(DRAFT) - Taxonomy
Species MUSSEL, PEARLY, LILLIPUT, PALE
Species Id ESIS404006
Date 13 MAR 96
TAXONOMY
NAME - MUSSEL, PEARLY, LILLIPUT, PALE
OTHER COMMON NAMES - MUSSEL, PEARLY, LILLIPUT, PALE; LILLIPUT and PALE
ELEMENT CODE -
CATEGORY - Aquatic Molluscs
PHYLUM AND SUBPHYLUM - MOLLUSCA,
CLASS AND SUBCLASS - BIVALVIA,
ORDER AND SUBORDER - UNIONOIDA,
FAMILY AND SUBFAMILY - UNIONIDAE,
GENUS AND SUBGENUS - TOXOLASMA,
SPECIES AND SSP - CYLINDRELLUS,
SCIENTIFIC NAME - TOXOLASMA CYLINDRELLUS
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Pale Lilliput Pearly Mussel
Toxolasma cylindrellus (Lea, 1868)
KINGDOM: Animal GROUP: Clam
PHYLUM: Mollusca CLASS: Bivalvia
ORDER: Unionoida FAMILY: Unionidae
T. cylindrellus is a small Cumberlandian species with a maximum
length of 44 mm (01). Valves are elongate and elliptical with
subparallel dorsal and ventral margins; beaks are full and lack
sculpturing (02,03). The posterior ridge is low or absent, and the
shell surface is smooth (03). Beak cavities are shallow and mussel
scars are deep. The periostracum is thick and cloth-like,
yellow-green in color and without rays (03). Nacre color is white
outside the pallial line and white to copper color inside (01,02,03).
This species exhibits sexual dimorphism; females have a slight
marsupial swelling at the posterior end of the valves.
This species is distinguished from closely related species by the
elliptical shape, yellow-green periostracum, and white nacre outside
the pallial line (03).
Original Federal listing of this species included the feminine,
cylindrella, with the masculine, Toxolasma; T. cylindrellus is the
Taxonomy - 1 (DRAFT) - Taxonomy
Species MUSSEL, PEARLY, LILLIPUT, PALE
Species Id ESIS404006
Date 13 MAR 96
correct binomial name. The only record of this species outside the
Tennessee River drainage is one of the type localities. The species
was described by Lea (1868) from Duck Creek, TN and northern Alabama,
but also Swamp Creek which is in the Mobile River drainage (04).
The taxonomic confusion with species of Toxolasma is extensive.
The genus Toxolasma was created by Rafinesque in 1831 for Unio lividus
whereas Carunculina was elevated to generic status much later (05).
Early species names in the genus included lividus, glans,
cylindrellus, and moesta. A description of the synonymy and confusion
among species is presented elsewhere (03). Although T. cylindrellus
may be another form of T. lividus (06), most malacologists accept it
as a valid species.
Detailed descriptions and photographs of this species are
included in previous publications (01,02,03,07).
Taxonomy - 2 (DRAFT) - Status
Species MUSSEL, PEARLY, LILLIPUT, PALE
Species Id ESIS404006
Date 13 MAR 96
STATUS
Coded Status
Alabama; Federal Endangered
Alabama; Unofficially Listed
Georgia; Federal Endangered
Georgia; State Recognized
Tennessee; Federal Endangered
Tennessee; State Listed
E: Federal Endangered
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The pale liliput pearly mussel (Toxolasma cylindrellus) has been
designated an Endangered species pursuant to the Endangered Species
Act of 1973 (50 CFR 17.11; P.L. 93-205, 87 Stat. 884; 16 U.S.C.
1531-1540), as amended. The species has this status wherever found
including the States of Alabama, Georgia, and Tennessee.
This species is protected by the Lacey Act (P.L. 97-79, as
amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import,
export, transport, sell, receive, acquire, or purchase any wild
animal (alive or dead including parts, products, eggs, or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
DOD (COE) -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public land under their control. Also responsible for
management/recovery on Department of Defense lands.
