identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
74498794FF83E41AFC302F17FC73020F.text	74498794FF83E41AFC302F17FC73020F.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Amuropaludina Moskvicheva 1979	<div><p>Amuropaludina Moskvicheva, 1979</p><p>Examined species:  Amuropaludina praerosa (Gerstfeldt, 1859)</p><p>(Figs 2H, 3H, 6H).</p><p>Remarks: Within  Viviparidae,  Amuropaludina is the only genus with an operculum that has a central nucleus. All other genera of  Viviparidae have an operculum with a subcentral nucleus. The wide semi-elliptical shape of  Amuropaludina is also a useful diagnostic character.</p></div>	https://treatment.plazi.org/id/74498794FF83E41AFC302F17FC73020F	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF83E41AFEC32F9EFEC90284.text	74498794FF83E41AFEC32F9EFEC90284.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Campeloma Rafinesque 1819	<div><p>Campeloma Rafinesque, 1819</p><p>Examined species:  Campeloma decisum (Say, 1817)</p><p>(Figs 2B, 3B, 6B).</p><p>Remarks: The elongated, inverted-comma-shaped and concentric operculum is the most important combination of diagnostic opercular characters for  Campeloma . The apex–nucleus distance is clearly longer than the base–nucleus distance. This character is seen only in  Campeloma and  Lioplax, the two extant genera of  Lioplacinae .</p></div>	https://treatment.plazi.org/id/74498794FF83E41AFEC32F9EFEC90284	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF83E41AFBF82DB9FA4700B3.text	74498794FF83E41AFBF82DB9FA4700B3.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Lioplax Troschel 1857	<div><p>Lioplax Troschel, 1857</p><p>Examined species:  Lioplax subcarinata (Say, 1817) (Figs 2A, 3A, 6A).</p><p>Remarks:  Lioplax is the only genus in the family with a paucispiral operculum at early developmental stages, which is different from the concentric operculum of all other genera of  Viviparidae . In addition, the semi-elliptical shape and lower central location of the nucleus are also diagnostic opercular characters for this genus.</p></div>	https://treatment.plazi.org/id/74498794FF83E41AFBF82DB9FA4700B3	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF83E41BFBFD2E33FEDD0232.text	74498794FF83E41BFBFD2E33FEDD0232.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Callinina Thiele 1931	<div><p>Callinina Thiele, 1931</p><p>Examined species:  Callinina georgiana (Lea, 1834) (Figs 2C, D, 3C, D, 6C, D);  C. intertexta (Say, 1829) (Figs 2E, 3E, 6E).</p><p>Remarks:  Callinina can be distinguished from  Viviparus and the other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: a thin marginal region that obviously differs in colour from the enamel region; a shiny, smooth and relatively small nuclear region; and a narrow inner enamel region.</p><p>The only opercular difference found between the two examined species was a relatively darker and thicker operculum in the single examined individual of  C. intertexta as compared with  C. georgiana .</p></div>	https://treatment.plazi.org/id/74498794FF83E41BFBFD2E33FEDD0232	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF82E41BFEAA2E40FC570393.text	74498794FF82E41BFEAA2E40FC570393.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Rivularia Heude 1890	<div><p>Rivularia Heude, 1890</p><p>Examined species:  Rivularia auriculata (Martens, 1875)</p><p>(Figs 2G, 3G, 6 G).</p><p>Remarks: The semi-elliptical operculum of  Rivularia is most similar to that of  Tulotoma . However, the operculum of  Rivularia has no obvious marginal region; there is, however, a smooth, large scar region.</p></div>	https://treatment.plazi.org/id/74498794FF82E41BFEAA2E40FC570393	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF82E418FC012FAFFF31035E.text	74498794FF82E418FC012FAFFF31035E.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Tulotoma Haldeman 1840	<div><p>Tulotoma Haldeman, 1840</p><p>Examined species:  Tulotoma magnifica (Conrad, 1834) (Figs 2F, 3F, 6F).</p><p>Remarks: The operculum of  Tulotoma can be easily distinguished from that of all other genera based on the following characters: semi-elliptical shape; inwardly folded opercular apex and opercular base; outwardly folded inner margin; a rough, nontransparent and small inner opercular region; and a wide, thin marginal region that obviously differs in colour from the enamel region, especially when it is compared with  Rivularia Heude, 1890 . Like  Tulotoma,  Rivularia has a semi-elliptical shape and subcentral nucleus.