Article

Ida, an adorable anomaly in the fossil record.

Illustration courtesy Esther van Hulsen

Little Miss Messy
Ida was not the fossils first name. The Oslo team first called her Little Miss Messy, after the Messel Pit where she was found, until they discovered Ida was a young primate, about the same age as paleontologist Dr. Jrn Hurums daughter, Ida. They briefly considered naming the fossil Nelson, after the monkey in Ida Hurums favorite Pippi Longstocking books. However, the name Nelson is so common in Sweden that many fossils already carry that name.

After discussing it with the family, Ida Hurum told her school that she was going to have a dead monkey named after her. That settled itthe fossil was forever nicknamed Ida.

Teutonic Tropics?
The Messel Pit, where Ida was discovered, was a volcanic lake in a lush, tropical rain forest during the Eocene epoch. The lake thrived at a latitude about the same as present-day Sicily, the island off the "boot" of Italy in the Mediterranean Sea.

Over millions of years, tectonic shifts moved the tropical maar thousands of kilometers north. Today, the Messel Pit is in temperate central Germany. Paleontologists are lucky Ida was preserved as the landmass moved northward!

Life on Maars
Maars like the one that formed the Messel Pit can be found in the U.S. states of Texas, Alaska, and New Mexico, and throughout the continents of South America and Africa. Maars in Alaska are up to 8 kilometers (5 miles) wide, among the biggest in the world.

The most well-known maar is Lake Nyos in Cameroon. On August 21, 1986, Lake Nyos suddenly emitted a large cloud of carbon dioxide that killed 1,700 people and 3,500 livestockthe same phenomenon that probably killed Ida. After that disaster, the community installed a tube that releases small amounts of carbon dioxide safely to the surface of the lake. However, the lake remains dangerous because of weak natural walls and seismic activity in the area.

By Mary Schons

Monday, October 24, 2011

Ida (pronounced EE-duh) is the most perfectly preserved primate fossil in the world. Paleontologists, scientists who study fossils, estimate that Ida died 47 million years ago. Ninety-five percent complete, she is the most complete primate fossil ever found. By comparison, the famous “Lucy” fossil, Australopithecus afarensis, is only 40 percent complete.

Ida was a small primate, about 9 months old when she died. From end to end she is only 58 centimeters (23 inches) long, about the size of a small house cat. Her body is 24 centimeters (9 inches) long. Ida's legs were longer than her arms, indicating she was a leaper. X-ray scans show she was a female. Ida’s remains also show she had a broken right wrist. She didn’t die of a broken wrist, but it almost certainly contributed to her early death.

Ida had large eye sockets, which suggests she was nocturnal. Nocturnal animals are active mainly at night. The shape of Ida’s teeth suggests she was a vegetarian. However, scientists didn’t have to guess what she ate. Her last meal—fruit—was still preserved in her gut millions of years after she ate it.

Ida had long fingers and toes, and opposable thumbs. Her hands show she had rounded fingertips with nails, not claws. Rounded fingertips with nails are classic primate features. 

The scientific team that introduced Ida to the world was led by Dr. Jørn Hurum, a paleontologist at the Natural History Museum in Oslo, Norway. Hurum persuaded the museum to purchase Ida.

A private collector discovered Ida near Messel, Germany, in 1983. Until 2000, Ida's remains were split into two pieces. The main part (“Slab A”) remained with the collector, while the other part ("Slab B") was sold to the Wyoming Dinosaur Center in Thermopolis, Wyoming, in the United States. Slab A and B were reunited in 2007. The identity of the person who first dug up Ida remains unknown.

One of the surprises Hurum and other paleontologists found when they X-rayed Ida was that she had many more teeth than the average primate. When the scientists looked closer, they discovered Ida was in the process of losing her baby teeth.

Unerupted molars—adult teeth that were pushing out her baby teeth—could still be seen in her jaw. From this, the paleontologists determined Ida was a juvenile primate—not a baby, but not fully adult, either. Developmentally, she was about the same age as Hurum’s daughter, Ida, who was also losing her baby teeth. They decided to name the fossil after her.

Darwinius masillae

Ida's scientific name is Darwinius masillae. The genus Darwinius was named in honor of Charles Darwin's 200th birthday. The species masillae was to commemorate the Messel Pit in Germany, where Ida was found.

The Messel Pit is an abandoned quarry about 35 kilometers (22 miles) southeast of Frankfurt, Germany, near the village of Messel. The pit was formed millions of years ago when hot magma bubbling from under the earth came too close to the underground water table. When the magma hit the water table, it instantly turned to steam. Hot air rises, but this air had nowhere to go. The pressure of the steam caused a massive explosion as the hot air tore into the earth. The explosion created a type of volcanic lake known as a maar.

