Dromedary naiad

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Dromedary naiad
Dromus dromas.jpg
Scientific classification
D. dromas
Binomial name
Dromus dromas
(I. Lea, 1834)

The dromedary naiad or dromedary pearly mussel (Dromus dromas) is a rare species of freshwater mussel in the family Unionidae. This aquatic bivalve mollusk is native to the Cumberland and Tennessee River systems in the United States, where it has experienced a large population decline. It is a federally listed endangered species of the United States.

This mussel is yellow-green in color with interrupted green rays on the shell. The nacre is white, pink, or reddish. The species got its name from the distinctive hump on the shell of larger individuals.[2]

This species lives in clear, clean, fast-flowing water. It cannot tolerate water of poor quality, for example, water with silt.[3]

Like other freshwater mussels, this species reproduces by releasing larvae called glochidia into the water. The glochidia are eaten by fish and lodge in the fish's gills, where they develop into juvenile mussels. Fish hosts for this mussel species include black sculpin (Cottus baileyi), greenside darter (Etheostoma blennioides), fantail darter (Etheostoma flabellare), snubnose darter (Etheostoma simoterum), tangerine darter (Percina aurantiaca), blotchside logperch (Percina burtoni), logperch (Percina caprodes), channel darter (Percina copelandi), gilt darter (Percina evides), and Roanoke darter (Percina roanoka).

This species was historically one of the most common mussels in the Tennessee River. Now only old individuals can be found there. The species has been reduced to no more than 4 populations. It has been extirpated from the wild in the state of Alabama, but it has been reintroduced there. The only remaining reproducing populations occur in the Clinch and Powell Rivers.[3] Reproducing populations remain in under 10% of the mussel's historical range, and the populations are disjunct.[4]

Factors contributing to its decline include the impoundment of waterways, increased silt, and pollution from sewage, coal mining, and oil and gas drilling.[3]


  1. ^ Bogan, A.E. 1996. Dromus dromas. 2011 IUCN Red List of Threatened Species. Archived June 27, 2014, at the Wayback Machine Downloaded on 26 September 2011.
  2. ^ USFWS. Dromus dromas Recovery Plan. July 1984.
  3. ^ a b c Dromus dromas. The Nature Conservancy.
  4. ^ Jones, J. W., et al. (2004). Life history and propagation of the endangered dromedary pearlymussel (Dromus dromas) (Bivalvia: Unionidae). J N Am Benthol Soc 23(3) 515-25.