</p></div>	https://treatment.plazi.org/id/74498794FF82E418FC012FAFFF31035E	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF81E418FEBD2F64FA5C0333.text	74498794FF81E418FEBD2F64FA5C0333.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Viviparus Montfort 1810	<div><p>Viviparus Montfort, 1810</p><p>Examined species:  Viviparus viviparus (Linnaeus, 1758) (Figs 2I, 3I, 6I);  V. contectus Millet, 1813 (Figs 2J, K, 3J, K, 6J, K).</p><p>Remarks:  Viviparus can be distinguished from the other genera with a concentric inverted-comma-shaped operculum (especially  Callinina) by the following combination of characters: a thickened marginal region, obvious concentric growth grooves on the interior surface, a wide inner enamel region, and a small and smooth nuclear region.</p><p>The operculum of  V. contectus differs from that of  V. viviparus in having a thicker marginal region and more obvious grooves.</p></div>	https://treatment.plazi.org/id/74498794FF81E418FEBD2F64FA5C0333	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF81E419FBFC2F79FDBF0315.text	74498794FF81E419FBFC2F79FDBF0315.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Angulyagra Rao 1931	<div><p>Angulyagra Rao, 1931</p><p>Examined species:  Angulyagra cf. polyzonata (Frauenfeld, 1862)</p><p>(Figs 4T, 5T, 7T).</p><p>Remarks: Apart from  Notopala,  Angulyagra can be distinguished from other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: a relatively small nuclear region with shiny grains or veins, a relatively thick enamel layer and a thin marginal region that obviously differs in colour from the enamel region.</p><p>One species of  Angulyagra (total of three specimens with operculum) has been examined for this study (Table 1).</p></div>	https://treatment.plazi.org/id/74498794FF81E419FBFC2F79FDBF0315	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF80E419FEC12F29FBE30315.text	74498794FF80E419FEC12F29FBE30315.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Anularya Zhang & Chen 2015	<div><p>Anularya Zhang &amp; Chen, 2015</p><p>Examined species:  Anularya mansuyi (Dautzenberg &amp; Fischer, 1905)</p><p>(Figs 4D, 5D, 7D);</p><p>A. bicostata (Tchang &amp; Tsi, 1949) (Figs 4E, 5E, 7E).</p><p>Remarks: Except for the larger overall size and inner opercular region, the operculum of  Anularya is most similar to that of  Sinotaia . Apart from  Sinotaia,  Anularya can be distinguished from other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: a thick, smooth, shiny, nontransparent and small nuclear region and a thick enamel region.</p><p>The operculum of  A. mansuyi differs from that of  A. bicostata by having a more acute opercular apex. The thickness of the adult operculum of  A. mansuyi can vary from relatively thin to thick. Therefore, its colour can be transparent orange red to relatively nontransparent dark red.</p></div>	https://treatment.plazi.org/id/74498794FF80E419FEC12F29FBE30315	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF80E419FC1A2F29FC6D0284.text	74498794FF80E419FC1A2F29FC6D0284.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Bellamya Jousseaume 1886	<div><p>Bellamya Jousseaume, 1886</p><p>Examined species:  Bellamya phthinotropis (Martens, 1892)</p><p>(Figs 4H, 5H, 7H);</p><p>B. trochlearis Martens, 1892 (Figs 4I, 5I, 7I).</p><p>Remarks:  Bellamya can be distinguished from other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: opercular height almost as same as width; a small, smooth shiny nuclear region; and a thin and narrow marginal region.</p><p>The operculum of  B. trochlearis differs from that of the other species examined,  B. phthinotropis, by having a more notably convex outer margin—this fits the shape of the aperture and has a strong keel.</p></div>	https://treatment.plazi.org/id/74498794FF80E419FC1A2F29FC6D0284	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8FE416FE902CC3FD9203D3.text	74498794FF8FE416FE902CC3FD9203D3.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Celetaia Clench 1966	<div><p>Celetaia Clench, 1966</p><p>Examined species:  Celetaia persculpta (Sarasin &amp; Sarasin, 1898)</p><p>(Figs 4A, 5A, 7A).