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status and Conservation Management of
Terrestrial Mollusks of Special Concern

in Montana

Prepared for:
The U.S. Forest Service

By:
Paul Hendricks

Montana Natural Heritage Program

Natural Resource Information System

Montana State Library

June 2003

MONTANA

Natural Heritage
Ftogtam

status and Conservation Management of
Terrestrial Mollusks of Special Concern

in Montana

Prepared for:
The U.S. Forest Service

Contract Number:
Ol-lA-11015600-64

By:
Paul Hendricks

MONTANA

Natuial Heritage
Ptt^jtam

^it ^-^ MUSTAFA j^S^ijk yf>WTAHA

^T^itate If jIV Natural Kesouice

^ Library *^jj^ Iniomiation System

P.O. Box 20 1800 • 1515 East Sixth Avenue • Helena, MT 59620-1800 • 406-444-5354

The preferred citation for this document is:

Hendricks, P. 2003. Status and Conservation Management of Terrestrial MoUusks of Special Concern
inMontana. Report to Region I, U.S. Forest Service. Montana Natural Heritage Program,
Helena. 67 pp. + appendicies.

EXECUTIVE SUMMARY

This document presents information on the distribution and status of 1 5 terrestrial moUusk taxa (species
and subspecies) of conservation concern in Montana that have been found on or near lands
administered by the Northern Region (Region 1 ), U. S . Forest Service. Included in this group are ten
snail taxa and five slug taxa. Each species or subspecies is on the current joint Montana Natural
Heritage Program and Montana Fish, Wildlife and Parks Animal Species of Concern list (Carlson
2003), as either a Species of Concern (eight snail and three slug taxa) or On Review (two snail and one
slug taxa); one slug species On Review (Udosarx lyrata) includes a subspecies {U. I russelli) that is a
Species of Concern.

Montana is the type locality (where the species or subspecies was first discovered and upon which the
formal description is based) for ten of the moUusk taxa discussed in this report. A review of available
literature and unpublished reports, museum records, personal discussions and correspondence, and field
survey results provided only 66 locality records for all species and subspecies combined. No species
has been reported in Montana at as many as 1 5 localities, and only two snails have been documented at
as many as ten localities. Two snails remain known from single localities each (the type localities), and
five other snails and slugs from two to four localities each. To date (2002), terrestrial moUusks of
conservation concern have been found on or near seven National Forests in Montana: Beaverhead-
Deerlodge, Bitterroot, Flathead, Gallatin, Kootenai, Lewis and Clark, and Lolo.

Of the 66 total localities. Heritage Program zoologists discovered nine since 1 997, and two additional
localities were first reported in 200 1 by other biologists. These results, obtained largely with a minimum
of survey effort, indicate that new populations for several of the species of conservation concern are
possible, even likely. However, given the history of collecting in the state west of the Continental Divide,
it is expected that most of the moUusk taxa on the Heritage list will remain there, although their global
and state ranks may ultimately be downgraded.

In this report, species accounts for each taxon are provided that include details of taxonomy and species
identification, life history and ecology notes, a distribution map, and comments on status, potential
threats, and land ownership at documented (historical and recent) locations. Appendices include a
summary of all location and museum collection information, guidelines for conducting surveys and
inventories of terrestrial moUusks, and a key to the genera of terrestrial moUusks in Montana. It is
hoped that this document will 1 ) bring to the attention of Forest Service biologists the existence of a
group of small animals of conservation concern that inhabit or may inhabit lands under their stewardship,
and 2) help Forest Service biologists design and conduct forest inventories for these species. The
ultimate goal of this document is to assure the long-term conservation of these species by having their
needs addressed in forest plans.

TABLE OF CONTENTS

Acknowledgments iv

Introduction 1

Species Accounts

Snails

Discus brunsoni 9

Discus shimeki 13

Oreohelix alpina 17

Oreohelix amariradix 21

Oreohelix carinifera 25

Oreohelix elrodi 29

Oreohelix strigosa berryi 33

Oreohelix yavapai mariae 37

Slugs

Hemphillia danielsi 41

Magnipelta mycophaga 45

Zacoleus idahoensis 49

Species on Review

Snails

Polygyrellapolygyrella 53

Radiodiscus abietum 57

Slugs

Udosarx lyrata 61

Bibliography 64

Appendix A. Global/State Rank Definitions

Appendix B. Locality and Collection Records for 1 5 Terrestrial MoUusk Taxa of Conservation

Concern in Montana
Appendix C. Guidelines for Designing and Conducting Surveys of Terrestrial MoUusks
Appendix D. Key to the Genera of Terrestrial MoUusks of Montana

ACKNOWLEDGMENTS

I am particularly grateful to Fred Samson (USDA Forest Service) for recognizing invertebrates as part
of the native fauna inhabiting The Northern Region, and concluding there is a need to address the
conservation issues invertebrates confront. John Carlson, Montana Natural Heritage Program
(MTNHP) Lead Zoologist, was instrumental in seeing solidified the agreement between the U.S. Forest
Service and MTNHP to develop this document.

Information gathered here was assembled from published literature, unpublished reports, field surveys,
museum collections, and personal communications with agency, academic, and private-sector biologists.
I am grateful to the moUusk collection managers of the California Academy of Sciences (CAS), the
Academy of Natural Sciences of Philadelphia (ANSP), the Field Museum of Natural History of Chi-
cago (FMNH), and the U.S. National Museum (USNM) for providing museum records. I also extend
thanks to Lee Fairbanks, Terry Frest, Bill Hammer, Bill Leonard, Tom Burke, Heike Reise, and Bryce
Maxell for providing specimen records, advice, or both. Bill Leonard was also generous in sharing his
photographs of several slug species.

For help in the production of this report, I thank Anne Dalton and Terrie Kenney for scanning photo-
graphs, Martin Miller for entry of location data into the MTNHP databases, Whitney Weber for map
production and Cobum Currier for report formatting and production, and John Carlson for feedback,
advice, and comments on earlier drafts of the report. All are, or were, fellow employees of the
MTNHP

Finally, I express my thanks to Dr. Royal Bruce Brunson (deceased). Emeritus Professor of the Depart-
ment of Zoology, University of Montana and mid-twentieth century student of Montana's moUusk fauna,
for sharing his knowledge and providing enthusiastic support of my novice attempts to rediscover what
was known decades before. This report is dedicated to him.

INTRODUCTION

Background. This document is intended to serve as a concise summary of current knowledge
on the status, distribution, Ufe history, and ecology of terrestrial mollusks (slugs and snails)
determined by the Montana Natural Heritage Program to merit state Species of Concern or On
Review designation (see Carlson 2003). The information gathered has been used to 1) identify
real and potential threats to terrestrial mollusks of conservation concern that may occur on U.S.
Forest Service, Northern Region lands in Montana, and 2) develop guidelines for field surveys
and monitoring schemes on Forest Service units for terrestrial mollusks of conservation concern.
The project is a joint venture of the U.S. Forest Service, Northern Region with the Montana
Natural Heritage Program.

Species and subspecies in this document (Table 1) are included on the joint Montana Natural
Heritage Program/Montana Department of Fish, Wildlife & Parks list of Animal Species of
Concern (Carlson 2003). They were so listed based on information and recommendations in
Frest and Johannes (1993, 1995) for species occurring in the Interior Columbia River Basin and
the Black Hills of South Dakota and Wyoming (the Black Hills region includes two species of
concern that also are present in Montana); several species included are covered in the Columbia
River Basin invertebrate assessment report (Niwa et al. 2001), where listing is also
recommended. Montana is the type locality (where the species or subspecies was first
discovered and upon which the formal description is based) for 10 of these taxa (see Appendix
B).

Table 1. Terrestrial snail and slug Species Of Concern or On Review in Montana (Carlson 2003). An asterisk (*)
following a scientific name indicates the species was recommended for listing in the Columbia River Basin
invertebrate assessment report (Niwa et al. 2001).

Scientific Name

Common Name

Heritage Rank^

Heritage Category

Snails

Discus brums oni"^

Mission Range Disc

GlSl

Concern

Discus shimeki

Striate Disc

G4S1

Concern

Oreohelix alpina''

Alpine Mountainshell

GlSl

Concern

Oreohelix amariradix^

Bitterroot Mountainshell

G1G2S1S2

Concern

Oreohelix carinifera^

Keeled Mountainshell

GlSl

Concern

Oreohelix elrodi^

Carinate Mountainshell

GlSl

Concern

Oreohelix strigosa berryi

Berry's Mountainshell

G5T2S1S2

Concern

Oreohelix yavapai mariae

Gallatin Mountainshell

G4?T1 SI

Concern

Polygyrella polygyrella

Humped Coin

GUSU

Review

Radiodiscus abietum

Fir Pinwheel

GUSU

Review

Slugs

Hemphillia danielsi"^

Marbled Jumping Slug

G1G3 S1S3

Concern

Magnipelta mycophaga"^

Spotted Slug

G2G3 SI S3

Concern

Udosarx lyrata^^

Lyre Mantleslug

GUSU

Review/Concern

Zacoleus idahoensis

Sheathed Slug

G3G4 S2S3

Concern

^ G = Global Rank, S = State Rank. See Appendix A for definitions of abbreviations and ranks.

^ A described subspecies, Udosarx lyrata russelli (Russell Mantleslug), is ranked G?T1 SI and placed on the

Concern list. It is discussed under the Lyre Mantleslug because separate treatment is not justified here. Both forms

of Udosarx lyrata were recommended for listing in the Columbia River Basin invertebrate assessment report (Nixa

etal.2001).

Although the two reports by Frest and Johannes form the basis for focus of mollusk conservation
in Montana, it is worth noting that large portions of Montana still await evaluation of their
molluscan fauna. The Interior Columbia River Basin report (Frest and Johannes 1995) covers
just that part of Montana west of the Continental Divide and two peripheral species of concern;
the Black Hills report (Frest and Johannes 1993) does not cover Montana at all, but discusses
two species of concern present also in Montana.

A Brief History of Land Mollusk Faunal Inventories in Montana. Only a few publications
provide accounts of the extant land mollusk faunas in Montana. Elrod (1902) presented the first
(and apparently only) list of known species for the state, while recognizing that the list was
necessarily incomplete due to inadequate collecting over much of the area, a problem persisting
to this day. Elrod' s (1902) report included brief mention of three species of conservation
concern {Pyramidula [=Oreohelix] elrodi, Pyramidula [=Oreohelix] alpina, and Polygyrella
polygyrelld) in western Montana, and included the records of Squyer (1984) from the Wibaux
area (known as Mingusville), which represented essentially the only information from the eastern
parts of Montana at that time. Shortly thereafter. Berry (1916) published a summary of his
collecting efforts in Meagher and Fergus counties, incorporating his earlier and briefer report
(Berry 1913) and including an account of Oreohelic strigosa berryi in the Big Snowy Mountains.
At this same time, Vanatta (1914) published a list of species collected by L. E. Daniels in the
Bitterroot Mountains, which included the first records of the endemic slug Hemphillia danielsi.

Little else appeared in print for some time, until Russell and Brunson (1967) compiled what was
known about the mollusk fauna of Glacier National Park, which updated an earlier report by
Berry (1919) and included many new observations by the authors. The Russell and Brunson
(1967) list is probably the most complete for any area of significant size in Montana.
Interestingly, none of the land mollusks of state conservation concern have been documented in
Glacier National Park. Unfortunately, Brunson (who qualified as the most knowledgeable
malacologist residing in Montana for the second half of the 20* Century) never wrote a revision
of Elrod' s (1902) out-dated state list, even though several additional species were known to
occur in Montana by the time Brunson retired from active collecting in the early 1980's.

The records of new terrestrial mollusk species and locations for Montana, including several of
conservation concern, remain scattered in publications of more narrow scope, many of them now
decades old (e.g., Bartsch 1916, Pilsbry and Brunson 1954, Brunson and Osher 1957, Brunson
and Russell 1967, Fairbanks 1984), or deposited as vouchers in museum collections and
otherwise unpublished. Fortunately, most or all of the species of greatest conservation interest in
Montana are discussed in Frest and Johannes (1993, 1995) as part of mollusk assessments of the
Black Hills and the Interior Columbia River Basin, respectively. Most recently (beginning in
1997), additional brief surveys for a few species have been made by Montana Natural Heritage
Program zoologists, who also continue to solicit and accumulate opportunistic observations of
mollusks for the Heritage databases, with focus on species of conservation concern as identified
in the documents of Frest and Johannes (1993, 1995).

Distribution and Status of Species of Conservation Concern. A review of available literature
and unpublished reports, museum records, personal discussions and field survey results provided
only 66 locality records (see Appendix B) for the set of 1 5 terrestrial mollusk taxa of
conservation concern listed in Table 1 (note that a subspecies of slug, Udosarx lyrata russelli, is
discussed in the account of the species). Three snails {Discus shimeki, Oreohelix strigosa berryi,
Oreohelix yavapai mariae) are known from sites east of the Continental Divide; the remaining
taxa, including all of the listed slugs, are known only from sites west of the Continental Divide.
No taxon has been reported in Montana at as many as 15 total localities, and only two {Oreohelix
strigosa berryi and Radiodiscus abietum) have been documented at as many as ten. Two taxa
{Discus brunsoni and Oreohelix yavapai mariae) remain known from single localities each, five
others {Oreohelix alpina, Oreohelix amariradix, Oreohelix carinifera, Oreohelix elrodi, and
Udosarx lyrata) from two to four localities each.

All but one terrestrial mollusk species, the Mission Range Disc {Discus brunsoni), on the joint
Montana Natural Heritage Program-Montana Department of Fish, Wildlife and Parks Animal
Species of Concern list (Carlson 2003) have been documented on or near at least one National
Forest unit in the Northern Region of Montana (Table 2). Other National Forests not listed in
Table 2 are likely to support one or more terrestrial mollusk species of conservation concern,
given the wide distribution of some of these, such as the Striate Disc {Discus shimeki) and
Berry's Mountainshell {Oreohelix strigosa berryi). Many of the listed National Forests are likely
to support additional taxa of conservation concern not yet documented on their lands.

Table 2. Terrestrial mollusk Species of Concern or On Review (Carlson 2003) that have been documented on
National Forest lands of the Northern Region (Region 1). Species in brackets ([ ]) indicate a species that has been
documented < 2 km from a particular forest boundary.

Forest

Mollusk Species

Beaverhead-Deerlodge

Zacoleus idahoensis

Bitterroot

Hemphillia danielsi, Radiodiscus abietum, Udosarx lyrata

Flathead

Magnipelta mycophaga, Oreohelix alpina, Oreohelix elrodi

Gallatin

Discus shimeki, Oreohelix strigosa berryi, Oreohelix yavapai mariae

Kootenai (including Kaniksu in Montana)

Discus shimeki, Magnipelta mycophaga, Radiodiscus abietum,
Zacoleus idahoensis

Lewis and Clark

Oreohelix strigosa berryi

Lolo

{Hemphillia danielsi], Magnipelta mycophaga, Oreohelix
amariradix, Oreohelix carinifera, Polygyrella polygyrella,
Radiodiscus abietum, Zacoleus idahoensis

These scant results lead to two conclusions: 1) most species/subspecies of special concern are
very rare, existing in small, often isolated populations, and 2) survey coverage in Montana has
been woefully inadequate to provide a reasonable assessment of the distribution and status of

most or all taxa. Field surveys and opportunistic observations indicate both conclusions
probably are reasonable. With very limited resources, Heritage Program zoologists have
documented four priority species at nine new localities (of the 66 total localities for all priority
species) since 1997, and determined that populations of three species remain extant at five
additional localities not sampled in the previous 30 years (see Appendix B). A new locality (one
of three) for the Carinate Mountainshell (Oreohelix elrodi) was discovered in 1999; two of five
total Montana localities so far documented for the Marbled Jumping Slug {Hemphillia danielsi)
were reported first in 2001 by other biologists. Thus, very brief field surveys and opportunistic
encounters in recent years have significantly increased the number of localities where terrestrial
mollusks of conservation concern have been found. Nonetheless, some species (especially
several species oi Oreohelix and Discus brunsoni) have been the focus of numerous searches
over the last several decades (Frest and Johannes 1995, R. B. Brunson pers. comm.) with few or
no new populations discovered.

Uncertainty regarding which species are present on National Forests is due to a general lack of
the most cursory of inventories to identify the terrestrial mollusk faunas occupying public lands
throughout Montana. Thus, to gauge the significance of federal lands for maintaining snails and
slugs considered rare and of conservation concern, a priority should be placed on conducting
field surveys of appropriate habitats where these species might occur on National Forests of the
Northern Region (see Appendix C for guidelines). The evidence from recent field work
indicates additional surveys will result in the discovery of several additional populations for
some species, most likely the slugs, but most or all mollusk species currently on the Species of
Concern lists (Carlson 2003) probably will continue to be identified as relatively rare and of
limited distribution in Montana.

The discovery of new locations will lead to a reassessment of the status of the listed species in
Montana as well as on particular National Forests. However, species new to the known mollusk
fauna of Montana are still possible. As an example, a slug species "discovered" (in a museum
collection) during the development of this document, the Smokey Taildropper {Prophysaon
humile) (see Frest and Johannes 1995), not yet on the joint Montana Natural Heritage
Program/Fish, Wildlife & Parks list of "Animal Species of Concern" (Carlson 2003), is now
known to be present in Montana (see Appendix C) and will be added to the list in the near future
because it is of conservation concern elsewhere in the Interior Columbia River Basin (Frest and
Johannes 1995, Niwa et al. 2001). Thus, with additional survey documentation, we can expect
that several species will be added to the individual National Forest lists, including some that may
not yet be known to occur in Montana. But with continued survey effort we can also anticipate
that some species will be dropped from the list of species of conservation concern in Montana
because they are known to be more secure than their current ranks indicate.

