Page 36 - Land Snails of New Mexico

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Habitat--Gastrocopta pilsbryana occurs at elevations as
low as the uppermost Upper Sonoran Zone, as in the relatively
arid Big Hatchet Mountains. It extends upward through the
TransitionandCanadianLifeZones.Pilsbry(1948.891)noted,
aswehave,thatinNewMexicoandArizona"hundredsof UpperSonoranZoneofthesouthernpartofthestate.Ithasbeen
specimens can often be obtained by sifting."
Remarks—A subspecies,G.p.amissidens,Pilsbry,1934,
taken as far north as Salinas Peak, Sierra Co.; the San Mateo Mountains, Socorro Co.; and the Zuñi Mountains and Mount Taylorarea,CibolaCo. Rev.E.H.Ashmun,himself,collected itnearGrantsandSanRafael,CibolaCo.(ANSP 47453 and
wasdescribedfromMahanMountaininCoconinoCo.,Arizona. ItdiffersfromtypicalG.pilsbryanainlackingabasaldenticle. SuchformsmayoccurinNewMexicoalso.Astheyarenot 79459).
geographically separable, they do not seem to be true subspecies, but simply another variant within populations of this species,whosetaxonomiccomplexitieswerediscussedabove, and which ultimately may prove to be a subspecies of G. pentodon.
Subgenus Staurotrema
Gastrocopta quadridens H. A. Pilsbry, 1916. Manual of Conchology, 24:57, Pl. 10, Figs. 7, 10. T.L.: Capitan Mountains, Lincoln Co., New Mexico. (cross Snaggletooth)
General and New Mexico Distribution--Like G.
pilsbryana, the present species is a snail of southwestern
mountains, but it is neither so widespread nor so abundant in
collectionsasisG. pilsbryana. Itoccurs inmountains ofeastern and northern Arizona and north into southern Utah. In N e w
Mexico, G. quadridens occurs in mountains of the western and central parts of the state from the Sacramento and Mogollon Mountains, northward. The type locality is in the Capitan Mountains, and is one of the southeasternmost records for the species.
Habitat-Gastrocopta quadridens is absent from many montane collections in the state and apparently does not occur at all in some mountain ranges within the circumference of its range. Often, when found, it is represented by only a few specimens,althoughithasproventobeabundantatafew localities. Along Sandia Crest itisa common snail,apparently finding this open-forest habitat with calcareous bedrock especiallyfavorable.Incontrast,we foundnumerousspecimens in dense forest in the Capitan Mountains, where the bedrock is igneous.
Remarks--Formerly, G. quadridens may have been much morewidespreadinNewMexico.Ithasnotbeenfoundliving in the Caballo Mountains, although itis a common fossil in Pleistocene slope deposits. Perhaps itonce enjoyed conditions in these mountains of limestone bedrock somewhat similar to those on Sandia Crest where itn o w flourishes.
Subgenus Immersidens
Gastrocopta ashmuni (V. Sterki, 1898, as Bifidaria). The N a u t i l u s , 1 2 : 4 9 . T . L . : S a n t a R i t a M o u n t a i n s , S a n t a C r u z Co., Arizona (T.L. selected by Bequaert and Miller,
1973:159).(sluicesnaggletooth) GeneralandNewMexicoDistribution—Thissouthwestern
Habitat-Gastrocoptaashmuniiscommoninlower,fairly arid mountains, such as the San Andres, Caballo, Florida, and Big Hatchet Mountains. It often occurs together with Gastrocopta pellucida (see below) in collections in such mountains. It has been obtained by collecting and searching through leaf litter from under shrubs and trees that occur in lower, arid mountains.
Gastrocopta cochisensis (H. A. Pilsbry and J. H. Ferriss, 1910, as Bifidaria). Proceedings of the Academy of NaturalSciencesofPhiladelphia, 1910:139,Figs.32,33.
T.L.: Tanner (Garden) Canyon, Huachuca Mountains, Cochise Co., Arizona. (Apache snaggletooth)
General Distribution--This is a snail probably with its center of distribution in México, as ithas been reported from Sinaloa, Sonora, and Chihuahua. It also has been reported by Bequaert and Miller (1973:163-164) from numerous stations in southernArizona,butbarelyseemstoenterNew Mexico.
N e w Mexico Distribution--The only N e w Mexico records
forthespeciesarefrom the Animas Mountains (Metcalf, 1976).
Nine specimens were taken in Indian Creek Canyon and a single
specimen from the north slope of Animas Peak, Probably, G.
cochisensisisfairlycommon intheAnimasMountains.Itseems.
likely that the species occurs in the Peloncillo Mountains to the
westoftheAnimasMountains,but,todate,ithasnotbeenfound
incollectionsfrom thatmore aridrange. Habitat--TheIndianCreekcollectioncamefromleaflitter
in a wooded canyon at 5,800-ft elevation. The Animas Peak s p e c i m e n w a s t a k e n a t 7 , 3 0 0 - f t e l e v a t i o n , f r o m s o i l a n d l e a f litter filling the interstices of igneous rock talus.
Gastrocopta prototypus (H. A. Pilsbry, 1899, as Bifidaria). Proceedings of the Academy of Natural Sciences ofPhiladelphia, 51:400. T.L.: Huingo, near Lago deCuitzco,40kmNW ofMorelia,Michoacán,México.
species occurs in N e w Mexico, Arizona, and Trans-Pecos Texas in the United States and in Chihuahua and Sonora in México
(collected at six localities in Sonora by Naranjo-García, 1991:168).InNew Mexico,itispreeminentlyaspeciesofthe
(Sonoran snaggletooth)
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General Distribution--United States specimens of G. prototypus were assigned previously to G. oligobasodon (Pilsbry and Ferriss, 1910). Bequaert and Miller (1973:164
165) synonymized G. oligobasodon with G. prototypus of M é x i c o , w h e r e t h e s p e c i e s is w i d e s p r e a d . It h a s b e e n r e p o r t e d from Michoacán and Jalisco and w e have taken itin Durango a n d C o a h u i l a . It a l s o o c c u r s i n G u a t e m a l a ( B e q u a e r t a n d M i l l e r ,
1973:54–55).PopulationsinsouthernArizonaandsouthwestern New Mexicoareonthenorthernperipheryofitsrange.
N e w Mexico Distribution—Pilsbry reported (1948:901) "G. oligobasodon" only from river drift: along the Mimbres River