Page 67 - Land Snails of New Mexico

Thysanophorahorniifullydeservestobecalleda"desert snail."ItistypicaloftheLowerandUpperSonoranLifeZones, being one of the few N e w Mexico land snails occurring in the Lower Sonoran Zone, outside of the floodplains of stream valleys.Itisespeciallycharacteristicofthelow,aridmountains o f t h e s o u t h e r n p a r t o f t h e state. It o c c u r s w h e r e t h e r e is s o m e cover, such as rock rubble and talus, leaf litter, or under the dead stalks of yuccas or dead caudices of sotoles (Dasylirion).
Paleontology—Bequaert and Miller (1973:56) remarked on the rarity of T. hornii in fossil deposits examined in theirwork inArizona.However,inNew Mexico,ithasbeentakenata number of fossil localities in deposits of both Holocene and Pleistoceneage.Itisthemostcommon speciestakenfromfossil depositsofPleistoceneageexcavatedfromU-Bar Cave,Hildago Co., by Dr. A. H. Harris, whose efforts have also supplied Pleistocenefossilsofthisspeciesfrom Dry Cave, Eddy Co. Both caves are in the Lower Sonoran Life Zone.
Genus Microphysula
Microphysula ingersolli (T. Bland, 1875, as Helix). AnnalsoftheLyceumofNaturalHistoryofNewYork, 11:151. T.L.: Bequaert and Miller (1973:136) write: "T.L.: not selected thus far, described from Howardsville, San JuanCo.,andotherStationsinSW Colorado,at9,300to
11,000 ft." (spruce snail)
Museum, 18:2. T.L.: Big Hatchet Peak (=Hacheta Grande), Hidalgo Co., New Mexico. (New Mexico talussmail)
As recognized by Pilsbry (1939:273-278), Sonorella
h a c h i t a n a w o u l d b e a s p e c i e s m o r e w i d e s p r e a d t h a n w h a t is
usual for species of Sonorella. In addition to the nominal
subspecies from the Big Hatchet Mountains and the subspecies
listed below, Pilsbry recognized S. h. orientis, which has
subsequently been elevated to a full species. It is likely that
further analysis of soft anatomy or other taxonomic approaches
might result in partitioning the hachitana complex into still
furtherspecies.Forconvenienceatpresent,allNew Mexico
Sonorellas west of the Rio Grande, are placed in the species S.
hachitana, except for S. animasensis from the Animas Mountains.
In addition to published records (noted below) from the Big
Hatchet, Florida, Carrizalillo, and Peloncillo Mountains, fresh
(dead) shells have been collected from Pyramid Peak, south of
Lordsburg, by Metcalf, and fresh shells and one living specimen
from the Tres Hermanas Mountains by Dr. Richard
Worthington. Fossil shells have been found in Pleistocene
depositsoftheTresHermanas Mountains and Howells Ridge of
the LittleHatchet Mountains. In light of this, itseems likely that
most mountains ofsouthwestern N e w Mexico were inhabited by Sonorellas in the Pleistocene,
Distribution a n d Habitat--Concerning distribution of S. h. hachitana in the Big Hatchet Mountains, Pilsbry (1939:274) PacificNorthwest,knownfromBritishColumbiasouthwardto noted:"Itwasfoundmostabundantatourstation7,onahill about11/8milessouthsoutheastofBigHatchetPeak,where thereissome shadeinthelargestgroupofpinyonpinesinthe
D i s t r i b u t i o n — T h i s is a s p e c i e s o f t h e R o c k y M o u n t a i n s a n d
NewMexicoandArizona.InNewMexico,M.ingersolliis typicaloftheCanadianLifeZone and upward totimberline. Itis mostcommon inthemountainsofthenorth-centralpartofthe state,theseprovidinglargeareasofitsfavoredhabitat.To the south, it is found in the higher elevations of the Mogollon Mountains, Black Range, and the Sacramento Mountains-Sierra Blanca complex. It was taken by Hoff (1962:54) in habitats described as "8400 feet, in debris of alder stump," "8500 feet, mixed litter of aspen, spruce, and fir," and "10,300 feet, under rocks and in a wet rotting log, spruce-fir forest."
Family Helminthoglyptidae Genus Sonorella
T h e s t r o n g h o l d o f S o n o r e l l a is f r o m t h e G r a n d C a n y o n a r e a of Arizona, southeastward across Arizona, and into northeastern Sonora, México. The genus also occurs, but with far fewer species,insouthwesternandsouth-centralNew Mexico,Trans Pecos Texas, and northern Chihuahua.
WalterB.Miller'sextensivestudiesofthisgenusledhim to recognize four "complexes" (Bequaert and Miller, 1973:111), which he did not deem as being equivalent to subgenera. The twocomplexesofMillerthatarepresentinNewMexicoare indicated below.
Sonorella hachitana Complex
Sonorella hachitana hachitana (W. H. Dall, 1896, as Epiphragmophora). Proceedings of the U.S. National
mountains, under large stones on the steep slope near the summit,atabout7400to7500feet." We founditataboutthese same elevations on the wooded northern face of Big Hatchet Peak, also under tallpinyon pines. Pilsbry (1939:275) also listed the nominal subspecies from the Carrizalillo Mountains on the basis of "bones" collected there by E. A. Mearns during the boundary survey in 1892.
Sonorella hachitana flora H. A. Pilsbry and J. H. Ferriss, 1915.ProceedingsoftheAcademy ofNaturalSciencesof Philadelphia, 67:347, Pl. 5, Figs 3-3c, Text-figs. F,G.
T.L.: west side of Florida Mountains in "Spring Canyon," LunaCo.,NewMexico.
This subspecies is endemic to the Florida Mountains. It appears to be distributed generally throughout the range, as w e haveacquiredcollectionsofthelargeshellsofthisspeciesfrom various parts of the range.
Sonorella hachitana peloncillensis H. A. Pilsbry and J.
H. Ferriss, 1915. ProceedingsoftheAcademy ofNatural
Sciences of Philadelphia, 67:349, Text-figs. 6A-E. T.L.:
Skull Canyon, Peloncillo Mountains, Hidalgo Co., New Mexico.
In addition to the type material of S. h. peloncillensis from Skull Canyon, Pilsbry (1939:277) noted that an immature shell in the U.S. National M u s e u m from "Doubtful Canyon," in the
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