SPECIES FACT SHEET
Scientific Name: Juga hemphilli subsp. nov.
Common Name: Indian Ford Juga
Phylum: Molluska
Class: Gastropoda
Order: Neotaenioglossa
Superfamily: Cerithiodea
Family: Semisulcospirinae
Taxonomic Note:
Recent nuclear and mitochondrial genetic analysis provides evidence that
Juga hemphilli represents a geographically disjunct lineage of the eastern
North American pleurocerid clade, and should be repositioned into the
genus Elimia, sister to Elimia livescens (Lee et al. 2006). There is some
question, however, as to whether the specimens used in Lee et al. (2006)
were perhaps based on mislabelled specimens (Terry Frest 2007, pers.
comm. with NatureServe).
Conservation Status (species-level):
Global Status (2009): G2
National Statuses: United States (N2); Canada (N1)
State Statuses: Oregon (S1)
Province Status: British Columbia (SNR)
(NatureServe, 2009; Oregon Biodiversity Information Center, 2010)
Technical Description:
Adult: Juga is a genus of medium-sized, aquatic, gilled snails
traditionally treated as part of the subfamily Semisulcospirinae within
the Pleuroceridae family, although the Semisulcospirinae subfamily was
recently elevated to family level based on morphological and molecular
evidence (Strong & Köhler 2009). The Pleuroceridae and
Semisulcospirinae families both differ from the Hydrobiidae family in that
the males lack a verge (male copulatory organ). The genus Juga is
distinct from related pleurocerid snails based on reproductive anatomy
and egg mass characters (Taylor 1966), as well as features of the
ovipositor pore, radula, midgut, kidney, and pallial gonoduct (Strong and
Frest 2007). Members of this genus have a tall, conic shell-shape and
thick, heavy shells which are commonly decollate (early whorls lost). The
operculum is present and they are gill breathing and dioecious (separate
sexes).
Juga hemphilli subsp. nov. is a new (undescribed) subspecies which
somewhat resembles Juga (Juga) hemphilli maupinensis in its relatively
large size (~25mm) (Frest & Johannes 1995). It is distinct from J. h.
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maupinensis in that the nacre is white (as opposed to light purple when
fresh) and the shell is dark brown and with two dark brown bands (as
opposed to a yellow-brown shell with one band) (Frest & Johannes 1995).
Additionally, the juvenile is narrower than in J. h. maupinensis, the shell
is more elongate, and there are several lirations (small raised ribs) on the
mature whorls (Frest & Johannes 1995). It should be noted that this
taxon is not the taxon described as Juga (Juga) hemphilli n. subsp. in
Frest & Johannes (1993).
Egg mass: The Juga egg mass generally consists of thick finger-like,
elongate, rather weakly coherent gelatinous aggregations, often several
cm in length and 2-4 cm in width, with hundreds to thousands of
moderately loosely packed, quite small (< 1 mm) eggs, with individual egg
boundaries not very apparent, and without regular arrangement of eggs.
The fresh egg mass deteriorates roughly a month after deposition, when
the embryos begin to acquire shells and hatch (Frest & Johannes 2006).
There is no veliger stage.
Life History:
Juga snails are characterized as rasper-grazers, feeding on both algae
and detritus, such as dead alder leaves (Furnish 1989, Allan 1995).
Individuals in the Juga genus may live for 5-7 years, reaching sexual
maturity in 3 years and continuing to grow (Furnish 1990). Adults in this
genus are gonochoristic (as opposed to hermaphroditic). Reproduction is
iteroparous (individuals are capable of having offspring many times), and
most Juga species appear to breed and lay eggs once a year as adults
(Frest & Johannes 2006). The same egg-laying localities are utilized year
after year if undisturbed. There is no veliger stage, and juvenile snails
emerge from eggs (Frest & Johannes 2006).
Range, Distribution, and Abundance:
As a whole, Juga hemphilli is known from the headwaters of the
Columbia River in British Columbia, the Columbia River Gorge of Oregon
and Washington, and the Deschutes River system in Oregon
(NatureServe 2009). Although this new subspecies may have been
historically widespread in the upper Deschutes system, it is currently
known from a single site: Indian Ford Creek near Black Butte in
Deschutes National Forest, Deschutes County, Oregon (Frest &
Johannes 1995).
Federal Land: The subspecies is documented on the Deschutes National
Forest (Frest & Johannes 1995).
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Abundance: No abundance estimates have been made for this
subspecies, but according to NatureServe (2009), Juga hemphilli is
declining (10-30%).
Habitat Associations:
The habitat for this subspecies is considered to be streams and springseeps (Duncan 2008). The only known site is a medium-sized spring-fed
creek, where the subspecies was found in mixed basalt cobble-mud
substrate (Frest & Johannes 1995). Since the known creek locality has
several fresh springs draining into it, the taxon appears to require good
water quality (Johannes 2009, pers. comm.). Macrophytes and epiphytic
algae are rare at the site, and the site is considered almost monospecific
as far as snails are concerned (Frest & Johannes 1995). This subspecies
is a perilithon grazer (Frest & Johannes 1995).
