Science Literature

In a report of a scientific meeting, Stokstad drew attention to the characters of the duck-billed platypus that baffled researchers at the end of the 18th Century. He went on: "Modern researchers have uncovered other implausible features, including 40,000 tiny glands in the broad bill that sense electric currents, which may help the platypus catch prey underwater." Nevertheless, the platypus has never quite escaped being regarded as primitive from an evolutionary perspective. Earlier this year, ARN's Denyse O'Leary asked these questions:

"Primitive? Most highly evolved? Or just different? A question that lurks just below the surface (and will likely stay there a long time) is, how much time was required for the evolution of this unique electrolocation sense? How likely is it to have been random?"

It is now possible to say more about the time question. The surprise is that there is evidence for this complex structure from the Early Cretaceous.

"A reanalysis of fossil jaws from Australia, reported at the meeting, suggests it belonged to a platypus that lived at least 112 million years ago. "It's really, really old for a monotreme," Timothy Rowe of the University of Texas (UT), Austin, told the audience."

Rowe is a palaeontologist who runs a computed tomography-scanning facility at UT Austin.

"Scans of three specimens revealed a large internal canal along the entire length of the jaw, like the canal in a modern platypus that carries nerve fibers from the electrosensory glands in the bill to the brain. "There's no other mammal that has a canal this size," Rowe said. Even back in the early Cretaceous, it seems, the platypus was using electrosensation."

Stokstad points out that the age of the fossil is "much older than current estimates from DNA of when platypuses and echidnas diverged from their most recent common ancestor. Molecular clocks put that date somewhere between 17 million and 80 million years ago." However, palaeontologists have grown used to mismatches like this and do not give too much weight to the figures emerging from molecular clocks. What this does show is that there are extreme constraints on time for any evolutionary story of the origin of platypuses and their electrolocation device. We appear to have a situation where intelligent design is demanded by the evidence of short timescales and the complexity of the "implausible" electrosensory system.

Jaw Shows Platypus Goes Way Back
Erik Stokstad
Science 318, 23 November 2007: 1237.

When scientists first laid eyes on the duckbilled platypus and the echidnas in the late 18th century, they were so baffled by these bizarre egg-laying mammals that some considered the specimens a hoax. Modern researchers have uncovered other implausible features, including 40,000 tiny glands in the broad bill that sense electric currents, which may help the platypus catch prey underwater. [snip]