Paleontology

[evelyn sobielski <koreke77@yahoo.de>]

In the same issue as _Mopsitta_:
TREVOR H. WORTHY, MICHAEL S. Y. LEE (2008) AFFINITIES OF MIOCENE WATERFOWL 
(ANATIDAE: MANUHERIKIA, DUNSTANETTA AND MIOTADORNA) FROM THE ST BATHANS FAUNA, 
NEW ZEALAND. Palaeontology 51 (3) , 677â708 
doi:10.1111/j.1475-4983.2008.00778.x 

Abstract: The recently described St Bathans Fauna, from the Manuherikia Group, 
EarlyâMiddle Miocene, 19â16 Ma, New Zealand, includes six anatid taxa. Here 
we present detailed morphological descriptions of all available skeletal 
elements of the three best represented anatids: Manuherikia lacustrina (551 
specimens), Dunstanetta johnstoneorum (7 specimens), and Miotadorna 
sanctibathansi (115 specimens). The affinities of these taxa, and of the 
similar-aged European taxon Mionetta blanchardi, are evaluated with 
phylogenetic analyses using a dataset of 133 characters (128 osteological, 5 
integumental) and 57 terminal taxa. Representatives of all main anatid groups 
were included, with dense sampling of Australasian taxa including the recently 
extinct New Zealand forms (Cnemiornis, Chenonetta finschi), and relatively 
primitive taxa (anserines, Dendrocygna, oxyurines, tadornines). Analyses were 
conducted with no constraints, and with certain taxa constrained
 to conform to arrangements supported by multiple independent genetic studies. 
In the preferred (constrained) analyses: (1) anserines were the most basal 
anatids; (2) the four Tertiary fossil taxa were more derived than anserines and 
Dendrocygna; and (3) the European Mionetta blanchardi was basal to an oxyurine 
clade. The New Zealand fossils Manuherikia and Dunstanetta either associated 
with this oxyurine clade or formed separate lineages of an approximately 
oxyurine evolutionary grade, depending on whether diving characters were 
included or excluded. Similarly, Biziura, Thalassornis, and a 
StictonettaâMalacorhynchus clade either associated with oxyurines or formed 
independent lineages of approximately oxyurine grade. Above oxyurines, a 
well-supported clade groups Miotadorna with Tadorna species exclusive of T. 
radjah. These results cast doubt on the distinctiveness of Dendrocheninae 
Livezey and Martin, 1988, and instead suggest oxyurine affinities for
 the Miocene fossils Mionetta, Dendrochen, Manuherikia and Dunstanetta, and the 
modern Biziura, Thalassornis, Oxyura, Nomonyx, Stictonetta and Malacorhynchus. 
The association of Mionetta with oxyurines indicates that the divergence 
between oxyurines and higher anatids occurred around 25 Ma, while the position 
of Miotadorna within Tadorna indicates that the basal divergence between living 
Tadorna occurred by the EarlyâMiddle Miocene; together, these two dates 
indicate that many basal splits within anatids occurred within a short interval 
during the Miocene.


A hefty piece of work. *Nice* taxon sampling too. The "approximately oxyurine 
evolutionary grade" is probably more correct. 


Regards,

Eike


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