On a representative of the genus Eukerria (Ocnerodrilidae, Oligochaeta)

Abstract

The relations between Eukerria subandina (Rosa, 1895) and E. borellii (Cognetti, 1900), hitherto uncertain and disputed, are reconsidered on the basis of the study of new material found in the province of Tucuman (Arroyo del Toro), Argentine. Possessing the inconspicuous spermathecal pores and the male genital field of the type of E. subandina, these worms show a series of features, including the position of the nephropores, which are characteristic simultaneously of both mentioned Ocnerodriles. Among the characters stressed as differential for the separation of E. subandina and E. borellii, the configuration of the male genital field, a little unequal in both forms, and the aspect of the spermathecal pores, inconspicouos in the former of these and provided of papillae in the last, alone remain valid. However these differences are considered as of morphic significance only, and the suggestion of Michaelsen (1900) for the synonymizing of E. subandina and E. borellii is accepted. A synthetized definition of E. subandina (Rosa, 1895) is added. The capacity of the uniparental reproduction (probably facultative parthenogenesis) was experimentally confirmed in this species.