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
Status - 1 (DRAFT) - Status
Species MUSSEL, PEARLY, LILLIPUT, PALE
Species Id ESIS404006
Date 13 MAR 96
STATE STATUSES AND LAWS:
State: Alabama
Unofficial Lists: Endangered, Bulletin No.2, Alabama Museum of
Natural History, Endangered and Threatened
Plants and Animals of Alabama.
State: Georgia
Designated Status: Recognized Endangered
Administrative Agency: Ga. Dept. of Natural Resources
State Statutes: Game & Fish Laws of Georgia, Title 27,
Chapter 3, p. 10
State: Tennessee
Designated Status: Endangered
Administrative Agency: Tennessee Wildlife Resources Agency
State Statutes: Proclamations 75-15, 76-4 and amendments
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
CITES I
ECONOMIC STATUSES:
There are no known commercial values for the pale lilliput.
However, the species' sedentary nature and filter feeding habits may
make it useful as a water quality indicator. It has been shown that
mussels accumulate such pollutants as heavy metals and pesticides.
74/10/17:39 FR 37078/37079 - Notice of review
75/09/26/40 FR 44329/44333 - Proposed rule
76/06/14:41 FR 24062/24066 - Final rule, listed as Endangered
76/06/16:41 FR 24367/24378 - Proposed - CITES I
77/02/22:42 FR 10484/10485 - Final rule - CITES I
81/02/27:46 FR 14652/14658 - Five year review
87/07/07:52 FR 25523/25528 - Notice of review
Status - 2 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
INLAND AQUATIC
LAND USE -
Streams and Canals
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Riverine, upper perennial UB1
Riverine, upper perennial SB1
COMMENTS ON HABITAT ASSOCIATIONS -
T. cylindrellus is a small species that occurs in small rivers
and streams. It occurs in shallow, fast-flowing riffles with stable,
clean substrate (02). Because of its restricted distribution, no
other data are available on specific environmental requirements for
the adults or any other life stage. The species does not occur in the
impounded sections of rivers where it once occurred.
Habitat of the glochidia is initially within the gills of the
female, then in the water collumn, and finally attached to a suitable
fish host. Any alteration of these life stage-specific habitats
during its life cycle would likely affect the long term success of a
population. Habitat requirements or associations for the juvenile
stage are unknown.
Habitat Associations - 1 (DRAFT) - Food Habits
Species MUSSEL, PEARLY, LILLIPUT, PALE
Species Id ESIS404006
Date 13 MAR 96
FOOD HABITS
TROPHIC LEVEL -
OMNIVORE
LIFESTAGE FOOD FOOD PART
General Detritus
General Bacteria
General Phytoplankton
General Diatoms
General Zooplankton
General Fish
Food Habits - 1 (DRAFT) - Environment Associations
Species MUSSEL, PEARLY, LILLIPUT, PALE
Species Id ESIS404006
Date 13 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Aquatic Features: Pool areas
Environment Associations - 1 (DRAFT) - Life History
Species MUSSEL, PEARLY, LILLIPUT, PALE
Species Id ESIS404006
Date 13 MAR 96
LIFE HISTORY
FOOD HABITS:
There are no known interspecific differences in feeding among
freshwater mussels (08). The glochidia are obligate parasites on the
gills or fins of fish. Adult mussels are filter-feeders and consume
particulate matter suspended in the water column. Identifiable
stomach contents almost invariably include mud, desmids, diatoms,
other unicellular algae, protozoa, and zooplankters (12,13). No study
of the food habits of T. cylindrellus has been conducted; required
or preferred foods are therefore unknown.
HOME RANGE/TERRITORY:
Non-territorial. The species is sedentary during its adult life
and generally occurs in small rivers and streams with others of its
kind.
PERIODICITY:
No known periodicity.
MIGRATION PATTERNS:
Non-migratory.
COVER/SHELTER REQUIREMENTS:
This species occurs in streams and small rivers with riffles and
clean, stable substrate (02). No species-specific information on
cover/shelter is available in the literature.
REPRODUCTIVE SITE REQUIREMENTS:
T. cylindrellus is a flowing water species that occurs in riffles
of streams and small rivers (02). Since this species is assumed to be
sedentary and movement is inconsequential, this is the type of
environment where all life history processes are carried out,
including reproduction.