The egg masses of Juga are most often found in loose (non-cemented) but
stable cobble substrate, with free and fairly vigorous flow through at
least the upper substrate layers (Frest & Johannes 2006). The egg
masses are affixed by a narrow basal stalk to the underside of a firm
surface, generally a cobble or boulder, although other stabilized hard
substrate objects, such as sunken logs, may also be used (Frest &
Johannes 2006).
Threats:
Any factors tending to downgrade water quality, including nutrient
enhancement, grazing, and water diversions, would negatively impact
this taxon. Many of the springs in the Black Butte area where this
subspecies occurs are in a resort development; Frest & Johannes
surveyed most of these and found no “interesting” mollusks and very few
mollusks of any kind surviving (Frest & Johannes 1995). Other springs
in the area are now dry due to groundwater mining and diversion and
capping for stock and for human water supply, e.g. in Cold Spring Camp
Ground. Additionally, most springs in this region are heavily grazed.
Indian Ford Creek now goes dry downstream from the site, due to recent
increases in diversion and groundwater pumping (Frest & Johannes
1995). The other Juga hemphilli subspecies are also faced with imminent
threats throughout their ranges (NatureServe 2009; Frest & Johannes
1995).
Conservation Considerations:
Inventory: Although there is currently only one site for this subspecies,
most mollusk surveys in the area took place at springs and in land snail
habitat, and streams in the area have not been well explored (Johannes
2009, pers. comm.). Further surveys of appropriate habitat in the area
will be valuable in evaluating the current status, range, population
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characteristics, and conservation needs of this taxon. Any creeks south
of Sisters in the Whychus Creek (formerly called Squaw Creek) Drainage
are potential habitat and could be surveyed for this subspecies
(Johannes 2009, pers. comm.). Streams and spring seeps in Glaze
Meadow could be surveyed, as well as Whychus Creek (the creek that
Indian Ford Creek drains into). The swampy Lower Indian Ford Creek
may not be appropriate habitat, since this subspecies appears to require
good water quality. Likewise, this taxon has not been found in Black
Butte Ranch Springs to the north, possibly due to modification to the
springs at this location (Johannes 2009, pers. comm.). The adjacent
Metolius River doesn’t contain this subspecies (Johannes 2009, pers.
comm.).
Management: Consider managing new and known sites and their
associated watersheds to reduce the impacts of water diversions, grazing,
recreational activity and other practices that may adversely affect water
quality.
Prepared by: Sarah Foltz Jordan
Xerces Society for Invertebrate Conservation
Date: August 2010
Edited by: Sarina Jepsen
Xerces Society for Invertebrate Conservation
Date: August 2010
Final Edits: Rob Huff
FS/BLM Conservation Planning Coordinator
Date: February 8, 2011
ATTACHMENTS:
(1) References
(2) List of pertinent or knowledgeable contacts
(3) Map of Subspecies Distribution
(4) Photographs of Genus
(5) Aquatic Gastropod Survey Protocol, including specifics for this
subspecies
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ATTACHMENT 1:
References:
Allan, J.D. 1995. Stream ecology: structure and function of running
waters. Chapman & Hall, New York, NY. 388 pp.
Deixis MolluscDB database. 2009. An unpublished collection of mollusk
records maintained by Ed Johannes.
Duncan, N. 2008. Survey Protocol for Aquatic Mollusk Species:
Preliminary Inventory and Presence/Absence Sampling, Version 3.1.
Portland, OR. Interagency Special Status/Sensitive Species Program.
U.S. Department of Interior, Bureau of Land Management,
Oregon/Washington and U.S. Department of Agriculture, Forest Service,
Region 6. 52 pp.
Frest, T.J. and E.J. Johannes. 1993. Mollusk species of special concern
within the range of the northern spotted owl. Final Report to Forest
Ecosystem Management Working Group, USDA Forest Service. Deixis
Consultants, Seattle, Washington. 98 pp.
Frest, T.J. and E.J. Johannes. 1995. Interior Columbia Basin mollusk
species of special concern. Final report: Interior Columbia Basin
Ecosystem Management Project, Walla Walla, WA. Contract #43-0E00-49112. 274 pp. plus appendices.
Frest, T.J. and E.J. Johannes. 2006. Draft. Review of the Status of Juga
(Western U. S. Cerithioidea, Pleuroceridae, Semisulcospirinae).
Unpublished document available from Ed Johannes.
Furnish, J.L. 1989. Factors affecting the growth production and
distribution of the stream snail Juga silicula (Gould) [Doctoral
Dissertation]: Department of Entomology, Oregon State University, 216
p.
Furnish, J.L. 1990. Factors affecting the growth, production and
distribution of the stream snail Juga silicula (Gould). Unpublished PhD
thesis, Oregon State University, 173 pp.
Johannes, Ed. 2009. Personal communication with Sarah Foltz Jordan,
Xerces Society.
Lee, T., J.J. Kim, H.C. Hong, J.B. Burch, and D.O. Foighil. 2006.
