Southern Pigtoe

Although the diets of freshwater mussels are poorly understood, it is believed to consist of algae, and or, bacteria. Some studies suggest that the diets of freshwater mussels may change throughout their life, with juveniles collecting organic materials from the substrate though pedal feeding and then developing the ability to filter feed during adulthood. Pedal feeding is a form of deposit feeding where the animal uses their muscular foot to bury into the sediment, collecting organic matter. Filter feeding is a process by which mussels feed off suspended organic material by pumping in water through their incurrent aperture and out through their excurrent apertures, capturing the particles and using them as food.

Many freshwater mussels spend the majority of their life sedentary and filter feeding on the bottom of rivers and streams. Sometimes they will bury into the sediment, only revealing a small portion of their aperture, which is used for gas exchange and filter feeding. 

Freshwater mussels live an interesting multi-stage life cycle which depends upon a fish host to complete. Males release sperm into the water column, to be hopefully siphoned in by the incurrent aperture of the females, where the eggs held within her gills are then fertilized. Once the fertilized eggs start to develop, the female becomes inflated, or gravid. The fertilized eggs develop into glochidia, which is the mussels larval stage. This stage requires a fish host for transformation into the juvenile stage, which sometimes requires a little coaxing by females. Glochidia are housed in packets called conglutinates and often mimic a food source of the fishes within that ecosystem to lure the fish to bite. Once the fish bites, the glochidia clamp down onto the fish, becoming encysted, and feed from the fish for several weeks until dropping off as juveniles. The Alabama shiner, blacktail shiner, and tricolor shiner have been reported as hosts for glochidia of the southern pigtoe.

The southern pigtoe is a short-term brooder, gravid during spring and early summer. The Alabama shiner, blacktail shiner, and tricolor shiner have been reported as hosts for this species (MRBMRC 2010). However, attempts in 2010 and 2015 to culture this species, found the blacktail shiner to be a poor host, producing only 49 juveniles from 31 infested blacktail shiners (Johnson 2018). 

The periostracum is yellow to yellow-brown. Growth lines are numerous and may be dark brown. Small specimens may have green spots at the growth lines along the posterior ridge and near the umbo

The southern pigtoe is a small to medium-sized mussel measuring up to 65 mm in length. The shell is elliptical to oval in outline and somewhat compressed. The posterior slope is smoothly rounded. The pseudocardinal teeth (protrusions on the dorsal interior surface of the shell) are small but well-developed, and the nacre is white. The periostracum is yellow to yellow-brown. Growth lines are numerous and may be dark brown. Small specimens may have green spots at the growth lines along the posterior ridge and near the umbo

The southern pigtoe occurs in riffles, runs, and shoals of medium creeks to large rivers in sand and gravel substrates.

A genetic analysis of Pleurobema species from the Mobile River Basin was conducted using a portion of the mitochondrial and nuclear DNA (Campbell et al. 2008). This analysis found that southern pigtoe and Canoe Creek clubshell (P. athearni) were closely related species.

P. georgianum physically resembles P. hanleyianum, but P. hanleyianum is typically more elongate.