Summary of Occupied Habitats. Generally speaking, the 15 terrestrial mollusk species of
conservation interest in Montana (Table 1) fall into two habitat groupings: 1) species often
associated with talus or rocky outcrops (Talus Group), and 2) species often associated with moist
valley and canyon (ravine) mixed-conifer forests (Moist Forest Group). The two groupings may
overlap in some cases; some of the moist mix-conifer forest species are often found in rocky
sites, and the talus-inhabiting species may occupy talus imbedded in a forested landscape. But
the microhabitats where these two groups occur are usually easy to differentiate.

All of the Oreohelix species listed in Table 1, as well as Discus brunsoni, associate with talus or
rocky ground, although the occupied sites may range from low-elevation canyons and valley
bottoms to high-elevation slopes well above treeline. Sites occupied by this group are typically
in terrain that is more open and mesic than where the second group associates. Sites occupied by
the second group (the four slugs, Discus shimeki, Polygyrella polygyrella, Radiodiscus abietum)
tend to be near permanent water, such as riparian corridors, and in dense conifer forests where
there is more precipitation, litter and decaying wood. This group of species also frequents areas
with a deciduous wood component of species such as aspen, cottonwood, alder and birch.

Potential Threats. No studies exist that document the response of any of the 15 terrestrial
mollusk species of conservation concern to disturbance. Threats to populations of these species
is largely guess work, and based on the type and extent of habitat alteration and disturbance that
has occurred in Montana in the last century.

Any kind of habitat alteration that reduces the humidity of the microhabitats where these species
occur is a potential threat to both groups, but probably greatest for the Moist Forest Group.
Canopy removal through logging and fire are probably the most significant disturbances for the
forest-inhabiting species; historical forest clearing has likely resulted in significant reductions
and fragmentation of their former ranges. Logging and fire are also potentially significant
factors of disturbance for talus-inhabiting species, but talus occupied by these species may be
deep enough to provide necessary humidity and temperature regimes that will protect them from
logging and fire, at least in some cases and in the short term. However, construction of roads to
support logging operations could threaten even some of these seemingly protected talus sites.

Grazing has the potential to negatively impact both groups, but some of the species inhabiting
talus (especially Discus brunsoni, Oreohelix alpina, and Oreohelix elrodi) are probably largely
buffered from grazing impacts due to the specific types of rocky terrain they occupy. For other
species in more expose sites, trampling and grazing could devastate the habitat occupied by the
snails and slugs, removing plant cover and potential food, and destabilizing occupied slopes.
Rural home development and highway and road maintenance also have the potential to
contribute to habitat loss for several species in both groups largely restricted to low-elevation
valleys and slopes in apparently very localized populations {Oreohelix amariradix and Oreohelix
carinifera are examples).

Use of chemicals for controlling noxious weeds could present land managers with situations
where protection of rare animal species is balanced against the need to control or eradicate exotic
pest species, and special effort may be required to assure the protection of the mollusks during
these operations. Several of the mollusk species of conservation concern probably occupy areas
where control of noxious weeds is desirable, especially along heavily used roads and trails.
During the writing of this report it was discovered through conversation with Forest Service
personnel that a weed control program will soon occur at the only site known for the Gallatin
Mountainsnail (Oreohelix yavapai mariae), A survey of the site should be conducted before
spraying to identify the area occupied by the snails, so that disturbance to this rare endemic snail
can be avoided. Similar situations such as the above will probably occur in the future as weed
control receives more emphasis. This further underscores the need for new surveys to identify

sites currently occupied by the terrestrial moUusks of conservation concern discussed in this
report.

Summary of this report. The species accounts that follow include information on taxonomy
and species/subspecies identification (including photographs when available), life history notes
on reproductive biology, ecology and habitat associations, information of the range-wide
distribution and distribution within Montana (including distribution maps), current abundance,
potential or real threats, and land ownership at known localities. In some sections, particularly
threats and distributions, what is written is too often speculation. This is unavoidable because so
little is known of these topics about most species of conservation concern.

A bibliography pertaining to the species of conservation concern, which includes most or all of
the published and gray literature mentioning the species that are the focus of this report, is
included at the end of the individual species accounts. A table summarizing available geo-spatial
data for each occurrence, along with collection/observation dates and museum accession
numbers, as well as available habitat information briefly noted, is provided in Appendix B.
Guidelines for designing and conducting field surveys are provided in Appendix C. A key to the
genera of terrestrial Montana mollusks is provided in Appendix D as an aid to field workers
encountering snails and slugs and attempting an initial determination of what they have found. It
is hoped that the production of this report will impress upon agency and private sector biologists
the magnitude of our ignorance, and spur them to take measures to reduce it.

Figure 1. Distribution of Discus brunsoni in Montana.

• Discus brunsoni
^^/Continental Divide
US Forest Service

(Mission Range Disc)

■

-4

^B?^h|'^-'

\ -

'■ 1

Wm . ms^

SPECIES ACCOUNTS
SNAILS

SPECIES: Discus brunsoni
HeritageRank:Gl,Sl
Natural History

A. Taxonomy

Family: Discidae

Discus brunsoni Berry, 1955

Berry (1 955) described this distinctive taxon as a full species. There remain questions regarding
its true taxonomic affinities, but complete knowledge will not affect the validity as a full species
(see Frest and Johannes 1 995).

B. Species Description

Morphology: The following description is taken from Berry (1 955). "Shell large for the genus,
thin, depressed-conic, with low spire, its slopes weakly convex. Whorls about five and a half,
decidedly compressed, moderately rounded both above and below the strongly but not acutely
carinate periphery, . . . ; base fiattened, the widely open vorticiform umbilicus contained about
three times in the major diameter of the shell; . . . Aperture transversely ovate, compressed, . . .
Color near olive-brown, ... the basal surface and that of young shells tending to be a little
brighter; no inherent variegation of color pattern evident." Maximum diameter of holotype 10.5
mm, minimum diameter 9. 1 mm; height of shell 4.2 mm, diameter of umbilicus 3.5 mm.
Maximum diameters of eight live individuals measured by Hendricks (1 998) ranged from 6.7
mm to 10.5 mm (mean = 9.5 + 1.4 mm).

Reproductive biology: Hermaphroditic, so far as known. Internal anatomy is not yet described
(Berry 1955, Frest and Johannes 1 995), and there are no descriptions of the reproductive
behavior and its seasonal occurrence. Lifespan is unknown. Age/size at maturity is unknown.

Ecology: Occupies open, south facing and rather dry talus slopes with very low canopy cover.
Vegetation at the margins of the talus slopes includes Douglas-fir (Pseudotsuga menziesii\
ponderosa pine (Pinus ponderosa), pockets of water birch (Betula occidentalis), quaking
aspen (Populus tremuloides), and mock orange {Philadelphus lewisii). Rock composition at
the type locality was described as limestone (Berry 1 955, Frest and Johannes 1 995), but more
recent examination (Hendricks 1 998) revealed the occupied talus to be a mix of diorite and
argillite with no limestone present. Apparently this species retreats deep into the talus when
surface conditions are unfavorable. Brunson (1956) suggested that D. brunsoni may be

crepuscular or nocturnal near the surface, because many collections were made shortly before
dusk, or at least in subdued light, following intensive mid-day searches. Hendricks (1 998),
however, located live animals at the surface during mid-day when ambient surface conditions
were overcast, wet and cool. Oreohelix elrodi is also present in the occupied talus. Foods are
unknown, but it may feed most often on plant material on rock surfaces (lichens, etc.) rather
than patches of accumulated leaf and conifer needle litter (Brunson 1 956, Hendricks 1 998).

C. Range and Known Sites

Discus brunsoni is known only from the Mission Mountains in Lake County, northwestern
Montana (Fig. 1 , Appendix B). The type locality is the south-facing slope above McDonald
Lake in the Mission Mountains Tribal Wilderness of the Confederated Salish and Kootenai
Tribes, at about 1 120 m (3700 ft) elevation. Several talus slopes are present above the north
shore of the lake; Brunson (1 956) indicates more than one slope is occupied, but Hendricks
(1 998) found D. brunsoni only in the talus slope where diorite was abundant.

To date, the type locality is the only location where D. brunsoni has been found. Over 70
specimens of this species have been uncovered in seven different years since the first shell was
found in August 1 948; the most recent known observation was in July 1 997 (Hendricks 1 998).

D. Species Abundance

Discus brunsoni is a local endemic, perhaps present only in the Mission Mountains. Because
the species occupies large and deep talus slopes it is difficult to make estimates of population
size. During favorable surface conditions, Hendricks (1 998) found it to be much less abundant
near the surface than sympatric Oreohelix elrodi, another regional endemic of conservation
concern.

Current Status

A. Why Species is of Conservation Concern

The Mission Range Disc {Discus brunsoni) is a Species of Concern in Montana because it is a
local endemic so far documented at a single site, despite several decades of widespread
collecting in the region by Dr. R. B. Brunson and students (Frest and Johannes 1 995, Brunson
personal communication). Population size and trends are unknown. Recommended for Federal
listing by Frest and Johannes (1 995).

B. Threats

Although the occupied habitat is not particularly threatened by development or agriculture
(logging and grazing), habitat requirements and food habits are poorly understood. Fire
suppression efforts (especially use of fire retardants) and talus destabilization (trail maintenance,
modification) could have negative impacts. Also, given the trail-side location, weed control
efforts could negatively impact the population.

C. Distribution Relative to Land Allocations

The only known occupied site is in the Confederated Sahsh and Kootenai Tribes Mission
Mountains Tribal Wilderness. Amajor hiking and packing trail bisects the site. Additional
populations associated with diorite and argillite talus may be present elsewhere in the Mission
Mountains on tribal and national forest lands. There are quartz diorite outcrops that should be
surveyed in the North Fork and South Fork of Elk Creek drainages in the Flathead National
Forest, and near the Crow Creek Lakes in the Mission Mountains Tribal Wilderness.

Figure 2. Distribution of Discus shimeki in Montana.

• Discus shimeki
^^/Continental Divide
US Forest Service

SPECIES: Discus shimeki (Striate Disc)

Heritage Rank: G4,S1
Natural History

A. Taxonomy

Family: Discidae

Discus shimeki (Pilsbry, 1 890)

Originally described from fossil material in Peoria Loess in Iowa. The extant western
subspecies, D. s. cockerelli, is considered by some authorities to be indistinguishable from the
nominate form (Frest and Johannes 1 993).

B. Species Description

Morphology: The following description is from Pilsbry (1 948). "The whorls are much more
robust than D. cronkhitei. It has a low conic spire, rounded periphery and rather narrowly
umbilicate base, the umbilicus contained about 3 .7 to 4 times in the diameter. The first whorl
projects somewhat, the first 1 V2 whorls smooth; following whorls regularly and rather strongly
rib-striate, . . . [the ribs] become somewhat lower and irregular on the last whorl, where they
disappear in the peripheral region, the base being marked only with weak wrinkles of growth."
This snail differs from the sympatric Discus cronkhitei (= whitneyi) by its smoother base and
weaker ribs on the last whorl. The shell is thin, and brownish in color. Height is about 3 .7 mm,
maximum diameter about 6-7 mm; 4.5 whorls.

Reproductive biology: Hermaphroditic. Copulation observed in March- June. Egg laying occurs
from April- August in the Black Hills; clutch size is relatively small (3-6). Apparently most
members of this species have a one-year life cycle (Frest and Johannes 1993). Age/size at
reproductive maturity has not been described.

Ecology: This species tends to associate with quaking aspen (Populus tremuloides) at Montana
sites where habitat was documented (Hendricks unpublished data). Elsewhere in the Rocky
Mountains it is also associated with spruce (Picea) and fir (Abies) intermixed with aspen or
other broadleaf trees and shrubs (Beetle 1957, 1997, Karlin 1961, Frest and Johannes 1993).
Soils often are derived from weathering limestone. D. shimeki is active most often in litter in
lowland forest, but sometimes is seen on downed wood and rock surfaces. Slopes are often
north-facing and shaded. This species appears to subsist largely on decaying deciduous leaves.

C. Range and Known Sites

Discus shimeki is widely distributed in the Rocky Mountains of Arizona, New Mexico, Utah,
Colorado, and Wyoming, with populations also extant in the Black Hills (Frest and Johannes
1 993). It is also found north of Montana in the Canadian Rockies (Piatt 1 980). Pilsbry (1 948)

lists only one Montana location for this species, along the Boulder River in Sweetgrass County
(also referenced in Frest and Johannes 1 993). The species has been documented in Montana
(Fig. 2, Appendix B) in five counties total (Gallatin, Hill, Lincoln, Park, Sweetgrass), at
elevations ranging from 640 m (2 1 00 ft) to 1 940 m (63 60 ft) . The most recent records are
from along Beaver Creek in the Bears Paw Mountains, Hill County (1 997) and west of Nurses
Lakes (Gallatin National Forest) in the Absaroka Mountains, Park County (2001).

D. Species Abundance

Population sizes are not reported. The species can be abundant in colonies, but colony sites are
relatively small in extent (Frest and Johannes 1 993). At some sites where the species has been
documented in Montana, D. shimeki is less abundant than D. cronkhitei (=whitneyi) (pers.
obs.).

Current Status

A. Why Species is of Conservation Concern

The Striate Disc {Discus shimeki) is a Species of Concern in Montana because of the limited
number of sites where it has been documented in the state, despite several decades of
widespread collecting in the region by Dr. R. B. Brunson and students (Frest and Johannes
1 993, 1 995). Recommended for Federal listing by Frest and Johannes (1 993).

B. Threats

Major threats to known sites include degradation due to timber harvest and livestock grazing,
with the latter likely the main threat. Fire is also a concern; stand replacement fires could
permanently eliminate populations in isolated colonies (see Beetle 1 997). Response of snails to
fire retardants has not been studied.

C. Distribution Relative to Land Allocations

Known sites in Montana include Forest Service and Tribal lands at widely separated locations.
Addition sites are possible on these as well as private lands throughout the montane regions of
Montana, including some of the island mountain ranges in the prairie regions east of the main
Rocky Mountain chain. None of the sites has special protection.

Figures. Distribution of Oreohelix alpina in Montana.

• Oreohelix alpina
^^/Continental Divide
US Forest Service

SPECIES: Oreohelix alpina

HeritageRank:Gl,Sl

Natural History

A. Taxonomy

Family: Oreohelicidae
Oreohelix alpina (Elrod, 1901)

(Alpine Mountainsnail)

Originally named Pyramidula strigosa alpina by Elrod (1 90 1 a, 1 903b). Pilsbry (1 939)
expressed some doubt about the validity of this taxon, but later examination of material by Frest
and Johannes (1995) and Fairbanks (2002) indicate treatment as a full species is appropriate.
Pilsbry (1 933) placed Oreohelix alpina with the O. strigosa group, as did Elrod (1 901 a,
1 902, 1 903b), but later (Pilsbry 1 939) moved it to the O. subrudis group. Recent study of the
internal anatomy (Fairbanks 2002) indicates affinity with the O. strigosa group. Pilsbry (1 939)
placed all Oreohelix in the Xanthonycidae.

B. Species Description

Morphology : Descriptions of shells from the Mission Mountains are provided in Elrod (1901,
1902, 1903b), Pilsbry (1939), Hendricks (1998), and Fairbanks (2002); reproductive anatomy
is described in Fairbanks (2002). Description from Pilsbry (1 939) follows: "shell small;
brownish-gray, tending toward light hom color, in dead shells tuming to pearly white; luster
somewhat silky; shell flat, little elevated; . . . aperture nearly circular, . . . somewhat higher than
wide; markings as in strigosa, the upper band continuing in the spire, gradually disappearing;
umbilicus medium, circular, deep, subcylindric." Shell diameter 7-10 mm, average often
specimens, 8.91 mm, shell height 3-5mm, whorls 4.0-4.5. Hendricks (1998) reported range in
diameter of 1 6 live shells = 2.5-8.5 mm, nine dead shells = 8.0-9.6 mm. Shells from the Swan
Range may average slightly larger in diameter: average of 1 3 was 9.4 mm, range 5.7-11.4 mm
(Hendricks unpublished data); average of four was 9.3 mm, range 8.5-11 . 1 mm (Fairbanks
2002).

Reproductive biology: Hermaphroditic; reproductive anatomy described in Fairbanks (2002).
There are no descriptions of reproductive behavior and its seasonal occurrence. Lifespan is
unknown. Age/size at reproductive maturity is unknown.

Ecology: Occupies open talus slopes at high elevations near and above treeline (Elrod 1 902,
1 903b, Hendricks 1 998). Vegetation at and near the alpine type locality on East St. Marys
Peak in the Mission Mountains (Hendricks 1 998) includes the wild flowers snow cinquefoil
(Potentilla nivea), mountain avens (Dryas octopetala), alpine sorrel (Oxyria digyna) and
moss campion (Silene acaulis). Subalpine fir {Abies lasiocarpa) is present at the margins of
the subalpine site above Lower Rumble Lake in the Swan Range (Hendricks unpublished data).
Rock substrate at all known sites is limestone. Live shells are found on surfaces of limestone

blocks, but often in the absence of direct sunlight (shaded areas and undersides of smaller
blocks). Block size where O. alpina was found on St Marys Peak averaged 20 x 30 cm
square and 4-8 cm thick (Hendricks 1 998), block size at the Swan Range site ranged from 1 5 x
1 5 X 4 cm to 1 m^ (Hendricks unpublished data). Some soil development and leaf litter was
present at each site where live snails were found; one group of live snails was found in leaf litter
near the base of snow cinquefoil partially protected overhead by rock. Food habits are
unknown.

