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Re: Fossil emus



Many thanks to Darren (and to Tim) for this info.  Isn't it wonderful what
you can learn about your local overburden from the other side of the world?

Cheers
Colin

-----Original Message-----
From: Tim Williams <twilliams_alpha@hotmail.com>
To: dinosaur@usc.edu <dinosaur@usc.edu>
Date: Thursday, 22 January 2004 2:22
Subject: Fossil emus


>The honorable Darren Naish requested that I forward this to the list.
>
>
>>
>>Emus have quite a good fossil record with definite members
>>of the Dromaiinae being known as early as the Pliocene
>>(note that in this discussion I follow most other recent
>>authors in regarding Dromaiinae and Casuariinae as sister-
>>taxa within the Casuariidae). Sibley & Ahlquist (1990)
>>proposed on the basis of DNA-DNA hybridisation that
>>dromaiines and casuariines diverged during the Late
>>Oligocene (c. 25 mya). Patterson & Rich (1987) reviewed
>>all fossil emus and this work should be your first stop if
>>you're interested in the fossil history of the group.
>>
>>_Emuarius_ from the Late Oligocene to Late Miocene of
>>Australia - originally placed within _Dromaius_ - has more
>>recently been argued to be a basal dromaiine outside
>>_Dromaius_ (see Boles 1992, 1997, 2001). _Emuarius_
>>combines features of cassowaries (e.g., femur, skull) with
>>those of emus (e.g., feet, tibiotarsus) and consequently its
>>generic name is a deliberate combination of 'emu' and
>>'_Casuarius_': on occasion Boles has even referred to
>>_Emuarius_ as a 'cassomu' or 'emuwary'. Two species are
>>presently known: _D. gidju_ from the Late Oligocene-early
>>Late Miocene of Riversleigh, Queensland; Early Miocene
>>Wipajiri Formation of South Australia; and Late Miocene of
>>Alcoota, Northern Territory, and _E. guljaruba_ from the
>>Late Oligocene Etadunna Formation of South Australia.
>>
>>The oldest known casuariines (cassowaries) are from the
>>Pliocene of Papua (Plane, 1967). Other fossil cassowaries
>>are known from the Pleistocene of New South Wales and
>>Papua.
>>
>>Charles De Vis named several fossil emu species, all from
>>the Pleistocene Darling Downs of Queensland, during the
>>1880s and 90s. _Dromaius patricius_ was based on an
>>assortment of bones, not all of which were avian: only a
>>partial tibiotarsus referred to this species is definitely from
>>an emu (De Vis, 1888, 1892, 1905) and it was shown by
>>Patterson & Rich (1987) to be indistinguishable from the
>>corresponding bone of _D. novaehollandiae_. De Vis
>>regarded _D. patricius_ as appreciably larger than _D.
>>novaehollandiae_ but in fact all the emu material of _D.
>>patricius_ overlaps in size with that of _D.
>>novaehollandiae_. A second species, _D. gracilipes_ (based
>>on a distal left tibiotarsus (De Vis, 1892)), is also
>>indistinguishable from the corresponding element of _D.
>>novaehollandiae_. _Metapteryx bifrons_, regarded by De
>>Vis (1892) as a giant kiwi and based on a partial left
>>tarsometatasus, is also a fossil emu and was shown by
>>Patterson & Rich (1987) to, again, be indistinguishable
>>from _D. novaehollandiae_.
>>
>>What appears to be the only valid species of entirely fossil
>>emu, _D. ocypus_, is from the Pliocene Mampuwordu
>>Sands of Lake Palankarinna, South Australia (Miller, 1963).
>>Only known from a damaged tarsometatarsus (though a
>>partial femur and partial tibiotarsus were later referred to
>>this species), _D. ocypus_ is smaller than both Pleistocene
>>and modern _D. novaehollandiae_ and it differs from _D.
>>novaehollandiae_ in having a more strongly convex
>>proximal intercotylar region.
>>
>>Finally, the extant species _D. novaehollandiae_ is known
>>from abundant Pleistocene records and there are even
>>questionable Late Pliocene sites yielding this species (e.g.,
>>Cooper Creek, SA; Lake Kanunka, SA). Pleistocene sites
>>that have yielded fossil _D. novaehollandiae_ include
>>Darling Downs (Queensland) as discussed above, Bingara
