New Jersey has treasure trove of amber

Jeff Poling

An American Museum of Natural History expedition to New Jersey has uncovered one of the richest deposits of amber ever found, with fossils of 100 unknown species of insects and plants trapped in the fossilized sap.

The fossils include:

• A tiny bouquet of miniature flowers from an oak tree that lived 90 million years ago,
• the world's oldest mosquito, with mouth parts tough enough to feed on dinosaurs,
• the oldest moth in amber, with mouth parts suggesting it was in transition from a biting insect to one that fed on the nectar of flowers,
• a feather that is the oldest record of a terrestrial bird in North America, and
• the oldest mushroom, bee and biting black fly to ever be found in amber.

The biting black fly is the only such insect known from the Cretaceous period, and it, along with the mosquito, may have counted dinosaurs among its victims.

David Grimaldi, curator and chairman of entomology at the American Museum of Natural History, said the species, all extinct, were found in 80 pounds of amber drawn out of deep mud in a complex of sites in central New Jersey. At one secret site in particular the clay is especially deep and rich. The clay contains streaks of peaty black material that are the remains of plants and other organic material. It is in these streaks that the amber was found.

The amber dates to 90 Ma to 94 Ma, meaning all the preserved species came from the "Age of the Dinosaurs" and from the era when flowers first evolved and began to spread through the ecosystem. At the time, insects were beginning to use flowers as food, and the flowers were beginning to use the insects to carry pollen from flower to flower.

An article describing the world's oldest preserved flowers, written by Grimaldi and his colleagues, Kevin Nixon and William Crepet of Cornell University, is to be published in early 1996 in The American Journal of Botany. It notes that the three flowers in the little bouquet are the only known flowers preserved from the Cretaceous period, which ended 65 Ma ago.

Until now, the study of plants from the Cretaceous has depended solely on the fossil impressions of flowers and pollen. Curiously, the flowers and some of the other fossils found at the New Jersey site are miniatures: the flowers and their stem together are no more than half an inch long.

Recent interest has focused on the DNA of plants and animals locked in amber. George Poinar, now at Oregon State University, one of the scientists credited with the discovery that bits of DNA exist in fossils inside amber, said that the material "is the best preserved protein on the face of Earth."

Such preservation was great enough to have kept even muscle tissue intact in a 125-million-year-old Lebanese weevil that Poinar studied. To date, scientists believe they have successfully extracted bits of DNA from half a dozen amber drops.

But a dispute has arisen about how to handle amber specimens: whether to open them to get at their DNA, how to open them, and whether there should be rules guiding expeditions and the use of existing collections.

There are tens of thousands of pieces of amber with fossil insects and other items in collections around the world, and most are common varieties of ants and flies. The rarest pieces contain lizards, frogs or the hairs of mammals. Several thousand of the specimens contain the only examples of now-extinct species.

Grimaldi said that because all creatures on Earth are classified according to their physical features, and it is this that scientists use to study how evolution has created or shaped the entire history of life, no specimens in amber should be tampered with unless they are quite common and others of the same species, era and location can be found to replace them. Grimaldi has criticized the extraction work of scientists such as Poinar, pointing out that the weevil from Lebanon was probably the only one of its kind.

Grimaldi said his approach is becoming more common in science, from archaeology to paleontology, in which large parts of discovery sites are left unexcavated, so as not to destroy things that might be useful to, or better extracted and preserved by, future scientists.

All amber fossils, Grimaldi says, should be coded, as at the American Museum of Natural History, according to rarity, and only those with more than two or three duplicates should be subjected to DNA extraction.

Poinar agrees that very little damage can be tolerated, but he said he and others have developed techniques to enter specimens in amber through a tiny hole, use a needle to extract tissue, and reseal the hole.

"This work will be going ahead, and people will be opening amber anyway, whatever we say, so we must develop ways to prevent or minimize damage to the specimens," Poinar said.