Page 23 - Land Snails of New Mexico

la
1b
2a
2b
3a
3b
4a
4b
5a
Sb
6 a
6 b
la
1b
2a
2b
Pupillidae Subfamily Vertigiminae
Shell cylindrical, peristome thin, without callus or teeth and not expanded, fine ribs present •********************************************************************* Columellacolumellaalticola(p.34)
Mature shell not cylindrical, peristome thickened on all sides, including parietal wall, and bearing
varying numbers of teeth ............................................................................... 2
Minuteshell(<1.8mm inheight)withstronglyindentedarea(sinus)inouter(palatal)lipofperistome,
below which there are no teeth. Elsewhere, there are 2 teeth on the columellar wall, a parietal and upper palatal tooth.InNew Mexico,foundonlyinthesouthwesternmountains ............................Vertigohinkleyi(p.33)
Shellwithoutabove(2.a)characteristics..............................................................- - - - - 3 Peristome with 6 or more teeth .......................................................................... 4
Peristomewithfewerthan6(usually5)teeth ....................... ...................................... 5
Shellminute(<1.8mm inheight),typicallywith6stronglydevelopedteeth(amouthful!):columellar, parietal,angular,upperandlowerpalatal,andbasal.PossiblyextinctinNew Mexico .............Vertigomilium(p.32)
Shell>2mm inheight,withsamedistributionof6teethasin4a,butseveralaccessoryteethmaybepresent.
Aperture not appearing so congested with teeth as in V. milium. Rare in N e w Mexico, at present,
mainlynearSprings ...................................................................Vertigoovata(p.32)
Shell>2mm inheight,Smoothandglossybrown ...........................................................6
Shell<2mm inheight,brownish,butfinelysetwithminuteriblets.Usually5teetharepresent,variously distributed(seespeciesaccount),butalwayswithacolumellar,aparietal,and2palatals.An angularorabasal (butnotboth)maybepresentinNewMexicospecimens................................... Vertigogouldii(p.32)
Peristome strongly calloused, with marked indentation (sinus) in outer (palatal) lip; small basal tooth present. Speciesisrareinstateandfoundathigherelevations .......................................Vertigoelation(p.33)
Peristome only moderately thickened, with w e a k indentation in outer (palatal) lip, basal tooth lacking. Thisspeciesisespeciallycommon inCanadianandHudsonianLifeZonesinNew Mexico
• * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * - - - - - - - - * * * * * * * * * * * * * * *-Vertigomodestaingersolli(p.33)
Valloniidae
Surfaceofshellsmooth,withoutwell-developedribs,apparentlyintroducedintoNew Mexicofrom easternstates,mainlyfoundinurbanandsuburbanareas .................................Valloniapulchella(p.64)
Surfaceofshellwithwell-developed,widelyspacedribs .....................................................2 Widthofmatureshellfrom2.5to3.0mm .................................................................3 Widthofmatureshell2.0mm orless.....................................................................4
The characters indicated for 3a and 3b below do not allow for species determination on immature shells. It is possible that V. gracilicostaandV cyclophorellaareactuallythesamespeciesorthatthereishybridizationbetweenthetwospeciesinsomecases. A situationsuchasthiscouldexplainthedifficultyencounteredinallocatingsomepopulationstospecies,asinthetaxonVallonia Sonorana of the Big Hatchet Mountains (not included in this key) and specimens from the Oscura Mountains.
3a Matureshellwithperistomethicklycallousedexceptfortheshortparietalwall ............Valloniagracilicosta(p.34)
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