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PeloncilloMountains,seemedtobelongtothissubspecies.We havenotfoundthissnailinoursearchesofSkeletonandClanton
CanyonstothesouthofSkullCanyon.Thus,itwouldseemtobe restricted to the Skull C a n y o n area.
Sonorella orientis H. A. Pilsbry, 1936. The Nautilus, 49:110. T.L.: atDripping Spring, Organ Mountains, D o ñ a A n a Co., N e w Mexico. (Organ Mountain talussnail)
Pilsbry (1905:257) first allocated this species to Sonorella h a c h i t a n a . L a t e r ( 1 9 3 6 ) , h e a s s i g n e d it t o t h e n e w s u b s p e c i e s orientis. Pilsbry (1939:277–278) assigned specimens from the Organ and San Andres Mountains, New Mexico, and from Sierra Blanca Peak, Hudspeth Co., Texas, to S. hachitana orientis. BequaertandMiller(1973:125)raisedorientisto species rank. Because the Sierra Blanca, Texas, population is separatedfromtheNewMexicopopulationsbyalmost100 miles,itseemslikelythatfurtherstudymay showthemtobe specifically distinct, leaving S. orientis as an endemic of the Organ, San Andres, and Oscura Mountains.
Distribution and Habitat--In the Organ Mountains, S. orientis is widespread and common, associated with various kinds of igneous rock talus, chiefly rhyolitic and monzonitic. Metcalf(1984b:Table2)founditat20 of25 localitiescollected, and at elevations ranging from ca. 4,900 to 7,900ft. Sonorella orientisseemslesscommonintheSanAndresMountainswhere
it was found at only 4 out of 25 localities sampled (Metcalf,
1984b:Table 1). In the San Andres chain, igneous rock talus is
confined to the area of Salinas Peak, where the species was takeninforestedhabitat.Italsowasfoundinlimestonetalusat severallocalitiessouthfromSalinasPeaktoSanAndresPeakin
xeric habitat supporting only shrubs and a few low trees. SmartthascollectedshellsfromtheOscuraMountainsthat
are probably attributable to this species. This range,
predominantly of limestone, parallels, to the east, the northern
part of the San Andres Mountains in the northern part of the Tularosa Basin.
SonorellametcalfiW. B.Miller1976.TheNautilus, 90:70, Figs. 1, 4. T.L.: Fusselman Canyon, Franklin Mountains, El Paso Co., Texas. (Franklin Mountain talussnail)
Sonorella metcalfi is mainly a species of the Franklin Mountains in Texas, to the south of the Organ Mountains (Metcalf and Johnson, 1971). However, Miller (1976:71) also assignedtothisspeciessome specimens from thehead ofFinley Canyon in the southern Organ Mountains, at about 6,000-ft elevation. This isaridhabitatoftheUpper Sonoran LifeZone. T h e snails are restricted to m o u n d s o f rhyolitic talus in the Finley
Canyon area.
Similar mounds from Finley Canyon southward in the
southernmost Organ Mountains yield shells, probably of this
s p e c i e s . H o w e v e r , it i s n o t k n o w n p r e c i s e l y h o w S . m e t c a l f i a n d
S. orientis are related, distributionally, in the southern Organ Mountains.
Sonorella todseni Miller, 1976. T h e Nautilus, 90:71, Figs. 2, 4. T.L.: northwestern slope of D o ñ a A n a Peak, D o ñ a
AnaMountains,DoñaAnaCo.,NewMexico. Sonorella todseni, as well as Ashmunella todseni, were named in honorofDr.ThomasK.Todsen,LasCruces,New Mexico, w h o first collected them. ( D o ñ a A n a talussmail)
Distribution and Habitat--Sonorella todseni is the most restricted, distributionally, of N e w Mexico Sonorellas. It is endemic to the Doña Ana Mountains, a small, arid range of igneous rock at the southern end of the Jornada del Muerto and north of Las Cruces. Within the range, to this time, the species hasbeentakenonlyatthetypelocalityon thenorth-facingslope of Doña Ana Peak, in an area of igneous rock talus under a sparse growth of live oaks and xeric-adapted shrubs. T h e types were collected after summer rains, when they were active. Specimensdidnotseemverycommon, andfurtherinvestigation is advisable to better ascertain the size of the population.
Sonorella binneyi Complex
Sonorella animasensis H. A. Pilsbry, 1939. Academy of Natural Sciences of Philadelphia Monograph, 3(I)1:322, Figs. 190, 191. T.L.: above Black Bill Spring, Animas Mountains, Hidalgo Co., N e w Mexico. (Animas talussmail)
Sonorella animasensis is an eastern outlier of a subgroup of Sonorellas (S. binneyi complex) centered in Arizona (Bequaert and Miller, 1973:111,118-121). In this and some other respects, theland-snailfaunaoftheAnimas Mountains shows affinitywith that of southeastern Arizona.
Distribution and Habitat--This speciesisendemic tothe Animas Mountains. In addition to the type locality (the only locality listed by Pilsbry in the description of the species), w e h a v e t a k e n it i n I n d i a n C r e e k C a n y o n i n t h e n o r t h e r n p a r t o f t h e range and on the northern slope of Animas Peak. Pilsbry's (1939,323) habitatdescription specified: "Itoccurs in deciduous forest on the steep sides of the canyon above the spring, under volcanicrock(andesite?),atfrom6500 to7000feet,theforest abovethatbeingpine." Ourcollectionswerealsofromrock rubble and talus on steep slopes. .
Family Humboldtianidae Genus Humboldtiana
This is mainly a genus of México, extending from the
Transverse Volcanic Belt in the region of México, D.F.,
northwestward, along the central highlands of the country, where
itoccurs in both lower and higher mountain ranges. The range
of the genus continues northwest across the mountains of the
central part of Trans-Pecos Texas, and barely into southeastern N e w Mexico.
Humboldtiana ultima H. A. Pilsbry, 1927. Proceedings of the Academy of Natural Sciences of Philadelphia, 79:184, Figs. 6, 12; Pl. 12, Figs. 12-14; Pl. 13, Fig. 4. T.L.:Pilsbryindicatedinhisdescriptionthathecollected Humboldtiana ultima in the Guadalupe Mountains in the areaoftheTexas-NewMexicoborderathisStations240
and 241, with the type locality at Station 241. His field notes (Metcalf, 1970:29) show that Station 241 was in