>>(NSW), Lake Callabonna (SA), Lake Menindee (NSW),
>>Naracoote (SA), Thorlindah (Queensland), and Wombeyan
>>Quarry (NSW). For the full details on all of these records
>>see Patterson & Rich (1987). These fossils show that _D.
>>novaehollandiae_ had appeared by the start of the
>>Pleistocene at least (1.6 mya) and possibly by the Late
>>Pliocene (somewhere around 2-3 mya).
>>
>>Several Pleistocene adult _D. novaehollandiae_ specimens
>>were smaller than living emus. This suggests that this
>>species underwent some periods of dwarfism in its history,
>>perhaps due to climatic or other palaeoenvironmental
>>factors.
>>
>>Fossils of both historically extinct emus, the King Island
>>(_D. ater_) and Kangaroo Island emus (_D. baudinianus_),
>>are known but are poorly dated: they are probably Holocene
>>but may be Late Pleistocene. How old these two species are
>>is unknown but it is likely that both were recently evolved
>>island endemics: Patterson & Rich (1987) write 'We favour
>>the idea that speciation on King and Kangaroo Island could
>>have taken place in very little time geologically speaking.
>>Strong selection for dwarfism quite likely occurred after
>>these emus became isolated at the beginning of the last
>>interglacial (i.e., the Holocene)' (p. 99). Incidentally both
>>_D. ater_ and _D. baudinianus_ can be distinguished from
>>_D. novaehollandiae_ on the basis of skull characters.
>>
>>The taxonomic status of the (also extinct) Tasmanian emu
>>(_D. diemenensis­_) is uncertain and whether this form was
>>part of _D. novaehollandiae_ or a distinct taxon remains
>>debated. Tasmanian emu fossils are known from the
>>Pleistocene (Scott, 1932). While the body size of the
>>historical Tasmanian emu population is controversial (there
>>is uncertainty as to whether it was a dwarf relative to _D.
>>novaehollandiae_), the Pleistocene Tasmanian fossils are
>>the same size as extant _D. novaehollandiae_.
>>
>>Refs --
>>
>>Boles, W. E. 1992. Revision of _Dromaius gidju_ Patterson
>>and Rich 1987 from Riversleigh, northwestern Queensland,
>>Australia, with a reassessment of its generic position.
>>_Science Series Natural History Museum of Los Angeles
>>County_ 36, 195-208.
>>
>>Boles, W. E. 1997. Hindlimb proportions and locomotion of
>>_Emuarius gidju_ (Patterson & Rich, 1987) (Aves:
>>Casuariidae). _Memoirs of the Queensland Museum_ 41,
>>235-240.
>>
>>Boles, W. E. 2001. A new emu (Dromaiinae) from the Late
>>Oligocene Etadunna Formation. _Emu_ 101, 317-321.
>>
>>De Vis, C. W. 1888. A glimpse of the post-Tertiary
>>avifauna of Queensland. _Proceedings of the Linnean
>>Society of New South Wales_ 3, 1277-1292.
>>
>>De Vis, C. W. 1892. Residue of the extinct birds of
>>Queensland as yet detected. _Proceedings of the Linnean
>>Society of New South Wales_ 6, 437-456.
>>
>>De Vis, C. W. 1905. A contribution of the extinct avifauna
>>of Australia. _Annals of Queensland Museum_ 6, 3-25.
>>
>>Miller, A. H. 1963. Fossil ratite birds of the late Tertiary of
>>South Australia. _Records of the South Australia Museum_
>>13, 413-420.
>>
>>Patterson, C. & Rich, P. V. 1987. The fossil history of the
>>emus, _Dromaius_ (Aves: Dromaiinae). _Records of the
>>South Australia Museum_ 21, 85-117.
>>
>>Plane, M. D. 1967. Stratigraphy and vertebrate fauna of the
>>Otibanda Formation, New Guinea. _Bureau of Mineral
>>Resources, Geology and Geophysics (Australia) Bulletin_
>>184, 1-64.
>>
>>Scott, H. H. 1932. The extinct Tasmanian emu.
>>_Proceedings of the Royal Society of Tasmania_ 1932, 103-
>>107.
>>
>>Sibley, C. G. & Ahlquist, J. E. 1990. _Phylogeny and
>>Classification of the Birds: A Study in Molecular
>>Evolution_. Yale Univ. Press (New Haven & London).
>>
>>--
>>Darren Naish
>>School of Earth & Environmental Sciences
>>University of Portsmouth UK, PO1 3QL
>>
>>http://web.port.ac.uk/departments/sees/staff/NaishD.htm
>>email: darren.naish@port.ac.uk
>>tel: 023 92846045
>
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