Crossing the continental divide: the Columbia drainage species, Juga
hemphilli (Henderson, 1935) is a cryptic member of the eastern North
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American genus Elimia (Cerithioidea: Pleuroceridae). Journal of
Molluscan Studies, 72: 314-317.
NatureServe. 2009. “Elimia hemphilli”. Version 7.1 (2 February 2009).
Data last updated: October 2009. Available at:
www.natureserve.org/explorer (Accessed 17 May 2010).
Oregon Biodiversity Information Center, 2010. List of Rare, Threatened,
and Endangered Invertebrate Species. Available at:
http://orbic.pdx.edu/rte-species.html (Accessed 8 February 2011).
Strong, E. & F. Köhler. 2009. Morphological and molecular analysis of
"Melania" jacqueti Dautzenberg & Fischer, 1906: from anonymous
orphan to critical basal offshoot of the Semisulcospiridae (Gastropoda:
Cerithioidea). Zoologica Scripta 38(5): 483-502. Available at:
doi:10.1111/j.1463-6409.2008.00385.x (Accessed 17 May 2010).
Strong, E.E. and T.J. Frest. 2007. On the anatomy and systematics of
Juga from western North America (Gastropoda: Cerithioidea:
Pleuroceridae). The Nautilus 121(2): 43-65.
Taylor, D.W. 1966. Summary of North American Blancan Nonmarine
Mollusks. Malacologia 4:1-172.
ATTACHMENT 2: List of pertinent or knowledgeable contacts
Ed Johannes, Deixis Consultants, Tacoma, Washington
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ATTACHMENT 3:
Maps of subspecies distribution
Distribution of Juga hemphilli subsp. nov. in Oregon, relative to Forest
Service and BLM lands. The only known record of this subspecies is from
Indian Ford Creek near Black Butte in Deschutes National Forest,
Deschutes County, Oregon.
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ATTACHMENT 4:
Photographs of this genus
Photographs of the rare Juga hemphilli are not available. Shells of other
western Juga are shown. (Juga newberryi, figure 6 and 13-15; Juga
silicula, figures 2-4 and 7-9; Juga acutifilosa, figure 5 and 10-12.) Scale
bar = 1.0 cm. This figure was extracted from Strong and Frest (2007);
used with permission.
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ATTACHMENT 5: Aquatic Gastropod Survey Protocol, including
specifics for this subspecies:
Survey Protocol
Taxonomic group:
Aquatic Gastropoda
How:
Please refer to the following documents for detailed mollusk survey
methodology:
1. General collection and monitoring methods for aquatic mollusks
(pages 64-71):
Frest, T.J. and E.J. Johannes. 1995. Interior Columbia Basin
mollusk species of special concern. Final report: Interior Columbia
Basin Ecosystem Management Project, Walla Walla, WA. Contract
#43-0E00-4-9112. 274 pp. plus appendices.
2. Standard survey methodology that can be used by field personnel to
determine presence/absence of aquatic mollusk species in a given
waterbody, and to document species locations and habitats in a
consistent format:
Duncan, N. 2008. Survey Protocol for Aquatic Mollusk Species:
Preliminary Inventory and Presence/Absence Sampling. Version
3.1. Portland, OR. Interagency Special Status/Sensitive Species
Program. U.S. Department of Interior, Bureau of Land
Management, Oregon/Washington and U.S. Department of
Agriculture, Forest Service, Region 6. 52 pp. [Available at:
http://www.fs.fed.us/r6/sfpnw/issssp/species-index/faunainvertebrates.shtml].
Species-specific Survey Details:
Juga hemphilli subsp. nov.
This subspecies is currently known from a single site in Deschutes
County, Oregon (Deschutes National Forest near Black Butte, Indian
Ford Creek) (Frest & Johannes 1995). Any creeks south of Sisters in the
Whychus Creek Drainage are potential habitat and should be surveyed
for this subspecies (Johannes 2009, pers. comm.). Although there is
currently only one site for this subspecies, most mollusk surveys in the
area took place at springs and in land snail habitat, and streams in the
area have not been well explored (Johannes 2009, pers. comm.). Streams
and spring seeps in Glaze Meadow should be surveyed, as well as
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Whychus Creek (the creek that Indian Ford Creek drains into). The
swampy Lower Indian Ford Creek may not be appropriate habitat, since
this subspecies appears to require good water quality (see below).
Likewise, this taxon has not been found in Black Butte Ranch Springs to
the north, possibly due to damage and modification to the springs by the
golf resort at this location (Johannes 2009, pers. comm.). The adjacent
Metolius River doesn’t contain this subspecies (Johannes 2009, pers.
comm.).
Standardized abundance estimates for this subspecies at new and
known sites would assist future conservation efforts, since population
size is important in evaluating the stability of a species at a given
locality.
Although the only known collection date for this subspecies is in July,
sampling for this genus can be done year round (Deixis MolluscDB
2009). Hand and dip-net collection are the recommended survey
techniques for this snail (Johannes 2009, pers. comm.). Specimens have
been collected at a depth of 1 to 2 inches. Identification is based on
external shell morphology and other characters outlined in the fact
sheet. Expert identification of this taxon is recommended.
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