REPROCUCTIVE CHARACTERISTICS:
The reproductive cycle of the pale lilliput is presumed to be
similar to other freshwater mussels. During spawning, males discharge
sperm into the water column, and the sperm are taken in by the
females during siphoning. Eggs are fertilized in the female's
suprabranchial cavity or gills, which serve as marsupia for embryos
developing to the parasitic stage (glochidia). Glochidia are released
by the female and must attach to a suitable fish host for
metamorphosis to the free-living juvenile stage.
The genus consists of long-term breeders (14), spawning in
summer, maintaining glochidia through fall and winter, and releasing
them in spring and early summer (02). Glochidia are probably hookless
and similar to those of T. moesta (02). Fish hosts are unknown, but
glochidia of T. moesta transformed on two species of sunfish (Lepomis
cyanellus and L. megalotis) (02).
PARENTAL CARE:
Except for retention of the glochidia within the gills of the
Life History - 1 (DRAFT) - Life History
Species MUSSEL, PEARLY, LILLIPUT, PALE
Species Id ESIS404006
Date 13 MAR 96
female prior to release, no parental care occurs.
POPULATION BIOLOGY:
No information exists on the population biology of this species.
Possible limiting factors include both man-made and natural factors
such as: High concentrations of heavy metals, seasonal oxygen
deficits, extreme water level fluctuations, reduced water flow,
turbidity, siltation, pollution (herbicide and pesticide), and altered
temperature regimes. Quantitative levels and duration of tolerance of
these factors is unknown. However, typical biological responses
attributable to these environmental changes include reductions in fish
and benthic microinvertebrate communities (02).
SPECIES INTERRELATIONSHIPS:
The required fish hosts for the parasitic glochidia of this
species are unknown, but glochidia of T. moesta transformed on two
species of sunfish (Lepomis cyanellus and L. megalotis) (02).
OTHER LIFE HISTORY DESCRIPTORS:
No life history information is available.
Life History - 2 (DRAFT) - Management Practices
Species MUSSEL, PEARLY, LILLIPUT, PALE
Species Id ESIS404006
Date 13 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Developing/maintaining stream structures
Beneficial Maintaining/Controlling Water Flow
Beneficial Controlling/Restricting Mining
Beneficial Controlling/Restricting Road Maintainance Actions
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Land Acquisition
Beneficial Controlling pollution [thermal, chemical, physical]
Beneficial Controlling/Restricting Pesticide Use
Beneficial Controlling/Restricting Herbicide Use
Beneficial Controlling/Restricting Agricultural Practice
Beneficial Restricting Timber Harvest
Beneficial Stocking captive-reared wild-strain animals
Beneficial Transplanting wild animals
Beneficial Transplanting Wild Eggs/Wild Seeds
Beneficial Restricting Poaching
Beneficial Controlling/Restricting Noncommercial Harvest
Adverse Inherent Reproductive Characteristics
Existing Inherent Reproductive Characteristics
Adverse Low Gene Pool
Existing Low Gene Pool
Adverse Underground Mines
Existing Underground Mines
Adverse Surface Mines
Existing Surface Mines
Adverse Siltation
Existing Siltation
Adverse Water Temperature Alteration
Existing Water Temperature Alteration
Adverse Dissolved Oxygen Reduction
Existing Dissolved Oxygen Reduction
Adverse Water Level Fluctuation
Existing Water Level Fluctuation
Adverse Reservoirs
Existing Reservoirs
Adverse Migration barriers
Existing Migration barriers
Adverse Dredging
Existing Dredging
Adverse Applying herbicides
Existing Applying herbicides
Adverse Applying pesticides
Existing Applying pesticides
Adverse Environmental Contamination/Pollution
Existing Environmental Contamination/Pollution
Adverse Exotic/Feral/Introducted Species
Existing Exotic/Feral/Introducted Species
Adverse Erosion
Existing Erosion
Adverse
Management Practices - 1 (DRAFT) - Management Practices
Species MUSSEL, PEARLY, LILLIPUT, PALE
Species Id ESIS404006
Date 13 MAR 96
RESULT MANAGEMENT PRACTICE
Existing
COMMENTS ON MANAGEMENT PRACTICES -
The mussel fauna in most streams of the Tennessee River drainage
has been impacted by dam construction, channelization, siltation, and
water pollution, which directly affect all mussel species (01,08).