</p><p>Remarks: Apart from  Torotaia,  Celetaia can be distinguished from other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: a blunt opercular apex; a large, smooth and shiny nuclear region, sometimes surrounded by concentric veins; and a thin marginal region.</p></div>	https://treatment.plazi.org/id/74498794FF8FE416FE902CC3FD9203D3	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8FE416FC582F4FFC0103E4.text	74498794FF8FE416FC582F4FFC0103E4.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Cipangopaludina chinensis (Gray 1834) ZMB Moll.	<div><p>Cipangopaludina chinensis (Gray, 1834)</p><p>(Figs 2Q, 3Q, 6Q)</p><p>Remarks: This species has a large nuclear region with a sandpaper-like layer (nontransparent); this layer is sometimes partly or even completely absent in the nuclear region of some individuals, especially juveniles.</p></div>	https://treatment.plazi.org/id/74498794FF8FE416FC582F4FFC0103E4	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8FE416FED02FEFFA1B0330.text	74498794FF8FE416FED02FEFFA1B0330.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Cipangopaludina Hannibal 1912	<div><p>Cipangopaludina Hannibal, 1912</p><p>Examined species:  Cipangopaludina chinensis (Gray, 1834);</p><p>C. nagaensis (Preston, 1914) n. comb.;  C. crassibuca (Sarasin &amp; Sarasin, 1898) .</p><p>Remarks: The  Cipangopaludina species examined have a similar operculum, which can be distinguished from the other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: regular growth lamellae on the exterior surface, a relatively small inner operculum region and a large nuclear region with a sandpaper-like layer (sometimes partly absent).</p></div>	https://treatment.plazi.org/id/74498794FF8FE416FED02FEFFA1B0330	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8FE417FC692E1AFE7B0259.text	74498794FF8FE417FC692E1AFE7B0259.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Cipangopaludina nagaensis (Preston 1914) Zhang & von Rintelen 2021	<div><p>Cipangopaludina nagaensis (Preston, 1914) new combination</p><p>(Figs 2O, 3O, 6O)</p><p>Vivipara nagaensis Preston, 1914: 20 (Naga Hills, India).</p><p>Remarks:  Vivipara nagaensis Preston, 1914 has been rarely mentioned in the literature after its description. Here, it is classified as a species of  Cipangopaludina based on its shell morphology and the fact that it exhibits the generic characters of the  Cipangopaludina operculum (i.e. as seen in the type species of the genus,  C. chinensis). The shell and operculum of  C. nagaensis are much smaller than those in  C. chinensis and only a small part of the nuclear region in  C. nagaensis is covered by the sandpaper-like layer.</p></div>	https://treatment.plazi.org/id/74498794FF8FE417FC692E1AFE7B0259	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8EE414FF4F2E65FEB10203.text	74498794FF8EE414FF4F2E65FEB10203.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Cipangopaludina crassibuca (Sarasin & Sarasin 1898)	<div><p>Cipangopaludina crassibuca (Sarasin &amp; Sarasin, 1898)</p><p>(Figs 2P, 3P, 6P)</p><p>Vivipara crassibuca Sarasin &amp; Sarasin, 1898: 60, figs 120, 131, 132 (Lake Poso, Central Sulawesi, Indonesia).</p><p>Cipangopaludina crassibuca —Prashad, 1928: 176.</p><p>Idiopoma crassibucca —Schuh et al., 2010: https://www.discoverlife. org/mp/20q?search=  Idiopoma+crassibucca .</p><p>Remarks:  Vivipara crassibuca Sarasin &amp; Sarasin, 1898 has been rarely mentioned after its description. Prashad (1928) regarded it as undoubtedly belonging to  Cipangopaludina based on shell morphology. Schuh et al. (2010) assigned this species to  Idiopoma in their online database but provided no justification. Here, we assign it to  Cipangopaludina based on its shell morphology and the fact that its operculum exhibits the generic characters of  Cipangopaludina . The operculum of  C. crassibuca has denser growth lamellae compared to the other two species of  Cipangopaludina examined. In addition, the convex inner margin of the first species is not as pronounced as in the other two species.</p></div>	https://treatment.plazi.org/id/74498794FF8EE414FF4F2E65FEB10203	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8DE415FEA02E3FFF2F0749.text	74498794FF8DE415FEA02E3FFF2F0749.