Three marsupial species described from teeth and pieces of jaw have become the basis for a proposed sixth Australian order called Keeunamorphia, which the fossils support without establishing that other taxonomists accept it. [1]

The animals lived about 18 million years ago at what is now the Riversleigh World Heritage Area in northern Queensland, and ScienceDaily, carrying edited material from the University of New South Wales, says their unusual teeth resembled those of Djarthia murgonensis, a much older extinct marsupial. [1]

Paleontologist Tim Churchill combined the fossil evidence with genetic information from living species to construct a phylogenetic tree, a model of relationships and estimated divergence times, and his analysis proposes that Keeunamorphia may have branched off early and persisted for about 35 million years alongside ancestors of modern groups. [1]

The word "may" carries much of the science because complete skeletons are uncommon and the proposed lineage rests on fragmentary anatomy across a fossil record with a gap approaching 20 million years, while character choices, support values and alternative trees can change where a species lands and more skeletal material could strengthen or unsettle the order-level claim.

ScienceDaily's lost-branch headline turns an inference into a discovery with a finished address, but the measured result is more interesting because it remains open: three species have been described, their teeth do not fit neatly among known neighbors, and one modeled tree supports a long-surviving lineage, making Keeunamorphia a proposal for scientific scrutiny rather than a consensus already carved into taxonomy.

-- PRIYA SHARMA, Delhi