New species of Southern Appalachian earthworms

Two species of earthworms, new to science, have now been formally described. My colleagues and I were studying the effects of the 2016 wildfires in the Southern Appalachian Mountains when we found a few earthworms that we could not identify. Back at the lab, we carefully examined the specimens and conducted molecular (DNA) analysis to confirm that the specimens were indeed previously unknown.  

We formally described these two new earthworm species as Bimastos nanae and Bimastos magnum. B. nanae is named in memory of Nan Heidiger,  mother of a collaborator who helped with specimen collection. B. magnum bears its name due to its large size relative to other species in the genus, and large swellings (called porophores) where its male pores are found. 

Like other members of their genus, these worms have very small sexual organs, but they also had differences that set them apart from their relatives. The two native earthworm species, along with the others in the genus, have adopted habits that seem to allow them to avoid the direct effects of fire. 

Most ecosystems in the Southern Appalachian Mountains likely developed under the influence of fires that burned every two to 20 years. However, this region experienced decades of fire exclusion, allowing for the accumulation of leaf litter and other fuels. Due to extremely dry conditions across the region, this resulted in several large wildfires in 2016.

Fires and invertebrates impact soil function in significant ways. Wildfires are predicted to be more common, so it is important to understand how earthworms and other soil invertebrates in the Appalachian Mountains respond to fires. Further research is needed on the apparent adaptation of these native worms for survival in ecosystems with frequent fires.  

Read the article in the journal Zootaxa. For more information, email Mac Callaham at mac.a.callaham@usda.gov.