Tomatillos Just Got A Lot Older

Tomatillos and ground cherries just got a bit older. Okay, a lot older. Exquisitely preserved fossils from an ancient lake bed in Argentina are shining a very bright light on the genus Physalis and the family Solanaceae as a whole. Despite the importance of this plant family around the globe, little fossil evidence has ever been found. That is, until now. 

Dated at 52 million years old, these fossils paint a picture of a snapshot in the evolution of the genus Physalis. The fossils are remarkable, allowing for close inspection of minute details like vein structure. Because of the level of detail discernible, experts can say without a doubt that these fossils could be nothing else other than a species of Physalis

One of the most interesting aspects of these fossils is their age. These sediments were deposited during the early Eocene Epoch. The fact that representatives of Physalis were alive and well during this time is quite remarkable. Because fossil evidence for Solanaceae has been so scarce, experts have had to rely solely on molecular dating in order to elucidate the origin and divergence of this family. 

Original estimates placed the origin of Solanaceae at sometime around 30 million years before present. Physalis, being much more derived, was thought to have an even more recent emergence, some 9 million years ago. Boy, was that ever wrong. At 52 million years of age, we can now confidently say that Physalis is at least 43 million years older than previously thought. These findings also tell us that Solanaceae is even older still! If such a derived genus was thriving in Eocene Argentina 52 million years ago, basil members of the family must have gotten their start much earlier than we ever imagined. 

Aside from big picture taxonomical revelations, the fossils also give us a window into the ecology of these ancient Physalis. The most obvious is that inflated bladder which surrounds the berry within. Though it is quite characteristic of this group, little attention has been paid to its function. The fact that the sediments in which they were preserved are of aquatic origin suggests that the inflated calyces may have evolved for aquatic seed dispersal. Experiments have shown that these structures on modern day ground cherries and tomatillos do in fact float, keeping the berry inside high and dry. 

To think that all of this was brought to light from a handful of fossils. It just goes to show you the importance the paleontological discoveries can have. Just think of the countless amount of museum drawers and shelves that are chock full of interesting fossils waiting to be looked over. Who knows what they might tell us about our planet. 

Photo Credit: Ignacio Escapa, Museo Paleontológico Egidio Feruglio

Further Reading: [1]

Fossilized Forest

A fossilized forest discovered in Arctic Norway is shedding light on one of the earliest forests to have evolved on this planet. Preserved in situ, these fossils reveal what life was like for these plants some 380 million years ago.

This was the Devonian Era, a time in which plants were starting to conquer the land. During this time period, the land mass that is now Norway was located on the equator. The tropical climate of this time likely fostered the growth of these early forests, causing a race for the sky. For their time, these forests were monstrous in proportion.

The fossils are comprised of a long extinct species of plant known scientifically as Protolepidodendropsis pulchra. These "trees" were not any sort of tree that we would readily recognize. To see their closest living relatives today, you will have to take a knee. These were forebearers of the club mosses (Lycopodiaceae).

These forests stood around 4 meters (13 feet) in height. Even more peculiar, they grew densely packed with only about 20 centimeters separating each trunk. The trunks themselves were stunning having been covered in diamond-shaped plates. Like the club mosses, they reproduced by spores.

Another interesting thing about such discoveries is that it allows us to infer quite a bit about what was going on in the atmosphere as well. With such densely packed forests spreading over the land, the Devonian world was, for the first time, seeing a massive drawdown of atmospheric CO2 levels. Plants were changing the globe as they rose to prominence. Along the way, they were irrevocably changing the course of life on Earth.

Photo Credits: Cardiff University, Illustration by Dr. Chris Berry from Cardiff University

Further Reading:
http://geology.geoscienceworld.org/content/43/12/1043.full