Scientists find how amber becomes death trap for watery creatures

A mosquito and a fly in this Baltic amber necklace are between 40 and 60 million years old
A mosquito and a fly in this Baltic amber necklace are between 40 and 60 million years old
Shiny amber jewelry and a mucky Florida swamp have given scientists a window into an ancient ecosystem that could be anywhere from 15 million to 130 million years old.

Scientists at the University of Florida and the Museum of Natural History in Berlin made the landmark discovery that prehistoric aquatic critters such as beetles and small crustaceans unwittingly swim into resin flowing down into the water from pine-like trees. Their findings are published this week in the Proceedings of the National Academy of Sciences.

The resin with its entombed inhabitants settled to the bottom of the swamp was covered by sediment and after millions of years became amber, a bejeweled version of the tar pits that trapped saber-toothed tigers in what is now California, said David Dilcher, a UF paleo-botanist and one of the study’s researchers.

“People never understood how freshwater algae and freshwater protozoans could be incorporated in amber because amber is considered to have been formed on land,” said Dilcher, who works at the Florida Museum of Natural History on the UF campus. “We showed that it just as well could be formed from resin exuded in watery swamp environments. Later the swamps may dry up and the resin hardens.”

Dilcher and Alexander Schmidt, a researcher at the Museum of Natural History in Berlin, replicated the prehistoric demise of the water bugs by taking a handsaw to a swamp on Dilcher’s property near Gainesville in north Central Florida. After they cut bark from some pine trees, the resin flowed into the water and they collected the goo and took it back to Dilcher’s lab on campus.

Stuck in the sticky sap were representatives of almost all the small inhabitants of the swamp ecosystem, Dilcher said. “We found beautiful examples of water beetles, mites, small crustaceans called ostracods, nematodes, and even fungi and bacteria living in the water,” he said.


The discovery not only solved the mystery of how swimming bugs could have been entombed in sticky sap from high up in a tree but could lead to new information about prehistoric, maybe even Jurassic, swamps, Dilcher said. Studying organisms that were trapped for millions of years in amber may help scientists to recreate prehistoric water ecosystems and learn how these life forms changed over time, he said.

While no one is claiming that the entombed bugs will be brought back to life through genetic splicing, the discovery may give clues about the evolution of microorganisms, he said.

“We all think of horses, elephants and people as having changed a great deal through time,” he said. “Have amoeba and other microscopic organisms changed much? Or have they found a niche or what we call a stasis in which their evolutionary lineage persists for many hundreds of millions of years? We don’t have the answers to those questions until we look at the fossil record.”

Insects such as bees, spiders, tics and fleas that become embedded in amber have received a great deal of attention because they are so abundant, Dilcher said. “Unfortunately, people have overlooked the little things while searching for the big bugs and the flowers in amber,” he said.

Microorganisms are important because they form relationships with higher organisms, making them the foundation of the pyramid of life, Dilcher said. “To understand more about their evolution adds an important step in our understanding of life itself,” he said.

Gene Kritsky, editor of the journal American Entomologist and a biology professor at the College of Mount St. Joseph in Cincinnati, said Dilcher has performed a great service in answering a question that has long puzzled scientists, the seemingly contradictory aspect of finding aquatic insects in tree resin.

“It’s been one of the strange things mentioned by biologists and entomologists for decades – how do you account for aquatic insects and organisms in what seemed to be an ancient terrestrial environment,” Kritsky said. “Dilcher examined this contradiction by creating the conditions that would cause sap deposits to flow into water to see what would happen. The results demonstrated that aquatic insects can be trapped in resin without leaving their aquatic world. Thus, the presence of aquatic organisms in amber is the result of a simple natural process.”


Note: This story has been adapted from a news release issued by the University of Florida

New 150 million-year-old crab species discovered

Researchers from Kent State University and the University of Bucharest, Romania, have discovered a new primitive crab species Cycloprosopon dobrogea in eastern Romania. Previously unexamined, these ancient crabs from the Prosopidae family existed more than 150 million years ago during the Jurassic period.

“Studying primitive and extant crabs helps determine various aspects of biodiversity and patterns of evolution, such as when arthropods diversified,” says Dr. Carrie Schweitzer, associate professor of geology at Kent State University.


Arthropods, which include crabs, insects, lobsters, spiders, millipedes and ticks, are a large part of the earth’s ecosystem, and they also are important economically in many countries as a source of food.

In addition, crabs have been remarkably resistant against extinction. “Our goal is to determine why they have been so resistant, so we might be able to better fight modern extinctions,” says Schweitzer.


