(DRAFT) - Taxonomy
Species SHELL, STIRRUP
Species Id ESIS404025
Date 13 MAR 96
TAXONOMY
NAME - SHELL, STIRRUP
OTHER COMMON NAMES - SHELL, STIRRUP; STIRRUPSHELL; SHELL and STIRRUP+
ELEMENT CODE -
CATEGORY - Aquatic Molluscs
PHYLUM AND SUBPHYLUM - MOLLUSCA,
CLASS AND SUBCLASS - BIVALVIA,
ORDER AND SUBORDER - UNIONOIDA,
FAMILY AND SUBFAMILY - UNIONIDAE,
GENUS AND SUBGENUS - QUADRULA,
SPECIES AND SSP - STAPES,
SCIENTIFIC NAME - QUADRULA STAPES
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Stirrup Shell
Quadrula stapes (I. Lea, 1831)
KINGDOM: Animal GROUP: Clam
PHYLUM: Mollusca CLASS: Bivalvia
ORDER: Unionoida FAMILY: Unionidae
The stirrup shell is a bivalve mollusk about 55 mm long, 50 mm
high, and 30 mm wide. The shell is yellowish-green, with the green
zigzag markings of young individuals becoming brown with age. It is
irregularly quadrate, with a sharp posterior ridge, truncated
posterior, tubercles, and a silvery white nacre that is thinner and
iridescent behind (01).
Quadrula stapes (Lea, 1821) has been listed in five different
genera. It was named Unio stapes by Lea in 1831; as Unio retusa by
Rafinesque in 1820 according to Say in 1834; as Margarita (Unio)
stapes by Lea in 1836; as Margaron (Unio) stapes by Lea in 1852; as
Quadrula stapes by Simpson in 1900; and as Orthonymus stapes by Haas
in 1969. Rafinesque's description of Unio retusa in the species
currently known as Obliquaria retusa, considered by some to be a
variant of Orthonymus, is considered to be a sub-genus with Quadrula
(01). The common name stirrup shell is also spelled stirrupshell
Taxonomy - 1 (DRAFT) - Taxonomy
Species SHELL, STIRRUP
Species Id ESIS404025
Date 13 MAR 96
(08).
The figured holotype is at the United States National Museum,
USNM 84212 (01). The type locality is the Alabama River.
Taxonomy - 2 (DRAFT) - Status
Species SHELL, STIRRUP
Species Id ESIS404025
Date 13 MAR 96
STATUS
Coded Status
Alabama; Federal Endangered
Alabama; Unofficially Listed
Mississippi; Federal Endangered
Mississippi; State Recognized
E: Federal Endangered
Commercial
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The stirrup shell (Quadrula stapes) 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 AL and MS. Critical Habitat has not been designated.
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 foreign law; 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.
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.
STATE STATUSES AND LAWS:
STATE: Alabama
UNOFFICIAL LIST: Endangered, Bulletin No.2, "Endangered and
Threatened Plants and Animals of Alabama",
Status - 1 (DRAFT) - Status
Species SHELL, STIRRUP
Species Id ESIS404025
Date 13 MAR 96
Alabama Museum of Natural History.
STATE: Mississippi
DESIGNATED STATUS: Recognized Endangered
ADMINISTRATIVE AGENCY: Department of Wildlife Conservation
STATE STATUTES: Public Notice No. 2156, Eff. Sept. 1, 1981.
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
The stirrup shell, Quadrula stapes, is listed as endangered in
the 1986 IUCN Red List of Threatened Animals.
ECONOMIC STATUSES:
The species may have some value in the cultured pearl industry.
79/05/01:44 FR 25589/ - Notice of review
80/04/11:45 FR 24904/24905 - Notice of review
84/05/22:49 FR 21664/21675 - Notice of review
86/04/07:51 FR 11761/11768 - Proposed rule
86/06/18:51 FR 22092/ - Notice of public hearing
87/04/07:52 FR 11162/11169 - Final rule, listed as Endangered
Status - 2 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
INLAND AQUATIC
LAND USE -
Streams and Canals
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Riverine, upper perennial SB2
Riverine, upper perennial SB1
COMMENTS ON HABITAT ASSOCIATIONS -
The stirrup shell is most commonly found in riffles and runs of
large rivers in habitat associated with moderate to strong current
over a relatively stable substrate of sand, gravel and cobble (01).
This stype of habitat is characteristic of most other species of the
subgenus Orthonymus in other drainage systems. Habitat requirements
would include: 1) moderate to strong current, 2) stable substrate of
coarse sediments, 3) sufficient amounts of the necessry life-materials
in solution or suspension in the river water, 4) lack of excessive
amounts of toxic materials and 5) the presence of the host species of
fish in adequate numbers at the right place at breeding time (01).
