Pliocene marine mammals from the Whalers Bluff Formation of Portland, Victoria, Australia
62(1): 67-89 (2005)
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The most diverse and locally abundant Australian fossil marine mammal assemblages are those fromlate Neogene (Late Miocene through Late Pliocene) sediments in Victoria and Flinders Island, Tasmania. However, none of these assemblages have hitherto been described. The Pliocene (>2.5–4.8 Ma) Whalers Bluff Formation, exposed in beach cliff sections and offshore reefs, at Portland, western Victoria (38°19'S, 141°38'E) has yielded a small but moderately diverse assemblage of marine mammals represented by fragmentary material. Taxa present include: right whales (Balaenidae); rorqual whales (Balaenopteridae); a physeterid similar to the extant sperm whale (cf. Physeter sp.); the first Australian fossil record of pygmy sperm whales (Kogiidae); at least three genera of dolphins (Delphinidae: cf. Tursiops sp., Delphinus sp. or Stenella sp., and an undetermined genus and species); and probable earless or true seals (Phocidae). This small assemblage represents the first Australian fossil marine mammal assemblage to be described in detail. The taxonomic composition of this Pliocene marine mammal assemblage is generally similar to the present day marine mammal assemblage in north-west Bass Strait. The occurrence of extant cetacean genera in the Portland Pliocene and Flinders Island Cameron Inlet Formation assemblages indicates that the marine mammal fauna off south-east Australia had acquired an essentially modern aspect by the Late Pliocene. Several of the cetacean genera recorded in the Portland Pliocene assemblage also occur in similar-aged assemblages in other ocean basins. This corroborates the hypothesis that many cetacean taxa that are widely distributed in the world’s oceans today were equally widespread during the Pliocene.
Keywords: Cetacea, Carnivora, Pinnipedia, Phocidae, Mysticeti, Odontoceti, Australia, Victoria, Portland, Whalers Bluff Formation, Pliocene