The explosion that formed Messel Lake happened about 50 million years ago, during the early Middle Eocene epoch. Because the maar had no rivers running into or out of it, the water at the bottom of the lake received very little oxygen. Anything that fell into the lake was remarkably well-preserved. They didn’t go through the same decomposition process that other living things do when they die.

Another characteristic of maars is that they sometimes spit out toxic gas. Maars have volcanoes under them, and from time to time they emit carbon dioxide gas. The pure CO2 travels up from the lake and can kill any living creature that breathes in the gas.

Scientists speculate this is what killed Ida. Her broken wrist meant she couldn’t leap and cling to high tree branches. Lower to the ground, she encountered the toxic gas in Messel Lake, lost consciousness, and drowned.

In 2001, a hole was drilled into the center of the Messel Pit. Scientists extracted volcanic rocks that formed the ancient lake. Dating the rocks in the Messel Pit showed that Ida was about 47 million years old.

The Nose Knows

Ida lived her short life during the Eocene. The Eocene lasted from 55 million to about 34 million years ago. The Eocene is an important period in human evolution, because it was during this time that the first primates were evolving. About 40 million years ago, there were two distinct primate groups: prosimians and anthropoids.

One way taxonomists separate prosimians and anthropoids is by their noses. Prosimians, or strepsirrhini, have dog-like, wet noses. Extant, or living, representatives of strepsirrhini include lemurs, lorises, and bush babies. Anthropoids, or haplorhini, have dry noses. Extant representatives of haplorhini include monkeys and apes. Humans are also dry-nosed primates. At some point during the Eocene, primates evolved into these two different branches.

So was Ida a wet-nosed or a dry-nosed primate? She contains qualities of both, making her a truly remarkable specimen.

The team from the Natural History Museum in Oslo believes her physical size and diet were similar to the eastern woolly lemur, a wet-nosed primate native to Madagascar. However, Ida doesn’t possess two key lemur traits: a toothcomb or a grooming claw. A toothcomb is a set of fused, forward-angled teeth in the lower jaw that lemurs use to groom their fur. A grooming claw is a long claw on the second toe that lemurs use to groom fur they can't reach with their toothcomb. Ida also has a tarsus bone in her ankle that is shaped like a dry-nosed primate ancestor’s.

The Oslo team believes Ida comes from a time when primates were still evolving into these two distinct groups. Because Ida has characteristics of both, they consider her a transitional species—a link between prosimian and arthropoid primates.

Other scientists who have read the published paper disagree with its conclusions. They say Ida is an ancestor of lemurs and lorises, not a “missing link.”

Girly Fossil

Hurum frequently speaks about Ida and other fossils to school groups. He says Ida attracts more questions from girls than boys. Girls are interested in how Ida lived—what she looked like, what she ate, how she moved, how she coped with her broken wrist.

"Most dinosaur outreach focuses on the big and dangerous ones, big teeth and fights,” Hurum said. “This is in my opinion, after giving lectures to several thousand school children over the years, mostly enjoyed by boys. They ask questions and contribute more to the dialogue.

“With Ida it is opposite. I get more questions from girls—the fossil is small and cute and the story is dramatic, but not bloody."

Vocabulary

Term Part of Speech Definition Encyclopedic Entry

abandon

Verb

to desert or leave entirely.

ancestor

Noun

organism from whom one is descended.

ancient

Adjective

very old.

anthropoid

noun, adjective

grouping of "higher primates," including monkeys, apes, and human beings.

ape

Noun

large, intelligent primate with no tail.

Australopithecus afarensis

Noun

extinct species of primate (hominid) that lived about 3-4 million years ago.

baby teeth

Plural Noun

first set of teeth in mammals, which eventually fall out as permanent teeth replace them. Also called primary teeth and deciduous teeth.

bush baby

Noun

small mammal (primate) native to Central African forests.

carbon dioxide

Noun

greenhouse gas produced by animals during respiration and used by plants during photosynthesis. Carbon dioxide is also the byproduct of burning fossil fuels.

Charles Darwin

Noun

(1809-1882) British naturalist.

claw

Noun

sharp, curved nail on the foot of some animals, used for protection, predation, climbing, or grooming.

commemorate

Verb

to honor an event on a specific date.

conscious

Adjective

aware of.

cope

Verb

to handle or deal with problems.

Darwinius masillae

Noun

extinct species of primate which lived in the Eocene, about 47 million years ago.

decompose

Verb

to decay or break down.

dialogue

Noun

conversation between two people or organizations.

diet

Noun

process of choosing food and drink in order to lose weight.

dinosaur

Noun

very large, extinct reptile chiefly from the Mesozoic Era, 251 million to 65 million years ago.

earth

Noun

soil or dirt.

eastern woolly lemur

Noun

primate native to eastern Madagascar. Also called eastern Avahi laniger or Gmelin's woolly lemur.

emit

Verb

to give off or send out.

encounter

Verb

to meet, especially unexpectedly.