C. Range and Known Sites

Oreohelix alpina is known from three sites (Fig. 3, Appendix B) in two counties (Elrod 1 902,
1 903b, Hendricks 1 998, Fairbanks 2002). The type locality is East St. Marys Peak in the
Mission Mountains of Lake County, from 2710m (8900 ft) to 2865 m (9400 ft) elevation. The
second site in the Mission Mountains is more extensive, and includes West McDonald Peak, the
summit area of McDonald Peak, and the slopes of McDonald Peak above Duncan Lake, all in
Lake County, from 2255 m (7400 ft) to 2957 m (9700 ft) elevation. The third site is above
Lower Rumble Lake in the Swan Range, Missoula County, at 21 95 m (7200 ft) elevation.

The known sites have been visited infrequently, probably because of difficult access. Prior to
1 997, the species had not been reported at either Mission Mountains site since 1 952 (specimen
in the Field Museum of Natural History, Chicago), and there remain few collections of this
species. The Swan Range site was not discovered until 1 975, and O. alpina had not been
documented again at this locality until 2000. Other sites within each mountain range are likely to
exist. Additional populations may be discovered in portions of the Bob Marshall Wilderness.

D. Species Abundance

Oreohelix alpina is a local endemic restricted to the Mission Mountains and nearby Swan
Range. The species was relatively abundant at some locations within sites of occurrence (Elrod
1 902, Hendricks 1 998). However, no population estimates are available, and nothing is known
regarding population trends at any site.

Current Status

A. Why Species is of Conservation Concern

The Alpine Mountainshell {Oreohelix alpina) is a Species of Concern in Montana because it is
a local endemic so far documented at three sites, despite several decades of widespread
collecting in the region by Dr. R. B. Brunson and students (Frest and Johannes 1 995).
Population size and trends are unknown. Recommended for Federal listing by Frest and
Johannes (1995).

C. Threats

Occupied habitat (alpine and high-elevation limestone talus) is not threatened by current land
use practices. Probably the greatest threat to species persistence is climate change.

C. Distribution Relative to Land Allocations

The two known sites in the Mission Mountains are in the Confederated Salish and Kootenai
Tribes Mission Mountains Tribal Wilderness. The Swan Range site is on the Flathead National
Forest (Swan Lake Ranger District). Additional populations are possible on adjacent Tribal and
Forest Service lands.

Figure 4. Distribution of Oreohelix amariradix in Montana.

• Oreohelix amariradix
^^/Continental Divide
US Forest Service

SPECIES: Oreohelix amariradix (Bitterroot Mountainsnail)

Heritage Rank: G1G2, S1S2
Natural History

A. Taxonomy

Family: Oreohelicidae

Oreohelix amariradix Pilsbry, 1 934

Originally identified by Elrod ( 1 90 1 a, 1 902, 1 903b) as a "small variety" of Oreohelix
(=Pyramidula) strigosa from the Bitterroot Mountains, but described by Pilsbry (1 933) as a
full species of the O. strigosa group, based only on dead shells. Fairbanks' (1980) analysis of
the internal anatomy confirmed Pilsbry 's designation. Pilsbry (1 939) placed all Oreohelix in the
Xanthonycidae.

B. Species Description

Morphology: Pilsbry (1 933, 1 939) describe the shell as "openly umbilicate, the umbilicus
contained about 4 times in the diameter; biconvex with the periphery rather sharply angular, the
angle disappearing on the last third of a whorl. Whorls 51/3, the embryonic 21/3 moderately
convex and nearly smooth. Susequent whorls rather coarsely and irregularly wrinkle-striate,
without spiral striation, but there is often a spiral impression above the suture on the penult
whorl. The last whorl descends shortly in front. Aperture rather strongly oblique, . . . The
specimens . . . show a reddish band immediately below the periphery, another a short distance
above it." Shell height 8.5 mm, diameter 14.5 mm. Elrod (1 903b) gives height of 1 0 shells 5.3-
7.4 mm, diameter 1 1 .9-16.7 mm; number of whorls 4.8-5.4. Fairbanks (1980) gives height of
6.9-10.9 mm and diameter of 1 2.8- 1 7.9 mm for 2 1 specimens from another site nearby;
number of whorls 4.75-5.5.

Reproductive biology: Hermaphroditic (Fairbanks 1980). No description of reproductive
behavior and its seasonal occurrence in natural settings. Life span is unknown. Age/size of
reproductive maturity is not described; in captivity young bom live after adults overwintered.

Ecology: This species occupies small talus slides, primarily the basal portions (Frest and
Johannes 1995), scattered among open grassy, south-facing slopes that become quite dry in
mid-summer (Elrod 1903b, Fairbanks 1980). Vegetation at one site included bunch grasses,
ponderosapine {Pinus ponderosa), serviceberry (Amelanchier alnifolia), and ninebark
(Physocarpus malvaceus). Food habits are unknown.

C. Range and Known Sites

Oreohelix amariradix is known only from the Lolo Creek drainage near Fort Fizzle, Missoula
County (Fig. 4, Appendix B) at about 1 070 m (3500 ft) elevation. Elrod (1 903b) gave the

elevation at the type locality as 1 524 m (5000 ft), but this is likely an error, as Lolo Pass is <
100 m elevation above this contour, nor does habitat at that elevation fit the description.
Reported records along the Clark Fork River at Ravenna and Nimrod (Frest and Johannes
1 995) appear to be an error, perhaps confiised with locations for O. carinifera (see next
species account), as no documentation was found for O. amariradix at these sites.

The known sites have been visited infrequently. Attempts by Frest and Johannes (1 995) to
locate living animals in 1 994 were unsuccessful, although these authors state that the species is
extant at two Lolo Creek drainage sites. Given their comments, and earlier ones by Elrod
(1901), populations other than those listed in Appendix B may exist in the Lolo Creek area.

D. Species Abundance

Oreohelix amariradix is a local endemic restricted to the Bitteroot Mountains. There are no
published estimates of population size or relative abundance. There may be an overall declining
trend in absolute abundance, given Frest and Johannes' (1 995) comments about local
extinctions.

Current Status

A. Why Species is of Conservation Concern

The Bitterroot Mountainshell {Oreohelix amariradix) is a Species of Concern in Montana
because it is a local endemic so far documented only in the Lolo Creek drainage , despite
several decades of collecting in the region by Dr. R. B. Brunson and students (Frest and
Johannes 1 995). Population size and trends are unknown.

B. Threats

Habitat occupied by Oreohelix amariradix (low elevation talus in slopes of open ponderosa
pine) is threatened by logging, grazing, weed control, highway development, home development,
and fire. The impact of fire retardant on this and other terrestrial moUusks in not known. Little
is known about this species, including its susceptibility to disturbance.

C. Distribution Relative to Land Allocations

The known sites (Appendix B) are on or near Lolo National Forest lands, as well as private
timber company lands. It is quite possible that additional populations occur on both, as well as
other private lands. None of the sites have special protection.

Figures. Distribution of Oreohelix carinifera in Montana.

• Oreohelix carinifera
^^/Continental Divide
US Forest Service

SPECIES: Oreohelix carinifera (Keeled Mountainsnail)

HeritageRank:Gl,Sl

Natural History

A. Taxonomy

Family: Oreohelicidae

Oreohelix carinifera Vilsbry, 1912

Affinities of this species are with the Oreohelix yavapai group (Pilsbry 1933, Frest and
Johannes 1 995), and based primarily on the intemal anatomy. Pilsbry (1 939) placed all
Oreohelix in the Xanthonycidae.

B. Species Description

Morphology: Pilsbry (1912, 1933, 1939) describes the shell as "lenticular, carinate, umbilicate,
the umbilicus contained 41/3 times in the diameter. The whorls increase slowly, the first 2 Yi
strongly convex, the rest strongly convex around the upper (inner) part, becoming concave near
the outer (peripheral) edge. The embryonic whorls are very finely obliquely striate; later whorls
rather coarsely wrinkle-striate, with some weak spiral striae in places; the last whorl is concave
above and below the peripheral keel, descends very little or not at all in front, . . . The aperture
is about as high as wide, and shows a slight angle at the end of the keel." Shell diameter 9-12
mm; shell height 5-7 mm; whorls 4/^-5. The intemal anatomy is described in Pilsbry (1 933,
1939).

Reproductive biology: Hermaphroditic (Pilsbry 1933, 1939). There is no description of
reproductive behavior and its seasonal occurrence. Life span is unknown. Age/size at
reproductive maturity is unknown.

Ecology: This species occupies small limestone outcrops and sandy limestone soils on arid
slopes with sparse vegetation cover; described sites have been south facing (Frest and Johannes
1 995, L. Fairbanks personal communication). Vegetation at sites includes open stands of
sagebrush (Artemisia)/}unvpQY (Juniperus) and Douglas-fir (Pseudotsuga menziesii).
Individuals have often been found under shrubs and junipers. Food habits are not described.

C. Range and Known Sites

Oreohelix carinifera is known in Montana from four sites in the Clark Fork River drainage,
Powell and Granite counties (Fig. 5, Appendix B) at 1 250- 1 480 m (4 1 00-4850 ft) elevation.
Frest and Johannes (1 995) found the species at a portion of the type locality at Garrison, but
failed to at another former location near Beavertail Hill where the species was present in 1 975.
There have been few or no additional searches for this species at former sites in recent years.

In August 2002, however, dead shells were found at a new site in the Garnet Range (personal
observation), indicating that additional sites are possible.

Both Pilsbry (1 939) and Frest and Johannes (1 995) listed O. carinifera as endemic to
Montana, but the species is on the Wyoming checklist (Beetle 1 989) for Park County.
Interestingly, Beetle ( 1 96 1 ) earlier identified this species from the Big Horn Mountains in Big
Horn and Washakie counties, of which neither location appeared on her 1 989 state checklist. It
is assumed in the present report that Oreohelix carinifera is a local endemic in Montana, as
stated by Frest and Johannes (1 995); the Wyoming material needs reexamination by experts for
final determination, as there are other small Oreohelix species present in that portion of
Wyoming with which O. carinifera might be confused.

D. Species Abundance

Oreohelix carinifera is a local endemic restricted to the upper Clark Fork River drainage.
There are no published estimates of population size or relative abundance. Pilsbry (1912) noted
that where the shells were "so abundant as to attract the attention of non-conchological
naturalists" (p. 88) there are plenty of living snails to be found nearby (the first collection was
made by two entomologists). Frest and Johannes's (1 995) limited success at locating the
species in the last decade, including finding dead shells where live ones were absent, suggests
that population sizes may be in recent decline, with possible extinctions at some sites.

Current Status

A. Why Species is of Conservation Concern

The Keeled Mountainshell {Oreohelix carinifera) is a Species of Concern in Montana because
it is a local endemic so far documented only in the upper Clark Fork River drainage between
Garrison and Missoula, despite several decades of collecting in the region by Dr. R. B. Brunson
and his students (Frest and Johannes 1 995). Population size and trends are largely unknown.

B. Threats

Habitat occupied by Oreohelix carinifera (low-elevation slopes of open juniper and Douglas-
fir) is threatened by logging, grazing, weed control, highway development, home development,
and fire. The impact of fire retardants on this and other terrestrial moUusks in not known. Little
is known about this species, including its susceptibility to disturbance.

C. Distribution Relative to Land Allocations

The known sites are on or near private timber land, Lolo National Forest land, state land.
Bureau of Land Management land, and private non-timber land. None of these sites have
special protection.

Figure 6. Distribution of Oreohelix eirodi in Montana.

• Oreohelix eirodi
^^/Continental Divide
US Forest Service

SPECIES: Oreohelix elrodi (Carinate Mountainsnail)

HeritageRank:Gl,Sl

Natural History

A. Taxonomy

Family: Oreohelicidae
Oreohelix elrodi (Vilshry, 1900)

Originally named Pyramidula elrodi by Pilsbry (1900). AflFmities of this species are with the
Oreohelix strigosa group (Pilsbry 1933, Frest and Johannes 1995), based on the internal
anatomy (see Pilsbry 1939); additional description of the intemal anatomy is available in
Fairbanks (1 984). Pilsbry (1 939) placed all Oreohelix in the Xanthonycidae.

B. Species Description

Morphology: Pilsbry (1900, 1939) describes the shell as "strongly depressed, biconvex, acutely
carinate, with open umbilicus contained about 4 times in the diameter; pale vinaceous fawn color
to nearly white (under a fugacious light brownish cuticle which is lost in all adult shells seen).
Spire low conoidal, often much depressed. Embryonic shell of 2 1/3 to 2 2/3 whorls, the first
smooth, the rest varying from unevenly striate to finely costellate. Later whorls are coarsely
sculptured with rude, unequal, retractive ribs, usually narrower than their intervals, which are

densely and finely striate spirally The last whorl descends shortly in front. Aperture angular

at termination of the keel." Shell diameter21-28 mm (Pilsbry 1939), 17.4-26.0 mm (Fairbanks
1984), 4. 1-22.6 mm (Hendricks 1998); shell height 8.8-13.3 mm (Pilsbry 1939), 8.4-13.1 mm
(Fairbanks 1984); whorls 5-5 V2 (Pilsbry 1939), 5-5 Va (Fairbanks 1984). Shell diameter of
new-bom young 3.6-3.7 mm; whorls 2.3-2.5 (Hendricks unpubhshed data). The intemal
anatomy is described in Pilsbry (1 939) and Fairbanks (1 984).

Reproductive biology: Hermaphroditic (Pilsbry 1939, Fairbanks 1984). There is no description
of reproductive behavior and its seasonal occurrence. Life span is unknown. Age/size at
reproductive maturity is unknown; a captive adult 1 8.2 mm diameter gave birth to 4 young after
overwintering (Hendricks unpublished data).

Ecology: This species occupies course talus, typically on south-facing slopes, and usually with
sparse canopy of ponderosapine {Pinus ponderosa), mountain ash (Sorbus) and serviceberry
(Amelanchier) (Frest and Johannes 1 995). Hendricks (1 998) described vegetation at three
talus sites in the Mission Range, each with 0% canopy cover in the search areas, as bordered
by Douglas-fir (Pseudotsuga menziesii) and ponderosa pine with pockets of water birch
(Betula occidentalis), quaking aspen (Populus tremuloides) and mock orange (Philadelphus
lewisii). At the two Swan Range locations, portions of the occupied terrain (Hendricks
unpublished data) are in talus under a forest canopy variably composed (depending on

microsite) of Douglas-fir, ponderosapine, quaking aspen, western red cedar (Thuja plicata),
paper birch (B. papyrifera) and western larch (Larix occidentalis); canopy cover is 0-10%.

Elrod (1 902) considered O. elrodi to be "a shell of the rocks" (p. 1 1 7), present on the surface
of exposed talus during favorable conditions, and present down among the stones when
conditions become dry (Elrod 1903 a). During favorable surface conditions (wet, 10-17°C) live
individuals are found attached to rocks near the surface but more often are present on organic
litter accumulations within the talus; some aestivating mature individuals (18-21 mm diameter)
are found near the talus surface during dry and warm (2 1 -23°C) conditions (Hendricks 1 998).
Food habits are not described, but presence on organic litter indicates O. elrodi may be a
detritivore.

Occupied talus at the Mission Range site is described by Berry (1 955) and Frest and Johannes
(1 995) as limestone. However, Hendricks (1 998) found O. elrodi in this mountain range at
sites comprised mostly of diorite and/or argillite; rock type at the two occupied sites in the Swan
Range is also argillite (Hendricks unpublished data). Clast (fragment) size of the rocks
comprising occupied talus ranges from 1 0 x 20 x 1 0 cm to 1 m^ at the Mission Range sites
(Hendricks 1 998), and 1 0 x 1 0 x 1 0 cm to 0.5 x 0.5 x 0.5 m at the Swan Range sites
(Hendricks unpublished data). Measured slope at occupied sites in both mountain ranges was
25-36° (Hendricks 1 998, unpublished data). How deep into talus slopes this species occurs is
unknown, but live individuals were found up to a meter below the surface at the Mission Range
microsite co-occupied by Discus brunsoni (see Hendricks 1998).

C. Range and Known Sites

Oreohelix elrodi is endemic to northwestern Montana, known from three sites in Lake County:
one (the type locality) in the McDonald Lake cirque on the west side of the Mission Range at
1 067-1 524 m (3500-5000 ft) elevation (Elrod 1 902 states shells occur up to 2286 m or 7500
ft elevation), two on the west side of the Swan Range at 1 1 58-1295 m (3800-4250 ft) elevation
along Lion and Goat creeks (Fig. 6, Appendix B). Live animals were found at the type locality
in the Mission Range as recently as 1 997 (Hendricks 1 998), and in 1 999 at both the Lion
Creek site and the Goat Creek site (which was discovered in 1 999). There have been few or
no additional searches for this species at the above sites, and no additional surveys for new
localities in either mountain range.