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Filopaludina Habe 1964	<div><p>Filopaludina Habe, 1964</p><p>Examined species:  Filopaludina martensi (Frauenfeld, 1864)</p><p>(Figs 4M, 5M, 7M);  Filopaludina bengalensis (Lamarck, 1822) (Figs 4N, 5N, 7N);  Filopaludina gigantea (von dem Busch, 1843) (Figs 4O, 5O, 7O);  Filopaludina luzonica (Kobelt, 1909) (Figs 4L, 5L, 7L).</p><p>Remarks: The opercular characters of  Filopaludina are broadly similar to those of  Idiopoma . Notably, both show an inner opercular region almost completely covered by a sandpaper-like layer. However, in  Filopaludina, this layer and the inner opercular region are maroon coloured, whereas in  Idiopoma they are brownish yellow. In addition, the enamel region of  Filopaludina lacks the fine grid-like pattern found in the enamel region of  Idiopoma .</p><p>The operculum of  F. martensi differs from that of the other examined species of  Filopaludina: it has a relatively small inner opercular region that is almost completely covered by a sandpaper-like layer, with many radial veins; is almost as high as it is wide; and has a notably convex outer margin.</p><p>The opercula of  F. bengalensis and  F. gigantea are similar, but the former is much smaller (as is the shell).  Filopaludina gigantea has been considered as a large variety of  F. bengalensis . The specimen of  F. gigantea examined partly lacks the sandpaper-like layer and instead exhibits a smooth maroon nuclear region that, if confirmed as being present in more specimens, might be a size-independent character for distinguishing the two species.</p><p>The operculum of  F. luzonica stands out because of the conspicuous difference in colour between the marginal and enamel regions. This character is absent in the other  Filopaludina species examined but is present in other genera, such as  Idiopoma and  Taia (Table 2).</p></div>	https://treatment.plazi.org/id/74498794FF8DE415FEA02E3FFF2F0749	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8CE415FEB12B75FE6A017F.text	74498794FF8CE415FEB12B75FE6A017F.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Heterogen Annandale 1921	<div><p>Heterogen Annandale, 1921</p><p>Examined species:  Heterogen longispira (E. A. Smith, 1886) (Figs 2S, 3S, 6S);  Heterogen japonica (Martens, 1861) (Figs 2T, 3T, 6T).</p><p>Remarks:  Heterogen longispira has always been considered as the only species of the genus  Heterogen, which is endemic to Lake Biwa, Japan. Recently, ‘  Cipangopaludina ’ japonica has also been assigned to the genus on the basis of molecular systematic data (Hirano et al., 2019a); the opercular characters of this species also match those of  H. longispira, including a relatively large, smooth and shiny nuclear region and a thin marginal region. The combination of these opercular characters differs from those found in other viviparid genera with a concentric inverted-comma-shaped operculum.</p><p>The operculum of  H. japonica is clearly higher than it is wide, while in  H. longispira the opercular height and width are roughly the same. In addition,  H. longispira has a larger inner opercular region as compared with  H. japonica .</p></div>	https://treatment.plazi.org/id/74498794FF8CE415FEB12B75FE6A017F	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8CE415FEA62D83FE5E0333.text	74498794FF8CE415FEA62D83FE5E0333.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Idiopoma Pilsbry 1901	<div><p>Idiopoma Pilsbry, 1901</p><p>Examined species:  Idiopoma umbilicata (Lea, 1856) (Figs 4J, 5J, 7J);  Idiopoma dissimilis (Müller, 1774) (Figs 4K, 5K, 7K).</p><p>Remarks:  Idiopoma can be distinguished from other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: a whole inner opercular region covered by a thick, rough, brownish-yellow sandpaper-like layer; a thin marginal region obviously differing from the enamel region in colour; and an enamel region that is smooth but has a fine grid-like pattern.</p><p>The operculum of  I. dissimilis is about as high as it is wide, while in  I. umbilicata the operculum is distinctly higher than it is wide. This difference can be attributed to differences in aperture shape between the two species.