Two new interesting species of Macrodasyida (Gastrotricha) from KwaZulu-Natal (South Africa)

This study is part of a larger research program aimed at shedding light on meiofauna and macrofauna communities of the subtropical Eastern Province of KwaZulu-Natal, South Africa. Previous articles on the phylum Gastrotricha have detailed faunistic and preliminary taxonomic data on marine and freshwater species found in the iSimangaliso Wetland Park. Here, two new interesting marine macrodasyidan species, in the families Cephalodasyidae and Turbanellidae, are reported from a wider area of the KZN coast. Descriptions are based on observations carried out on living specimens using differential interference contrast microscopy. Pleurodasys incomptus new species is the second species in the genus; surprisingly, it lacks the peculiar gravireceptor organs (pharyngeal knobs) thought to be an autapomorphic trait of the genus. Paraturbanella africana new species is a mid-sized species (up to 520 µm in length), showing a peribuccal swelling; its most obvious autapomorphic trait pertains to the testes, which are located well passed half the body rather than at- or near the pharyngo-intestinal junction as occur in the other species of the genus. The relevant anatomical novelties shown by the two new species testify that current knowledge about gastrotrich basic morphology is far from complete. This holds true also for taxa that are considered to be well-known (e.g. the speciose genus Paraturbanella), and stresses once again the importance of investigating new geographic areas in order to improve our understanding of global gastrotrich morphological diversity and species richness.