D. Species Abundance

Oreohelix elrodi is a local endemic restricted to the Mission and Swan ranges. There are no
published estimates of population size. Elrod (1901-1902, 1902, 1903 a) stated dead shells
were abundant in many locations on the slopes above McDonald Lake but live animals were
relatively uncommon sometimes. Live O. elrodi were 4-6 times more abundant than Discus
brunsoni near the talus surface in the microsite where the two species are sympatric. Among
the three sites, live individuals were found at a rate of 0. 1 67/min on 1 July at the type locality
co-occupied by D. brunsoni, 0. 1 74/min on 1 9 May at Lion Creek, and 0.350/min on 9 June at
Goat Creek; conditions were overcast, wet and 7-1 FC at the time of the searches (Hendricks

1 998, unpublished data). Population trends are unknown, but the species has persisted at the
type locality for a century following its discovery in 1 899 (Elrod 1 903a).

Current Status

A. Why Species is of Conservation Concern

The Carinate Mountainshell (Oreohelix elrodi) is a Species of Concern in Montana because it
is a local endemic so far documented at only three sites in the Mission and Swan ranges of Lake
County, despite several decades of collecting in the region by Drs. M. J. Elrod and R. B.
Brunson and their students (Frest and Johannes 1 995). Population size and trends are
unknown.

B. Threats

Habitat occupied by Oreohelix elrodi (low-elevation slopes of mixed conifers, especially
Douglas-fir, ponderosa pine and western larch) is threatened to some extent by logging, grazing,
and fire, although occupied habitat is often in talus surrounded by mixed coniferous forest.
Habitat requirements and food habits are poorly understood, however. Fire suppression efforts
(especially use of fire retardants) and talus destabilization (trail maintenance, modification) could
have negative impacts, as could chemical control of weeds.

C. Distribution Relative to Land Allocations

The type (and only) locality in the Mission Range is in the Confederated Salish and Kootenai
Tribes Mission Mountains Tribal Wilderness. A major hiking and packing trail bisects the site.
The Lion Creek site in the Swan Range occupies lands administered by Plum Creek Timber
Company and the Swan Lake Ranger District of the Flathead National Forest; a major hiking
trail bisects the site. The Goat Creek site in the Swan Range occupies lands administered by
the Swan Lake Ranger District of the Flathead National Forest. It is a small talus patch just
upslope from FS Road 9530 in an area where logging has occurred previously.

Figure 7. Distribution of Oreohelix strigosa berryi in Montana.

• Oreohelix strigosa berryi
^^/Continental Divide
US Forest Service

SPECIES: Oreohelix strigosa berryi (Berry's Mountainsnail)

Heritage Rank: G5T2, S1S2
Natural History

A. Taxonomy

Family: Oreohelicidae

Oreohelix strigosa berryi (Pilsbry, 1915)

Originally described as a subspecies oi Oreohelix cooper i but changed in 1 933 to a subspecies
of O. strigosa (Pilsbry 1933, Henderson 1936), with cooper i also reduced to a subspecies of
O. strigosa. External and internal anatomy indicates O. strigosa berryi is distinct to the
subspecies level (Pilsbry 1933, 1939, Frest and Johannes 1993). Beetle (1989) considered
this subspecies a form of O. pygmaea, but Frest and Johannes ( 1 993) separate the forms in the
Black Hills on the basis of shell morphology. Pilsbry (1 939) placed all Oreohelix in the
Xanthonycidae.

B. Species Description

Morphology: Pilsbry (1939) describes the shell as having " the same shape characteristic of O.
cooperi except that the last whorl is distinctly angular in front, the angle disappearing on the last
half or third, leaving the periphery rounded. Color cinnamon to snuff brown, from third whorl
profusely marked with white patches and narrow streaks; last whorl having a chocolate band
below the periphery . . . The surface is irregularly striate and shows traces of spiral striation in
places. Whorls 41/3, all convex. Embryonic shell of nearly two whorls, which are finely striate
and covered with very fine spirals, the last half of the second whorl having distinct spiral striae.
Umbilicus narrow, contained 5 Yi times in the diameter of the shell" (p. 445-446). Frest and
Johannes (1 993) add "full adult with about 5-5 1/4 whorls; shell low dome-shaped . . ." (p. 76).
Shell diameter 7-13 mm (types 9.3 and 9.4 mm); shell height of types 6. 1 and 6.3 mm (Pilsbry
1939). Intemalanatomy described in Pilsbry (1933, 1939).

Ecology: Found among small loose rock, shrubbery, and under creeping juniper (Juniperus
horizontalis) on west-facing canyon slopes at the type locality in the Big Snowy Mountains,
and under sticks and logs in moister locations in the same mountain range (Berry 1916). This
snail was present in the Mammoth area of Yellowstone National Park on a north exposure of
limey soil with plenty of cover, but neither very wet nor dry (Henderson 1 936). Substrate
typically is derived from limestone (Frest and Johannes 1 993, 1 995). In the Black Hills and
Bear Lodge Mountains of Wyoming and South Dakota, it occurs in mixed and open ponderosa
pine {Pinus ponderosa) forests with relatively thin litter, often with aspen (Populus

tremuloides) and birch (Betula) in the canopy, and violets (Viola) and Canada dogwood
(Cornus canadensis) in the understory (Frest and Johannes 1 993); the deciduous tree
component was relatively important for the occurrence of this subspecies.

C. Range and Known Sites

Oreohelix strigosa berryi is documented from several locations in and near the Big Snowy
Mountains of Fergus and Golden Valley counties, Montana (Fig. 7, Appendix B), and more
recently (Hendricks unpublished data) from the Judith Mountains, also in Fergus County, and
the vicinity of Montanopolis in the Absaroka Mountains, Park County (Frest and Johannes
1995); elevation ranges from 1295-2438 m (4250-8000 ft). Also documented in Wyoming in
Yellowstone National Park near Mammoth (Henderson 1933,1936, Pilsbry 1 93 9) and in the
Black Hills National Forest of Wyoming and South Dakota (Frest and Johannes 1 993).

D. Species Abundance

Oreohelix strigosa berryi in Montana has been fully documented only in the Big Snowy
Mountains. Population sizes are not reported for any of the Montana locations, nor have most
of these sites been revisited in recent decades. Berry (1916) found it to be the most
conspicuous land snail near the mouth of Swimming Woman Creek Canyon in the Big Snowy
Mountains. Colonies outside of the Big Snowy Mountains generally appear to be small and
isolated (Frest and Johannes 1 993), although the recent collection of shells in the Judith
Mountains (Hendricks unpublished data) indicate colonies, some fairly large, may be present in
some of the other "island mountains ranges" of eastern Montana. Henderson (1 936) said the
species occurred in abundance near Mammoth in Yellowstone National Park, Wyoming.
Population trends are unknown for any locality.

Current Status

A. Why Species is of Conservation Concern

Berry's Mountainshell {Oreohelix strigosa berryi) is a Species of Concern in Montana because
it is a relict subspecies so far documented in Montana at ten localities in three mountain ranges,
and only present in two additional areas outside of Montana in Wyoming and South Dakota
(Yellowstone National Park, Black Hills National Forest) despite several decades of collecting
in the region by Dr. R. B. Brunson and Stillman Berry. Population size and trends in Montana
are unknown, but outside of Montana where intensive surveys have been undertaken in recent
years (Frest and Johannes 1 993) this subspecies appears to exist in only a few small colonies.

B. Threats

Habitats occupied by Oreohelix strigosa berryi are may be threatened by logging and grazing,
and possibly weed control and mining, but most documented localities have not been revisited in
decades, so current threats are unknown. Fire and fire suppression efforts could have negative
impacts (numerous dead shells found in the Judith Mountains were in a decade-old bum).

Logging and grazing threaten the Black Hills National Forest colonies (Frest and Johannes
1 993). Habitat requirements and food habits are poorly understood. Colonies may be local
and small.

C. Distribution Relative to Land Allocations

The type locality (Swimming Woman Creek Canyon) and all other known locations (six total) in
the Big Snowy Mountains are on lands administered by the Musselshell Ranger District of the
Lewis and Clark National Forest. Two other sites north of the Big Snowy Mountains
apparently are on private and possibly state land. The site in the Judith Mountains is on land
administered by the Lewistown Field Office of the Bureau of Land Management. The Park
County site is on land administered by the Livingston Ranger District of the Gallatin National
Forest.

Figures. Distribution of Oreohelix yavapai mariae in Montana.

• Oreohelix yavapai maria^
^^/Continental Divide
US Forest Service

SPECIES: Oreohelix yavapai mariae (Gallatin Mountainsnail)

HeritageRank:G4?Tl,Sl

Natural History

A. Taxonomy

Family: Oreohelicidae

Oreohelix yavapai mariae Bartsch, 1916

The original description of this taxon by Bartsch (1916) and his placement as a subspecies of
Oreohelix yavapai are still valid. Pilsbry (1 939) and Frest and Johannes (1 995) consider this
taxon distinct from another subspecies, O. yavapai extremitatis, that is present in the Big Horn
Mountains, Wyoming, and the nearby Bridger Range, Montana. Pilsbry (1 939) placed all
Oreohelix in the Xanthonycidae.

B. Species Description

Morphology: Bartsch (1916) describes the shell as "decidedly depressed helicoid, almost
lenticular, flesh colored, with a narrow brown band on the upper surface, which is a little nearer
the peripheral cord than the suture, and a second even narrower one bordering the peripheral
cord on the lower surface. Nuclear whorls scarcely differentiated from succeeding turns,
bearing the same sculpture as the adult whorls, but a little less strongly expressed. Periphery of
the whorls provided with a cord-like keel, which becomes somewhat weakened on the last
quarter of the last turn. Entire surface both above and below marked by slender thread-like
incremental lines and fine spiral striations; last whorl slightly descending near the aperture. Base
broadly, openly umbilicated, well rounded; a little more convex at the umbilical wall than at the
lateral margin. Aperture very oblique, oval; peristome neither thickened nor refiected at the
edge; parietal wall strong, rendering the peristome complete" (p. 331). Shell diameter 20.7 mm
(1 8.3-22.5 mm; n = 9); shell height 9.2 mm (8.2-1 0.0 mm; n = 9); number of whorls 5.5 (5.2-
5.6; n = 9). Internal anatomy not described.

Reproductive biology: Presumably hermaphroditic, but the intemal anatomy is not described.
There is no description of reproductive behavior and its seasonal occurrence. Life span is
unknown. Age/size at reproductive maturity is unknown.

Ecology: Present on a south-facing slope in grassy habitat near the base of a limestone outcrop
(L. Fairbanks personal communication). Nothing else about the ecology of this species is
known or described.

C. Range and Known Sites

Known only from the type locality at Squaw Creek near the mouth of Gallatin Canyon in the
Gallatin Range, Gallatin County, Montana (presumably above the confiuence of Squaw Creek

with the Gallatin River) at 1 707 m (5600 ft) elevation (Fig. 8, Appendix B).

D. Species Abundance

No inft)nnation. Specimens have been collected at the type locality as recently as 1 976 (L.
Fairbanks personal communication). Population trends are unknown.

Current Status

A. Why Species is of Conservation Concern

The Gallatin Mountainshell (Oreohelix yavapai mariae) is a Species of Concern in Montana
because it is known only fi-om a single locality. Decades of collecting across Montana by R. B.
Brunson, Stillman Berry, and others have revealed no additional colonies, although additional
searches in the Gallatin Range may result in discovery of additional populations.

B. Threats

Logging and road construction along the Gallatin River and Squaw Creek are likely the main
threats that could impact the only known population (Frest and Johannes 1 995). Fire, fire
suppression, weed control, and grazing could also have negative impacts.

C. Distribution Relative to Land Allocations

The only known site is on lands administered by the Bozeman Ranger District of the Gallatin
National Forest.

Figure 9. Distribution of Hemphillia danieisi in Montana.

• Hemphillia danieisi
^^/Continental Divide
US Forest Service

SLUGS
SPECIES: Hemphillia danielsi (Marbled Jumping-slug)

Heritage Rank: G1G3, S1S3
Natural History

A. Taxonomy

Family: Arionidae

Hemphillia danielsi Vanatta, 1914

The original species description by Vanatta ( 1 9 1 4, see also Pilsbry 1 948) and placement in the
Arionidae are still valid. This species is the eastern-most member of a small genus restricted to
the Pacific Northwest.

B. Species Description

Morphology: Vanatta {\9\AJn Pilsbry 1948) describes Hemphillia danielsi as "sluglike, with
the shell partly exposed, and the mantle elevated into a visceral hump, as usual in this genus.
The color in formalin is yellowish-gray with bluish-black markings, but in alcohol it is white with
black maculations. The shell pore is about one-third the length of the mantle. The posterior
part of the foot is narrow, with a dorsal median groove and a tail pore" (p. 747). Length 3 .4 cm
(Vanatta 1914, Pilsbry 1948); Pilsbry considered this individual an immature. A recent
specimen collected along Mill Creek (Appendix B) measured 6.4 cm (Hendricks unpublished
data), and Pilsbry (1948) quotes L.E. Daniels as stating that the living slug is "about two inches
[5.1 cm] long, with a high hump showing the shell" (p. 748). In live animals, and some
preserved specimens, the tail portion of the foot is laterally compressed, keeled, and tipped with
a horn-like projection (Hendricks personal observation; see also photos oiH dromedarius in
Ovaska et al. 2002). Internal anatomy is described in Vanatta (1914) and Pilsbry (1948).

Reproductive biology: Hermaphroditic, based on internal anatomy; the congeneric Malone
Jumping-slug {Hemphillia malonei) is hermaphroditic, but spermatophore delivery is
sometimes non-reciprocal (Leonard and Ovaska 2002). There is no description of the
reproductive behavior and biology of /Z danielsi, but it may be similar to H malonei for which
there exists a recent description of breeding behavior in captivity (Leonard and Ovaska 2002).
H malonei captive-raised from eggs reached sexual maturity in the first year.

Ecology: There are few descriptions of the habitat occupied by this species. Frest and Johannes
(1 995) indicate that moderate-elevation ponderosa pine forest (Pinus ponderosa) is
characteristic; moist valley, ravine, gorge, or talus sites are preferred (i.e., low on slopes near
water). This description is supported by more recent observations (W. Leonard, B. Maxell, H.
Reise personal communications). Each of the correspondents reported finding Hemphillia
danielsi in riparian areas very near water (Appendix B). Sites included an overstory of

deciduous and coniferous trees and shrubs (Picea engelmanii, Pseudotsuga douglasii,
Populus, Alnus). Rock or soils at known sites have not been described, but igneous rock
types dominate the range of this species.

C. Range and Known Sites

Hemphillia danielsi is virtually a Montana endemic known only from the eastern side of the
Bitterroot Mountains in Ravalli County (Fig. 9, Appendix B), with the exception of one or two
records a short distance west of the Bitterroot crest into Idaho (see below); the type locality is
at Camas Creek. Five total sites in Montana have been documented, from Mill Creek in the
north to Medicine Hot Springs in the south at elevations between 1341-1 524 m (4400-5000
ft). Two of the five sites (Bunkhouse Creek, Mill Creek) were first discovered in 2001 .
Additional populations in the Bitterroot Mountains are likely to be discovered as more surveys
are conducted. Hemphillia danielsi has been documented infrequently in surveys on the Idaho
side of the Bitterroots (Frest and Johannes 1 995); the first Idaho record apparently is that of
Webb (1959) near Lolo Pass, and Hemphillia collected more recently at the confiuence of
Apgar Creek with the Lochsa River in Idaho County may be this species (W. Leonard personal
communication).

D. Species Abundance

No information. Animals were collected at the type locality as recently as 2001 (H. Reise
personal communication), four individuals were found at the Bunkhouse Creek site in 200 1 , two
individuals at the Mill Creek site in 2001 (W. Leonard, B. Maxell personal communications).

Current Status

A. Why Species is of Conservation Concern

The Marbled Jumping-slug {Hemphillia danielsi) is a Species of Concern in Montana because
it is nearly a Montana endemic so far documented at but five sites in the Bitterroot Mountains of
Ravalli County, despite several decades of collecting in the region by Dr. R. B. Brunson and
students (Frest and Johannes 1 995). Population sizes and trends are unknown.

B. Threats

Habitat occupied by Hemphillia danielsi (moderate elevation mixed conifer forest, often near
water) is threatened by logging, grazing, fire, and possibly weed control and rural home
development. The impact of fire retardant on this and other terrestrial moUusks is not known.
Little is known about this species, including its sensitivity to disturbance.

C. Distribution Relative to Land Allocations

Probably four, and possibly all, of the known sites in Montana (Appendix B) are on lands
administered by the Stevensville, Darby, and Sula Ranger Districts of the Bitterroot National
Forest. The specific collection site at Medicine Hot Springs is uncertain and may be on private
land.

Figure 10. Distribution of Magnipelta mycophaga in Montana.

• Magnipelta mycophaga
^^/Continental Divide
US Forest Service

^^H^

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^^^^^^^^Hi^^^LVf

MlRSLF^i^^^^^^l

^^^^^^^^HRr l^F^

Hi^^

F-_ ^^j fc 'L_Ji^3Liia l^^^^^^^^B

'•' '^\^^^^|

'■jAmW^^HH

SPECIES: Magnipelta mycophaga (Spotted Slug)

Heritage Rank: G2G3, S1S3
Natural History

A. Taxonomy

Family: Arionidae

Magnipelta mycophaga Pilsbry, 1 953

The original species description by Pilsbry (1 953, see also Pilsbry and Brunson 1 954) and
placement in the Arionidae are still valid, although Webb and Russell ( 1 977) noted possible
alliance with the Camaenidae, based on anatomical features. The genus is monospecific and
restricted to the interior Pacific Northwest.

