Abstract:
The ostracod genus Krithe is reported from four grab, two box-core, 62 coretop samples, and Neogene to Quaternary DSDP cores from the abyssal and bathyal regions of the Tasman Sea and off southern Australia. Species identification followed the taxonomic system proposed by Coles et al. (1994), in which the anterodorsal radial pore canals are of fundamental importance. A total of 19 species are recognised, five species are described as new: K. comma, K. dilata, K. pseudocomma, K. prolata, and K. triangularis. Fifteen species are referred to previously described species, and the remaining rare species are left in open nomenclature. Although no living specimens have been recovered, shells of all species have been found in modern sediments and are, therefore, considered to be extant. Overall, the stratigraphic distribution of the species demonstrates an increase in diversity from 3 to 19 species since the Early Miocene, with no extinction. The bathymetric range of most species is wide, though in certain species there are significant differences between the two study regions, such as on the Australian Continental Slope, the relatively much deeper occurrences of K. triangularis and K. marialuisae, and the absence of K. dolichodeira a species found commonly elsewhere. An explanation for such differences is most likely to relate to nutrient, substrate, and oceanographic differences between the two regions.