The change from lotic to lentic conditions because of dams has also
altered the species composition of the fish community, thus
jeopordizing the reproductive success of some mussel species by
eliminating required fish hosts. Although siltation has been
suggested as the most significant adverse effect of impoundments on
mussels (08), other detrimental factors include lowered water
temperatures, pH changes, oxygen depletion, and dewatering of mussel
beds below dams (08). Mussel deaths can occur in substrate on which
0.6-2.5 cm of silt has accumulated, resulting in interference with
feeding and suffocation (09). The siphoning period and metabolic
rate of mussels can also be affected by such contaminants as heavy
metals and agricultural chemicals (10).
Water pollution has probably contributed to the decline of this
species. Numerous tributaries in the Tennessee River drainage were
polluted already by the twentieth century, and the mussel fauna was in
a decline at that time (11). Coal and mineral mining wastes have
contributed additional particulate and chemical pollutants to the
tributaries.
In the Duck River, completion of Normandy Dam in 1976 and the
proposed Columbia Dam have or will probably eliminate any specimens of
T. cylindrellus in that river. Completion of Tims Ford Dam on the Elk
River probably contributed to the elimination of that historic
population. The population in Larkin Fork may have been eliminated by
agricultural chemical spraying (01). Poor land use practices and
environmental contaminants are the most likely future threats to
remaining populations of the pale lilliput. Other factors that may
and will be affecting this species include invasion of the Asiatic
clam (Corbicula fluminea), and the smaller gene pool which may be
approaching the minimum population size needed for sufficient genetic
variation to respond to environmental changes.
APPROVED PLAN:
U.S. Fish and Wildlife Service. 1984. Pale Lilliput Pearly Mussel
Recovery Plan. U.S. Fish and Wildlife Service, Atlanta, GA. 46 pp.
Actions for the recovery of Toxolasma (=Carunculina)
cylindrellus include:
(1) Conduct population and habitat surveys to determine the status
and range of the species.
(2) Determine specific threats to the species. Impacts that are
potentially harmful include road construction, dredging,
Management Practices - 2 (DRAFT) - Management Practices
Species MUSSEL, PEARLY, LILLIPUT, PALE
Species Id ESIS404006
Date 13 MAR 96
herbicide or pesticide spraying, presence of chlorinated
effluents, strip mining, oil and gas drilling, industrial
development, some agricultural practices, incidental commercial
harvest, and logging.
(3) Identify essential habitat areas in need of protection. Utilize
Scenic River Status, mussel sanctuaries, and land agreements or
acquisitions where feasible.
(4) Continue to use existing legal mechanisms to protect the species
and its habitat.
(5) Determine the feasibility of reintroduction into the historic
range, and the best methods for doing so (e.g. introduction of
adults, juveniles, infected fish hosts, and/or artificially
propagated individuals). Reintroduce where feasible.
It is considered unlikely that removal of this species from
the list of federal endangered or threatened plants and animals
is possible without the expansion of the Paint Rock, Estill Fork,
and Hurricane Creek populations, and the establishment of new
populations in other rivers.
Except for enforcement of regulations, there are no recovery
efforts presently underway for this species.
Management Practices - 3 (DRAFT) - References
Species MUSSEL, PEARLY, LILLIPUT, PALE
Species Id ESIS404006
Date 13 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Stansbery, D.H. 1976. Status of endangered fluviatile mollusks
in central North America, Toxolasma cylindrellus (Lea, 1868).
Ohio St. Univ. Res. Found. RF 3712. 9 pp.
02 U.S. Fish and Wildlife Service. 1984. Recovery Plan for the Pale
Lilliput Pearly Mussel, Toxolasma (=Carunculina) cylindrellus
(Lea 1868). U.S. Fish and Wildlife Service., Atlanta, GA. 46 pp.