B. Species Description

Morphology: Does not closely resemble any other described North American slug (Frest and
Johannes 1 995). In the original description, based on an immature specimen, Pilsbry (1 953)
states the appearance of Magnipelta mycophaga as "characterized by the structure of the
mantle and foot ... the mantle covering far the greater part of the upper surface. The mantle is
free anteriorly for more than one-fourth of its length, smooth, chamois colored with an irregular
black stripe on each side and elsewhere unevenly spotted with black. The quite short
respiratory slit is slightly post-median on the right side. Length of mantle 1 6 mm. The foot is
lighter colored than the mantle, spotted with black on the flanks posteriorly. It has an irregular
polygonal impressed reticulation. The pedal margin is quite narrow, the pedal grooves meeting
above the tail without any trace of a caudal pore. The sole is transversely wrinkled at the sides,
the middle third smoother, but it is not distinctly tripartite" (p.37-38). In a second preserved
and partly contracted specimen collected at a later date the mantle measured 34 mm in length,
free anteriorly for 9 mm and posteriorly for 5 mm (Pilsbry and Brunson 1 954); in this specimen
the slit to the pneumostome was 1 5 mm from the anterior end of the mantle. Magnipelta
mycophaga can be a moderately large slug; a May sample of 12 extended animals ranged from
1 .5-6.7 cm (mean = 3.6 cm), a June sample of 20 animals from the same locality ranged from
1 .4-8.0 cm (mean = 4.3 cm) (Brunson and Kevem 1 963). Two other individuals from widely
separate localities measured ca. 7.0 cm and 8.0 cm (Hendricks personal observation). Internal
anatomy is described and illustrated in Pilsbry (1 953), Pilsbry and Brunson (1 954), and Webb
and Russell (1977).

Reproductive biology: Hermaphroditic, based on internal anatomy (Pilsbry and Brunson 1 954,
Webb and Russell 1 977). There is no description of reproductive behavior and its seasonal
occurrence; Pilsbry and Brunson (1 954) suggest reproduction may occur early in the year,
based on finding immature animals in late May. Life span is unknown. Age/size at reproductive
maturity is unknown, but Pilsbry (1 953) mentioned that the type specimen, with a mantle length

of 1 6 mm, was immature with a genital system only partly developed, the ducts thread-like and
extremely fragile.

Ecology: Found in a variety of low- to mid-elevation sites, often with water in the general
vicinity. Moist, cool sites in relatively undisturbed forest with an intact duff layer, such as are
found in moist valleys, ravines, and talus areas, are preferred (Frest and Johannes 1 995).
Forest canopy composition at sites includes Picea engelmannii, Pseudotsuga menziesU,
Pinus ponderosa, Pinus albicaulis, Larix occidentalism Abies lasiocarpa, dind Abies
grandis, often with Alnus present (Appendix B; Pilsbry and Brunson 1 954, Brunson and
Kevem 1 963, Hendricks personal observation); spruce-fir appears to be the most frequent
forest association. The Thompson River, Sanders County location (Appendix B) is an area of
near-minimal tree canopy cover, though brushy, indicating slugs may move some distance when
conditions are favorable, or that the species can persist in some relatively exposed and
disturbed habitats. Often found on the ground under pieces of loose bark, logs, loose stones,
and in rotted wood; surface active on cool (10-1 6°C), wet and overcast days, probably most
active at night. Feeds on green plant material, possibly including moss (Brunson and Kevem
1 963); the type specimen was found feeding on one of the larger fungi, hence the specific Latin
name of the species (Pilsbry 1953).

C. Range and Known Sites

Magnipelta mycophaga is found in northwestern Montana, northern Idaho, northeastern
Washington (Frest and Johannes 1 995), and probably adjacent regions of British Columbia. In
Montana, this species has been documented at six localities in four counties: Flathead, Lincoln,
Missoula, and Sanders (Fig. 1 0, Appendix B). Aprobable seventh Montana locality, mentioned
in Pilsbry and Brunson (1 954) as in the Blackfoot Valley near Bonner, Missoula County, was
too vague to be mapped and was not included in Appendix B; the Lincoln County site, centered
on McGuire Creek in the Ural-Tweed Bighorn Sheep range (see Forrester 1 960, 1 962) is also
poorly described in the literature, but included in Appendix B because it represents a location
far removed from other reported sites. This slug species has been found at elevations between
762- 1585m (2500-5200 ft) in Montana, and up to ca. 1 829 m (6000 ft) in northeastern
Washington (T. Burke personal communication). The Deer Creek, Missoula County, colony
site is described by Brunson and Kevem (1 963) as about 400 m (440 yds) in length. Additional
populations in northwestern Montana are likely to be discovered with additional survey effort,
given that half of the known Montana sites were found since 1 998.

D. Species Abundance

Almost no information. In 1 954 at the Deer Creek, Missoula County site 1 9 individuals were
found in May and 1 0 in June. Counts at the same locality in 1 957 were 29 April: 1 , 5 May: 1 ,
10 May: 12, 1 June: 18, 7 June: 86, 23 June: 20, 20 July: 4, 4 August: 3, 5 September: 10, 22
September: 1 (Brunson and Kevem 1 963), indicating that the species may be relatively
abundant in some localities. Numbers reported at other sites are 1 -2 individuals, but none of
these sites have been visited more than twice, nor searched thoroughly like the Deer Creek site.

Apparently the Deer Creek site has not been revisited in recent decades, but the species
persists (as of 2001) at the Little Park Creek site only 5.6 km (3.5 mi) to the south.

Current Status

A. Why Species is of Conservation Concern

The Spotted Slug {Magnipelta mycophaga) is a Species of Concern in Montana because it is
a regional endemic so far documented at six sites in four Montana counties, despite several
decades of collecting in the region by Dr. R. B. Brunson and his students (Frest and Johannes
1 995), and limited collecting by others in recent years. Population sizes and trends are
imknown.

B. Threats

Habitat occupied by Magnipelta mycophaga (moderate elevation mixed conifer forest,
especially spruce-fir, often near water) is threatened by logging, grazing, fire, possibly rural
home development, and possibly recreation and weed control. The impact of fire retardant on
this and other terrestrial moUusks is not known. Little is known about this species, including
sensitivity to disturbance.

C. Distribution Relative to Land Allocations

Documented Montana sites are on lands administered by the Cabinet Ranger District, Kootenai
National Forest (1 site), Rexford Ranger District, Kootenai National Forest (1 site). Glacier
View Ranger District, Flathead National Forest ( 1 site), Missoula Ranger District, Lolo National
Forest (1 site). Plum Creek Timber Company (2 sites).

Figure 11. Distribution of Zacoleus idahoensis in Montana.

• Zacoleus idahoensis
^^/Continental Divide
US Forest Service

SPECIES: Zacoleus idahoensis (Sheathed Slug)

Heritage Rank: G3G4, S2S3
Natural History

A. Taxonomy

Family: Arionidae

Zacoleus idahoensis Pilsbry, 1903

The original species descriptions by Pilsbry (1 903, 1 948) and placement in the Arionidae are
still valid. The genus is monospecific and restricted to the interior Pacific Northwest.

B. Species Description

Morphology: Pilsbry (1 948) states "In the field this inconspicuous slug might be mistaken for
Deroceras, having a tripartite sole and postmedian pneumostome . . . , but it differs by the
weakly carinate back" (p. 732). The species is black to dark brown (deep grayish olive) on the
mantle and back; the sole is cream- white. The reticulation on the posterior half of the body
(tail) is indistinct, predominately with longitudinal lines above and oblique on the sides. The
back of the mantle is keeled, the tail strongly so. The oval mantle somewhat exceeds about
one-third the length of the body; the pneumostome is present in the posterior half of the mantle
margin. The foot-margin is rather narrow. There is no caudal pore, but the tail appears
somewhat abruptly truncate in profile. The shell is completely buried in the mantle. Body
lengths of two animals from Idaho were 1 .4 cm (mantle length 5.5 mm) and 2.3 cm (Pilsbry
1 948). Internal anatomy is described and illustrated in Pilsbry (1 948).

Reproductive biology: Hermaphroditic, based on internal anatomy (Pilsbry 1 948). There is no
description of reproductive behavior and its seasonal occurrence. Life span is unknown. Age/
size at reproductive maturity is unknown.

Ecology: Habitat descriptions are limited. Most occurrences in Idaho are in moist microsites in
relatively intact Pseudotsuga menziesii, Pinus ponderosa, and Picea engelmannii forests
(Frest and Johannes 1 995) in moist valleys, ravines, and talus on both north- and south-facing
slopes. Pilsbry (1 948) lists collections made in meadows and cedar swamps, white pine stands,
spruce valleys, rockslides, and near springs. Populus and Alnus present at several north Idaho
locations (H. Reise personal communication). Rocky substrates include sedimentary, igneous
and metamorphic types; the Prospect Creek, Sanders County, Montana site (Appendix B) is
described as composed of calcareous shales (Pilsbry 1 948). Herbivorous; food includes the
epiphytic cryptogam Frullania (Pilsbry 1948).

C. Range and Known Sites

Zacoleus idahoensis has so far been documented only in northern Idaho and northwestern
Montana. In Montana, records exist for four widely separated sites in four counties: Granite,
Lake, Lincoln, and Sanders (Fig. 1 1 , Appendix B). Three of the localities (Kootenai Falls, Wild
Horse Island, Squaw Rock Campground) were discovered during surveys of moUusks on
bighorn sheep ranges (Forrester 1 960, 1 962); specific collection sites provided by Forrester
(1 960, 1 962) are somewhat vague. The Prospect Creek site in Sanders County was the only
one known in Montana at the time of publication of Pilsbry 's monograph (Pilsbry 1 948).
Reported elevations of sites inldaho range between 488- 1707 m (1600-5600 ft) (Pilsbry
1948, H. Reise personal communication), the Montana sites range between 640-1494 m
(2100-4900 ft).

D. Species Abundance

No information, although it appears to still be present at several sites in Idaho (Frest and
Johannes 1995), including as recently as 2001 (H. Reise personal communication). Pilsbry
(1 948) stated it was often abundant. Montana sites have not been revisited in decades.

Current Status

A. Why Species is of Conservation Concern

The Sheathed Slug {Zacoleus idahoensis) is a Species of Concern in Montana because it is a
regional endemic so far documented at only four sites in four counties, none of which has been
revisited in recent decades. Population sizes and trends are unknown, but habitat loss has
occurred throughout the historic range (Frest and Johannes 1 995).

B. Threats

Habitat occupied by Zacoleus idahoensis (moist sites in moderate elevation mixed conifer
forest) is threatened by logging, grazing, fire, trail and highway expansion, possibly rural home
development, and possibly recreation and weed control. The impact of fire retardant on this
species and other terrestrial moUucks is unknown. Little is known about the biology of this
species, including its sensitivity to disturbance.

C. Distribution Relative to Land Allocations

Documented Montana sites are on lands administered by the Libby Ranger District, Kootenai
National Forest (1 site), Thompson Falls Ranger District, Lolo National Forest with some
private in-holdings (1 site), Philipsburg Ranger District, Beaverhead-Deerlodge National Forest
(1 site), and State of Montana (1 site); the Beaverhead-Deerlodge site may be on Bureau of
Land Management lands.

Figure 12. Distribution of Polygyrella polygyrella in Montana.

• Polygyrella polygyrella
^^/Continental Divide
US Forest Service

SPECIES ON REVIEW
SNAILS

SPECIES: Polygyrellapolygyrella (Humped Coin)

Heritage Rank: GU,SU
Natural History

A. Taxonomy

Family: Ammonitellidae

Polygyrellapolygyrella (Bland and Cooper, 1 861)

Originally described by Bland and Cooper (1 861) as Helix polygyrella, with later placement
by Cooper (1 868) as Helicodiscus polygyrella. The genus is monospecific and restricted to
interior Pacific Northwest.

B. Species Description

Morphology: Pilsbry (1 939) describes the shell as "discoidal, with wide umbilicus about one-
third of the diameter; of a pale greenish yellow tint, somewhat translucent, glossy. Spire varies
from nearly flat to convex, of very closely coiled whorls. Initial 2 to 3 whorls smooth, the rest
with rather strong radial ribs which become obsolete near the aperture . . . Suture impressed,
descending a little to the aperture. Umbilicus well-like, enlarging in the last half whorl. Aperture
lunate-triangular, the peristome thickened within; parietal wall with an erect, triangular tooth
connected with the ends of the lip. Within the last whorl there are one or two radial rows of
three teeth each, visible through the shell" (p. 558-559). Shell diameter of 26 Idaho specimens
ranged from 8.6 to 1 0.5 mm (mean = 9.7 mm), but diameter of specimens from other localities
ranges to 13.0 mm. Number of whorls varies from 6.5 to 8.5. Shell height is from 40-50% of
the diameter. Diameter of the type specimen, presumably from Sanders County, Montana, is
11.5 mm, height 5 mm (Bland and Cooper 1 861). Internal anatomy is illustrated and described
in Pilsbry (1939).

Reproductive biology: Hermaphroditic, based on internal anatomy (Pilsbry 1 939). There is no
description of reproductive behavior and its seasonal occurrence. Life span is unknown. Age/
size at reproductive maturity is unknown.

Ecology: Often found in moist forests of Pseudotsuga menziezn and Picea engelmannii, often
in association with outcrops and talus of various rock types (Bland and Cooper 1 861 , Pilsbry
1 939, Frest and Johannes 1 995). Inhabits moss and decaying wood in dampest areas of forest
cover (Bland and Cooper 1 861 , Cooper 1 868); moist valley, ravine, and talus sites are

preferred, apparently near water (Frest and Johannes 1 995). There is no information on food
habits. Associated moUusk species include the slugs Zacoleus and Hemphillia.

C. Range and Known Sites

Polygyrellapolygyrella is found in northwestern Montana, northern Idaho, and the Blue
Mountains of extreme southeastern Washington and extreme northeastern Oregon (Pilsbry
1 939, Frest and Johannes 1 995). The eastern slope of the Coeur d' Alene Mountains, Sanders
County, Montana is considered the type locality (Pilsbry 1 939, Frest and Johannes 1 995),
although the original description (Bland and Cooper 1861) places the locality only as the eastern
slope of the Coeur d' Alene Mountains (later identified as Montana by Cooper 1 868), which led
others to place the type locality in Idaho (Elrod 1 902, Henderson 1 93 6, Coan 1981). The type
locality may actually be somewhere in Mineral County; Cooper traveled along the road
constructed by Lt. John Mullen up the St. Regis River from its confluence with the Clark Fork
River at St. Regis (Coan 1981), passing through Mullen Gulch. In Montana, this species is
currently recognized from four sites at elevations between 792 and 1097 m (2600 and 3600 ft)
in two counties: Sanders and Mineral (Fig. 12, Appendix B). However, Elrod (1902) and
Pilsbry (1 939) note an unique variety oi Polygyrellapolygyrella, named montanensis, found in
the "Deer Lodge Valley" sometime prior to 1 902 by Mr. Hemphill. The locality is not listed in
Appendix B, but indicates that the species may also be present in Powell or Deer Lodge
counties. Additional locations are possible. Requirements may be similar to Radiodiscus
abietum/judging by the similarity in their distributions.

D. Species Abundance

No information. A few Idaho populations were still extant in the early 1 990 's (Frest and
Johannes 1 995), but there is no indication that the species has been found in Montana, even at
the known localities, in recent decades.

Current Status

A. Why Species is of Conservation Concern

The Humped Coin (Polygyrellapolygyrella) is a Species on Review in Montana because it is a
regional endemic of unknown status so far documented at only four (possibly five) sites in two
Montana counties, despite several decades of collecting in the region by Dr. R. B. Brunson and
his students. There is evidence of extirpations and population declines in other states (Frest and
Johannes 1 995). Population sizes and trends in Montana are unknown, and there is no
evidence that the snail has been documented in Montana in recent decades.

B. Threats

Logging and grazing over most of the known range are probably the greatest threats, through
alteration of appropriate habitat. However, alteration of habitat from fire, highway and road

construction, rural home development and land clearing could represent threats, as could fire
suppression retardants and chemical methods of weed control.

C. Distribution Relative to Land Allocations

Documented Montana sites are on lands administered by the Thompson Falls Ranger District,
Lolo National Forest with private in-holdings (1 site), Superior Ranger District, Lolo National
Forest (1 possibly 2 sites), and 1 site on private land near Thompson Falls. The vague locality
for the Deer Lodge Valley site precludes assigning ownership to the lands where it was found.

Figure 13. Distribution of Radiodiscus abietum in IVIontana.

• Radiodiscus abietum
^^/Continental Divide
US Forest Service

SPECIES: Radiodiscus abietum (Fir Pinwheel)

Heritage Rank: GU,SU
Natural History

A. Taxonomy

Family: Helicodiscidae
Radiodiscus abietum Baker, 1930

The original designation and placement remain valid and unchanged (Pilsbry 1 948, Frest and
Johannes 1995).

