Generally speaking, paleobotanists assume that any plant fossils dating from the beginning of the Cenozoic 65 million years ago must be related to plants that are alive today, and Othniophyton elongatum was no exception.
After a close study of the leaves, scientists thought that they may be compound leaves, made up of many smaller leaves, like some ginseng family plants.
And that could have been that… until the discovery of another set of 47-million-year-old plant fossils came to light.
With so many more components of the plant in hand, Manchester and his colleagues set about trying to learn more about Oreopanax elongatum.
The researchers renamed the extinct plant Othniophytum elongatum – Greek for “elongated alien plant” – and concluded that it likely belongs to a family of plants that no longer exists on Earth.
A plant that grew in what is now Utah 47 million years ago is very different from anything that exists today on Earth.
As scientists had first hypothesized, a species discovered in 1969 is not a member of the ginseng family, according to the discovery of new fossils. The fact that the entire family of the recently discovered Othniophyton elongatum is extinct instead indicates that flowering plant history is more nuanced than previously thought.
Exhibits of Othniophyton elongatum were initially discovered in Utah’s Green River Formation, an exceptionally abundant Eocene fossil bed. Othniophyton elongatum was not an exception to the general rule among paleobotanists that any plant fossils excavated from 65 million years ago must be related to living plants.
It was given the name Oreopanax elongatum by the paleobotanist Harry MacGinitie, who was the first to study the fossils. This puts it in the same family as ginseng, angelica, and ivy. Scientists believed that after closely examining the leaves, they might be compound leaves, similar to those of some ginseng family plants, composed of numerous smaller leaves. An example is Oreopanax xalapensis.
And that might have been the case until a second set of plant fossils dating back 47 million years was found. Like the fossils from 1969, it had leaves, but that wasn’t all.
“The twig with attached fruits and leaves is rare in this fossil,” says paleobotanist Steven Manchester of the Florida Museum of Natural History. “Those are typically found independently. “.”.
After obtaining numerous additional plant parts, Manchester and his associates began their quest to gain more knowledge about Oreopanax elongatum. The more they examined their new fossils, however, the more they saw that the Eocene plant had nothing in common with either the Araliaceae family or the genus Oreopanax.
The first clue was the leaves, which were affixed to the twig directly. In contrast to what was first believed in the 1960s, they were not compound leaves. And the plant became even more perplexing when you looked at the berries. The researchers discovered that the peculiar collection of traits the fossil displayed had no resemblance to any living flowering plants.
The museum’s installation of a new microscopy station marked a breakthrough. This gave the researchers the opportunity to examine the plant in far more detail than they had previously been able to. They could examine the seeds of the plant by peering inside the berries and dissect the delicate details of the flowers.
During the development of the berries, Manchester and his associates noticed something strange: the male component of the reproductive system, the stamens, had not fallen off the plant.
According to Manchester, “that’s not something we typically expect to see preserved in these kinds of fossils, but perhaps we’ve been missing it because our equipment didn’t pick up that kind of topographic relief.”.
Stamens typically fall out as the fruit ripens. Additionally, it appears unusual that it is keeping its stamens when it has fully developed fruits with seeds that are ready to be released. Nothing in the modern era has shown us that. “.”.
It was then compared to plants from the Cenozoic era found in the fossil record. The researchers were unsuccessful once more. Simply put, no known plants resembled what they were observing sufficiently. There were too many variations to draw a connection, even in cases where there were resemblances to other plants.
Simply put, we have no idea how this plant compares to other plants. Though there are too many differences, it is the order most similar to the Caryophyllales.
The extinct plant was given the new name Othniophytum elongatum, which translates to “elongated alien plant” in Greek. The researchers came to the conclusion that it most likely belonged to a plant family that is extinct on Earth.
Paleobotanists now have a new tool at their disposal to examine how plants changed, adapted, and diversified over millions of years in a changing environment. They can also use this tool to determine which strategies may have been less successful in surviving.
It’s also a bit of a warning not to let preconceptions and biases cloud the facts.
According to Manchester, “you can’t always shoehorn these things, but there are many things for which we have good evidence to put in a modern family or genus.”.