Eocene

adjective, noun

(55-34 million years ago) epoch of the Tertiary Period in the Cenozoic Era.

evolution

Noun

process of how present types of organisms developed from earlier forms of life.

explosion

Noun

violent outburst; rejection, usually of gases or fuel

extant

Adjective

living or in existence; prominent or standing out.

extract

Verb

to pull out.

eye socket

Noun

hole in the skull where the eyeball and its associated tissues are secured. Also called the orbit and eye socket orbital cavity.

fossil

Noun

remnant, impression, or trace of an ancient organism.

Encyclopedic Entry: fossil

frequent

Adjective

often.

fruit

Noun

edible part of a plant that grows from a flower.

fuse

Verb

to combine or meld together.

gas

Noun

state of matter with no fixed shape that will fill any container uniformly. Gas molecules are in constant, random motion.

groom

Verb

to tend or carefully clean, brushm and make tidy.

grooming claw

Noun

specialized claw on the toe of some primates used for grooming their fur. Also called a toilet claw.

gut

Noun

part of the abdominal cavity including the digestive tract, stomach, and intestines.

Haplorhini

Noun

suborder of primates, ("dry-nosed primates") including monkeys, apes, and human beings.

Ida

Noun

nickname of the nearly complete skeleton of the primate species Darwinius masillae, approximately 47 million years old, discovered in Germany in 1983.

jaw

Noun

set of bones or exoskeleton that form the framework of the mouth.

juvenile

Noun

animal that is no longer a baby but has not reached sexual maturity.

lake

Noun

body of water surrounded by land.

lemur

Noun

type of small mammal (primate).

loris

Noun

small primate native to Southeast Asia.

Lucy

Noun

nickname of an incomplete skeleton of the species Australopithecus afarensis, approximately 3.2 million years old, discovered in Ethiopia in 1974.

maar

Noun

depression formed as magma reacts with groundwater.

magma

Noun

molten, or partially melted, rock beneath the Earth's surface.

Encyclopedic Entry: magma

massive

Adjective

very large or heavy.

missing link

Noun

species that has characteristics of two different clades, or species and all its descendents. Usually refers to species sharing characteristics of apes and humans.

molar

Noun

large, flat tooth used for chewing and grinding.

monkey

Noun

mammal considered to be highly intelligent, with four limbs and, usually, a tail.

nocturnal

Adjective

active at night.

opposable thumb

Noun

thumb that can be placed opposite the fingers of the same hand.

oxygen

Noun

chemical element with the symbol O, whose gas form is 21% of the Earth's atmosphere.

paleontologist

Noun

person who studies fossils and life from early geologic periods.

possess

Verb

to have or own.

preserve

Verb

to maintain and keep safe from damage.

primate

Noun

type of mammal, including humans, apes, and monkeys.

prosimian

adjective, noun

grouping of primates, including lemurs, lorises, and tarsiers.

quarry

Noun

site where stone is mined.

Encyclopedic Entry: quarry

remarkable

Adjective

unusual and dramatic.

river

Noun

large stream of flowing fresh water.

Encyclopedic Entry: river

species

Noun

group of similar organisms that can reproduce with each other.

specimen

Noun

individual organism that is a typical example of its classification.

speculate

Verb

to consider or guess.

steam

Noun

water vapor.

Strepsirrhini

Plural Noun

one of the two suborders of primates ("wet-nosed primates"), including lemurs and lorises.

tarsus

Noun

group of bones, including the ankle, between the leg and the foot.

taxonomist

Noun

scientist who studies the description, identification, naming, and classification of organisms.

toothcomb

Noun

long, flat, fused, forward-facing teeth on the lower jaw that some primates, such as lemurs and lorises, use for grooming their fur. Also called a dentalcomb.

toxic

Adjective

poisonous.

trait

Noun

characteristic or aspect.

transitional species

Noun

species that has characteristics of two different clades, or species and all its descendents. Sometimes called a transitional fossil or missing link.

unerupted

Adjective

tooth that remains below the surface of the gum. Also called impacted or embedded teeth.

vegetarian

Noun

person who does not eat meat.

village

Noun

small human settlement usually found in a rural setting.

Encyclopedic Entry: village

volcanic

Adjective

having to do with volcanoes.

volcano

Noun

an opening in the Earth's crust, through which lava, ash, and gases erupt, and also the cone built by eruptions.

water table

Noun

underground area where the Earth's surface is saturated with water. Also called water level.

Encyclopedic Entry: water table

X-ray

Noun

radiation in the electromagnetic spectrum with a very short wavelength and very high energy.

Credits

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Writer

Mary Schons

Editors

Kara West
Jeannie Evers

Producer

Caryl-Sue, National Geographic Society

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