B. Species Description

Morphology: Pilsbry (1948) describes the shell as "small (6.7 mm), subdiscoid, umbilicate, thin,
but with heavy, almost opaque epidermis. Color: light chocolate-brown. Whorls: maximum 5
3/4, gradually increasing in diameter, well rounded but markedly flattened above; last slightly
descending; suture deep. . . Sculpture of later whorls: growth-riblets quite low but angular and
sharply defined, markedly and broadly concave below periphery . . . Umbilicus: about 6. 1 times
in maj . diam. of shell; with almost vertical walls. Aperture: crescentric, slightly oblique . . ." (p.
658, 660). Shell diameter is 4.9 to 6.7 mm, shell height 2.6 to 3.2 mm, with 5.0 to 5.75 whorls
(Pilsbry 1 948). Diameter of 1 5 "representative" shells from seven Montana localities ranged
from 2.5 to 7.0 mm (mean = 5.1 mm); shell height ranged from 1 .4 to 4.0 mm (mean = 2.8
mm); number of whorls ranged from 3 .5 to 6.0 (Brunson and Russell 1 967). Internal anatomy
is illustrated and described in Pilsbry (1 948).

Ecology: Surprisingly little detailed information is available. Most often found in moist and rocky
Douglas-fir (Pseudotsuga menziesii) forest at mid-elevations in valleys and ravines (Frest and
Johannes 1 995). At some Montana locations. Western Red Cedar (Thuja plicata) formed the
canopy. Often this species is found in or near talus of a variety of rock types or under fallen
logs (Pilsbry 1948, Brunson and Russell 1967, Frest and Johannes 1995).

C. Range and Known Sites

Radiodiscus abietum is known from extreme northeastern Oregon, extreme northeastern and
southeastern Washington, northern Idaho, and northwestern Montana (Pilsbry 1 948, Frest and
Johannes 1995). In Montana, this species has been found at 13 sites in six counties: Lake,
Lincoln, Mineral, Missoula, Ravalli, and Sanders (Fig. 1 3, Appendix B). All sites are west of

the Continental Divide (Brunson and Russell 1967) at elevations from 823 to 1707 m (2700-
5600 ft). Requirements may be similar to Polygyrellapolygyrella/judgmg by the similarity of
their distributions.

D. Species Abundance

No information. Usually only single individuals were collected at the Montana sites (Brunson
and Russell 1 967). Frest and Johannes (1 995) consider Radiodiscus abietum a species that
was once common and widespread that is now much more rare.

Current Status

A. Why Species is of Conservation Concern

The Fir Pinwheel {Radiodiscus abietum) is a Species on Review in Montana because it is a
regional endemic of unknown status, so far documented at 1 3 sites in six Montana counties,
despite several decades of collecting in the region by Dr. R. B. Brunson and his students. There
is evidence of extirpations and population declines in other states (Frest and Johannes 1 995).
Population sizes and trends in Montana are unknown, and there is no evidence that the snail has
been documented in Montana in recent decades.

B. Threats

Logging and grazing over most of the known range are probably the greatest threats, through
alteration of appropriate habitat. However, alteration of habitat from fire, highway and road
construction, rural home development and land clearing could represent threats, as could fire
suppression retardants and chemical methods of weed control.

C. Distribution Relative to Land Allocations

Documented Montana sites are on lands administered by the Confederated Salish and Kootenai
Tribes (3 sites). State of Montana (1 site, but bounded closely by the Missoula Ranger District,
Lolo National Forest), Superior Ranger District, Lolo National Forest (1 site). Darby Ranger
District, Bitterroot National Forest (3 sites). Cabinet Ranger District, Kootenai National Forest
(2 sites), Fisher River Ranger District, Kootenai National Forest (1 site), Libby Ranger District,
Kootenai National Forest (1 site), and the Rexford Ranger District, Kootenai National Forest
(1 site).

Figure 14. Distribution of Udosarx lyrata in Montana.

• Udosarx lyrata
^^/Continental Divide
US Forest Service

SLUGS

SPECIES: Udosarx lyrata (Lyre Mantleslug)

Heritage Rank: G?TU, SU {U. I lyrata);
G7TI, SI (airusselli)

Natural History

A. Taxonomy

Family: Arionidae

Udosarx lyrata Webb, 1959

The original species determination and name (Webb 1 959) are still valid, although Udosarx
lyrata is now included in the Arionidae instead of Webb's (1959) tentative placement in the
Philomycidae and later placement (Russell and Webb 1 980) with the Oreohelicidae. Udosarx
lyrata russelli is a subspecies recognized by Russell and Webb (1 980), however, they
suggested that the subspecific designation might become useless once new material from
additional localities is available for study. Because Webb's (1 959) species description did not
include a subspecies name, the original material was named Udosarx lyrata lyrata by Russell
and Webb (1 980). The genus is monospecific and restricted to the interior Pacific Northwest.

B. Species Description

Morphology: Webb (1 959) notes that the external form of Udosarx lyrata is "much as in
Zacoleus, mantle more elongate, back more carinate. Respiratory pore posterior, and
posterior-edge of mantle notched (as in Zacoleusy (p. 22). Udosarx differs from Zacoleus
especially in the shape of the radular teeth. Webb (1 959) continues that Udosarx is about half
as large as sexually mature Zacoleus. The body is "bluish gray with a lighter tawny zone on the
keel of the back. Grooves on the body darker than adjoining areas; 7-8 grooves from posterior
mid-dorsum to posterior-edge of respiratory pore, much as in Zacoleus. Mantle with blackish
lateral lines. Mid-mantle to front-edge with black punctuations vaguely delineating a grid
pattern. Right line is more sinuous than the left, and the two lateral lines for a lyre-shaped
symbol — Whence the species name, lyrata. The intensity of coloration may vary" (p. 22).

An alcohol-preserved specimen of Udosarx lyrata russelli measured 2.4 cm in length (Russell

and Webb 1 980). For this subspecies, "the head and neck uniformly dark but not black

The mantle is attached far back, so that the anteriorly a long free-lobe overlies the neck. The
central area of the fore-half of the mantle bears a number (18-30) of scattered black dots and
bars; unlike the holotype, the black lines of the upper sides extend forward to almost the front
edge of the mantle. Otherwise the lines are as in the holotype, diverging from each other in very
short arcs to give the lyre shape. The posterior mantle-edge is deeply notched . . . The
respiratory pore is posterior and on the right edge of the mantle. The mantle covers somewhat

less than half the body, which is moderately carinate (not keeled) dorsally. The tail-tip is acutely
pointed. . ." (p. 8). Internal anatomy is illustrated and described in Webb (1 959) and Russell
and Webb (1 980); the latter publication also includes photographs of live animals that clearly
show the lyre-pattern on the mantle.

Reproductive biology: Hermaphroditic, based on internal anatomy (Webb 1959, Russell and
Webb 1 980). Courtship and copulation were observed in captive animals in November
(Russell and Webb 1 980). Otherwise there is no description of reproductive behavior and its
seasonal occurrence. Life span is unknown. Age/size at reproductive maturity is unknown,
although presumably the individual 2.4 cm in body length (Russell and Webb 1 980) was mature.

Ecology: Found in moist mixed-conifer subalpine forest, preferably in moist valleys, ravines, and
talus sites (Webb 1 959, Frest and Johannes 1 995). Also found in riparian areas with a canopy
of Picea engelmannii, Pseudotsuga menziesn, Populus andAlnus (W. Leonard personal
communication). The subspecies U. I ra^^^/// was found in south-facing open P/a2i/^
ponderosa forest with little undergrowth (Russell and Webb 1 980). At all sites, individuals
were located on the undersurfaces of fallen logs or within nearly completely rotten logs, and
under rocks. Animals were active in wet and cold (1 0°C [50°F]) conditions (Webb 1 959,
Russell and Webb 1 980); captive animals preferred temperatures <21 °C (70°F).

C. Range and Known Sites

Udosarx lyrata has so far been documented only in northern Idaho and northwestern Montana
(Frest and Johannes 1 995). The type locality is near Lolo Pass, but on the Idaho side (Webb
1 959). In Montana, records exist for only three sites in two counties: Missoula and Ravalli (Fig.
1 4, Appendix B). The two Missoula County sites, discovered in 1 965 and 1 966 near Potomac
and Gold Creek (Russell and Webb 1 980), are far from the Ravalli County site, discovered at
Bunkhouse Creek in the Bitterroot Mountains in 200 1 (W. Leonard personal communication).
Reported elevations are 1067-1524 m (3500-5000 ft). Additional locations are likely to be
discovered.

D. Species Abundance

Little information. Only one individual was found at the Ravalli County site (W. Leonard
personal communication). Russell and Webb (1980) reported finding 1 7 individuals at the
Potomac, Missoula County, site on 3 May 1 965, several individuals on 2 1 November 1 965,
and 3 individuals on 5 May 1 966. Two individuals were found at the Gold Creek, Missoula
County, site on 5 May 1 966. Russell (Russell and Webb 1 980) collected an individual at the
species type locality in 1 966, almost 1 2 years after it was first found there (Webb 1 959).
Known to be present at some Idaho sites in recent years (Frest and Johannes 1 995, W.
Leonard personal communication).

Current Status

A. Why Species is of Conservation Concern

The Lyre Mantleslug (Usosarx lyrata) is a Species on Review in Montana because it is a
regional endemic of unknown status so far documented at three sites in two Montana counties,
despite several decades of collecting in the region by Dr. R. B. Brunson and his students. There
is evidence of extirpations or population declines, largely inferred from loss of habitat (Frest and
Johannes 1 995). Population sizes and trends in Montana are unknown, and there is no
evidence that the Missoula County sites have been resurveyed in recent decades.

B. Threats

Habitat occupied by Udosarx lyrata (moist sites in valley and mid-elevation mixed conifer
forest) is threatened by logging, grazing, fire, possibly rural home development and road
construction, and possibly recreation and weed control. The impact of fire retardant and
chemical means of weed control on this and other terrestrial moUusk species is unknown. Little
is known about the biology of this species, including its sensitivity to disturbance.

C. Distribution Relative to Land Allocations

Documented Montana sites are on lands administered by the Darby Ranger District, Bitterroot
National Forest (1 site). Plum Creek Timber Company (1 site), and private ownership (1 site).
The type locality in Idaho is 4 km (2.5 mi) from land in Montana administered by the Missoula
Ranger District, Lolo National Forest and Plum Creek Timber Company.

Bibliography of Montana Terrestrial MoUusks of Special Concern

Bartsch, P. 1916. Two new land shells from the western states. Proceedings of the United States
National Museum 51:331-333.

Beetle, D.E. 1957. The moUusca of Teton County, Wyoming. The Nautilus 71:12-22.

Beetle,D.E. 1961. MoUusca of the Big Horn Mountains. The Nautilus 74:95-102.

Beetle, D.E. 1989. Checklist ofrecent moUusca of Wyoming, USA. Great Basin NaturaUst 49: 637-
645.

Beetle, D.E. 1997. Recolonization of burned aspen groves by land snails. Yellowstone Science
5(summer):6-8.

Berry, S.S. 1913. A list ofmoUusca from the MusselsheU Valley, Montana. The Nautilus 26:130-131.

Berry, S.S. 1916. Notes on moUusca of central Montana. The Nautilus 29: 124-128.

Berry, S.S. 1919. MoUusca ofGlacier National Park. Proceedings ofthe Academy of Natural
Sciences of Philadelphia 71 : 1 95-205.

Berry, S.S. 1 955. An important new land snail from the Mission Range, Montana. Bulletin ofthe
Southern California Academy of Sciences 54:17-19.

Bland, T, and J. G. Cooper. 1 861 . Notice of land and freshwater shells collected by Dr. J. G. Cooper
in the Rocky Mountains, etc., in 1 860. Annals ofthe Lyceum of Natural History of New York

7:362-370.

Boag, D. A., and W. D. Wishart. 1 982. Distribution and abundance of terrestrial gastropods on a

winter range of bighorn sheep in southwestern Alberta. Canadian Journal of Zoology 60:2633-
2640.

Brunson,R.B. 1956. The mystery of Discus brunsoni. The Nautilus 70:16-21.

Brunson, R. B., and N. Kevern. 1 963 . Observations of a colony of Magnipelta. The Nautilus 77:23-
27.

Brunson, R.B., and U. Osher. 1957. Haplotrema from wQstemMontSimi. The Nautilus 70:121-123.

Brunson, R. B., and R. H. Russell. 1 967. Radiodiscus, new to moUuscan fauna of Montana. The
Nautilus 81:18-22.

Carlson, J. 2003. MontanaAnimal Species of Concern. Montana Natural Heritage Program and

Montana Fish, Wildlife and Parks, Helena, Montana. 1 4 pp.
Coan, E. 1981. James Graham Cooper, pioneer western naturalist. University Press of Idaho,

Moscow, ID. 255 pp.

Cooper, J. G. 1868. The shells of Montana. American Naturahst 2:486-487.

Elrod,M.J. 1901a. Montana shells. Rocky Mountain Magazine 2:691-697.

Elrod,M. J. 1901b. Limnological investigations at Flathead Lake, Montana, and vicinity, July, 1899.
Transactions of the American Microscopical Society 22:63-80.

Elrod,M.J. 1901-1902. Collecting shells in Montana. The Nautilus 15:86-89, 103-104, 110-112,
129-130.

Elrod, M. J. 1 902. Abiological reconnoissance in the vicinity of Flathead Lake. University of
Montana Bulletin No. 10, Biological Series No. 3.

Elrod, M.J. 1903a. l<iotQS on PyramidulaelrodiVils. The Nautilus 16:109-112.

Elrod, M.J. 1903b. Montana shQlls-Pyramidulastrigosa. The Nautilus 17:1-6.

Fairbanks, H.L.I 980. Morphological notes on Oreohelix amariradix Pilsbry, 1 934 (Pulmonata:
Oreohelicidae). The Nautilus 94:27-30.

Fairbanks, H. L. 1984. Anew species of Oreohelix (Gastropoda: Pulmonata: Oreohelicidae) from the
Seven Devils Mountains, Idaho. Proceedings of the Biological Society of Washington 97: 1 79-
185.

Fairbanks, H. L. 2002. The reproductive anatomy, taxonomic status, and range of Oreohelix alpina
(Elrod, 1901) (Gastropoda: Pulmonata: Oreohelicidae). The Nautilus 116:in press.

Forrester, D. J. 1 960. Apreliminary investigation of the protostrongylin lungworm-bighom sheep
relationships in Montana. M.S. thesis, Montana State University, Missoula. 79 pp.

Forrester, D. J. 1 962. Land moUusca as possible intermediate hosts of Protostrongylus stilesi, a
lungworm of bighorn sheep in western Montana. Proceedings of the Montana Academy of
Sciences 22:82-92.

Frest, T. J., and E. J. Johannes. 1 993 . Land snail survey of the Black Hills National Forest, South

Dakota and Wyoming. Final report to USDA Forest Service, Black Hills National Forest and
USDI Fish & Wildhfe Service, South Dakota State Office. 1 56 pp. + appendices.

Frest, T. J., and E. J. Johannes. 1 995. Interior Columbia Basin moUusk species of special concern.
Final Report to Interior Columbia Basin Ecosystem Management Project. Deixis Consultants,

Seattle. 274 pp.
Henderson, J. 1924. MoUuscaofColorado, Utah, Montana, Idaho, and Wyoming. The University of
Colorado Studies 13:65-223.

Henderson, J. 1933. MoUusca of the Yellowstone Park, Teton Park and Jackson Hole region. The
Nautilus47:l-3.

Henderson, J. 1 936. MoUusca of Colorado, Utah, Montana, Idaho, and Wyoming-supplement. The
University of Colorado Studies 23:81-145.

Hendricks, P. 1998. Rediscovery of D/^ct/^ /)rt//7^o^/ Berry, 1955 and Oreohelix alpina (Elrod,

1 90 1 ) in the Mission Mountains, Montana, with comments on Oreohelix elrodi (Pilsbry, 1 900).
The Nautilus 112:58-62.

Karlin, E.J. 1 96 1 . Ecological relationships between vegetation and the distribution of land snails in
Montana, Colorado and New Mexico. American Midland Naturalist 65 :60-66.

Leonard, W. P., and K. Ovaska. 2002. Reproduction of the Malone jumping-slug, Hemphillia

malonei Vilshry, 1917 (MoUusca: Gastropoda: Arionidae): laboratory observations. Nemouria
45:1-15.

Niwa, C. G, R. E. Sandquist, R Crawford, and 1 8 others. 2001 . Invertebrates of the Columbia River
basin assessment area. Gen. Tech. Rep. PNW-GTR-5 12. Portland, OR: U.S. Department of
Agriculture, Forest Service, Pacific Northwest Research Station. 74 pp.

Ovaska, K., L. Chichester, H. Reise, W. P. Leonard, and J. Baugh. 2002. Anatomy of the dromedary
jumping-slug, Hemphillia dromedariusBmnson, 1972 (Gastropoda: Stylommatophora:
Arionidae), with new distributional records. The Nautilus 1 1 6:89-94.

Pilsbry, H. A. 1900. Notices of new American snails. The Nautilus 14:40-41

Pilsbry, H. A. 1912. Two newAmerican land shells collected by Messrs. Hebard and Rehn. The
Nautilus 26:88-90.

Pilsbry, H. A. 1 933 . Notes on the anatomy of Oreohelix, — III, with descriptions of new species and
subspecies. Proceedings of the Academy of Natural Sciences of Philadelphia 85:383-410.

Pilsbry, H. A. 1 939. Land moUusca of North America (north of Mexico), Volume I Part 1 . The
Academy of Natural Sciences of Philadelphia Monographs Number 3 (1 ): 1 -573 .

