Morphological variability, distribution and taxonomic relationships of Dendrobaena illyrica (Cognetti, 1906) (Lumbricidae).

This paper provides clear and definitive answers to the confusion caused by parthenogenetic forms in the delimitation of species in the earthworm taxonomy of the Balkan Peninsula. Dendrobaena illyrica (Cognetti, 1906) is a species group with high morphological variability. Its varieties have been described several times under specific names, and erroneous identifications still need to be corrected. Dendrobaena illyrica has been considered a parthenogenetic species. The taxonomic relationships between D. illyrica and the little-known Balkan endemic species Dendrobaena serbica Karaman, 1973 have been a long-standing puzzle. The taxonomic status of D. serbica was clarified by comparing specimens from our collections and literature data, to determine the intraspecific variations of morphological characters. Our specimen's research has significantly corrected previous misconceptions, indicating that D. serbica shows biparental reproduction with phoral insemination. Considering the morphological and biogeographic differences of the species mentioned, we propose that D. serbica is not a parthenogenetic form of D. illyrica.