Note: This story has been adapted from a news release issued by Kent State University

Seafood Makes Waves: Humans Leave Home

Cave 13B is one of several caves overlooking the Indian Ocean along the coastline of Pinnacle Point, a sea-cliff on the south coast of South Africa. Researchers here uncovered evidence of early human use of shellfish and other marine resources dating to the middle Pleistocene. The cave is the focus of intense excavation work and has been since 2000. - Credit: South African Coast Paleoclimate, Paleoenvironment, Paleoecology, Paleoanthropology Project (SACP4), Arizona State University, Director - Curtis W. Marean
Cave 13B is one of several caves overlooking the Indian Ocean along the coastline of Pinnacle Point, a sea-cliff on the south coast of South Africa. Researchers here uncovered evidence of early human use of shellfish and other marine resources dating to the middle Pleistocene. The cave is the focus of intense excavation work and has been since 2000. – Credit: South African Coast Paleoclimate, Paleoenvironment, Paleoecology, Paleoanthropology Project (SACP4), Arizona State University, Director – Curtis W. Marean
Ever hanker for Mrs. Paul’s fish sticks or have an overwhelming need to trust the Morton’s fisherman? Well, you’re not alone. New research suggests humans may have eaten seafood more than 40,000 years earlier than previous estimates and it may have been a catalyst for early human migration out of Africa following a coastal route.

The discovery, funded by the National Science Foundation (NSF), was made by scientists from Arizona State University and a group of national and international colleagues. See sidebar below for a related discovery.

Curtis Marean, from the university’s Institute of Human Origins, said introduction of shellfish into the early human diet might be the result of climate changes that caused the availability of earthbound foods to decrease, and thus people switched to coastal foods to survive. The ability of humans to use food from the sea also meant they could travel around the coasts of Africa and establish new settlements.

The team’s findings come from studies of archaeology joined to the climatic, environmental and ecological history of Pinnacle Point, a sea cliff along the south coast of South Africa where a large number of caves overlook the Indian Ocean. One cave, called cave 13B, is the focus of intense excavation work and has been since 2000. Researchers seek clues about how environmental changes affect human behavior and evolution.

“Shellfish may have been a critical food source for the survival of early human populations,” Marean said. “For millions of years, humans survived on inland plants and animals. Shellfish was one of the last additions to human diet before the introduction of domesticated plants and animals at the end of the Ice Age, also called the Pleistocene.”

He bases his premise, in part, on archaeological deposits and finds including 15 categories of marine invertebrates and a whale barnacle fragment found in cave 13B. The team’s conclusions also result from a scientific analysis of the Pinnacle Point coastline. Researchers associate collection of marine invertebrates, with hunter-gatherers developing more complex economic and social systems and reducing mobility.

In this case, the evidence supports a conclusion that humans in the Pinnacle Point area collected shellfish at low tides during the Middle Pleistocene, about 164,000 years ago, as estimated by radiometric dating techniques. A 3-dimensional geographic information system (GIS) model that maps Pinnacle Point sea levels at 1,500 year increments for the last 400,000 years also supports the dating.

Prior studies suggest foragers rarely transported marine resources more than 5-10 kilometers. The GIS model shows the coastline moved within that distance 167,000 years ago, a result consistent with dating of the archeological deposits found in cave 13B.

Until now, the earliest dated archeological evidence for human use of seafood, sea shells and other marine resources dated to 125,000 years ago. These new results indicate coastlines may have become attractive for human settlement and movement earlier than originally thought.

“They prove humans had an ability to move out of Africa via the Red Sea coast and migrate to Australia and New Guinea along the coastal corridor thousands of years before we originally suspected,” Marean said.

Marean’s paper, “Early human use of marine resources and pigment in South Africa during the Middle Pleistocene,” is scheduled for publication in the Oct. 18 edition of the science journal Nature.


Humans wired for art: Ancient artifacts foreshadow timeless art

How do scientists know a whale was eaten here? Whale bones typically are too large for people to carry long distances to archaeological sites. Early humans carried only the skin and blubber. Turns out there are barnacle species that only live on the skin of whales. When people scavenged a beached whale and ate it, all that remained was the barnacle as a sign that says, 'a whale was eaten here 164,000 years ago!' - Credit: South African Coast Paleoclimate, Paleoenvironment, Paleoecology, Paleoanthropology Project (SACP4), Arizona State University, Director - Curtis W. Marean
How do scientists know a whale was eaten here? Whale bones typically are too large for people to carry long distances to archaeological sites. Early humans carried only the skin and blubber. Turns out there are barnacle species that only live on the skin of whales. When people scavenged a beached whale and ate it, all that remained was the barnacle as a sign that says, ‘a whale was eaten here 164,000 years ago!’ – Credit: South African Coast Paleoclimate, Paleoenvironment, Paleoecology, Paleoanthropology Project (SACP4), Arizona State University, Director – Curtis W. Marean
An amazing foreshadowing of Leonardo Da Vinci’s Mona Lisa and Mike Tyson’s facial tattoos was also found in the 164,000 year-old sediment in cave 13B.

