Snails: Indian Ford Juga (Juga hemphilli subsp. nov.)

(Gastropoda: Neotaenioglossa: Semisulcospirinae)
Profile prepared by Sarah Foltz Jordan, Sarina Jepsen and Julia Janicki, The Xerces Society for Invertebrate Conservation.

Juga is a genus of medium-sized, aquatic, gilled snails. Juga hemphilli subsp. nov. is a new (undescribed) subspecies with its nacre white and its shell dark brown with two dark brown bands. Juga snails are characterized as rasper-grazers, feeding on both algae and detritus, such as dead alder leaves. The habitat for this subspecies is considered to be streams and spring-seeps; it 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. Nutrient enhancement, grazing, water diversions and such activities that degrade the water quality are the major threats to Juga hemphilli. Further surveys should be done in order to evaluate better the current status of the species.

conservation status
Global Status (2009): G2
National Statuses: United States (N2); Canada (N1)
State Statuses: Oregon (S2); Washington (S2)
Province Status: British Columbia (SNR)
(NatureServe 2009)
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. 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.

taxonomic status
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).
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).
distribution
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).

Abundance: No abundance estimates have been made for this subspecies, but according to NatureServe (2009), Juga hemphilli is declining (10-30%).

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 (Black Butte Ranch); 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). According to Frest & Johannes (1995), this subspecies should minimally be considered a sensitive taxon by the Forest Service, BLM, and other land management and wildlife agencies, and should probably be Federal and State (OR) Endangered. The other Juga hemphilli subspecies are also faced with imminent threats throughout their ranges (NatureServe 2009; Frest & Johannes 1995).
conservation needs
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 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 should be surveyed for this subspecies (Johannes 2009, pers. comm.). Streams and spring seeps in Glaze Meadow should 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 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.).

Management: Manage 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.

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 #43-0E00-4-9112. 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 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).

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.

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