Page 38 - Land Snails of New Mexico

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C u b a . P i l s b r y ( 1 9 4 8 : 9 1 3 – 9 1 6 ) c o n s i d e r e d t h a t t h e W e s t I n d i e s
representatives belonged to the nominal subspecies, and that
"themainlandforms belonged to: 1) G. p. hordeacella (Pilsbry,
1890),withtypelocalitydesignatedasNew Braunfels,Comal
Co., Texas, and 2) G. p. parvidens (Sterki, 1899), with type
locality at Jerome, Yavapai Co., Arizona. Pilsbry (1948:916)
reported G. p. parvidens from Pecos River driftatPecos, San
MiguelCo.,NewMexico,andfromtheJemezMountainsnear
Valle Grande, Santa F e Co. Surely, the latter record is in error
because this is a snail of low elevations. After studying
specimens of these subspecies, Bequaert and Miller concluded
(1973:81): "We are unable to separate pellucida and
hordeacella, except by locality, and follow B. A. Branson et al.
(1966:149) in synonymizing both G. p. hordeacella and G. p.
parvidens with G. pellucida." This recommendation isfollowed here.
General and New Mexico Distribution--Gastrocopta pellucida is a species of the West Indies and southern United States, extending from Florida to California and southward into
México.
New Mexico Distribution--Itiscommon intheLower and
UpperSonoranLifeZonesinsouthernandeasternNew Mexico. In the eastern part of the state, itis a typical species along the Ogallala Caprock escarpment.
Habitat--This is one of the few N e w Mexico species that
occur in the Lower Sonoran Zone of the Chihuahuan Desert,
w h e r e it m a y b e f o u n d o n s l o p e s a n d b a j a d a s u n d e r s h e l t e r s u c h
as large stones, fallen yucca stems, or caudices of sotol
(Dasylirion). It is frequent in the Upper Sonoran Zone of
mountains in the southern part of the state. Many specimens were recovered from localities in the San Andres Mountains
whereG.pellucidawasthemostcommonspeciestakenina surveyofthatrange(Metcalf, 1984b).Italsowas abundantin leaf-littersamples taken in the Big Hatchet Mountains.
Remarks--Gastrocopta pellucida is a common fossil in southern and eastern New Mexico, especially in alluvial sediments along the Rio Grande and Pecos River Valleys.
Subfamily Vertigininae
Intheliteratureofrecentyears,thisgroup may be treatedas a family or considered a subfamily, Vertigininae, under the familyPupillidae,aswe dohere,
Genus Vertigo
Vertigo milium (A. A. Gould, 1840, as Pupa). Boston Journal of Natural History, 3:402. T.L.: Oak Island, Chelsea,nearBoston,Massachusetts (bladevertigo)
Vertigo milium occurs throughout the eastern United States fromMainetoFloridaandwestwardtoNorthDakotaandTexas.
In Arizona, Bequaert and Miller (1973:182) cite only two collections as m o d e r n records, these m a d e b y Pilsbry a n d Ferriss inthefirstdecadeofthecenturyintheHuachuca and Chiricahua Mountains, the latter collection represented by only one shell.
V e r t i g o m i l i u m i s n o t k n o w n a s l i v i n g i n N e w M e x i c o ; it i s a marsh-associated species that may be found with more systematic searching of such habitats in the state. Ashbaugh and
M e t c a l f ( 1 9 8 6 : 9 ) f o u n d it i n d e p o s i t s a s s o c i a t e d w i t h P l e i s t o c e n e springs in Lincoln and Eddy Counties. There are a number of otherfossilrecordsofthespeciesinNew Mexico.
Vertigo ovata Say, 1822. Journal of the Academy of Natural Sciences of Philadelphia, 2.375. T.L.: Philadelphia, Pennsylvania (selected by H. A. Pilsbry,
1919). (ovate vertigo)
Bequaert and Miller (1973:183) indicated that Say described this species in the genus Pupa. In the description it is listed as P. ovata, but under the genus Vertigo, and another species under the same heading, is listed as V. pentodon. It appears that the "P." was simply an error.
General Distribution--Vertigo ovata is a widespread species.ItoccursinAlaskaandmuch ofCanada,andithasbeen recordedfromMainetoFlorida,andwestwardtoCaliforniaand Washington. However, in the Southwest, records are scattered widely, as indicated in maps for Oklahoma and Texas by Hubricht (1985:Map 67). Neck (1990) recorded it living in the Texas Panhandle. Bequaert and Miller (1973:183) recognized only six modern records for Arizona, four of these lots were collected by Pilsbry before 1920.
N e w Mexico Distribution and Habitat-–We have collected live specimens only from the environs of Blue Springs, south of CarlsbadinEddyCo.,butothermarshy orspring-brookareasat low elevationsmay revealthespecies. Vertigo ovata liveswithin a f e w m e t e r s o f t h e b r o o k i s s u i n g f r o m B l u e S p r i n g s , w h e r e it occursundershelterofdeadtree-branchesandondamp soil.
Remarks--The scarcityofrecordsoflivingpopulationsof V. ovata in the Southwest is in marked contrast to the fossil
record. In both Arizona and N e w Mexico, there are numerous records from Pleistocene and Holocene deposits. Ashbaugh and Metcalf (1986:10) found the species in spring-related deposits in Eddy, Lincoln, and Doña Ana Counties. It is especially common inHolocenedepositsalongthelowerTularosaRiver, Otero Co., and still may occur along the marshy area that extends a few miles southward from Mescalero. -
The reduction in populations of V. ovata follows the pattern of several species that were associated with marshy habitats, especiallythose depending on discharge from springs. Holocene warming, exacerbated in the past century by entrenchment of streamside marshes, drainage of wetlands, and other human developmentshavereducedgreatlythehabitatavailableforsuch species.
Vertigo gouldii (A. Binney, 1843, as Pupa). Proceedings of Boston Society of Natural History, 1:105. N o precise T.L. selected. (variable vertigo)
ThisisthemostcommonspeciesofVertigoinNew Mexico. It is highly variable in regard to dentition and, for this reason, several subspecies or variants have been described. Bequaert and Miller (1973) recognized several of these (tooth formula in parentheses): basidens (0 angular, 1 parietal, 1 columellar, 1 basal, 2 palatals), arizonensis (1 angular, 1 parietal, 1 c o l u m e l l a r , 0 b a s a l , 2 p a l a t a l s ) , i n s e r t a ( 1 a n g u l a r , 1 p a r i e t a l , 1 columellar,1basal,2palatals),andcoloradensis(0angular,1 parietal, 1 columellar, 0 basal and 2 palatals).