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Two new species of bairdiid Ostracoda are described from the lower Barremian – Hauterivian interval of the Valhall and Åsgard formations in the northern and central North Sea and Atlantic margin off Norway. The new species are Pontocyprella valhalla (lsid:zoobank.org:act:CA6B273F-CFF6-4C38-B9F4-18188225A711, 18 January 2018) and Bairdia asgarda (lsid:zoobank.org:act:4A4DC817-A028-45FB-9287-ABF3794F2FCB, 18 January 2018). These species dominate the ostracod assemblage that occurs abundantly in early Barremian–Hauterivian deep marine sediments of the northern and central North Sea and Haltenbanken area off Norway. Pontocyprella valhalla is restricted to this interval and because of its large size and distinct shape is a useful stratigraphic marker species, its last appearance being within the early Barremian.

From an examination of 34 grab and dredge samples ranging from 110 m to 3584 m water depth, collected during Eltanin cruise 47 across the Kerguelen Plateau, 26 shallow-water and 35 deep-sea benthonic ostracod species have been identified. Systematic notes and illustrations of the common and some of the rare species are presented. Two new species are described: Philoneptunus cassidyi n. sp. and Taracythere abyssora n. sp. Comparisons made with the Atlantic and SW Pacific Oceans and circum-Antarctic regions indicate that the fauna comprises dominantly cosmopolitan deep-sea species while most of the other species have close affinities with the SW Pacific. In the Kerguelen material, seven distinct depth assemblages appear to correspond well with differing watermasses and there is evidence that the relatively shallow position of Antarctic Intermediate Water permits elevation of the upper depth limits of some deep-sea species. Some species have developed ornament of fine reticulation, features not previously seen in those species outside the Kerguelen region.

A well-preserved and diverse ostracod fauna of late Eocene, Kaiatan Stage age is described from a mudstone sample (Ashley Mudstone Formation) from the Waihao River outcrop near McCulloch's Bridge, South Canterbury, New Zealand. A total of 8,662 specimens are assigned to 104 species including one new genus and 13 new species. Of the new species all but the Cytheruridae are described herein. The new genus is Taracythere, type species T. proterva (Hornibrook, 1953) and the new species described here are: Pseudeucythere biplana, Eucythere sulcocostatula, Copytus pseudoelongatus, Neocytherideis reticulata, Patagonacythere waihaoensis, Munseyella pseudobrevis, Actinocythereis microagrenon and Pennyella leptodictyota. Because of a need for reillustration of established species, most of the remaining 91 species are illustrated and the systematics of some of these is remarked upon. Sixty-two species have been previously described, eight are tentatively referred to previously described species, and 21 are left in open nomenclature mainly due to paucity of material. The assemblage is interpreted as having lived in a low energy marine environment on the outer shelf or upper slope. Comparison with contempory ostracod faunas of southeastern Australia indicates very high affinity: 56 common genera, out of the 61 genera listed here. Considering the timing of Tasman seafloor spreading (Paleocene to Middle Eocene) and foundering of continental crustal regions of the eastern Tasman Basin to bathyal depths (initially Middle Eocene), trans-Tasman ostracod dispersal probably predates late Eocene times. The greater number of endemic Eocene genera recorded in Australia suggests that migration was dominantly eastwards.

During examination of the large ostracode assemblage collections at the Department of Scientific and Industrial Research, Geology & Geophysics, Lower Hutt, New Zealand, a single specimen of unusual shape was encountered. So unusual is the crescentic outline and infolding of the entire shell periphery that assignment even to a phylum was difficult, and it was only upon scanning electron microscopic study that subcentral muscle scars were clearly observed and these enabled confident identification of the specimen as an ostracode. One specimen is not usually considered sufficient to propose a new taxon; however, in this case there is no doubt that this unique specimen clearly represents a new species, genus, and probably family of Ostracoda. A search for additional specimens from the type unit is underway, but has, as yet, been unsuccessful to find this rare intriguing ostracode. Unlike other unusual ostracodes described from the Southern Hemisphere such as the punciids, this specimen appears to have no similarity with Paleozoic taxa.

The new cyprid genus, Aratrocypris, based on four species ranging in age from Upper Palaeocene to Recent, is described. One species is left in open nomenclature and three, A.rectoporrecta (the type species), A.vaccamaris and A.praealta are described as new. The genus bears a unique plough-like structure anteroventrally and the possible function of this and the palaeoecology of the animal are discussed in detail. It is suggested that the plough-like structure, in association with other carapace structures such as the posterior position of the adductor muscle scars and the hinge, together with the strong degree of anterodorsal overlap, are indicators of a feeding mode associated with forward movement through the sediment. However, it is also possible that the animal was a filter feeder living within the sediment at a steep angle to the sea floor with the anteroventral structure protruded beyond the sediment water interface.

Two new deep sea species of the genus Cytheropteron (C. branchium and C. pherozigzag spp. nov) are described. Both species occur in abyssal and bathyal Pliocene to Quaternary environments in the S. W. Pacific; the latter species has also been recovered from abyssal palaeodepths in the N.E. Atlantic and E. Indian Ocean in the Late Quaternary. Both species are unusual in possessing shallow yet prominent slit-like structures below and posteroventral to the alar process. Such structures are unknown in other species of the genus; their possible function is discussed.