True to its name, the lilliput is one of Missouri’s smallest freshwater mussels. Adult shells are no more than 2 inches long. It is fairly widespread, occurring in large rivers with slow to no current in silt, mud, silt and sand, or fine gravel; also in ponds, lakes, large reservoirs, and overflow waters.
Externally, the lilliput's shell is small, stout, thick, elliptical, and inflated. The umbo (beak) is moderately broad and low. The periostracum (thin outer layer) is light brown to greenish brown, becoming dark brown to black with age.
Inside the shell, the beak cavity is shallow to moderately deep; the pseudocardinal teeth are thin, high, triangular, and roughened; the lateral teeth are also thin but well developed, long, high, and bladelike; the nacre (mother-of-pearl layer) is bluish white, sometimes with a salmon tinge, and iridescent posteriorly.
For a fuller introduction to Missouri’s native freshwater mussels, and to learn the terms for their anatomy, see their group page.
Similar species: The purple lilliput (Toxolasma lividum) has a larger, more rounded shell with distinctive purple nacre and are found in the southern Ozarks. The Texas lilliput (Toxolasma texasiense) has a satiny sheen to its shell. The salamander mussel (Simpsonaias ambigua) is also similar.
Adult length: 1–2 inches. One of Missouri's smallest freshwater mussels.
In appropriate habitats, fairly widespread throughout the state, in part due to its ability to adapt to lake environments (including the Lake of the Ozarks, Lake Hunnewell, and Stockton Reservoir).
Habitat and Conservation
Large rivers with slow to no current in silt, mud, silt and sand, or fine gravel; also in ponds, lakes, large reservoirs, and overflow waters.
Food
Freshwater mussels consume algae, bacteria, and fine particles of decaying organic matter. They extract nutrients and oxygen from water drawn into the body cavity through a specialized structure called the incurrent siphon; sediment, undigested food, and waste (called pseudofeces) are expelled through the excurrent siphon.
Status
Uncommon. Sporadic, but more common than the other two lilliput species.
Life Cycle
Males release sperm directly into water. Females downstream siphon sperm into the gill chamber, where eggs are fertilized. Eggs mature into larvae (called glochidia), which discharge into the water and attach to host fish. The tiny mussel eventually breaks away and floats to the bottom of the stream, and the cycle repeats.
For its larval hosts, the lilliput has been recorded using white crappie, green sunfish, orangespotted sunfish, bluegill, warmouth, and even the Johnny darter.
Human Connections
Mussels play important roles in maintaining the health of Missouri’s water resources:
- As food for fish, they are important for Missouri’s fisheries. Small mammals and some birds eat them, as well.
- They filter algae, bacteria, and other particles from the water, improving water quality and cycling nutrients and energy in streams and lakes. Clean water is necessary for people and nature.
- Because mussels are sensitive to habitat disturbance and pollution, they are good indicators of the overall health of aquatic ecosystems and water quality.
The shells of several types of mussels were an important resource historically for button manufacture. Some species are still commercially important in the cultured pearl and jewelry industries.
Ecosystem Connections
Mussels play important roles in maintaining the health of Missouri’s water resources:
- As food for fish, they are important for Missouri’s fisheries. Small mammals and some birds eat them, as well.
- They filter algae, bacteria, and other particles from the water, improving water quality and cycling nutrients and energy in streams and lakes. Clean water is necessary for people and nature.
- Because mussels are sensitive to habitat disturbance and pollution, they are good indicators of the overall health of aquatic ecosystems and water quality.
The shells of several types of mussels were an important resource historically for button manufacture. This species is one that was used to make buttons. Some species are still commercially important in the cultured pearl and jewelry industries.
