Earlier we looked at Vintana (Fig. 1, Krause et al. 2014a, b). To Krause et al. Vintana represented the first specimen in the clades Allotheria and Gondwanatheria to be known from more than teeth and minimal skull material.
To Krause et al.
Allotheria included Multituberculata and nested between the clade Eutriconodonta (including Repenomamus and Jeholodens) and the clade Trechnotheria (including the spalacotheres Maotherium and Akidolestes) and Cronopio, Henkelotherium, Juramaia, Eomaia, Eutheria and Metatheria.
Taxon exclusion issues
The large reptile tree (LRT, 1005 taxa) did not recover the above clades or relationships. Alotheria does not appear in the LRT.
- Multituberculata, Henkelotherium and Maotherium nest within Glires (rats and rabbits and kin) in the LRT.
- Repenomamus and Jeholodens nest within the pre-mammalian trityllodontid cynodonts in the LRT.
- Akidolestes nests within basal Mammalia, close to Ornithorhynchus in the LRT.
- Cronopio and Juramaia nest within basal Mammalia between Megazostrodon and Didelphis in the LRT.
- Eomaia nests at the base of the Metatheria in the LRT.
- Vintana nests with Interatherium among the derived Metatheria (marsupials), with wombats, like Vombatus and Toxodon in the LRT.
Despite a paper in Nature
and a memoir of 222 pages in the Journal of Vertebrate Paleontology; despite CT scans and firsthand examination with electron microscopes; despite being examined and described by many of the biggest name and heavy hitters in paleontology… Krause et al. never understood that Vintana was just a derived wombat, evidently due to taxon exclusion problems.
The large reptile tree now includes
1005 taxa, all candidates for sisterhood with every added taxon. Despite the large gamut of 74 taxa employed by Krause et al. they did not include the best candidates for Vintana sisterhood. Perhaps the fault lies in the reliance of prior studies and paradigms. Perhaps the fault lies in the over reliance by Krause et al. and other mammal workers, on dental traits. Perhaps the fault lies in the absence of pertinent sisters to the above-named taxa, including Interatheriium for Vintana.
In any case
Vintana does not stand alone as the only taxon in its clade represented by skull material. Based on its sisterhood with Interatherium, we have pretty good idea what its mandibles and post-crania looked like. Yes, Vintana is weird. But Interatherium is also weird in the same way, just not as weird.
Krause DW, Hoffmann S, Wible JR, Kirk EC, and several other authors 2014a. First cranial remains of a gondwanatherian mammal reveal remarkable mosaicism. Nature. online. doi:10.1038/nature13922. ISSN 1476-4687.
Krause DW et al. 2014b. Vintana sertichi (Mammalia, Gondwanatheria) from the Late Cretaceous of Madagascar. Journal of Vertebrate Paleontology Memoir 14. 222pp.