</p></div>	https://treatment.plazi.org/id/74498794FF8CE415FEA62D83FE5E0333	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8CE415FE912F4EFD950229.text	74498794FF8CE415FE912F4EFD950229.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Margarya Nevil 1877	<div><p>Margarya Nevil, 1877</p><p>Examined species:  Margarya melanioides (Dautzenberg &amp; Fischer, 1905) (Figs 2R, 3R, 6R).</p><p>Remarks:  Margarya can be distinguished from other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: a large nuclear region with many grains and veins, and a large inner opercular region.</p></div>	https://treatment.plazi.org/id/74498794FF8CE415FE912F4EFD950229	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8CE415FEE32E55FC310464.text	74498794FF8CE415FEE32E55FC310464.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Mekongia Crosse & P. Fischer 1876	<div><p>Mekongia Crosse &amp; P. Fischer, 1876</p><p>Examined species:  Mekongia jullieni (Deshayes, 1876) (Figs 2L, 3L, 6L).</p><p>Remarks:  Mekongia is not a monophyletic group according to two recent molecular systematic studies (Hirano et al., 2019a; Stelbrink et al., 2020). Here, we only examined the type species of  Mekongia,  M. jullieni .  Mekongia can be distinguished from the other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: a nucleus very close to the inner margin, an inner enamel region that is very narrow in width, a large inner opercular region and a relatively small nuclear region with fine shiny grains.</p></div>	https://treatment.plazi.org/id/74498794FF8CE415FEE32E55FC310464	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8CE415FC10289AFA8707B8.text	74498794FF8CE415FC10289AFA8707B8.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Neothauma E. A. Smith 1880	<div><p>Neothauma E. A. Smith, 1880</p><p>Examined species:  Neothauma tanganyicense E. A. Smith, 1880 (Figs 4G, 5G, 7G).</p><p>Remarks: Apart from  Mekongia, the monotypic genus  Neothauma can be distinguished from other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: height clearly larger than width and a small nuclear region that is relatively rough, with many shiny grains or veins.</p></div>	https://treatment.plazi.org/id/74498794FF8CE415FC10289AFA8707B8	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8CE415FBF82BC6FBF406DC.text	74498794FF8CE415FBF82BC6FBF406DC.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Notopala Cotton 1935	<div><p>Notopala Cotton, 1935</p><p>Examined species:  Notopala ampullaroides (Reeve, 1863) (Figs 4S, 5S, 7S).</p><p>Remarks: Apart from  Angulyagra,  Notopala can be distinguished from other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: a relatively small nuclear region with shiny grains or veins, a relatively thick enamel layer and a thin marginal region that obviously differs in colour from the enamel region.</p></div>	https://treatment.plazi.org/id/74498794FF8CE415FBF82BC6FBF406DC	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8CE415FBE62AE2FC5701CA.text	74498794FF8CE415FBE62AE2FC5701CA.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Sinotaia Haas 1939	<div><p>Sinotaia Haas, 1939</p><p>Examined species:  Sinotaia angularis (Müller, 1774) (Figs 4C, 5C, 7C).</p><p>Remarks: Apart from  Anularya,  Sinotaia can be distinguished from other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: a thick, smooth, shiny, non-transparent and small nuclear region and a thick enamel region.</p></div>	https://treatment.plazi.org/id/74498794FF8CE415FBE62AE2FC5701CA	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8CE415FBFF2DE8FC4703B4.text	74498794FF8CE415FBFF2DE8FC4703B4.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Taia Annandale 1918	<div><p>Taia Annandale, 1918</p><p>Examined species:  Taia naticoides (Kobelt, 1909) (Figs 4Q, 5Q, 7Q);  Taia shanensis (Kobelt, 1909) (Figs 4R, 5R, 7R).</p><p>Remarks:  Taia can be distinguished from other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: a subcentral nucleus that is very close to the inner margin; a large nuclear region with many fine, dense grains or veins; an inner opercular region completely or partly covered by a rough sandpaper-like layer; an enamel region that is thickened and deeper in colour near the inner opercular region; and a thin, wide marginal region that obviously differs in colour from the enamel region.