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Mercyhurst research casts doubt on ‘first animal’ claim

Monday, November 26, 2018

Researchers Scott McKenzie, Nicole Law

Dickinsonia, a peculiar blob-like creature believed to be among Earth’s earliest life forms, continues to baffle scientists who have debated its place in the tree of life for nearly a century.

Fungus? Protist? Animal?

Entering the fray this month is Mercyhurst University Paleontology Director Scott McKenzie and student Nicole Law, whose recent discovery about the creature’s unusual feeding method raises new questions about its identity.

In a study published in the September issue of Science, scientists examined fat molecules in the ancient fossil and concluded it to be the oldest known animal fossil, dating back nearly 600 million years. Their research supports mounting evidence of Dickinsonia’s animal origins.

But a month later, in the November issue of New Scientist, research by McKenzie and Law introduced a new wrinkle. The article stated that through their examination of a Dickinsonia fossil, the Mercyhurst researchers discovered an unusual feeding strategy: inflating its body like a balloon. Because this isn’t seen in any animal today, their research raises questions about whether this round, flat-ribbed blob belongs in the animal kingdom at all.

A pufferfish can inflate its stomach to deter predators, they suggested, but Dickinsonia appeared to inflate its entire body, suggesting it might not fall on the animal branch of the tree, but on an unidentified neighboring branch.

The article quoted Law as saying, “Perhaps it wasn’t an animal. I don’t believe we have enough evidence to know for sure right now.”

McKenzie and Law, joined by Rex Powell of the University of California at Berkeley, presented the inflatable theory at the Geological Society of America meeting in Indianapolis in mid-November.