Description of loxocythere (novoloxocythere) pelius subgen. sp. nov. (ostracoda) from the cenozoic of S.E. Australia with comments on species of antarctiloxoconcha hartmann, 1986 and loxoreticulatum benson, 1964 from Australian and Antarctic marine waters

<i>Loxocythere (Novoloxocythere) pelius</i> subgen. et sp. nov. is described from Upper Miocene strata of the Port Phillip and Western Port Basins. Victoria. It has its acme in shallow open marine facies of latest Miocene (Cheltenhamian) age. This species, along with <i>Loxocythere</i><span style="font-style: italic;"> </span><i>(Novoloxocythere) kerryswansoni</i> Yassini and Jones, 1995, forms a discrete group of rotund Australian <i>Loxocythere</i> species that possess posterior extremities in both valves that are positioned well above mid carapace height (i.e. adjacent to dorsal margin). This feature along with a sub-triangular inner margin outline, defines a carapace shape that is distinct from that of rotund species of <i>Loxocythere (loxocythere)</i> Hornibrook, 1952 and<span style="font-style: italic;"> </span><i>Antarctiloxoconcha</i> Hartmann, 1986. The type species of <i>Antarctiloxoconcha – A.frigida</i> (Neale. 1967), possesses internal carapace features that are very similar to the type species of <i>Loxocythere - L. crassa</i> Hornibrook, 1952. Both have relatively short carapaces and sub-quadrate inner margin outlines with posterior extremities in both valves positioned below mid carapace height. Species of <i>Loxocythere (Novoloxocythere)</i>, in particular <i>L. (N.) kerryswansoni</i>, have a carapace shape that is transitional between<span style="font-style: italic;"> </span><i>Loxocythere</i> and <i>Loxoreticulatum</i> Benson, 1964. Species of <i>Loxoreticulatum</i> generally possess a sub-parallelogram shaped carapace/inner margin and arched median hinge element. The latter feature is distinct from the mostly straight median hinge elements of <i>Loxocythere (Loxocythere)</i> and<span style="font-style: italic;"> </span><i>Loxocythere (Novoloxocythere)</i> species. Species of <i>Loxocythere (Novoloxocythere)</i> are also readily distinguishable from relatively elongate species of <i>Loxocythere</i>, such as <i>L. (L.) hornibrooki</i> McKenzie, 1967, as the latter possess long (for genus), sub-rectangular shaped carapaces/inner margin outlines and posterior extremities below mid height.<br /><br />