Cycads are a group of “unusual evergreen gymnosperms” dating back to the Mesozoic Era, which stretches between 252 million and 66 million years ago and is divided into the Triassic, Jurassic, and Cretaceous periods.
Just like its conifer and Ginko cousins, cycads are non-flowering plants that bear their seeds in the form of cones. But, unlike these other gymnosperms that rely on wind for pollination, cycads are pollinated by insects. In fact, it seems that they may have been the first insect-pollinated plants to emerge in the Mesozoic, reports Phys.org.
According to a new study published today in the journal Current Biology, paleontologists have found substantial evidence that cycads were being pollinated by an ancient species of beetles during the Cretaceous Period.
More to the point, the team uncovered a tiny beetle fossil trapped inside 99-million-year-old amber alongside several clumps of cycad pollen grains. The insect in question, no more than two millimeters long, belongs to the ancient boganiid family — known cycad pollinators, notes Gizmodo.
“Boganiid beetles have been ancient pollinators for cycads since the Age of Cycads and Dinosaurs,” said study lead author Chenyang Cai, a paleontologist from the University of Bristol in the U.K.
This incredible find is all the more valuable considering that boganiid beetles scarcely turn up in fossil records. This particular beetle fossil was discovered in Burmese amber recovered from the Cretaceous biota found in northern Myanmar’s Kachin State.
The boganiid beetled stuck inside the Myanmar amber hails from the mid-Cretaceous, the upper period of the Mesozoic Era (145 million to 66 million years ago) and has been described as a new species, dubbed Cretoparacucujus cycadophilus.
The interesting thing about this insect, aside from the cycad pollen encapsulated along with it, is that it sports a series of special adaptations which indicate it had a pollen diet. For instance, the beetle fossil, which has been extremely well preserved, has mandibular cavities that would have helped it carry the pollen.
Moreover, the researchers discovered that Cretoparacucujus cycadophilus is related to both Jurassic beetles and the modern-day Australian Paracucujus, which pollinates a species of cycad known as Macrozamia riedlei. All these findings suggest that beetles started pollinating cycads a long time ago, Cai points out.
“Our finding indicates a very ancient origin of beetle pollination of cycads at least in the Early Jurassic, long before the [emergence and spread] of flowering plants and their pollinators — such as bees and butterflies — later in the Cretaceous or later.”
According to the paleontologist, even older beetle pollinators of cycads, dating back to the Jurassic Period, could be uncovered. In addition, Cai is confident that the same Myanmar deposit could yield larger cycad fossils as well, such as fossilized leaves.