Natural Science Forum / Biology / Paleontology / August 2006

The above news report is based on the paper "A bizarre new toothed
mysticete (Cetacea) from Australia and the early evolution of baleen
whales"

Abstract:

Extant baleen whales (Cetacea, Mysticeti) are all large filter-feeding
marine mammals that lack teeth as adults, instead possessing baleen,
and feed on small marine animals in bulk. The early evolution of these
superlative mammals, and their unique feeding method, has hitherto
remained enigmatic. Here, I report a new toothed mysticete from the
Late Oligocene of Australia that is more archaic than any previously
described. Unlike all other mysticetes, this new whale was small, had
enormous eyes and lacked derived adaptations for bulk filter-feeding.
Several morphological features suggest that this mysticete was a
macrophagous predator, being convergent on some Mesozoic marine
reptiles and the extant leopard seal (Hydrurga leptonyx). It thus
refutes the notions that all stem mysticetes were filter-feeders, and
that the origins and initial radiation of mysticetes was linked to the
evolution of filter-feeding. Mysticetes evidently radiated into a
variety of disparate forms and feeding ecologies before the evolution
of baleen or filter-feeding. The phylogenetic context of the new whale
indicates that basal mysticetes were macrophagous predators that did
not employ filter-feeding or echolocation, and that the evolution of
characters associated with bulk filter-feeding was gradual.

http://www.journals.royalsoc.ac.uk/link.asp?id=h6h887j21g07641r

Erich Fitzgerald's homepage:
http://www.geosci.monash.edu.au/postgrad/directory/fitzgerald/index.html