The Species
Australian snubfin Orcaella heinsohni
Australian snubfin Orcaella heinsohni
Image courtesy of Dr Guido Parra, University of Queensland
Until recently, only one species of Orcaella was recognised in the Indo-Pacific region. However, new morphological and genetic studies of Orcaella showed that populations in north-eastern Australia are a separate species (the Australian snubfin Orcaella heinsohni) to the Asian species (the Irrawaddy Orcaella brevirostris).
The newly described species of Orcaella the
Australian snubfin Orcaella heinsohni is
Australia’s only endemic dolphin. The taxonomic revision was based on a range of
parameters including genetic samples from Asia and north Queensland, but only one
genetic sample from the NT. Due to this small sample size, the taxonomic identity of
Orcaella in Northern Territory waters remains uncertain. Nonetheless, there are a
number of differences in the external morphology, skull, colour pattern and genetic
distance within Orcaella specimens from Asia and Australia. The molecular
analyses demonstrated clear genetic differentiation between Australian and Asian
Orcaella .
Indo-Pacific humpback Sousa chinensis
Indo-Pacific
humpback Sousa chinensis
Image courtesy of Dr Guido Parra, University of Queensland
Within the Genus Sousa, three species are presently recognised including the Indian Sousa plumbea, Atlantic Sousa teuszi and the Indo-Pacific Humpback Sousa chinensis. While Australian Sousa populations are currently treated as Sousa chinensis there are doubts about species level taxonomy throughout the species distribution, and the taxonomy of Australian populations is poorly known.
There is strong geographical and individual variation, and currently only a small number of specimens and genetic samples (across most of the animals range) are available. Overall, for Sousa there are no clear patterns in external morphometrics, skeletal morphometrics or molecular datasets but to date, few genetic samples have been available from northern Australia and none for the Northern Territory.