Habitat Associations - 1 (DRAFT) - Food Habits
Species SHELL, STIRRUP
Species Id ESIS404025
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 SHELL, STIRRUP
Species Id ESIS404025
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 SHELL, STIRRUP
Species Id ESIS404025
Date 13 MAR 96
LIFE HISTORY
FOOD HABITS:
Glochidia are probably obligate parasites on the tissues of the
gills or fins of fish. Adult Quadrula stapes are filter-feeders and
consume particulate matter suspended in the water column (02).
Identifiable stomach contents almost invariably include detritus,
bacteria, phytoplankton, diatoms, and zooplankters (02). No study of
the food habits of adult Quadrula stapes has been conducted;
specific required/preferred foods are therefore unknown.
HOME RANGE/TERRITORY:
Non-territorial. The species is sedentary during its adult life
and generally occurs in rivers with others of its kind.
PERIODICITY:
No known periodicity.
MIGRATION PATTERNS:
Non-migratory.
COVER/SHELTER REQUIREMENTS:
The stirrup shell requires flowing water, frequently a riffle,
over stable sand and gravel. Water velocity can vary greatly. The
sand and gravel substrate must remain free of any heavy sediment (01).
REPRODUCTIVE SITE REQUIREMENTS:
Since Q. stapes is a sedentary species reproductive site
requirements are the same as habitat requirements in general (See also
Cover/Shelter Requirements, above). Water velocity can vary greatly.
The sand and gravel substrate must remain free of any heavy sediment
(01).
REPRODUCTIVE CHARACTERISTICS:
Sperm are discharged into the surrounding water and dispersed by
water currents. Females downstream from the males obtain sperm during
the normal process of siphoning water while feeding and during
respiration. Fertilization occurs within the gills of the female,
which serve as marsupia for embryos developing to the parasitic stage
(glochidia) and are then released (02). The specifics of reproductive
characteristics for this species are unknown.
PARENTAL CARE:
No parental care occurs.
POPULATION BIOLOGY:
The population biology of this species is unknown.
SPECIES INTERRELATIONSHIPS:
The required fish hosts for the parasitic glochidia of this
species are unknown.
OTHER LIFE HISTORY DESCRIPTORS:
Life History - 1 (DRAFT) - Life History
Species SHELL, STIRRUP
Species Id ESIS404025
Date 13 MAR 96
None.
Life History - 2 (DRAFT) - Management Practices
Species SHELL, STIRRUP
Species Id ESIS404025
Date 13 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Maintaining/Controlling Water Flow
Beneficial Land Acquisition
Beneficial Creating Artificial Habitat/Nesting Structure
Adverse Siltation
Existing Siltation
Adverse Water Level Fluctuation
Existing Water Level Fluctuation
Adverse Reservoirs
Existing Reservoirs
Adverse Dredging
Existing Dredging
COMMENTS ON MANAGEMENT PRACTICES -
Loss of habitat due to impoundment and channelization is the
primary reason for the stirrup shell's decline. The type locality in
the Alabama River and most of the remaining river has been impounded
for navigation, flood control and hydro-power production.
Construction of the Tennessee-Tombigbee Waterway destroyed almost the
entire known habitat for this species. Modification of the remaining
habitat in the Sipsey River for flood control continues to threaten
this species (01).
UNAPPROVED PLAN:
No recovery plan is yet developed for the stirrup shell. Recovery
planning should be initiated in FY 1988.
Recovery actions that are anticipated for the stirrup shell
include: Maintaining water flow; creating artificial habitat (e.g.,
gravel bars); prohibiting sand and gravel dredging; and land easement
protection for remaining habitat.
At present, dredging is being prohibited and water flow is being
maintained.
Management Practices - 1 (DRAFT) - References
Species SHELL, STIRRUP
Species Id ESIS404025
Date 13 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Stansbery, D.H. 1981. The status of Quadrula stapes (Lea, 1831)
(Mollusca:Bivalvia:Unionoida). Unpubl. rep. on file at: USFWS,
Jackson Field Office, Jackson, MS. 10 pp + 4 pp museum records.
02 U.S. Fish and Wildlife Service. 1984. Recovery Plan for the Rough
Pigtoe Pearly Mussel [Pleurobema plenum (Lea, 1840)]. U.S. Fish
and Wildlife Service, Atlanta, GA. 51 pp.
03 Turgeon, D.D., A.E. Bogan, E.V. Coan, W.K. Emerson, et al. 1986.
Mollusks; A list of common and scientific names of aquatic
invertebrates from the United States and Canada. Am. Fish. Soc.
Special Publ., Bethesda, MD. 156 pp.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 Stansbery, D.H. 1981. The status of Quadrula stapes (Lea, 1831)
(Mollusca:Bivalvia:Unionoida). Unpublished rep. on file at:
USFWS, Jackson Field Office, Jackson, MS. 10 pp + 4 pp museum
records.
02 U.S. Fish and Wildlife Service. 1987. Endangered and threatened
wildlife and plants: Endangered status for five Mississippi and
Alabama clams. Fed. Reg. 52:11162-11169.
References - 1