{{Short description|Genus of gastropods}} {{Automatic_taxobox | image = Neoplanorbis tantillus shell.jpg | image_caption = Three views of a shell of ''Neoplanorbis tantillus'' oriented as if it were a dextral shell. (All planorbids are in fact sinistral.) | taxon = Neoplanorbis | authority = Pilsbry, 1906 | type_species = ''Neoplanorbis tantillus'' | type_species_authority = Pilsbry, 1906 | type_species_ref = <ref name=WoRMS>{{cite WoRMS |id=743615 |title=''Neoplanorbis'' Pilsbry, 1906 |db=mollusca |access-date=11 March 2026}}</ref> | subdivision_ranks = Species | subdivision = {{linked species list |abbreviated=yes |Neoplanorbis carinatus|Walker, 1908 |Neoplanorbis smithii|Walker, 1908 |Neoplanorbis tantillus|Pilsbry, 1906 |Neoplanorbis umbilicatus|Walker, 1908}} | subdivision_ref = <ref name=WoRMS/> }}
'''''Neoplanorbis''''' is a genus of small, freshwater, air-breathing snails. They are aquatic pulmonate gastropod mollusks in the family Planorbidae, the ram's horn snails.
''Neoplanorbis'' is the type genus of the subfamily Neoplanorbinae.<ref>{{Bouchet 2005}}</ref>
The shells of species in this genus appear to be dextral in coiling, but as is the case in all planorbids, the shell is actually sinistral. The shell is carried upside down with the aperture on the right, and this makes it appear to be dextral.
== Species == The genus ''Neoplanorbis'' includes the following species: * † ''Neoplanorbis carinatus'' Walker, 1908<ref>{{cite iucn |author=Bogan, A.E. |date=2000 |title=''Neoplanorbis carinatus'' |volume=2000 |article-number=e.T14553A4444062 |doi=10.2305/IUCN.UK.2000.RLTS.T14553A4444062.en |access-date=14 November 2021}}</ref> * † ''Neoplanorbis smithii'' Walker, 1908<ref>{{cite iucn |author=Bogan, A.E. |date=2000 |title=''Neoplanorbis smithi'' |volume=2000 |article-number=e.T14554A4444132 |doi=10.2305/IUCN.UK.2000.RLTS.T14554A4444132.en |access-date=14 November 2021}}</ref> * † ''Neoplanorbis tantillus'' Pilsbry, 1906<ref name="IUCN2012">Cordeiro, J. & Perez, K. 2012. Neoplanorbis tantillus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 20 October 2012.</ref> the type species * † ''Neoplanorbis umbilicatus'' Walker, 1908<ref>{{cite iucn |author=Bogan, A.E. |date=2000 |title=''Neoplanorbis umbilicatus'' |volume=2000 |article-number=e.T14555A4444202 |doi=10.2305/IUCN.UK.2000.RLTS.T14555A4444202.en |access-date=14 November 2021}}</ref>
== Original description == Genus ''Neoplanorbis'' was originally described by Henry Augustus Pilsbry in 1906.<ref name="Pilsbry">Pilsbry H. A. (September 1906). "Two new American genera of Basommatophora". ''The Nautilus'' '''20'''(5): [https://archive.org/stream/nautilus20amer#page/n67/mode/2up 49]–51.</ref>
Note that Pilsbry described the shell as if it were dextral, whereas planorbids are now known to be sinistral in shell coiling. In other words what Pilsbry describes as the "impressed and turned in" apex of the shell is actually the center of the umbilicus.
Pilsbry's original text (the original description) reads as follows:
{{Cquote|Genus NEOPLANORBIS n. gen.
The shell is minute, subdiscoidal, nearly flat above, convex below, perforate, carinate at the periphery, composed of about two rapidly enlarging whorls, the apex impressed and turned in. The aperture is very oblique, wider than high, a little dilated at the base. Peristome thin, not continuous, the columellar margin straight and broadly dilated, somewhat thickened within.
The dentition and so far as known, the soft anatomy, is similar to ''Amphigyra''.
Type ''N. tantillus''.
The type of this group was at first taken for a ''Planorbis'' of the ''P. dilatatus'' group, (It was reported as ''Planorbis tantillus'' in Mr. Hinkley's list, [https://archive.org/details/nautilus18amer Nautilus XVIII], p. 54.) but when the dentition was examined it became obvious at once that the snail could not belong to the Planorbinae. The radula is not materially unlike that of ''Amphigyra'', but the conchological features of the two groups are quite diverse, ''Amphigyra'' being Crepiduloid with a distinct "deck" or columellar plate, while ''Neoplanorbis'' is Planorbis-shaped, perforate, with a carinate periphery and no "deck." }}
== References == {{Reflist}}
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Category:Planorbidae Category:Taxonomy articles created by Polbot Category:Taxa named by Henry Augustus Pilsbry