Page 21 - Land Snails of New Mexico

3b Peristomewith3teeth(columellar,parietalandlowerpalatal).................................................5
4a ShellwithnoteethinspecimensthatwehaveseeninNewMexico,peristomethin,withnothickening callousdeposit,shellglossybrown. ......................................................Pupillahebes(p.26)
4b Shellwithorwithouttubercularcolumellarand/orparietalteeth,peristomewithathick,light-colored callousdeposit,prominentcrestbehindpalatalwallofaperture ...........................Pupillamuscorum(p.26)
5a Parietaltoothlongandcrescentshapedwhenviewedfrombelow,crestbehindpalatallipwelldeveloped,
SouthernNew Mexico mountains .................................................... Pupillasonorana(p.27)
5b Parietaltoothshort,straight,itsbackpartslopingdownward,notcrescent-shaped,crestbehindpalatallip moderatelydeveloped,acommon speciesinmostNew Mexicomountains ......................Pupillablandi(p.25)
6a Shellwithoutteeth,speciesofLowerandUpperSonoranZones.................................GenusPupoides7 6b Shellwith3ormoreteeth.............................................................GenusGastrocopta8
7a Shellelongate-conic(Fig.3D,peristomegreatlythickenedwithwhitishcallousmaterial(hence, thenamealbilabris),withoutwell-developedribs. .....................................Pupoidesalbilabris(p.27)
7b Shellcylindrical(Fig.3G),withoutgreatlythickenedperistome,ribsmoderatelytostronglydeveloped. RibsaremorestronglydevelopedinPupoideshordaceus(p.27)ofnorth-centralandnorthwesternNew Mexicoand lesswelldevelopedinPupoidesinornatus(p.27)ofnortheasternNew Mexico.Itispossiblethatthetwotaxaare subspecies of one species.
Notes concerning Gastrocopta, below: Pilsbry (1948:874) treated the genus Gastrocopta as comprising several subgenera, five
ofwhichoccurinNew Mexico.InmostspeciesofGastrocopia,the"tooth"oftheparietalaperturalwallactuallyconsistsofacombined
angular and parietal tooth (angulo-parietal). In m a n y species, this dual combination can be discerned in inspecting the tooth. However,
in the subgenera Vertigopsis and Staurotrema, an angular tooth is small or lacking and the resulting parietal tooth is simple. In the
subgenus Albinula, on the other hand, two elements are clearly observable in the angulo-parietal complex, which descends a third or
more of the height of the aperture. Members of the subgenus Gastrocopta are recognized by their cylindrical shell shape, usually
brownish color, and an angulo-parietal tooth that has a bifid appearance because of the hybrid origin as angular and parietal. M e m b e r s
of the subgenus Immersidens have a complex dentition. Pilsbry (1948:874) described the parietal-wall denticles in this subgenus as
follows: "the angular lamella is united with the parietal at the inner end of the former, the two diverging forward, and together shaped like ...a reversed Y."
8a Parietalwallwithasingle,simpletoothwithanangulartoothcomponentgreatlyreducedorabsent, periostracumwhitishtograyish...................................................... SubgenusVertigopsis9
8b Parietal-walltoothclearlycomprisedof2combinedcomponents:parietalandangularteeth(angulo-parietal)..........11
9a Shellbearing3ormoreteethonawell-developedcallusinsidethepalatalandbasalwallsofthe
peristome.. ................................................................. Gastrocoptapentodon (p.29)
The nominal subspecies (G. p. pentodon) is cylindrical and similar to G. pilsbryana (below) except for development of the callus. The subspecies G. pentodon tappaniana ismore conic-ovate, bears 4 or more teeth on the combined palatal and basal walls, and may beextinctinNew Mexico.
9b Shellbearing2or3teethonthemoderatelydevelopedcallusofthepalatalplusbasalwallsoftheperistome...........10
10a Shell>2.5mminheight,4teeth(columellar,parietal,palatal,andbasal)arrangedasthoughattheends
ofacross .............................................SubgenusStaurotrema:Gastrocoptaquadridens(p.30)
10b Shell<2mm inheight,usually5(sometimes4)teeth,notcruciforminarrangementasin10a......................... **********************************************************@4esassa******** Gastrocoptapilsbryana(p.29)
1la Shellwhitishtograyish,ovate-conic,2palatalteetharisefromathick,whitepalatalcallus.........SubgenusAlbinula12
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