. Bursa copulatrix small, pyriform, longer than wide. Bursal duct slightly longer than bursal length. Renal oviduct black-pigmented until the area above the insertion of seminal receptacle, relatively straight. Seminal receptacle elongate, with a short duct, joining renal oviduct at the insertion point with bursal duct (Fig. 14 D, E; Supporting Information, Table S 5). Male genitalia with a prostate gland approximately twice longer than wide, bean-shaped; seminal duct entering the middle-posterior region; pallial vas deferens emerging close to its anterior edge (Fig. 14 H). Penis as long as head, gradually tapering, with many folds over the entire surface and a small patch of pigmentation on its distal region (Fig. 14 F, G; Supporting Information, Table S 6); base moderately wide; attached well behind the right eye; penial duct narrow, curved, coursing close to outer edge.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB95304299BF913F372F1D0.taxon	biology_ecology	Habitat Endemic to a small coastal spring.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB95304299BF913F372F1D0.taxon	discussion	Remarks We dissected six of the eight specimens of P. reticulatus deposited in the UGSB collection and found only one female. All specimens had an eroded shell apex and a fine net-like shell sculpture, the latter feature atypical in Pseudamnicola. Delicado et al. (2015) identified the Pseudamnicola population occurring in the same spring near Fiumefreddo di Sicilia as P. orsinii. There is, however, a large genetic divergence (4 % for COI) between the P. reticulatus and the newly sequenced snail from the type locality region of P. orsinii, in addition to morphological differences detected in shells and other anatomical structures, which might disprove this identification. The phylogenetic studies of Delicado et al. (2018) and Boulaassafer et al. (2020) inferred that the P. reticulatus clade was phylogenetically distant from the P. moussonii clade. The two species differ according to a set of morphological characters: the shell spire and aperture are wider in P. reticulatus (for comparison, see Giusti 1976; Falkner and Boeters 2003); the bursal duct and seminal receptacle of the single dissected female from the type locality of P. moussonii are slightly longer than the ones measured in the P. reticulatus female, but this difference needs confirmation; and the penis is generally wider in P. reticulatus.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB6530629F3F88FF1FCF7E1.taxon	description	(Figs 15, 16) Pseudamnicola sp. 7 — Delicado et al. 2018 Pseudamnicola sp. 7 — Boulaassafer et al. 2020 ZooBank registration: urn: lsid: zoobank. org: act: 6 A 58528 E- 3 FD 4 - 4 AC 3 - 8 BAC- 589039156 CFD	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB6530629F3F88FF1FCF7E1.taxon	etymology	Etymology The species name refers to the occurrence of this species on the island of Sardinia.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB6530629F3F88FF1FCF7E1.taxon	materials_examined	Type material Holotype (MNCN 15.05 / 200504 H) and three paratypes in the UGSB collection (UGSB 15501). Type locality: stream near Bau sa Mela, Nurallao, Sardinia, Italy. Material studied Stream near Bau sa Mela, Nurallao, Sardinia, Italy, 39.8400 ° N, 9.1052 ° E, leg. M. S., September 2000, MNCN 15.05 / 200504 and UGSB 15501 (80 % ethanol).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB6530629F3F88FF1FCF7E1.taxon	diagnosis	Diagnosis Shell small, ovate-conic, with a short spire; protoconch microsculpture pitted; central radular tooth formula (5) 4 - C- 4 (5) / 1 - 1; penis gradually tapering, with many folds over the entire surface, a moderately wide base and a small patch of pigmentation on its distal region; nervous system darkly pigmented, elongate (mean RPG ratio =. 64).	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB6530629F3F88FF1FCF7E1.taxon	description	Description Shell ovate-conic, whorls 4, height 2.0 – 2.5 mm (Fig. 15 A, B; Supporting Information, Table S 6). Periostracum yellowish. Protoconch ~ 400 µm wide, whorls 1.5; nucleus ~ 150 µm wide; protoconch microsculpture pitted (Fig. 15 C). Teleoconch whorls moderately convex, with deep sutures; body whorl large, occupying about three-quarters of total shell length. Aperture longer than wide, slightly oval; inner lip thicker than outer lip; peristome margin simple, straight. Umbilicus narrow, not covered by the inner lip. Holotype: SL = 2.29 mm, SW = 1.75 mm, AL = 1.34 mm, and AW = 1.03 mm. Operculum oval, yellowish, about two and a half whorls; muscle attachment area oval and located near the nucleus. Radular length intermediate, ~ 500 µm (~ 25 % of total shell length), with ~ 45 rows of teeth (Fig. 15 D). Central tooth formula (5) 4 - C- 4 (5) / 1 - 1 (Fig. 15 E); basal tongue V-shaped, length about equal to lateral margin. Lateral tooth formula 4 - C- 4. Inner marginal teeth having 20 – 25 tapered cusps, shortening towards the base. Outer marginal teeth with ~ 25 sharp cusps (Fig. 15 F). Animal darkly pigmented, except for neck and tentacles (Fig. 16 D). Snout as long as wide, with medium distal lobation; foot size intermediate, with dorsal pigmentation. Ctenidium with ~ 15 well-developed gill filaments, occupying ~ 50 % of pallial cavity length and posteriorly positioned. Osphradium of intermediate width and opposite middle of ctenidium (Fig. 16 A). Stomach slightly longer than wide, with two chambers almost equal in size and a medium-sized posterior caecum; style sac longer than wide, surrounded by an unpigmented intestine (Fig. 16 B; Supporting Information, Table S 4). Nervous system elongate (mean RPG ratio =. 64), darkly pigmented, darker on ganglia than on connectives and commissures; cerebral ganglia approximately equal in size (Fig. 16 C). Female genitalia unknown. Male genitalia with a prostate gland approximately twice longer than wide, bean-shaped; seminal duct entering the middle-posterior region; pallial vas deferens emerging close to its anterior edge (Fig. 16 F). Penis as long as head, gradually tapering, with many folds over the entire surface and a small patch of pigmentation on its distal region (Fig. 16 D, E; Supporting Information, Table S 6); base moderately wide; attachment area central; penial duct narrow, curved, coursing close to outer edge.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB6530629F3F88FF1FCF7E1.taxon	biology_ecology	Habitat Endemic to a small stream, where the species was found in low abundance.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
536F827BFFB6530629F3F88FF1FCF7E1.taxon	discussion	Remarks We dissected three of the eight specimens of P. sardiniensis deposited in the UGSB collection and found no female specimens. The shell of this species has a lower spire than that of the other two newly discovered species in Sardinia (Pseudamnicola sp. 10 and 11). Its penis is slightly narrower than in the other two species. There is, however, a large genetic divergence (7.5 % for COI) between P. sardiniensis and the other two species endemic to Sardinia (Pseudamnicola sp. 10 and 11). The average sequence divergence with P. moussonii, another species of Pseudamnicola reported from the island (Giusti and Castagnolo 1983), was 8 % for COI.	en	Delicado, Diana, Boulaassafer, Khadija, Khalloufi, Noureddine, Hauffe, Torsten (2025): A holistic perspective on species delimitation outperforms all methods based on single data types in freshwater gastropods (Caenogastropoda: Hydrobiidae: Pseudamnicola). Zoological Journal of the Linnean Society 203 (1): 1-31, DOI: 10.1093/zoolinnean/zlae010, URL: https://doi.org/10.1093/zoolinnean/zlae010
