Page 39 - Land Snails of New Mexico

It appears that the above forms cannot be regarded as geographically valid subspecies because two or three of them may occur together in a population. Bequaert and Miller observed (1973:184): "Even in our limited experience, a population of V. gouldii is seldom in Arizona of one type of teeth." Forexample,shellsoftheinserta,arizonensis,and basidens types were taken, all in one collection, from along EagleCreekintheSacramentoMountains,New Mexico.We are not employing here the above names for N e w Mexico material, deeming these variants to be without any clear-cut, cohesive,
geographicalranges,and,inmany cases,onlyintrapopulational. Hubricht (1985:11) also treats the taxon only at the species level.
Nevertheless, there are some broad patterns in regard to the differentdentitionalforms.Thearizonensisformwasindicated
byBequaertandMiller(1973:186)asthemostcommon variant
in Arizona, and this is also true for southern and central N e w
Mexico. The majority ofshellsfrom New Mexico have an
angularandaparietal.The coloradensisform,withno angular,
is c o m m o n o n l y i n t h e S a n J u a n a n d S a n g r e d e C r i s t o M o u n t a i n s in the north.
General Distribution--Vertigogouldiiisfoundintwo regionsatpresent.As indicatedbyHubricht(1985:Map75),it occurs in the northeastern quadrant of the United States, but it isrepresented only by fossils in the Great Plains states. It occurs againintheRockyMountainstates,asacommon species.Italso occurs in Canada in the southeastern provinces, in the Rocky Mountains, and in northwestern Chihuahua, México.
NewMexicoDistributionandHabitat--InNewMexico,
V. gouldii is widespread, found in the forested zones of most mountains of the state. It is a snail of the Transition and
Canadian Life Zones, extending to lower elevations than its congener and c o m m o n habitat associate, V. modesta ingersolli. Conversely, V. m. ingersolli gains ascendancy at higher elevations, whereas gouldii becomes rarer as elevation increases.
Vertigo modesta ingersolli (T.D.A. Cockerell, 1891, as Pupa ingersolli).BritishNaturalist1891:101.T.L.:"San Juan District" (=San Juan Co.), Colorado. (cross vertigo)
In revising the Vertigos of Arizona, Bequaert and Miller (1973:189)placedseveralkindsinthesynonymyofV.modesta ingersolli. These include 1) V. concinnula T.D.A. Cockerell, 1897 (described as V. coloradensis form concinnula) and 2) V. m. insculpta H. A. Pilsbry, 1919.
Pilsbry (1948:989) had considered V. m. insculpta to occur intheBlackRangeofNewMexico,butnotedthat"thereisa certain amount of intergradation" between V. m. insculpta and V. concinnula in regard to size and length of palatal folds. These were featuresthathe was using to separate the two species. Our observations indicate that there is only one Vertigo larger than V. gouldii in montane forests of the Black Range. The assignment of Pilsbry's two taxa to V. m. ingersolli, as done by Bequaert and Miller, seems to resolve the problem posed by Pilsbry, and to be consonant with observations made in other partsofNew Mexico.
eastern United States, Hubricht (1985:12, M a p 76) found no living V. m. modesta (Say, 1824) and noted "All of the definite recordsIhaveseenareofPleistocenefossils,butithasbeen reported from the N e w England states. A primarily Canadian species." The species modesta occurs as far north as Greenland andAlaskaandalsoinnorthernAsiaandEurope.Itseems,then, thatintheUnited Statesthemodesta complex isfound mainly in the western mountain states, extending from Canada south to N e w Mexico and Arizona. Pilsbry (1948:982) noted this also: "The typical modesta replaced in the Rocky Mountain system
andCaliforniabyvariousweaklydifferentiatedraces." NewMexicoDistributionandHabitat--InNewMexico, this species is found in high mountains from the Sacramento
Mountains, Black Range, and Mogollon Mountains northward.
It d o e s n o t o c c u r i n t h e u p p e r m o s t U p p e r S o n o r a n Z o n e a s d o e s
V.gouldii,andprefershabitatsfromtheUpperTransitionZone to the Hudsonian Zone. It is found in forests of these zones in
leaflitterofdeciduoustrees(mainlyaspen)andunderstones, deadlogs,andbranches.
VertigoelatiorV.Sterki,1894(asVertigoventricosavar. elation).EighthAnnualReportoftheOhioStateAcademy of Science, 1900, p. 33. T.L.: Fulton Co., Illinois. (tapered vertigo)
General Distribution--Vertigo elation seems to be widespread in southern Canada, having been reported from British Columbia to Ontario. Its range extends into the northern United States from Maine to North Dakota, and makes an intrusion southward, along the Rocky Mountains into New Mexico.InArizona,itisknownasaPleistocenefossil.
New Mexico Distribution and Habitat--Vertigo elationis of rare occurrence in N e w Mexico. It is a species of high montaneforests,andwehavetakenitintheSacramento,Jemez, Z u ñ i , a n d S a n g r e d e C r i s t o M o u n t a i n s . It w a s r e p o r t e d f r o m t h e OscuraMountains,SocorroCo.,byPilsbry(1948:956). Asa speciesofmore northernaffinities,itseems likelythatitisina marginal situation, so far south, and may be something of a Pleistocene relict of scattered occurrence. This argument seems strengthened by the occurrence of fossil shells at lower elevationsinsouthernNewMexicoandArizona.AlisonSimcox
collected a fine suite of fossil shells of this species in Holocene sedimentsintheSacramentoMountainsnearCloudcroft.
Vertigo hinkleyi H. A. Pilsbry, 1921. Manual of Conchology, 26:234, Pl. 6, Figs. 12-16. T.L.: Cave Canyon, Huachuca Mountains, Arizona. (heartvertigo)
General and New Mexico Distribution--Therearefew records of this species. Bequaert and Miller (1973:182) found it in several canyons in the Huachuca and Dos Cabezas Mountains of southeastern Arizona. Pilsbry (1953:164) reported it from the Sierra de la Breña in northwestern Chihuahua, México. Metcalf (1976:410,411) recorded itfrom two stations intheAnimasMountains,HildagoCo.,New Mexico.Thus,the speciesseems tobe ofrathercircumscribeddistribution,unless itismorewidespreadinMéxicothanpresentrecordsshow.
General Distribution--In his survey of land snails of the
Habitat--Vertigo hinkleyi was taken with Gastrocopta
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