[Taxacom] fossil potato relative

[John Grehan]

Not making any judgement about this one, but notice comment on molecular
clocks at the end.

John Grehan

http://www.iflscience.com/plants-and-animals/52millionyearold-fossil-relative-to-the-potato-discovered-in-patagonia/

Despite becoming ubiquitous in almost every corner of the world,
surprisingly little is known about the deep evolutionary history of the
group of plants that gave rise to potatoes, tomatoes, and tobacco.
Now, researchers
have found
<http://phys.org/news/2017-01-south-american-fossil-tomatillos-nightshades.html>
 just how far back these organisms go, with the discovery of a fossil
relative that dates back to 52 million years ago, tens of millions of years
older than previously thought.

The fossil belongs to a fragile berry of a plant known as a tomatillo, or
ground cherry. They form fruit that is often surrounded by a thin, papery
lantern, making it difficult for them to be fossilized
<http://www.bbc.co.uk/news/science-environment-38511034>. Members of the
*Physalis* genus, they form a small branch of the nightshade family, which
in turn includes many commercially important crops, from potatoes
and petunias to chillies and aubergines.

The only fossil fruits ever found from this family of almost 2,000 species
of plants, the two specimens were discovered in a fossilized rainforest
that once grew across Patagonia in South America. With a lack of available
fossils for this group of plants, researchers have had to rely on molecular
dates for when the nightshade plants first evolved, and had settled on the
figure of around 35 to 51 million years old, while the tomatillo was
thought to be a relative newcomer at only 10 million years old.

This new discovery, however, completely changes this. The fossils, dating
to 52 million years ago, show that the ground cherries are actually a
relatively ancient branch of the nightshade family. “We exhaustively
analyzed every detail of these fossils in comparison with all potential
living relatives and there is no question that they represent the world's
first physalis fossils and the first fossil fruits of the nightshade
family,” says
<http://phys.org/news/2017-01-south-american-fossil-tomatillos-nightshades.html>
 Professor Peter Wilf, from Pennsylvania State University.

The fossils underpin the need for researchers to be careful when deducing
an organism's evolutionary age solely from molecular clocks.