DNA barcoding reveals cryptic diversity in Lumbricus terrestris, resurrects L. herculeus

This paper is now in press at PLoSONE:

DNA Barcoding Reveals Cryptic Diversity in Lumbricus terrestris L.,
1758 (Clitellata): Resurrection of L.
herculeus (Savigny, 1826)

Samuel W. James¹, David Porco², Thibaud Decaëns³, Benoit Richard³, Rodolphe
Rougerie², Christer Erséus⁴

¹Biodiversity Institute, Kansas University, 1345 Jayhawk Blvd., Lawrence,
KS 66045, USA. sjames@ku.edu 1-319-351-1300 Corresponding Author

²Canadian Centre for DNA Barcoding, Biodiversity Institute of Ontario, 579 Gordon street, Guelph, Ontario,
N1G 2W1 Canada

³Laboratoire d’Ecologie, UPRES-EA 1293 ECODIV, FED SCALE, Bâtiment IRESE A,
UFR Sciences et Techniques, Université de Rouen, F-76821 Mont Saint
Aignan cedex, France

⁴Department of Zoology, University of Gothenburg, Box 463, SE-405 30 Göteborg,
Sweden

Abstract

The widely studied and invasive earthworm, Lumbricus terrestris L., 1758 has been the subject
of nomenclatural debate for many years. However these disputes were not based on suspicions of heterogeneity, but rather on the descriptions and
nomenclatural acts associated with the species name.
Large numbers of DNA barcode sequences of the cytochrome oxidase I obtained for nominal L. terrestris
and six congeneric species reveal that there are two distinct lineages within nominal L. terrestris. One of those lineages contains the Swedish population from which the name-bearing specimen of L. terrestris was obtained. The other contains the population from which the syntype series of Enterion herculeum
Savigny, 1826 was collected. In both cases modern and old
representatives yielded barcode sequences allowing us to clearly
establish that these are two distinct species, as different from one
another as any other pair of congeners in our data set. The two are
morphologically indistinguishable, except by overlapping size-related
characters. We have designated a new neotype for L. terrestris. The newly designated neotype and a syntype of L. herculeus
yielded DNA adequate for sequencing part of the cytochrome oxidase I
gene (COI). The sequence data make possible the objective determination
of the identities of earthworms morphologically identical to L. terrestris
and L. herculeus, regardless of body size and segment number. Past work on nominal L. terrestris could have
been on either or both species, although L. herculeus has yet to be found outside of Europe.