Page 18 - Land Snails of New Mexico
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la
1b
2a
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Sb
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8a.
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Animal with externally visible shell, commonly called "snails". ................................................ 2
Animal with no externally visible shell ( N e w Mexico species do, however, have a small vestigial shell buried inthefleshy,dorsalmantle),commonlycalled"slugs"........-********************************************** 28
Mature shell higher than wide ........................................................................... 3
Matureshellwiderthanhigh ..........................................................................11
Matureshell>10mm inheight.......................................................................... 4
Matureshell<10mminheight.......................................................................... 7
Upper whorls of mature shellsbroken off. This distinctive condition isreferred to as being decollate (Fig. 3E) and
inNew Mexicoisexhibitedonlybythisspecies,whichhasbeenintroducedinareasofhumanactivity,especiallyin lawnsandgardens. .....................................................Subulinidae:Ruminadecollata(p.64)
Shellsnotdecollate ...................................................................................5
Height of aperture <1/3 height of shell, aperture with thickened (calloused) peristome. Uniquely a m o n g
New Mexicolandsnails,apertureanditsperistomeareseparatedfromolder(preceding)whorlsbyadistinct "neck."Thedistinctiveshellformofthisfamilyhasbeenreferredtoas"urocoptiform"(Fig.3B) ......Urocoptidae(p.18)
Height of aperture >1/3 height of shell, peristome not thickened nor separated from preceding whorls
by a "neck". ......................................................................................... 6
Heightofapertureis60% orlessofheightofentireshell,shellvariouslymottledwithgrayishorlight-brownish
pigment, two oldest (embryonic) whorls with close-set, equidistant vertical ribs, shells of this form have been referredtoas"bulimoid"(Fig.3C) ........................................................Bulimulidae(p.18)
Heightofapertureismorethan60% ofheightoftheentireshell,shellnotmottledwithgrayorbrown;noribs onembryonicwhorls,shellsofthisfamilyhavebeenreferredtoasbeing"succiniform"(Fig.3D) .....Succineidae(p.19)
Shellslackingboththickenedperistomeandteeth,brownishperiostracum .......................................8
Columellar, palatal, and basal walls of peristomethickened, with the peristome bearing one or more teeth in most species,periostracumwhitish,grayish,orbrownish......................................** * * * * * * * * * * * * * * * * * * 9
Shell easily recognized, even in the field, by its highly glossy, light-brown periostracum; shell-shape fusiform(Fig.3F);matureshell5.0–7.5mm inheight............................Cionellidae(Cochlicopidae)(p.25)
Shell with numerous, low growth lines, not markedly glossy, cylindrical shell shape (Fig. 3G),
matureshell2.5-3.0mm inheight.Pupillidae(inpart): .........................Columellacolumellaalticola(p.34)
Shellwhite,minute,2.0mm orlessinheight,withadistinctivesingletoothlocatedatthetopofthe columellarwallatitsjuncturewiththeparietalwall.ThereisonlyonespeciesinthisfamilyinNew Mexico, anditseemstoberare. ................................................Carychiidae:Carychiumexiguum(p.25)
Shell1.7-5.0mm inheight,periostracumwhitishtograyishtobrownish.Shellspupilliform(Fig.3A),ranging
from cylindrical to ovate- or elongate-conic in shape. Teeth are present in many species (Figs. 2F-H), but not with asingletooth,locatedasin9a ......................................................................... 10
The following two subfamilies sometimes are given family status.
Shellminute,notover2.5mm inheight,brownish,oftenwithlow,close-setgrowthlines,ovate-conicshellshape (Fig. 2C), with at least 4 teeth around the peristome in N e w Mexico species
A KEY TO FAMILIES
---------------------------------------------------------- Pupillidae(subfamilyVertigininae);Vertigo(p.17)
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