Clues About the Evolution of Flight and Birds Discovered in Burmese Amber

Mummification, embalming, mellification (steeping in honey), plastination (a four-stage plasticizing procedure) and cryogenics – humans are always looking for the next big idea when it comes to preserving the body, but nature always seems to do one better. Amber, as it turns out, is more than just a beautiful, translucent gemstone that sometimes contains trapped animal and plant material. It seems that the process for creating amber – the result of tree resin bleeding, hardening, becoming buried and hardening even further – creates a time capsule of sorts, allowing scientists a look back at our planet's early history.

For a long time, researchers were fascinated by the amber found in the Baltic region – an area that once contained rich, dense forests – and those finds told us much about what our planet looked like 45 million years ago.

Now, the scientific community is all abuzz about huge amber finds in Burma containing insects, creatures and plant life from about 100 million years ago. It's exciting because of the era (the mid-Cretaceous period), the sheer abundance of the specimens and the diversity of life forms being discovered in these golden tombs.

The Houston Museum of Natural Science is featuring more than 100 specimens of Burmese amber in “Amber Secrets: Feathers from the Age of Dinosaurs,” with flowers, snails, parasites, millipedes, velvet worms, spiders, ants and termites entombed in amber.

The exhibit was curated for HMNS by Dr. David Grimaldi, who serves as the curator of invertebrate zoology at the American Museum of Natural History, and the Burmese amber is news-breaking stuff: He published a paper last year about the earliest specialist pollinators, he recently had two papers published on highly social ants and termites and, just this month, his paper on the earliest mosquitoes was released (which is timely as we learn more about the Zika virus). Other discoveries are coming down the pipeline, with more revelations promised for later this spring.

All of this is important because, up until now, we didn't really know how things evolved between the beginning of the Cretaceous period 145 million years ago (the landscape was green) and the end of the period 66 million years ago (the forests were full of flowers and vibrant color). Through both destructive sampling (cleaving an amber specimen in half) and the less invasive CT scans, scientists are finding muscle tissue, brain matter, nuclei, mitochondria, membranes and subcellular matter; however, it is “doubtful that DNA can be preserved in amber,” says Dr. Grimaldi. He refers to previous claims that DNA had been extracted from amber but, upon further examination, it appears that those early finds actually were the result of contamination.

So, what are the top three finds from the Burmese amber mother lode?

Find #1: Feathers. Researchers have found lots of feathers, which is critical in telling the story of the “evolution of flight and the evolution of birds,” says Dr. Grimaldi. The quality of the samples is very good, and they're finding “lots of different kinds of feathered theropods,” which are described as fairly basic in comparison to modern birds. Since the melanosomes (responsible for color or pigment) have been preserved, they know that the bird-like creatures from this era were always black or white in color. There's one amazing specimen that “could look like a microraptor,” and preserved within the amber are “bones, feathers, a claw, toe bones, part of a wing or claw and webby muscle,” says Dr. Grimaldi.

Find #2: Diversity. “We have some really beautiful flowers on exhibit. Some defy classification,” says Dr. Grimaldi. Other finds include parasites (worms, mites, a bloated tick); spiders (they're abundant and diverse); and what can best be described as the “earliest and most primitive mosquitoes.” He published a paper about a type of fly last year; “it was an extraordinary discovery,” says Dr. Grimaldi. “A fly, with long whiplike antennae. The only thing that looks like this is in limestone in Brazil, and something similar in shale in China.”

Find #3: Ants and termites are eusocial. “A new study revealed that [ants and termites] were highly social. They had castes. There is the queen and soldiers and workers, major and minor workers, major and minor soldiers.” This mechanism (they cooperate in child care, there is a division of labor among castes, and there are at least two generations present) is responsible for the “unparalleled ecological success of ants and termites,” says Dr. Grimaldi. He was fairly excited when he (along with co-author Phillip Barden) discovered Krishnatermes yoddha (a new termite species); they were able to determine that it was a soldier termite because “it has a huge head, which is important for using its mandible.” But that discovery was soon eclipsed when they discovered another new termite species that dwarfed the earlier find. Given the honor of naming this new species, Dr. Grimaldi settled on “Gigantotermes Rex,” a fairly fitting name for this “very impressive insect” that was about an inch in length, with scissor-like jaws and an enormous head. Though it's not contained in the HMNS exhibit, Dr. Grimaldi has a piece of amber that shows these “two worker ants of different species engaged in combat, which is cool. Territorial aggression only comes with highly social species.”

Dr. Grimaldi stresses that research and discoveries are occurring at a very fast pace, with new finds taking place on a weekly basis. The HMNS exhibit is the only kind of its type in the world; there are other amber exhibits, but none as scientifically important or unique as the Burmese amber.

There's actually a Find #4, but we're sworn to secrecy until March 4, when the breakthrough is published and the specimens are revealed. This is a fantastic exhibit, containing brand-new scientific discoveries from this abundant “rainforest paleo-concentrate.”

There's an amber workshop at 6 p.m. Tuesday, March 1 ($35 to $45), and a behind-the-scenes tour at 6 p.m. on Monday, March 7 ($17 to $27). Regular viewing hours are 9 a.m. to 5 p.m. daily. Through March 26, 2017. Houston Museum of Natural Science, 5555 Herman Park. For information, call 713-639-4629 or visit $30. 
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Susie Tommaney is a contributing writer who enjoys covering the lively arts and culture scene in Houston and surrounding areas, connecting creative makers with the Houston Press readers to make every week a great one.
Contact: Susie Tommaney