[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: Cretaceous, yes -- Netherlands, yes -- marsupial, unlikely



Ups!

Should have read the article first before I jumped to conclusion about the
authority of the analysis presented...
Those trees where original... :(

Cheers!

--Mikko Haaramo

> -----Original Message-----
> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu] 
> On Behalf Of Mikko K. Haaramo
> Sent: 2. tammikuuta 2006 9:46
> To: david.marjanovic@gmx.at; 'DML'
> Subject: RE: Cretaceous, yes -- Netherlands, yes -- 
> marsupial, unlikely
> 
> Thank you for using "Archive", take the trees persented with 
> a grain of salt... :)
> 
> So, based on David's analysis, I should place this critter as 
> a "Ameridelphia incertae sedis"?
> 
> Question: Who is Nortedelphys??
> 
> --Mikko Haaramo
> 
> ********************************************************************
> 
> Mikko K. Haaramo, M.Sc.
> 
> Paleontologist & IT-Manager
> 
> Department of Geology
> P.O.Box 64 (Gustaf Hällströminkatu 2)
> FIN-00014  University of Helsinki
> 
> sposti: mailto:mikko.haaramo@helsinki.fi
> www: Mikko's Phylogeny Archive 
> [http://www.fmnh.helsinki.fi/users/haaramo/]
> 
> ******************************************************************** 
> 
> > -----Original Message-----
> > From: owner-dinosaur@usc.edu 
> [mailto:owner-dinosaur@usc.edu] On Behalf 
> > Of David Marjanovic
> > Sent: 2. tammikuuta 2006 0:55
> > To: DML
> > Subject: Cretaceous, yes -- Netherlands, yes -- marsupial, unlikely
> > 
> > The most spectacular news first. Mammal hair is mentioned 
> in passing 
> > to occur in amber from the Campanian of Siberia!!!
> > 
> > -----------------------------------
> > 
> > I've now read the paper:
> > 
> > James E. Martin, Judd A. Case, John W. M. Jagt, Anne S. 
> > Schulp & Eric W. A. 
> > Mulder: A New European Marsupial Indicates a Late Cretaceous 
> > High-Latitude Transatlantic Dispersal Route, Journal of Mammalian 
> > Evolution 12(3/4),
> > 495 -- 511 (December 2005)
> > 
> > The authors don't even try to find out whether 
> *Maastrichtidelphys*, 
> > called a "pouched mammal" once, is a crown-group marsupial or not. 
> > Before the paleobiogeography section the word Metatheria is never 
> > mentioned; even in it, *Didelphodon*, peradectids and 
> pediomyids are 
> > "marsupials". Only
> > *Marsasia* and *Asiatherium* are not "marsupials". It seems 
> to follow 
> > that "Marsupialia" is used for something like the 
> "Neometatheria" of 
> > http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma
> > /Chordata/Synapsida/Metatheria/Metatheria.htm
> > or the "Archimetatheria" of
> > http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma
> > /Chordata/Synapsida/Metatheria/Metatheria_2.htm,
> > which may or may not be the crown-group depending on the phylogeny, 
> > and is much bigger than the crown-group on the currently accepted 
> > phylogenies.
> > Which phylogenies Martin et al. consider likely (let alone
> > why!) is never explained, and neither do they even just 
> mention that 
> > some (most??) people use a different definition of 
> Marsupialia. IMHO 
> > this counts as a significant failure of peer-review.
> > 
> > Martin et al. say *Maastrichtidelphys* is a herpetotheriid, 
> say that 
> > Herpetotheriidae is known from the early Maastrichtian (of North 
> > America) onwards, and say that this group is "seemingly 
> related to the 
> > North American opossum".
> > In the "Systematic Paleontology" section, they accordingly 
> put Family 
> > Herpetotheriidae into Superfamily Didelphoidea and Order 
> > Didelphimorphia, which they put into Cohort Ameridelphia -- I'm 
> > certain they know that this latter taxon is paraphyletic. 
> (Marsupialia 
> > is a supercohort, in case you're wondering...) In other words, they 
> > clearly don't think that only clades (and species) should be named.
> > 
> > *Maastrichtidelphys* "shares the greatest number of 
> character states 
> > with species (albeit not all) of" the early Eocene herpetotheriids
> > *Amphiperaterium* (Europe) and *Garatherium* (Africa). I 
> wonder what 
> > this exercise in phenetics is for.
> > 
> > Despite the phenetics, a phylogenetic analysis is done. 
> > *Nortedelphys* (described a year earlier by the same authors) comes 
> > out as a herpetotheriid.
> > 
> > First analysis -- only North American taxa and 
> *Maastrichtidelphys*, 
> > to find out which of the former is closest to the latter:
> > 
> > --+--+--*Maastrichtidelphys*
> >   |  `--*Nortedelphys*
> >   `--+--*Didelphodon*
> >      `--+--*Alphadon*
> >         `--+--*Albertatherium*
> >            `--+--*Protalphadon*
> >               `--+--*Pediomys*
> >                  `--*Turgidodon*
> > 
> > The authors do not explain how this tree was rooted.
> > 
> > Second analysis -- to find out where *Maastrichtidelphys* 
> lies among 
> > "other latest Cretaceous and Paleocene didelphoid marsupial taxa":
> > 
> > --+--*Didelphodon*
> >   `--+--*Alphadon*
> >      `--+--*Jashkadelphys*
> >         `--+--*Mizquedelphys*
> >            `--+--*Pucadelphys*
> >               `--+--*Itaboraidelphys*
> >                  `--+--*Maastrichtidelphys*
> >                     `--*Nortedelphys*
> > 
> > This tree is rooted with *Didelphodon* and *Alphadon* as outgroups. 
> > Note that the topology contradicts the first tree.
> > *Pucadelphys* and
> > *Itaboraidelphys* come from the Paleocene of South America, 
> making the 
> > idea that Herpetotheriidae belongs to the crown-group more plausible
> > (*Pucadelphys* is close to the crown, but apparently outside). But 
> > note that the monophyly of "Didelphoidea" is not tested; not one 
> > non-"didelphoid" is included, if we assume that the authors still 
> > include everything in "Didelphoidea" that was included 
> _fifty_ years 
> > ago.
> > 
> > I could obviously be wrong, but I conclude that the authors have 
> > likely a priori assumed that their "Didelphimorphia" and 
> > "Didelphoidea" are clades and built their conclusions (like a South 
> > American origin for
> > *Nortedelphys*) on this assumption that they have not tested. 
> > Both of their poorly supported cladograms can probably be safely 
> > ignored (in spite of the rather high number of characters -- 41 in 
> > total).
> > 
> > On the other hand, the biogeography looks quite robust, despite the 
> > disgusting mixture of Cretaceous and recent coastlines in fig. 4.
> > 
> > BTW, the specific epithet should end in -orum instead of -i. 
> > Mr Meuris and Mr Smet are two people. <blood pressure rising>
> > 
> > 
> 
>