Jirka, K. J. and R. J. Neves (1992).  Reproductive biology of four species of 
freshwater mussels (Mollusca: Unionidae) in the New River, Virginia and West 
Virginia. Journal of Freshwater Ecology.  7:35-44.
	
The gametogenic cycle, spawning and glochidial release periods, and age at 
sexual maturity were determined for four unionid species from the New River in 
Virginia and West Virginia: musket, Actinonaias ligamentina ; spike, Elliptio 
dilatata ; purple wartyback Cyclonaias tuberculata ; and pistolgrip, Tritogonia 
verrucosa . The mucket is a long-term brooder, spawning in mid-summer, brooding 
glochidia throughout fall and winter, and releasing them in spring. The spike, 
purple wartyback, and pistolgrip are short-term brooders. Spawning began in mid-
March and continued into May for T. verrucosa , into June for C. tuberculata , 
and into July for E. dilatata . Glochidia were release upon maturation, 
beginning in mid-April and continuing through June for T. verrucosa , into 
August for E. dilatata , and extending from March through June for C. 
tuberculata.  All four species are sexually mature at 4 to 6 years of age.