Gondwanatherian mammals launch claim for defamation

[K and T Dykes <ktdykes@arcor.de>]

Gondwanatherian mammals launch claim for defamation

(About 650 words)



The thoroughly dead gondwantherians had decided to seek legal action 
concerning libels about their affinities, and they've hired several teams of 
lawyers to represent them.  These critters routinely get called enigmatic, a 
polite way of saying: "What the hell is it?"  They were Upper 
Cretaceous-Paleocene (perhaps also Eocene) botanists; small fry with, in 
more derived forms, tall (hypsodont), open-rooted molariform teeth, some 
with occlusal outlines audacious enough to serve as fine models for aliens 
in video games.



When first encountered, during the early 1980s, they were asked if they'd 
like to have been responsible for later generations of placental 
xenarthrans, such as armadillos and anteaters.  After all, xenarthran 
ancestors in the Upper Cretaceous of South America could've been around. 
Anyway, they weren't keen on that kind of sex.  They were then asked whether 
they fancied multituberculates per chance, and their teeth seemed to show 
some interest.



However, a jaw rather spoilt things when described in 2000, and the gondwans 
were told to stop squeaking so perversely.  There were two obvious molars, 
facilities for another pair behind, and two and two makes too many for half 
a multi jaw.  They're only allowed two such grinders.  This also meant some 
"undoubted" (my word) multi premolars from Patagonia couldn't be assigned to 
the gondwan known as /Ferugliotherium/.



However, that meant fossil beds have been playing strange games.  For some 
reason, they seem to be yielding some multi premolars but no molars, and 
some gondwan molars.  (The jaw had claimed not to have premolars about its 
person.)  The premolars and molars appear to indicate two similarly sized 
critters with, on the basis of uncontroversial molar similarities between 
gondwans and multis, similar interests in food.



One team of gondwan lawyers are: Gurovich & Beck (2008), The phylogenetic 
affinities of the enigmatic mammalian clade Gondwanatheria, Journal of 
Mammalian Evolution.  This case builds upon Gurovich's epic thesis from the 
year 2005, a work of not all that much more than 600 pages.  These authors 
maintain the "undoubted" multi lower premolars actually belong to 
/Ferugliotherium/, the basal gondwan.  The first two "obvious molars" of 
more derived gondwans are actually molariform premolars.  These can evolve 
from blade-like premolars whether certain placentals want to believe it or 
not.  Without demeaning myself with appeals to authority, I know this to be 
so because some leading authorities, sthenurine kangaroos, say their 
ancestors did just that.



G & B also adopted a data matrix for around fifty (mostly) mammals and 269 
characters from a Rougier et al, 2007 paper.  They interviewed their three 
SAm gondwans and flung them into the pot.  Two points should be mentioned. 
/Ferugliotherium/ is here based partly on material others have sought to 
banish from the genus.  Secondly, the missing scores for gondwans range from 
around 70 to 80%, with that latter number applying for two out of three 
(including Feruglio).  Anyway, the computer began to whiz and whir.



The gondwans ganged up with both plagi and cimolod multis.  They could 
perhaps be multis again or maybe a sister lineage.



Some caution is advisable.  The result for gondwans depends heavily upon 
dental characteristics and, as those sthenurine kangaroos and others argue, 
convergence happens.  Should that apply in this case, then the grouping up 
of multis and gondwans into one clade would be misleading.  Testing for 
possible convergence would be a good thing, but it would require information 
on presently unknown other bits of gondwan bodies.



A paper on mammals from Patagonia's Allen Formation from other authors 
should be appearing soon.  It's already available for subscribers of 
Cretaceous Research in a pre-publication version, so I don't see why I 
shouldn't mention its content.  The pre-publication version has reason to 
also discuss ferugliotheriid gondwans.  It accuses them of being members of 
?Multituberculata (note the question mark) and, as far as it goes, seems 
fully consistent with the conclusions of Gurovich and Beck.