Pilsbry, H. A. 1948. Land moUusca ofNorth America (north ofMexico), Volume II Part 2. The
Academy of Natural Sciences of Philadelphia Monographs Number 3 (2) : 52 1 - 1 1 1 3 .

Pilsbry, H. A. 1 953 . Magnipelta, a new genus of Arionidae from Idaho. The Nautilus 67:37-3 8.

Pilsbry, H. A., and R. B. Bmnson. 1 954. The Idaho-Montana slug Magnipelta (Arionidae). Notulae
Naturae 262:1-6.

Piatt, T. R. 1 980. Observations on the terrestrial gastropods in the vicinity of Jasper, Alberta
(Canada). The Nautilus 94: 1 8-21 .

Russell, R. H., and R. B. Brunson. 1967. Acheck-list of molluscs of Glacier National Park, Montana.
Sterkiana26:l-5.

Russell, R. H., and G. R. Webb. 1980. The slug Udosarx lyrata: additional data on distribution,
anatomy, and taxonomy. Gastropodia2:8-10.

Squyer,H. 1894. List ofshells from the vicinity of Mingusville, Montana. The Nautilus 8:63-65.

Vanatta,E. G 1914. Montana shells. Proceedings ofthe Academy ofNatural Sciences of Philadelphia
66:367-371.

Webb, G R. 1959. Two new north-western slugs, Udosarx lyrata and Gliabates oregonia.
Gastropodia l(3):22-23, 28.

Webb, G R., and R. H. Russell. 1 977. Anatomical notes on a Magnipelta: Camaenidae?
Gastropodia 1(10):107-108.

APPENDIX A. GLOBAL/STATE RANK DEFINITIONS

Heritage Program Ranks

The international network of Natural Heritage Programs employs a standardized ranking system to
denote global (range-wide) and state status (NatureServe 2002). Species are assigned numeric ranks
ranging from 1 (critically imperiled) to 5 (demonstrably secure), reflecting the relative degree to which
they are "at-risk". Rank definitions are given below. Anumber of factors are considered in assigning
ranks — the number, size and distribution of known "occurrences" or populations, population trends (if
known), habitat sensitivity, and threat. Factors in a species' life history that make it especially vulnerable
are also considered (e.g., dependence on a specific pollinator).

Rank Definitions

G 1 S 1 Critically imperiled because of extreme rarity and/or other factors making it highly

vulnerable to extinction.

G2 S2 Imperiled because of rarity and/or other factors making it vulnerable to extinction.

G3 S3 Vulnerable because of rarity or restricted range and/or other factors, even though it may

be abundant at some of its locations.

G4 S4 Apparently secure, though it may be quite rare in parts of its range, especially at the

periphery.

G5 S5 Demonstrably secure, though it may be quite rare in parts of its range, especially at the

periphery.

GU SU Possibly imperiled, but status uncertain; more information needed.

GA S A Native in nearby states, but in Montana believed to be accidentally introduced,

deliberately planted, or escaped from plantings.

GH SH Historical, known only from records over 50 year ago; may be rediscovered.

GX SX Believed to be extinct; historical records only.

Combination Ranks

G#G# or S#S# Indicates a range of uncertainty about the rarity of the species.

Subranks

T# Rank of a subspecies or variety; appended to the species' global rank of the full

species, e.g. G4T3.

Qualifiers

Q Taxonomic questions or problems exist, more information needed; appended to the

global rank, e.g. G3Q.

? Denotes uncertainty or for numeric ranks, inexactness.

A-1

APPENDIX B. LOCALITY AND COLLECTION RECORDS FOR 15
TERRESTRIAL MOLLUSK TAXA OF CONSERVATION CONCERN IN

MONTANA

Species

Location

TRS

Elev (ft) County

Date

Habitat

Notes^

Discus brunsoni

Discus stiimeki

McDonald Lake, T19N,R19W,
Mission Mtns sec 1 1 NE

3700

Lake 26 Aug. 1948; 23 diorite talus, TYPE Berry 1955, Brunson

W of Nurses
Lakes

T3S,R12E, sec
30SWNE

6360

Park

June

1950; 1 June

LOCALITY

1956, Hendricks 1998;

1954

4 May, 2 July

CAS #1264413; FMNH

1955

16 May

#'s 98033, 108561;

1957

27 April

USNM# 673345

1960

16 and 29

(paratype); Hendricks

May 1964; 1 and

specimens

10 July 1997

2 August, 2000

aspen

stand

Hendricks record

Discus stiimel<i
Discus stiimel<i

Discus sliimel<i
Discus sliimel<i

Beaver Creek, T28N,R16E, sec 4240

Bears Paw Mtns 3NWNE

falls of Natural T3S,R12E, sec

Bridge, Boulder 26NW

River, Absaroka

Mtns.

E of Kootenai T31N,R32W,

Falls sec 15

Gallatin River
corridor

T6S,R4E, sec
22

IHempliillia danieisi Bunkhouse T3N,R21W, sec

Creek, Bitterroot 7 middle
Mtns

l-iempiiillia danieisi Camas Creek,
Bitteroot Mtns

l-lempliillia danieisi Mill Creek,

Bitterroot Mtns

Hemphillia danieisi Medicine Hot
Springs,
Bitterroot Mtns

Hill 20 June, 1997

5100 Sweetgrass ??

2100

6000

Lincoln 17 Sept., 1959
Gallatin 23 April, 1960

5000

T5N,R21W, sec ca.

33SW 4800?

T6N,R22W, sec 4950

1NENE

T1N,R20W, sec 4400

12SW

aspen stand

limestone, with
Doug-fir cover

Ravalli

26 July, 2001

nparian spruce,
Doug-fir,
Cottonwood, alder

Ravalli

12 May 1912; 7

riparian mixed

October 2001

conifer/deciduous,
TYPE LOCALITY

Ravalli

20 Oct., 2001

streamside, under
cobble

Ravalli

1912

Hendricks record
Pilsbry 1948

Forrester 1960; FMNH
#108487: Kootenai
Falls sheep range
Forrester 1960; USNM
#762513; Clyde
Senger specimen,
FMNH #108538:
Gallatin sheep range
Bill Leonard record;
photo

Pilsbry 1948; ANSP#
110052 (holotype);
Heike Reise record
B. Maxell record;
Hendricks specimen
Pilsbry 1948

B-1

Species

Location

TRS

Elev (ft) County

Date

Habitat

Notes^

Hemphlllla danieisi N end Ward Mtn,

T5N,R21W, sec

4825

Ravalli

21 April, 1912

Pilsbry 1948; ANSP#

Bitterroot Mtns

17NW?

110053

Magnipelta

Thompson River

T24N,R27W,

3140

Sanders

16 May, 2001

shrubby

Hendricks record;

mycophaga

bottom, 3 mi S of
Bend

^sec12NWNE

willow/dogwood,
Ribes, snowberry;
scattered ponderosc
pine and Douglas-fir
nearby

photo

Magnipelta

Little Park Creek

, T12N,R18W,

4300

Missoula

24 May 1998; 26

riparian alder.

Hendricks record;

mycophaga

Sapphire Mtns

secSONESW

Sept. 2000

spruce, subalpine fir photo

Magnipelta

Marten Creek

T25N,R33W,

2500

Sanders

7 May, 1999

grand fir, alder

Hendricks record;

mycophaga

sec25SESE

photo

Magnipelta

Deer Creek,

T12N,R18W,

4100

Missoula

26 May and 14

Doug-fir, spruce.

Pilsbry and Brunson

mycophaga

Sapphire Mtns

sec7NENW

June 1954; 29

subalpine fir.

1954, Brunson and

April-23 Sept. 1957 western larch.

Kevern1963; FMNH

ponderosa pine

#108562

Magnipelta

Red Meadow

T35N,R23W,

ca. 5200

Flathead

31 July, 1951

subalpine fir-

Pilsbry and Brunson

mycophaga

Lake

sec 34NW

whitebark pine

1954; Brunson catalog
#M6151

Magnipelta

centered on

T34N,R29W,

3500?

Lincoln

1959?

Forrester 1960,1962:

mycophaga

McGuire Creek

sec 24

centered on Ural-
Tweed sheep range.
Inch and McGuire
Mtns.

Oreohelix alpina

above Lower

T21N,R16W,

7200

Missoula

lOAug. 1975; 11

limestone talus

Fairbanks 2002;

Rumble Lake,

sec 36SESW

Sept. 2000

Hammer and

Swan Mtns

Fairbanks specimens;
Hendricks specimens

Oreohelix alpina

E. St Marys Pk,

T18N,R18W,

8900-

Lake

15 July 1900; 27

alpine limestone

Elrod1902, 1903b;

Mission Mtns

sec21SW

9400

Aug. 1997

talus: TYPE
LOCALITY

Hendricks 1998;
FMNH #108485

Oreohelix alpina

West McDonald

T19N,R19W,

7400-

Lake

22 July, 1900

limestone talus.

Elrod1902, 1903b

Peak, Mission

sec 24SE

8000

west ridge crest

Mtns.

Oreohelix alpina

McDonald Peak,
120 ft below
summit on S
ridge

T19N,R18W,
sec29NWNE

9700

Lake

18 Sept., 1952

limestone talus

J. Chapman specimen,
FMNH #108486

B-2

Species

Location

TRS

Elev (ft) County

Date

Habitat

Notes^

Oreohelix alpha McDonald Peak; T19N,R18W,

above Duncan sec 30NE
Lake

Oreohelix 4.5-4.6 mi W of T12N,R21W,

amariradix Lolo along US sec 36SWSE

Oreohelix
amariradix

near Lolo Creek,
across from
other location

T12N,R21W,
sec36SWNE

8500 Lake 2 Aug., 1949

3500 Missoula 20 July 1902; 9

July 1950; 23 and
30 May 1976; 29
May 1977; March
1978

3500 Missoula 5 June, 1976

limestone talus

small talus slides on
N slope opposite Ft.
Fizzle; in ponderosa
pine, serviceberry,
ninebark, bunch
grasses. TYPE
LOCALITY
talus slope (in
ponderosa pine?)

Brunson catalog
#M31349

Fairbanks 1 980; ANSP
# 78740 (holotype),
345588, 347820;
FMNH# 74757, 84740

Fairbanks record

Oreohelix
carinifera

Oreohelix eirodi

old Byrne
Resort, Nimrod
Hot Springs
Grouse Creek

Wet Mulkey
Gulch

Garrison Jet.

Goat Creek,
Swan Mtns

T11N,R15W,
sec14SESW

T11N,R15W,
sec 35/36S

T12N,R13W,
sec 32SENW

T9N,R10W,

sec14SofSE,

sec23NofNE

T23N,R17W,
sec12NENW

4100 Granite 13 July, 1975

4300? Granite 15 Nov., 1975

4850 Granite 3 Aug. 2002

4300 Powell 1907; 1909; 4

Sept. 1931; 25
Aug. 1934; 7 July
1947; 28 April
1960; 17 July
1976; 28 May 1977

4250 Lake 9 June, 1999

small rock outcrops
above pond

sandy limestone, S
facing slopes
w/juniperand Doug-
fir

sandy limestone, S
facing slope, open
Doug. Fir canopy
with common juniper
in understory
S facing limestone
slope, on surface of
outcrop and among
junipers: TYPE
LOCALITY

Fairbanks record

Hendricks specimens
(MTHP 4293); dead
shells

argillite talus

ANSP #'s 99253
(paratypes), 345537,
A14840; FMNH #'s
84747,97987,98161,
111794

Hendricks specimens

Oreohelix eirodi

Lion Creek, T22N,R17W, 3600-

Swan Mtns sec 11SW-13NE 4000

Lake ca. 1975; 25 Sept. argillite talus
1997; 19 May 1999

Fairbanks 1984;
Hendricks specimens

B-3

Species

Location

TRS

Elev (ft) County

Date

Habitat

Notes^

Oreohelix eirodi

McDonald Lake,

T19N,R19W,

3700

Lake

July 1899; July

argillite and diorite

Elrod1902, 1903a,

Mission Mtns

secllNE

1900; June 1901;
1902; 16 May, 7
and 17 July, 7 Aug.
1947; 26 Aug.
1948; 7 Sept.
1950; 2 Oct. 1955;
29 June 1956; 11
May 1959; 27 April
1960; 10 June, 1
July 1997

talus: TYPE
LOCALITY

Pilsbry 1939,
Hendricks 1998; ANSP
#'s 78740 (lectotype),
348135, 346218,
345811; FMNH#'s
40079, 40080, 60312,
74395, 74754, 86584,
90351,90352,90492,
90527, 97864, 98120,
117891, 146468,
172603; USNM #
160833

Oreohelix strigosa

1 mi E Piper

T14N,R20E, sec

4500

Fergus

12 Sept., 1944

SW facing slope.

USNM # 592753

berryi

9SE

under creeping
juniper

Oreohelix strigosa

"vicinity of

T6S,R10E, sec

6200

Park

1994

Frest and Johannes

berryi

Montanapolis"

1995

Oreohelix strigosa

7miS

T14N,R19E, sec

4250

Fergus

13 Sept., 1944

S facing slope

USNM # 592752

berryi

Lewistown, near
Big Spring

5SE

Oreohelix strigosa

Half Moon Pass,

T12N,R19E, sec

7300

Fergus

USNM #477463

berryi

Big Snowy Mtns.

28SW

Oreohelix strigosa

Dry Pole

T12N,R17E

5500-

Fergus

USNM #477391

berryi

Canyon, Big
Snowy Mtns.

6500

Oreohelix strigosa

Swimming

T11N,R19E, sec

5880

Golden

4 July, 1914

TYPE LOCALITY

see Pilsbry 1933 for

berryi

Woman Canyon,
Big Snowy
Mtns., about half
a mile above the
mouth

16NW

Valley

location

Oreohelix strigosa

Blake Creek

T11N,R18E

Fergus

14 Sept., 1919

berryi

Canyon, Big
Snowy Mtns.

Oreohelix strigosa

Judith Mtns.

T16N,R19E, sec

5320

Fergus

20 April, 1998

rocky slope of

Hendricks specimens:

berryi

16SENE

limestone in old burn ID not confirmed, but

likely

B-4

Species

Location

TRS

Elev (ft) County

Date

Habitat

Notes^

Oreohelix strigosa
berryi

Oreotielix yavapai
mariae

Polygyrella
polygyrella

Prophysaon
humile

Timber Creek
Canyon, Big
Snowy Mtns.
W of head,
Middle
Cottonwood
Canyon, Big
Snowy Mtns.
1/4 mi from
mouth of Squaw
Creek, and also
N side of canyon

3-6 mi up
Prospect Creek
W of Thompson
Falls, Coeur
d'Alene Mtns.
2mi. W

Thompson Falls
at confluence of
Clear Cr. With
Prospect Cr.
West Fork Big
Creek, DeBorgia

T11N,R18E

T12N,R18E, sec ca.
26?

Fergus ??
8000 Fergus ??

T4S,R4E, sec
34SWSW

T21N,R30W,
sec 21-23

T21N,R30W,sec
. 13NESW

T19N,R30W,sec
.30SE?

2600

Sanders 1 May, 1949

E slope of Coeur ?? (? SW of

d' Alene Mtns.

Yellow Bay Biol.
Stn.

DeBorgia;
possibly Dry Cr.,
or NW of St.
Regis in Mullen
Gulch?)
T24N,R19W,
sec. 4NE

3600? Mineral 17 May, 1964

?? ? Sanders Sept., 1860

or Mineral ?

ca. 3000 Lake 11 July. 1960

Berry specimen
Berry specimen

5600 Gallatin prior to 1 91 6; 30

Aug. 1925; 30 Aug.
1939; 8 July 1947;
4 May 1976

2800 Sanders ??(priorto 1936)

S-facing open Bartsch 1916; USNM #

grassy slope at base 522585, 215132 (types
of outcrop: TYPE
LOCALITY

moss and decaying
wood in dampest
parts of spruce
forest

in moss and
decaying wood in
damp spruce forest:
TYPE LOCALITY

and paratypes); ANSP
#345575, 113374
(paratype)
Henderson 1936,
Baker record in Pilsbry
1939

Brunson catalog
#M 10049

Brunson catalog
#M2964, M3364: TRS
not given

Bland and Cooper
1861; Coan 1981
gives type locality as in
ID, but Pilsbry 1939
lists Sanders Co., MT:
Cooper 1868 gives MT
FMNH #119010

Radiodiscus
abietum

between Leigh
Lake trail and
Leigh Creek,
Cabinet Mtns.

T28N,R31W,sec
.6NWNE

3900

Lincoln 27 July, 1960

under log

Brunson and Russell
1967

B-5

Species

Location

TRS

Elev (ft) County

Date

Habitat

Notes^

Radiodiscus
abietum

4 mi. W Noxon

T26N,R33W,sec
.17SESE

T26N,R32W,sec
.20NW

Government

Creek at Noxon,

Cabinet Mtns.

South Crow T20N,R19W,sec

Cirque, Wend of . 10SESE

Schwartz Lk.,

Mission Mtns.

3000

2700

3950

Sanders

Lake

2 May, 1965
20 June, 1956
7 July, 1960

Brunson and Russell
1967

Brunson and Russell
1967; Brunson catalog
gives 26 June
Brunson and Russell
1967; FMNH #105851

Radiodiscus
abietum

McDonald Lake
at dam. Mission
Mtns

McDonald
Cirque above
McDonald Lake,
Mission Mtns.

