This earlier tracing and nesting
saw improvement with a higher resolution image.
Henkelotherium guimarotae (Krebs 1991; Late Jurassic 150 mya; Figs. 1-3) was traditionally considered a pantothere or eupantothere. Here Henkelotherium nests with Nambaroo (Fig. 4) in the Plesiadapis + rabbits clade as a Late Jurassic member of the clade Glires. Like its sisters, the manus was small and the pes had long digits with sharp claws. The lumbar region was long and flexible. A tiny taxon, the image below (Fig. 2) is about twice natural size.
“Eupantotheres are derived compared to symmetrodonts in having wider upper than lower teeth (although they still lack the protocone of tribosphenic forms.” The large reptile tree does not recover this clade. Rather the clade Lagomorpha should be extended to include the taxa found here (Fig. 3).
I reconstructed the hind leg and foof of Nambaroo and was shocked to see the similarity to the kangaroo pes (Fig. 4). At first I thought I had made a mistake. The Nambaroo foot was exactly like that of a kangaroo… only different. As it turns out, Macropus, the kangaroo, enlarges pedal digit 3. Nambaroo enlarges pedal digit 4.
Nambaroo gillespieae (N. tarrinyeri Flannery & Rich 1986; Kear et al. 2007; Late Oligocene, 25 mya) was reported to be the “granddaddy of kangaroos” and to have had fangs, ‘probably for display,’ and mostly ate soft food such as fruit and fungi (Kear et al. 2007). It was found in Australia. In the large reptile tree Nambaroo nested far from kangaroos, with Henkelotherium and Plesiadapis + rabbits, close to the base of rodents + multituberculates. The first dentary premolar has the look of the same tooth in multituberculates. The short rostrum suggests a long soft trunk or nose.
Convergence is a wonderful thing.
It makes one taxon seem like another, but always betrays its true identity somehow. That’s what the LRT is for… testing a wide gamut of taxa so we don’t get fooled.
Flannery TF and Rich TH 1986. Macropodoids from the middle Miocene Namba Formatiion, South Australia, and the homology of some dental structures in kangaroos. Journal of Paleontology 60:418-447.
Kear BP, Cooke BN, Archer M and Flannery TF 2007. Implications of a new species of the Oligo-Miocene kangaroo (Marsupialia: Macropodoidea) Nambaroo, from the Riversleigh World Heritage Area, Queensland, Australia, in Journal of Paleontology 81:1147-1167.
Krebs B 1991. Skelett von Henkelotherium guimarotae gen. et sp. nov. (Eupantotheria, Mammalia) aus dem Oberen Jura von Portugal. Berl Geowiss Abh A.: 133:1–110.