“The placental ancestor was a scampering species that had a diet of insects, a fleshy nose, a light underbelly in its fur, and a long tail,” wrote study co-author Maureen O’Leary, a paleontologist at Stony Brook University in Stony Brook, N.Y. “It was larger than a mouse, but smaller than a rat.”
Not everyone has fallen in love with the furry, hypothetical bug eater however, and discussion is likely to continue for some time as to when placental mammals began to proliferate.
“The bottom line is that this study is not convincing and will not settle the debate,” said Mark Springer, an evolutionary geneticist at the University of California, Riverside, who was not involved in the study. “In contrast to what is reported by authors, the most fascinating result from this study is the tremendous amount of incongruence between the morphological and molecular data.”
Study co-author Novaceck said he did not expect the paper to end discussion, but he did say he hoped it would add weight to an ongoing argument.
Another debate involves the creatures name, and whether it deserves a less cumbersome moniker.
“People who think this organism is cute have asked me for a name,” Novacek said. “I tell them we can’t give it a Latin name, because it never really existed. It doesn’t have a nickname either. It’s just the hypothetical placental mammal ancestor.”