Crystal Lake
Trail, ca. 5 mi.
DeBorgia

T19N,R19W,sec
.10NENE

T19N,R19W,sec
. 11NW

3600

Lake 19 June, 1960

Lake 11 May 1959, 17
and 23 June 1960,
16 May 1964

wet bank W side of
talus slide

T18N,R30W,sec
.15SW

4000

Mineral 17 Oct., 1965

under fallen logs in
cedar forest

FMNH #110641

Brunson and Russell
1967; elev must be in
sec. 11, not sec. 2 as
given for 1960 record;
1959 and 1964
records not published
(Brunson catalog
#M1259andM664)
Brunson and Russell
1967; elev given as
2800' with no TRS but
trail starts higher up

Radiodiscus
abietum

Deep Creek,
Bitterroot Mtns.

T13N,R21W,sec
.20NW

T5N,R22W,sec.
35SWSE

N. Fork Lost

Horse Cr.,

Bitterroot Mtns.

Lost Horse T4N,R22W,sec.

Creek, Bitterroot 6NWNW

Mtns.

4000 Missoula 11 May, 1957

5600 Ravalli May, 1960

5000 Ravalli 5 June, 1960

Brunson and Russell
1967

B-6

Species

Location

TRS

Elev (ft) County

Date

Habitat

Notes^

Radiodiscus
abietum

Sleeping Child
Cr. below
Sleeping Child
Hot Springs,
Sapphire Mtns.
SW shoulder
Stenerson Mtn.

Tweed Creek

T4N,R19W,sec.
7NW

4550

T32N,R28W,sec ca. 5000
.3

T34N,R29W,sec ca. 4000
.35

Ravalli 31 December,
1965

Lincoln 15 Sept., 1959

Lincoln 18 July, 1962

Brunson and Russell
1967

Forrester specimen in
FMNH #108508: Ural-
Tweed sheep range
FMNH #117379; Ural-
Tweed sheep range

Udosarx lyrata

Udosarx lyrata
russelli

Zacoleus
idahoensis

Bunkhouse
Creek, Bitterroot
Mtns

ca. 2 mi. N Twin
Creeks Lumber
Camp, near
wetland and F.S.
road

1 miWof
Potomac

E of Kootenai
Falls, Purcell
Mtns.

T3N,R21W, sec 5000
7 middle

Ravalli 26 July, 2001

T14N,R17W,sec
25SW

4000 Missoula 5 May, 1966

T13N,R16W, 3500

sec 10 (possibly
sec 15)

T31N,R32W, 2100

sec 15

Missoula

3 May and 21 Nov.
1965, 5 May 1966

Lincoln 1959?

nparian spruce,
Doug-fir,

Cottonwood, alder
under rocks near
spring-fed 0.5 acre
pond; open
coniferous
ponderosa pine and
Douglas-fir
S slope above Union
Creek, under logs;
ponderosa pine and
undergrowth: TYPE
LOCALITY for
subspecies

Bill Leonard record;
photo

Russell and Webb
1980; in Dick Russell
unpublished notes and
correspondance

Russell and Webb
1980; ANSP# 358248

Forrester 1960, 1962:
Kootenai Falls sheep
range

Zacoleus
idahoensis

centered on T7N,R16W, sec

Squaw Rock CG, 21
Sapphire Mtns.

3-6 mi up
Prospect Creek
W of Thompson
Falls, Coeur
d'Alene Mtns.

T21N,R30W,
sec 21-23

4900 Granite 1959?

2800 Sanders ??

Forrester 1960, 1962:

Rock Creek sheep

range

Baker record in Pilsbry

1939

B-7

Species

Location

TRS

Elev (ft) County

Date

Habitat

Notes^

Zacoleus
idahoensis

centered on
landing site at
Wild Horse
Island, Flathead
Lake

T24N,R20W,
sec 13

2900

Lake

1959?

under driftwood near Forrester 1960: Wild
shoreline Horse sheep range

^ ANSP (Academy of Natural Sciences, Philadelphia), CAS (California Academy of Sciences), FMNH (Field Museum of Natural History, Chicago), USNM (U.
S. National Museum).

B-8

APPENDIX C. GUIDELINES FOR DESIGNING AND CONDUCTING
SURVEYS OF TERRESTRIAL MOLLUSKS

Survey Guidelines for Terrestrial MoUusks

The design of surveys for terrestrial moUusks is fairly simple if the objective is to look specifically for
selected target species. In addition to determining presence-absence, some additional habitat
information can be collected relatively quickly that will add significantly to the extremely limited body of
knowledge on the ecology of most species of conservation concern in Montana. With this in mind, the
few suggestions that follow on survey methods should provide biologists unfamiliar with terrestrial
moUusks the rudiments needed to determine presence-absence, relative abundance, and habitat
associations of any of the species discussed in the species accounts of this report. Remember that with
experience comes familiarity. I have also included a short list of references where some of the
techniques are discussed in more detail and applied to particular field situations. Frest and Johannes
(1 995) provide a summary of survey, monitoring, and collection methods. New (1 998) provides a
broad overview on survey design for invertebrates of conservation interest.

Survey Design

The target species of conservation interest in Montana (Table 1) can be readily detected through labor-
intensive hand searching. Hand searching involves picking through litter, shallow soil, and turning over
rocks and fallen logs looking for attached animals. The length of time spent searching is recorded to
provide a relative measure of search effort and rate of encounter (relative abundance) of the target
species. In some cases it may be desirable to do searches at random locations along transects for
quantitative comparisons by habitat or site. Search areas of some size (e.g. 1x1 m) are examined along
transects for a set time, and the number of individuals found in each search plot recorded.

Habitat data associated with each transect and/or plot can include simple things such as estimates of
overhead canopy cover and species composition, the same for ground cover, soil type or source rock
type, slope and exposure; mean particle size of stones, talus, or boulders should be documented at sites
in rocky terrain. For very small snails, soil samples are extracted from plots and screened on the spot
using fine sieves, or placed in bags for later screening either through sieves or under Berlese funnels;
these soil/litter extraction methods are not especially useful for the species discussed in this report.
Ambient temperature, cloud cover, comments on precipitation (current, recent, and duration) and
related weather data should be recorded, as weather is a significant factor in determining the degree of
success of surveys. For recent examples of how sampling can be tied to habitat analyses of a terrestrial
moUusk fauna, see Kralka (1986) and Ports (1 996). A broader perspective for quantitative
descriptions of moUusk populations and habitats is presented in Bishop (1 977).

Use of cover boards provides an alternative to hand searching, and is also useful in conjunction with
hand searching. Cover boards provide quantitative assessments of relative abundance that are suitable
for statistical analyses, and they also are useful for long-term sampling of rare species at specific
locations when resources for field surveys are limited to only a few (or no) periods of hand searching.
However, the cover board technique still needs assessment in talus sites to determine its usefulness in
that kind of substrate.

At selected sites, either transects or grids of cardboard or masonite squares (transects of 30 x 30 cm
masonite [Boag 1982]; selected sites with 56 x 71 cm cardboard [Gleich and Gilbert 1976]; grids of 75
X 75 cm cardboard [Stray er et al. 1 986]) are placed apart at regular distances, often in a variety of

C-1

habitats or microhabitats in comparative studies. Each cover board represents a sample plot that can be
checked as frequently or infrequently as resources (money and personnel) allow. The ground where
boards are placed can first be wetted to elevate humidity beneath the boards (useful for revisits of only a
few days apart), but for long-term sampling with few visits it is probably preferable to place boards
early in the field season (spring, once ground is snow-free) and retrieve them in mid to late fall before
snow again covers the ground (or left in place over winter and revisited the following spring). Multiple
visits to check snails and slugs under the boards can be made during a field season; visits should be
made to all transects or grids at regular sampling periods (e.g., monthly, bi-monthly, annually).

Vouchers of target species should be collected to confirm identification. Dead shells can be placed in
film containers and protected with cotton. Live snails and slugs can be kept in containers with moist
paper towels or wood until a determination can be made. If preservation is necessary, snails and slugs
should be drowned in warm water, fixed in formalin, and stored in vials of 70% ethyl alcohol. All
collected material should be accompanied by the date and location of collection.

Timing of Surveys

Terrestrial moUusks are most active when conditions are cool and wet. During warm and dry
conditions, a site may be searched with few or no encounters, when under moist and cool conditions the
same site may reveal an abundance of live animals. Of course, dead shells may be found regardless of
the weather, but finding extant populations is a first priority, and finding slugs will require favorable
conditions if hand collecting is conducted. All species may be active shortly after the ground becomes
snow-free, when the ground is moist from snowmelt, and will remain active until snow covers the ground
or hard freezes occur, except during periods of hot dry summer weather. For Montana, the field season
extends from late March or early April through October in most years and at lower-elevation sites.

Some searching at night may be fruitful during drier periods, but this is yet to be determined for the
species discussed in this report. Brunson (1 956) speculated that the Mission Range Disc {Discus
brunsoni) could be most active in talus at night, when moisture conditions are more favorable, and that
might explain how it was overlooked for so many years at the same locality where the Carinate
Mountainsnail (Oreohelix elrodi) was collected frequently. Talus-inhabiting species (all species, for that
matter) could show heightened surface activity at night when humidity levels are probably elevated. This
possibility is worth investigating, as it has implications for future survey protocols for terrestrial moUusk
species of conservation concern in Montana.

Literature Cited

Bishop, M. J. 1 977. Approaches to the quantitative description of terrestrial moUusk populations and
habitats. Malacologia 16:61-66.

Boag,D.A. 1982. Overcoming sampling bias in studies of terrestrial gastropods. Canadian Journal of
Zoology 60:1289-1292.

Brunson,R.B. 1956. The mystery of Discus brunsoni. The Nautilus 70:16-21.

C-2

Frest, T. J., and E. J. Johannes. 1 995. Interior Columbia Basin moUusk species of special concern.
Final Report to Interior Columbia Basin Ecosystem Management Project. Deixis Consultants,
Seattle. 274 pp.

Gleich J. G, and F. F. Gilbert. 1 976. A survey of terrestrial gastropods from central Maine. Canadian
Journal of Zoology 54:620-627.

Kralka, R. A. 1 986. Population characteristics of terrestrial gastropods in boreal forest habitats.
American Midland Naturalist 1 1 5 : 1 56- 1 64.

New,T. R. 1998. Invertebrate surveys for conservation. Oxford University Press. Oxford, UK. 240
pp.

Ports, M. A. 1 996. Habitat affinities and distributions of land gastropods from the Ruby Mountains
and East Humboldt Range of northeastern Nevada. The Vehger 39:335-341 .

Strayer, D., D. H. Pletscher, S. P Hamburg, and S. C. Nodvin. 1986. The effects of forest

disturbance on land gastropod communities in northern New England. Canadian Journal of
Zoology 64:2094-2098.

C-3

APPENDIX D. KEY TO THE GENERA OF TERRESTRIAL MOLLUSKS

OF MONTANA

(undir marrltil | lunbsi martJt)

WunWs defl-

Figure D.l Anatomy of a Slug

The following dichotomous key to the genera of terrestrial moUusks (slugs and snails) in Montana is
based on one developed and revised in 1 967 by Dr. Royal Bruce Brunson, Lee Fairbanks, and Richard
Russell. Excluded in this current version are all aquatic taxa. The key is presented here to land
managers and biologists as an aid in identifying slugs and snails that may be of special conservation
concern. In the case of slugs, all genera of special interest are monotypic (represented by a single
species) in Montana.

All Terrestrial MoUusks

1 a. Shell absent externally or greatly reduced (go to slug key),
lb. Shell present, covering the entire animal (go to snail key).

Slugs

1 a. Mantle elevated as a hump, shell may be partly exposed in a dorsal slit in the mantle — Hemphillia
lb. Mantle not elevated, shell never exposed — 2

2a. Length of mantle greater than two-thirds the length of the animal — Magnipelta
2b. Length of mantle less than two-thirds the length of the animal — 3

3a. Sole tripartite (having 2 longitudinal furrows), back generally keeled near posterior end,

pneumostome (breathing pore) in posterior half of mantle margin — 4

3b. Sole undivided, back not keeled, pneumostome in anterior half of the mantle margin — 7

4a. Posterior margin of mantle notched, pneumostome above or in front (anterior) of mantle cleft — 5
4b. Posterior margin of mantle unbroken, pneumostome behind (posterior) mantle cleft — 6

5a. Color black or dark brown — Zacoleus

5b. Base color bluish-gray, dark lateral lines on mantle — Udosarx

6a. Greater than 50 mm in length, base color tan, variously spotted with black — Umax
6b. Less than 50 mm in length, color brown or black — Deroceras

Idi. Base color orange, color of sole much the same as upper (dorsal) surface, anterior third of mantle
free (unattached to dorsum), caudal pit at tip of tail indistinct, length up to 70 mm — Prophysaon
7b. Base color gray or orange to brown, sole generally much paler than upper (dorsal) surface, caudal
pit at tip of tail distinct, length varies, up to 1 50 mm — Arion

D-1

Haklfann

Pt^irlDrm

LyiiinapTomi

EkimtGr

Figure D.2 Some shell shapes.

he^t

paflB'iBl ihHtn

basal loDth

Figure D.3 Shell terminology, (a): striate (indented spiral lines, (b): lirae (raised spiral lines), (c): ribs
(raised transverse lines), (d): wrinkles.

Snails

1 a. Shell lymnaeform (elongated coiled spire that is sharply pointed) — 1
lb. Shell not lymnaeform — 4

2a. Body whorl greatly enlarged, spire relatively short; shell generally thin and transparent — Oxyloma
2b. Body whorl not greatly enlarged or only slightly enlarged; length of spire at least a third the length of
the shell— 3

3a. Aperture (opening of shell) round; shell yellowish, clear; shell surface smooth or with nothing more

than fine striae — Succinea

3b. Aperture oval; shell often chalky; surface with very fine file-like markings — Catinella

4a. Shell heliciform (fiattened coil, wider than tall) — 5

4b. Shell pupiform (elongated coiled spire, taller than wide, with blunt or rounded apex) — ^23

5a. Adult shell with reflected lip at aperture — 6
5b. Adult shell without reflected lip — 8

6a. Aperture with teeth — Triodopsis (Cryptomastix)
6b. Aperture without teeth — 7

7a. Size 2-3 mm — Vallonia
7b. Size to 20 mm — Allogona

8a. Shell thin and transparent, generally smooth, less than 1 0 mm in diameter — 9

8b. Shell opaque or with a color pattern; surface generally with ridges or striae; size varies — 1 7

9a. Body whorl greatly enlarged, consisting of three quarters of the shell — Vitrina
9b. Body whorl not greatly enlarged or only slightly enlarged — 1 0

1 Oa. Widely umbilicated, width of umbilicus (central depression on the undersurface penetrating into the
layered coils) one third or more the width of the shell — 1 1
1 Ob. Narrowly umbilicated — 1 2

11a. Shell less than 2 mm in diameter; 3.0-3.5 whorls — Striatura
1 lb. Shell 2.5 mm in diameter; 4.0-5.0 whorls — Hawaiia

12a. Whorls about 5, tightly coiled — 1 3
12b. Whorls not tightly coiled — 15

13a. Shell nearly as high as broad, beehive-shaped — Euconulus
1 3b. Height of shell little more than half of the diameter — 1 4

D-2

14a. Umbilicus closed; less than 5 whorls, spire somewhat elevated — Pristiloma
14b. Umbilicus open; more than 5 whorls; spire flat — Microphysula

1 5a. Shell height less than half of the diameter; more than 5 whorls — Oxychilus
1 5b. Shell height greater than half of the diameter; less than 5 whorls — 1 6

1 6a. Whorls increasing in size, the body whorl being quite enlarged; shell clear and shiny — Retinella
1 6b. Whorls much the same size; shell amber or horn-colored, cloudy — Zonitoides

1 7a. Composition of shell chalky, often with a color pattern (banding) or various ridges — Oreohelix
1 7b. Composition of shell chitinous or homy; color yellow or brown — 1 8

1 8a. Diameter of shell greater than 1 5 mm; whorls 5-6 — 1 9
1 8b. Diameter of shell less than 12 mm; whorls 4-8 — 20

1 9a. Height of shell greater than half the diameter; size 1 7-25 mm — Anguispira
1 9b. Height of shell less than half the diameter; size 22-32 mm — Haplotrema

20a. Diameter of shell less than 2.5 mm — Punctum
20b. Diameter of shell 5-12 mm — 21

21a. Apical 1 .5 whorls with spiral striations — Radiodiscus
21b. Apical whorls bare or with radial growth lines — ^22

22a. Whorls 7-8, tightly coiled; aperture with teeth — Polygyrella
22b. Whorls 4-5, not tightly coiled; aperture without teeth — Discus

23 a. Aperture without teeth — 24
23b. Aperture with teeth — 25

24a. Aperture round; shell 3 mm in height — Columella
24b. Aperture ovate; shell 5 mm in height — Cionella

25a. Six whorls; 2-3 teeth in aperture — Pupilla
25b. Seven whorls; more than 3 teeth in aperture — 26

26a. Three teeth in the aperture on parietal (outer) wall; whorls about the same width — Vertigo
26b. Four teeth in the aperture on parietal wall; body whorl widest of the whorls — Gastrocopta

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Full text of "Status and conservation management of terrestrial mollusks of special concern in Montana"

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