No, it wasn’t the chair in which Mona Lisa posed for her famous painting or the high-quality tattoo machine used to draw the equally artistic tribal tattoo on Mike Tyson’s cheek. It was something social scientists say is more valuable–the oldest known evidence that humans are wired for artistic expression, whether fine art or body art.

In an ancient cavern near the Western Cape province of South Africa, researchers found 57 pieces of pigment or substances used as coloring agents. The pigments were among the oldest artifacts in the cave traced to human activity.

“The pigments have all the hallmarks of those used for body-painting and perhaps coloring of other organic surfaces,” said Marean.

Most of the pigments have a pinkish-brown or reddish-brown surface color. Natural color systems show the majority as intermediate reddish-brown, followed by saturated reddish-brown and saturated very red. All the pigments can be classified as ‘red ochre.’

According to the researchers, 10 pieces of pigment were definitely used and two pieces probably were used.

There is extensive evidence of pigment use dating to 120,000 years ago. However, many coloring agents near this age, or older, are variably distributed outside South Africa. For example, in Israel some are dated to 92,000 years ago, and at Twin Rivers in Zambia, they are dated to between 141,000 and 400,000 years ago.

According to Marean, the find shows humans who lived in cave 13B preferred processing the reddest pigments, which is similar to finds in more recent sites. However, this pattern of pigment use occurred 40,000 years before such use apparently flourished post 120,000 years ago.

Coloring agents found in cave 13B now join this patchy sample of middle to late Pleistocene evidence for early pigment use by humans. But dating them to 164 thousand years ago makes them the most securely dated of the small sample of old finds.

“We have identified the earliest appearance of pigment use and dated it to a time close to the biological emergence of modern humans,” Marean said.


Note: This story has been adapted from a news release issued by NSF

Earliest evidence for reptiles

Close up of a handprint showing five slender fingers, characteristic of reptiles. - Photo by Howard Falcon-Lang
Close up of a handprint showing five slender fingers, characteristic of reptiles. – Photo by Howard Falcon-Lang
Newly discovered fossilised footprints provide the earliest evidence yet for the evolution of reptiles – a major event in the history of life. They are 315 million years old, making reptiles up to 3 million years older than previously thought.

The footprints were discovered by Dr Howard Falcon-Lang from the University of Bristol in sea cliffs, New Brunswick, Canada. The results of his study, undertaken with UK and Canadian colleagues, are published today in the Journal of the Geological Society of London.

Until now, the oldest reptile fossils were skeletons found in 1859 by William Dawson in Nova Scotia, and named Hylonomus lyelli after the nineteenth century geologist, Sir Charles Lyell.

Falcon-Lang said, “The new fossils were found in the same general region but at a level in the rock strata almost a kilometer below Dawson’s discovery. Consequently we can be confident the footprints are older than the skeletons. They were preserved when reptiles walked across the muddy bottom of a dry riverbed.


One of the metre-sized blocks of sandstone covered with fossil reptile tracks - Photo Credit: Howard Falcon-Lang
One of the metre-sized blocks of sandstone covered with fossil reptile tracks – Photo Credit: Howard Falcon-Lang
“The discovery was pure luck. As I walked along remote sea-cliffs at the end of a long day in the field, I passed a recent rock fall. One large slab of rock was covered with hundreds of fossil footprints! The sun was low in the sky and I probably wouldn’t have seen them if it hadn’t been for the shadows.”

Unlike their amphibian cousins, reptiles do not need to return to water to breed so they paved the way for the widespread colonization of dry land, and the establishment of diverse land-based ecosystems today. The difficult part of the study was proving that the footprints were actually those of reptiles and not just primitive amphibians.

“It was a bit like a crime scene investigation,” said Falcon-Lang, “we had found the footprints but who had made them?”

Professor Mike Benton, also of the University of Bristol, who co-authored the study, added, “There were only a few species capable of making prints like this around at the time so we came up with a short-list of suspects. However, the prints showed that the hands had five fingers and scales, sure evidence they were made by reptiles and not amphibians”.

The footprints prove that reptiles evolved even earlier than previously thought and existed in seasonally dry river-plains, a bit like those of northern Australia today. As the first pioneers of dry continental environments, they paved the way for the diverse terrestrial ecosystems that exist today.


