[PaleoOrnithology • 2016]
Dromornis murrayi • The Extinct Flightless Mihirungs (Aves, Dromornithidae): Cranial Anatomy, A New Species, and Assessment of Oligo-Miocene Lineage Diversity
ABSTRACT
Giant flightless fowl (Aves, Dromornithidae) similar to the Northern
Hemisphere gastornithids and weighing up to 350–650 kg evolved on
Gondwana and existed in what is now Australia from the Eocene to the
late Quaternary. Understanding cranial morphology of dromornithids has
until now been based almost wholly on species of Dromornis, with
that of species in three other genera either previously unknown or very
fragmentary. Here we rectify this deficiency and describe a
well-preserved cranium from the middle Miocene Bullock Creek Local Fauna
referred to Ilbandornis woodburnei, rich, fragmentary crania,
quadrates, pterygoids, and mandibles for the Oligo-Miocene Barawertornis tedfordi Rich, and additional material of the species of Ilbandornis.
The morphological similarity of this cranial material suggests that the
emu-sized B. tedfordi is a smaller precursor to and differs little from
species of Ilbandornis. Dromornis murrayi, n. sp.,
from late Oligocene–Early Miocene sites at Riversleigh, based on
cranial and postcranial elements, is the oldest and smallest species in
its genus. Placed in the context of other data, these observations
suggest that the dromornithids comprised only two lineages throughout
the Oligo-Miocene. The Barawertornis-Ilbandornis lineage attained
maximum diversity in the middle Miocene Bullock Creek and late Miocene
Alcoota local faunas (LF), with two species in each, but the Dromornis
lineage seems to have been monotypic throughout its temporal range. The
low diversity of these giant galloanseres in Australia mirrors that of
the giant herbivorous ratites (ostriches and kin), which similarly have
low diversity where they coevolved with diverse mammalian faunas.
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| Dromornis murrayi, A newly discovered flightless bird, reached 1.5 metres high and weighed up to 250 kilograms.
Illustration: Brian Choo/ Flinders University
|
Trevor H. Worthy, Warren D. Handley, Michael Archer and Suzanne J. Hand.
2016. The Extinct Flightless Mihirungs (Aves, Dromornithidae): Cranial
Anatomy, A New Species, and Assessment of Oligo-Miocene Lineage
Diversity. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.1031345
Researcher discovers ancestor of biggest bird ever http://phy.so/375346820 via @physorg_com
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