FWS Focus

Overview

Characteristics
Overview

This snail is an integral part of a complex food web found in freshwater ponds exclusively along coastal North Carolina. This rare snail can no longer be found in the wild places it once inhabited and is not to be confused with a common relative (the ramshorn snail) found abundantly in pet shops and aquariums. The magnificent ramshorn was pushed out of its natural habitat and since 1993 remains in existence only in captivity. If enough habitat is secured in suitable ponds and sustained into the future, magnificent ramshorn snails could be released to repopulate their historical habitat. 

 This gastropod, freshwater snail is presumed extirpated from the Lower Cape Fear River Basin and has been a candidate for Endangered Species Act protection since 2011. 

Partnerships, Research and Projects 

The U.S. Fish and Wildlife Service works with others to implement conservation. Three organizations maintain a captive population of the species to ensure its survival and produce individuals for future reintroductions. Known surviving individuals of the species are held and propagated by the following organizations: 

  • North Carolina Wildlife Resources Commission’s Watha State Fish Hatchery currently has thousands of snails in captivity. 

  • Coastal Plain Conservation Group (CPCG) provides ecosystem research, conservation education, and habitat management. 

  • North Carolina State University’s Veterinary School. 

In captivity, the magnificent ramshorn snail is thriving by the thousands. Finding the high-quality and salt-free habitat it needs is a priority to securing its future. A team of experts led by the North Carolina Wildlife Resources Commission is evaluating the reintroduction potential of several sites. 

The next step is recruiting private landowners in the Wilmington area who are willing to carry out conservation actions to benefit the snail. During the summer of 2018, Service biologists conducted field surveys to identify presence of spatterdock and lily pads, general site conditions and pH levels. 

How you can help 

Landowners in a few areas within (or with similar characteristics to) the historic range can shore up dams that protect ponds, providing safe homes for the snails and other valued species, and preserving the scenic appeal of cypress trees and water lilies that share their need for freshwater. Finding enough suitable ponds for the snails in the lower Cape Fear River basin is an urgent need. Biologists are optimistic that Endangered Species Act protection will not be necessary to ensure the species’ survival if enough suitable ponds are made available to the species and sustained into the future. 

Scientific Name

Planorbella magnifica
Common Name
Magnificent Rams-horn
Magnificent Ramshorn
FWS Category
Snails
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Similar Species

Characteristics
Similar Species

Planorbella duryi and Planorbarius corneus are common snails with coiled shells that are found in the aquarium trade

Characteristic category

Habitat

Characteristics
Habitat

The snail is adapted to still or slow-flowing aquatic habitats, and lays eggs on spatterdock and lily pads. Salinity and pH appear to have been major factors limiting the distribution of the magnificent ramshorn, as the snail prefers freshwater bodies with pH within the range of 6.8–7.5. 

Coastal

The land near a shore.

Wetland

Areas such as marshes or swamps that are covered often intermittently with shallow water or have soil saturated with moisture.

Characteristic category

Food

Characteristics
Food

The magnificent ramshorn snail is an herbivore. It eats submerged aquatic plants, algae, and detritus. In captivity, one of their favorite food items is ripe seed head of spatterdock. They eat various other plants, including lettuce, and algae wafers with spirulina. Juveniles have been observed feeding on detritus and biofilm. Like other snails, it has a radula, sometimes called a “rasping tongue,” that scrapes against the substrate they are crawling across. 

Characteristic category

Physical Characteristics

Characteristics
Size & Shape

As a member of the pulmoate family, the magnificent ramshorn is an air-breathing snail, gastropod and mollusk. It has a coiled shell in the shape of a ram’s horn. Its brown coiled shell - often with leopard-like spots-grows to the size and weight of a U.S. dollar coin, roughly 1.38 inches in diameter and 0.79 inch in height. The width of its shell, in relation to the diameter, makes it easily identifiable at all ages to those familiar with freshwater snails. It’s also distinctive in that its aperture is very large, bell-shaped, and is the widest section of the coil. It also loses its eyesight over time as the eyes become covered by the thickened cuticle. Download a presentation on magnificent ramshorn conservation. 

Geography

Characteristics
Range

Historical range 

The magnificent ramshorn is believed to be found only in southeastern North Carolina. The species was historically known from only four sites in the lower Cape Fear River Basin in North Carolina — the snail appears to be extinct at all four sites. Those sites were: 

  • Greenfield Lake, a millpond located on a tributary to the Cape Fear River within the present city limits of Wilmington, New Hanover County 
  • Orton Pond (aka Sprunt’s Pond), a millpond located on Orton Creek in Brunswick County 
  • Sand Hill Creek Pond (aka Pleasant Oaks Pond), a millpond on Sand Hill Creek in Brunswick County. 
  • McKinzie Pond, a millpond on McKinzie Creek, in Brunswick County 

Surveys of more than 100 potential sites over the last few decades have not uncovered any additional localities with this snail. Although the complete historical range of the species is unknown, its size and the fact that it was not reported until 1903 suggest that the species may have always been rare and localized. 

Current Range 

Believed to be extirpated from the wild. The last individual seen in the wild was in 2004-2005. 

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Timeline

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