An ongoing debate over whether cellular material can be preserved within fossils for long periods of time got a fresh round of ammunition in October. Two new studies of DNA and proteins offered support for opposite perspectives.

In the first, published in Proceedings of the Royal Society B, Australian scientists drilled into 158 semifossilized leg bones from extinct, flightless moa birds and extracted DNA samples. Relying on carbon dating, the researchers measured the bones to be between 600 and 8,000 years old. They calculated how much DNA had degraded in the older and younger fossils, and by comparing those amounts, estimated that DNA has a half-life of 521 years—meaning about half of DNA breaks apart every 521 years. The upshot is that little readable DNA should be able to survive in a fossil beyond 1.5 million years, and none beyond 6.8 million.

In the second study, published in Bone, a team led by North Carolina State University researcher Mary H. Schweitzer used mass spectrometry to show evidence for the existence of dinosaur proteins inside Tyrannosaurus rex and duck-billed hadrosaur fossils, both purported to be more than 60 million years old. The team also found evidence of material within the fossils that behaved, chemically, like DNA.

Schweitzer is famous for discovering soft tissue inside a fossilized T. rex femur in 2004. Although subsequent studies have backed up her findings, critics who can’t swallow the idea of 67-million-year-old dinosaur protein argue the T. rex proteins actually came from a “biofilm” deposited by microbes that invaded the fossils in more recent years. In defense, Schweitzer contends that a previously unknown chemical mechanism allows cellular matter to be preserved over geologic time. An apparent solution to the dispute—that dinosaurs may be considerably younger than current theory dictates—is unlikely to get much consideration, given the commitment to Darwinian evolution in mainstream science.

Thus, the riddle remains scientifically unsolved. According to Scientific American reporter Kate Wong, Schweitzer poked fun at her opponents during a talk at an Oct. 17 paleontology conference in North Carolina. “Here’s the data in support of a biofilm origin,” she said, showing everyone a blank slide. “We haven’t found any yet.”