NOTE: Hover over the bold words for definitions or see the Glossary.
R. I. Johnson described this species in 1984. The shell shape of the Waccamaw fatmucket is sexually dimorphic. In males, the posterior ridge is angular (sometimes bi-angulate), while in females the posterior slope is broadly rounded to accommodate the marsupium. The periostracum is golden yellow to brown with green rays along the posterior third or more of the shell. The nacre has a pink-lavender cast. The marsupium has a dark margin. Two well developed pseudocardinal teeth are found in the left valve; one well developed pseudocardinal tooth in the right valve, one vestigial. Lateral teeth are short and straight, two in the left, one in the right. The male Waccamaw fatmucket may be confused with the Waccamaw spike; however, the spike has a much more angular posterior ridge and rarely has discernable rays on the periostracum. Genetics work by Stiven and Alderman (1992) suggests that the Waccamaw fatmucket is very closely related to the eastern lampmussel. Additional studies are recommended to confirm these findings.
The Waccamaw fatmucket is restricted to Lake Waccamaw in North Carolina.
Distribution by County: Columbus Co. (Lake Waccamaw) NOTE: All headwater areas that flow into these occupied habitats should receive special management.
Highest densities of this species are found in the "deep sand region" of Lake Waccamaw (Porter 1985).
This species is a bradytictic brooder; females may be gravid from September to June (Porter 1985). No fish hosts have been identified for this species at this time.
General Life History For Mussels