Note: This story has been adapted from a news release issued by the University of Bristol

Early Apes Walked Upright 15 Million Years Earlier Than Previously Thought, Evolutionary Biologist Argues

A)-The LTP (lumbar transverse process) in humans differs markedly from related primates. It is dorsal to the position of the spinal canal. It is thick and strong (triangular or box-like cross-section) instead of flat and thin. (B,C)-Styloid comparison. Lateral view of lumbar vertebrae of human, macaque monkey and Proconsul africanus. The human vertebra, like Morotopithecus, appears to demonstrate absence of the styloid process and relocation of the LTP onto the arch of the vertebra at the base of the structure that carries the facet joint. (D) The Middle Miocene proconsulid hominoid Proconsul africanus appears to have the more primitive LTP and styloid as seen in most euarchontoglirans. (Credit: Courtesy of Aaron Filler, MD, PhD)
A)-The LTP (lumbar transverse process) in humans differs markedly from related primates. It is dorsal to the position of the spinal canal. It is thick and strong (triangular or box-like cross-section) instead of flat and thin. (B,C)-Styloid comparison. Lateral view of lumbar vertebrae of human, macaque monkey and Proconsul africanus. The human vertebra, like Morotopithecus, appears to demonstrate absence of the styloid process and relocation of the LTP onto the arch of the vertebra at the base of the structure that carries the facet joint. (D) The Middle Miocene proconsulid hominoid Proconsul africanus appears to have the more primitive LTP and styloid as seen in most euarchontoglirans. (Credit: Courtesy of Aaron Filler, MD, PhD)
An extraordinary advance in human origins research reveals evidence of the emergence of the upright human body plan over 15 million years earlier than most experts have believed. More dramatically, the study confirms preliminary evidence that many early hominoid apes were most likely upright bipedal walkers sharing the basic body form of modern humans.

Research from Harvard University¹s Museum of Comparative Zoology and from the Cedars Sinai Institute for Spinal Disorders connects several recent fossil discoveries to older fossils finds that have eluded adequate explanation in the past. The report deals with the “homeotic” genetic mechanisms that encode anatomical assembly in the embryo, and their relevance to a series of discoveries of hominoid fossil vertebrae.

The report analyses changes in homeotic embryological assembly of the spine in more than 200 mammalian species across a 250 million year time scale. It identifies a series of modular changes in genetic assembly program that have taken place at the origin point of several major groups of mammals including the newly designated ‘hominiform’ hominoids that share the modern human body plan.

It concludes that a specific gene change ­ in the Pax system — that generated the upright bipedal human body form — may soon be identified. The various upright “hominiform” hominoids appear to share this morphogenetic innovation with modern humans. Homeotics concerns the embryological assembly program for midline repeating structures such as the human vertebral column and the insect body segments.

The critical event involves a dramatic embryological change unique to the human lineage that was not previously understood because the unusual human condition was viewed as “normal.”


“From an embryological point of view, what took place is literally breathtaking,” says Dr. Aaron Filler, a Harvard-trained evolutionary biologist and a medical director at Cedars Sinai Medical Center’s Institute for Spinal Disorders.

In most vertebrates (including most mammals), he explains, the dividing plane between the front (ventral) part of the body and the back (dorsal) part is a “horizontal septum” that runs in front of the spinal canal. This is a fundamental aspect of animal architecture. A bizarre birth defect in what may have been the first direct human ancestor led to the “transposition” of the septum to a position behind the spinal cord in the lumbar region. Oddly enough, this configuration is more typical of invertebrates.

The mechanical effect of the transposition was to make horizontal or quadrupedal stance inefficient. “Any mammal with this set of changes would only be comfortable standing upright. I would envision this malformed young hominiform — the first true ancestral human — as standing upright from a young age while its siblings walked around on all fours.”

The earliest example of the transformed hominiform type of lumbar spine is found in Morotopithecus bishopi an extinct hominoid species that lived in Uganda more than 21 million years ago. “From a number of points of view,” Filler says, “humanity can be redefined as having its origin with Morotopithecus. This greatly demotes the importance of the bipedalism of Australopithecus species such as Lucy (Australopithecus afarensis) since we now know of four upright bipedal species that precede her, found from various time periods on out to Morotopithecus in the Early Miocene.”

Citation: Filler AG (2007) Homeotic Evolution in the Mammalia: Diversification of Therian Axial Seriation and the Morphogenetic Basis of Human Origins. PLoS One 2(10): e1019. doi:10.1371/journal.pone.0001019, http://www.plosone.org/doi/pone.0001019


Note: This story has been adapted from a news release issued by the Public Library of Science