Three-Horn Wartyback
ExploreInvertebrate
Three-Horn Wartyback
obliquaria reflexa
The Three-Horn Wartyback (Obliquaria reflexa) is a fascinating freshwater mussel native to the river systems of North America, particularly the Mississippi River Basin. Named for the distinct, alternating row of prominent knobs running down its thick shell, this species looks like a tiny, armored river-dweller. As a filter feeder, it plays a vital ecological role by purifying water, making it an unsung hero of aquatic ecosystems. Like many freshwater mussels, the Three-Horn Wartyback possesses an incredibly unique life cycle that involves a temporary parasitic stage. Its microscopic larvae, called glochidia, must attach to the gills or fins of specific host fish to develop into juvenile mussels. This remarkable evolutionary strategy allows the relatively sedentary mussel to disperse far and wide across river networks, hitching rides on fast-moving fish before dropping off to begin its life in the riverbed. Want to find and snap Three-Horn Wartyback yourself? Get the Snappit app.
Habitat: Found primarily partially buried in the sand and gravel substrates of medium to large rivers with moderate currents.
Appearance
This medium-sized mussel typically grows up to 8 centimeters in length and is easily identified by its thick, somewhat rounded, and inflated shell. Its most defining characteristic is a prominent central row of 3 to 4 large, raised bumps or 'horns' that uniquely alternate in position from one valve to the other, rather than lining up symmetrically. The exterior shell color ranges from yellowish-green to brown, often patterned with faint, broken green rays, while the interior nacre (mother-of-pearl) is typically solid white and slightly iridescent.
KingdomAnimaliaPhylumMolluscaClassBivalviaOrderUnionidaFamilyUnionidaeGenusObliquaria
Category
InvertebrateRarity
Common
Danger
1/5 · Very low
Snaps
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Interesting facts
A single adult freshwater mussel can filter and clean up to 15 gallons of river water every single day.
During the late 19th and early 20th centuries, their thick, white-nacred shells were heavily harvested and punched out to make natural pearl buttons for clothing.
They rely entirely on fish to spread their young; without their specific host fish in the river system, the mussel population cannot expand.
Unlike most other bumpy mussels whose knobs line up symmetrically, the Three-Horn Wartyback's 'horns' alternate from the left shell to the right shell.
Special abilities
Ability
Water Filtration
Functions as an active biofilter, siphoning gallons of water daily to extract food and consequently improving water clarity and quality in its habitat.
Ability
Parasitic Hitchhiking
Utilizes specific fish species as temporary hosts for its microscopic larvae, allowing its young to be transported safely across vast river networks.
Ability
Asymmetrical Armor
Grows thick, alternating knobs on its valves which provide structural reinforcement against strong river currents and crushing forces from predators.
Measurements & details
- Length
- 3-8 cm
- Weight
- 0.05-0.15 kg
- Lifespan
- 10-30 years
- Clutch Size
- 10000-95000
- Incubation
- 14-60 days
Diet & Feeding
Relies entirely on filter feeding to strain microscopic plant and animal matter from the water column.
Age differences: During the larval stage (glochidia), it absorbs nutrients directly from a host fish; as an adult, it filter feeds independently.
Primary Foods
- Phytoplankton
- Zooplankton
- Detritus
- Bacteria
Foraging Method
- Filtering
Ecological connections
eaten by
Muskrat
Ondatra zibethicus
Muskrats actively hunt and eat adult freshwater mussels, often leaving distinct piles of empty shells known as middens on riverbanks.
host
Common Shiner
Luxilus cornutus
Serves as a vital host species for the mussel's parasitic glochidia larvae.
competitor
Zebra Mussel
Dreissena polymorpha
An invasive species that aggressively attaches to native mussels' shells, competing for resources and often suffocating them.
Traits
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Also known as
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Safety
Danger
1/5 · Very low
No special safety notes yet.
Frequently Asked Questions
How to identify Three-Horn Wartyback?
The easiest way to identify Three-Horn Wartyback is to use the Snappit nature identifier app.
How long is Three-Horn Wartyback?
3-8 cm
How much does Three-Horn Wartyback weigh?
0.05-0.15 kg
How long does Three-Horn Wartyback live?
10-30 years
What does Three-Horn Wartyback eat?
Relies entirely on filter feeding to strain microscopic plant and animal matter from the water column.
Where is Three-Horn Wartyback usually found?
Found primarily partially buried in the sand and gravel substrates of medium to large rivers with moderate currents.
How does Three-Horn Wartyback hunt?
Filtering
How many eggs does Three-Horn Wartyback lay?
10000-95000
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