</p><p>The inner nuclear region of  T. shanensis is almost completely covered by a thick sandpaper-like layer, which is mostly absent in  T. naticoides .</p></div>	https://treatment.plazi.org/id/74498794FF8CE415FBFF2DE8FC4703B4	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8CE412FC022FCAFEF00719.text	74498794FF8CE412FC022FCAFEF00719.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Tchangmargarya He 2013	<div><p>Tchangmargarya He, 2013</p><p>Examined species:  Tchangmargarya yangtsunghaiensis (Tchang &amp; Tsi, 1949) (Figs 2N, 3N, 6M);  Tchangmargarya multilabiata (Zhang &amp; Chen, 2015) (Figs 2M, 3M, 6N).</p><p>Remarks: The two species of  Tchangmargarya examined show the largest opercular differences within one genus of  Viviparidae . This is especially true of the position of the nucleus. Nevertheless, these two species can still be assigned to a single genus and distinguished from other genera with a concentric inverted-comma-shaped operculum by the following combination of characters: a nuclear region with many grains or veins, an enamel region that is thickened near the inner opercular region and deeper in colour, and a thin marginal region obviously differing in colour from the enamel region.</p><p>The operculum of  T. multilabiata is obviously different from that of  T. yangtsunghaiensis . In the former, the nucleus is positioned close to the inner margin and inner opercular region is larger; while the outer inner and upper inner margins of  T. yangtsunghaiensis are inwardly curved, in  T. multilabiata only the upper inner margin is inwardly curved.</p></div>	https://treatment.plazi.org/id/74498794FF8CE412FC022FCAFEF00719	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8BE412FE982B25FDD3063C.text	74498794FF8BE412FE982B25FDD3063C.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Torotaia Haas 1939	<div><p>Torotaia Haas, 1939</p><p>Examined species:  Torotaia mainitensis (Bartsch, 1907) (Figs 4F, 5F, 7F).</p><p>Remarks: The operculum of  Torotaia is distinct from that of most genera, but similar to that of  Celetaia in the following characters: a large, smooth and shiny nuclear region, which is sometimes surrounded by concentric veins, and a thin marginal region. However, the operculum of  Torotaia is more fragile and thinner, with the apex being noticeably more acute than in  Celetaia .</p></div>	https://treatment.plazi.org/id/74498794FF8BE412FE982B25FDD3063C	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8BE412FEA32A41FEA90151.text	74498794FF8BE412FEA32A41FEA90151.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Trochotaia Brandt 1974	<div><p>Trochotaia Brandt, 1974</p><p>Examined species:  Trochotaia trochoides (Martens, 1860) (Figs 4P, 5P, 7P).</p><p>Remarks:  Trochotaia can be distinguished from the other genera by a concentric inverted-comma-shaped operculum that exhibits the following combination of characters: a thick, rough layer with many grains or veins over the whole of the inner opercular region; a clearly convex outer margin; and a smooth enamel region with a dense ray-like pattern.</p></div>	https://treatment.plazi.org/id/74498794FF8BE412FEA32A41FEA90151	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
74498794FF8BE412FF1D2D6DFCC90075.text	74498794FF8BE412FF1D2D6DFCC90075.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Ussuripaludina Zatravkin & Bogatov 1987	<div><p>Ussuripaludina Zatravkin &amp; Bogatov, 1987</p><p>Examined species:  Ussuripaludina ussuriensis (Gerstfeldt, 1859) (Figs 4B, 5B, 7B).</p><p>Remarks:  Ussuripaludina can be distinguished from the other viviparid genera studied by a concentric inverted-comma-shaped operculum that shows the following combination of characters: a shiny, smooth and convex nuclear region; a shiny and smooth scar region; a relatively large inner opercular region; and a narrow marginal region.</p></div>	https://treatment.plazi.org/id/74498794FF8BE412FF1D2D6DFCC90075	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zhang, Le-Jia;von Rintelen, Thomas	Zhang, Le-Jia, von Rintelen, Thomas (2021): The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae). Journal of Molluscan Studies 87 (2): 1-14, DOI: 10.1093/mollus/eyab008, URL: https://doi.org/10.1093/mollus/eyab008