03 Bogan, A.E. and P.W. Parmalee. 1983. Tennessee's rare wildlife
Volume II: the mollusks. Tenn. Wildl. Resour. Agency, Tenn. Dep.
Conserv., and Tenn. Heritage Prog., Univ. Tenn., Knoxville, TN.
123 pp.
04 Lea, I. 1868. Description of sixteen new species of the genus
Unio of the United States. Proc. Acad. Nat. Sci., Phila.
20:143-145.
05 Ortmann, A.E. 1914. Studies in naiades. Nautilus 28:65-69.
06 Ortmann, A.E. 1925. The naiad fauna of the Tennessee River
system below Walden Gorge. Am. Midl. Nat. 9:321-371.
07 Parker, W. and L. Dixon. 1980. Endangered and Threatened wildlife
of Kentucky, North Carolina, South Carolina, and Tennessee. N.C.
Agric. Ext. Serv. 116 pp.
08 Fuller, S.L.H. 1974. Clams and mussels (Mollusca:Bivalvia).
Pages 215-273. IN: C. W. Hart and S. L. H. Fuller (eds.),
Pollution ecology of freshwater invertebrates. Academic Press,
N.Y.
09 Ellis, M.M. 1931. Some factors affecting the replacement of the
commercial fresh-water mussels. U.S. Bur. Fish Circ. No.7 10 pp.
10 Salanki, J. 1979. Behavioural studies in mussels under changing
environmental conditions. Symp. Biol. Hung. 19:169-176.
11 Ortmann, A.E. 1918. The nayades (freshwater mussels) of the
upper Tennessee drainage with notes on synonymy and distribution.
Proc. Am. Phil. Soc., Phila. 57:521-626.
12 Coker, R.E., A.F. Shira, H.W. Clark, and A.D. Howard. 1921.
Natural history and propagation of fresh-water mussels. Bull. U.S.
Bur. Fish. 37:77-181.
13 Churchill, E.P., Jr. and S.I. Lewis. 1924. Food and feeding in
freshwater mussels. Bull. U.S. Bur. Fish. 39:439-471.
14 Heard, W.H. and R.H. Guckert. 1970. A re-evaluation of the
recent Unionacea (Pelecypoda) of North America. Malacologia
10:333-355.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 U.S. Fish and Wildlife Service. 1984. Recovery Plan for the Pale
Lilliput Pearly Mussel, Toxolasma (=Carunculina) cylindrellus
(Lea 1868). U.S. Fish and Wildlife Service, Atlanta, GA. 46 pp.
02 Tennessee Valley Authority (TVA). 1980. Freshwater mussels of the
Paint Rock River. Unpublished data.
03 Isom, B.G., P. Yokley, Jr., and C.H. Gooch. 1973. The mussels
of the Flint and Paint Rock River systems of the southeast slopes
References - 1 (DRAFT) - References
Species MUSSEL, PEARLY, LILLIPUT, PALE
Species Id ESIS404006
Date 13 MAR 96
of the Cumberland Plateau in North America, 1965-1967. Am. Midl.
Nat. 89:442-446.
04 Bogan, A.E. and P.W. Parmalee. 1983. Tennessee's rare wildlife
Volume II: the mollusks. Tenn. Wildl. Resour. Agency, Tenn. Dept.
Conserv., and Tenn. Heritage Prog., Univ. Tenn., Knoxville, TN.
123 pp.
05 Stansbery, D.H. 1976. Status of Endangered fluviatile mollusks
in central North America. Toxolasma cylindrellus (Lea 1868). Ohio
State Univ. Res. Found. RF 3712. 9 pp.
06 Lea, I. 1868. Description of sixteen new species of the genus
Unio of the United States. Proc. Acad. Nat. Sci., Phila.
20:143-145.
07 Ortmann, A.E. 1925. The naiad fauna of the Tennessee River
system below Walden Gorge. Am. Midl. Nat. 9:321-372.
08 Ortmann, A.E. 1924. The naiad fauna of the Duck River in
Tennessee. Am. Midl. Nat. 9:18-62.
09 Van der Schalie, H. 1973. The mollusks of the Duck River drainage
in central Tennessee. Sterkiana 52:45-55.
References - 2