First Flower Seeds from Dino Era Discovered

The world may never know if dinosaurs stopped to smell the flowers, but scientists have uncovered a few more clues about the ancient blossoms that grew alongside ankylosaurs and iguanadons. Recently, researchers discovered tiny Cretaceous flower seeds dating back 110 million to 125 million years, the oldest-known seeds of flowering plants. These puny pips offer a glimpse into the biology powering the ancient predecessors of all modern flowers.

The seeds are miniscule — the largest was no more than 0.1 inch (2.5 millimeters) in diameter — and unusually well-preserved, in such good condition that their internal cell structures were still visible. For the first time, scientists were able to detect seed embryos, the part of the seed where a new plant grows and emerges, and food storage tissues surrounding them. These structures offered a rare glimpse into how the Cretaceous seeds grew, and how they compare with plants alive today.

Else Marie Friis, lead author of the study and professor emerita at the Swedish Museum of Natural History, has analyzed some of these fossil remains of angiosperms — flowering plants — preserved in soils in Portugal and North America. She and her colleagues used a relatively new visualization technique — synchrotron radiation X-ray tomographic microscopy (SRXTM), which allowed them to explore the delicate fossils without damaging or destroying them. They imaged 250 seeds spanning 75 different species (some were also different genera), revealing the embryos and nutrient structures inside the seeds in exquisite detail.

Around half of the fossil seeds they examined contained preserved cell structures within their seed coats, and about 50 seeds held partial or complete embryos. Once they had 2D images of the embryos, they used software to model the embryos’ shapes in 3D, finding that their size and shape varied between seeds. In some cases, the embryos resembled those in modern plants believed to be distant relatives of the Cretaceous angiosperms.

“These observations give us new insights into the early part of the life cycle of early angiosperms, which is important for understanding the ecology of flowering plants during the emergence and dramatic radiation through the early Cretaceous,” Friis said in a video statement.

During the Cretaceous period, angiosperms evolved and diversified rapidly. Many new insect species, which also appeared during the Cretaceous, may have played a part in how quickly flowering plants took hold and thrived in the ancient landscape.

Read more at Discovery News