Treasures Archive

Revisit specimens that were recently on display in our Natural Wonders exhibit

Butterfly fossil


Praepapilio colorado
Lived 48 million years ago
Found in Douglas Pass, Garfield County, Colorado

This extinct butterfly is related to one that lives in the dry tropical forests of Mexico today. Different colors remain on the male butterfly wings even though it is a fossil! The body of the female butterfly, shown here, had fallen apart before being preserved as a fossil. Chris Durden, Curator Emeritus of Entomology at TMM, named and described this ancient butterfly species.

dragonfly fossil


Tupus permianus
Lived 258 million years ago
Found in Elmo, Dickinson County, Kansas

The fossil imprint of this extinct dragonfly shows that it did not hover like dragonflies do today. It does not have struts near the base of the wing that are needed for powerful hovering. There were no mammals or birds on Earth when it lived—in fact it was the only flying predator of its time.

E. H. Sellards collected this specimen in Kansas in 1903, and later named and described the species. Dr. Sellards became the second director of the Texas Memorial Museum in 1938.

Lots of animal horns

Horns Galore

Ungulate mammals are animals that walk on the tips of their toes, which are covered in a hard thick hoof. They can also have different types of head ornamentation, including horns, antlers, or ossicones. The animals use these “horns” for display communication with each other, to defend themselves against predators, and in combat between males of a species.

The skulls shown here are part of the museum’s Recent vertebrate collection. Look for the nilgai, sable antelope, hirola, and gazelle skulls. These animals all have true horns. True horns have a bony core that grows from the skull bones. True horns are covered by an outer layer of keratinized skin called the sheath. Since true horns grow from the skull, these animals do not shed their horns during life. You might be familiar with other animals that have true horns like antelopes, gazelle, cattle, and sheep.

Pronghorns have horns that are similar to true horns, with a solid bony horn core and sheath. In males, part of the sheath extends forward from the head, like a “prong.” The sheath is shed and re-grown every year. The knobs on a giraffe’s skull are not even horns at all. They are called ossicones, and are separate bony deposits that are fused to the skull bones. These knobs develop and grow in older giraffes. Scientists think they help protect the skull when male giraffes use their heads as weapons during combat. The black rhinoceros’ “horn” is not a true horn, either. The “horn” itself is a mass of skin cells cemented together with thick, hair-like keratin fibers. The black rhinoceros is an endangered species, primarily as a result of illegal poaching for their horn. There are only about 3100 individuals surviving in the wilds of Africa.

Black rhinoceros
Diceros bicornis
TMM M-1839
Lives in reserves in Kenya, Tanzania, Namibia, Zambia, Zimbabwe and South Africa. Wild populations may be in several other African countries.

Boselaphus tragocamelus
TMM M-7497
Lives in India and eastern Pakistan; introduced and now free-ranging in Texas.

Giraffa camelopardalis
TMM M-6815
Lives in sub-Saharan Africa, primarily in the eastern and southern region.

Sable antelope
Hippotragus niger
TMM M-6816
Lives from southeast Kenya to northern South Africa, west to Botswana and Angola.

Hirola or Hunter’s hartebeest
Damaliscus hunteri
TMM M-6821
Lives from southern Somalia to northern Kenya.

Mountain gazelle
Gazella gazelle
TMM M-4153
Lives in Syria, Israel, Lebanon, the Arabian Peninsula.

Antilocapra americana
TMM M-5394
Lives in Southern Alberta and Saskatchewan, western US, Baja California, western Sonora

brain cast fossils

Oreodont brain casts

Bathygenys reevesi
TMM 40209 – multiple specimens
Lived about 36 million years ago
Found in the Reeves Bonebed, Presidio County, Texas

This bowl is filled with casts, or natural copies of the brain, from extinct mammals called Oreodonts. Think of it as a bowl of brains! After the animals died, sand and mud filled the empty skulls and hardened into these fossils. Since soft brain tissue is never preserved in a fossil, these casts give scientists important clues about what the brain was like. The brain lobes and creases can be seen on the darker brown casts.

Oreodonts were small hoofed mammals that are most-closely related to present-day camels and llamas. These fossils are part of over 100 brain casts that were found at the Reeves Bonebed northwest of Presidio, Texas. Scientists have found so many skulls and broken limb bones in the Reeves Bonebed that they believe it was the home of a carnivore that preyed on oreodonts.

petrified wood

Petrified palm wood

Palmoxylon sp.
NPL 523, and B 382
Found in Dimebox, Lee County, and in the Gulf coastal plain of Texas
Palms date back to 80 million years ago

This interesting fossil is cut vertically so that we can see the inside and outside of a petrified palm tree. Small secondary roots would have been attached to the small bumps of the outer side. Most of the time dead trees lying on the ground decompose completely in as little as three years. Luckily this part was a root and probably underground when it died. Over the years silica-rich fluids penetrated the dead tree, forming hard rock. The resulting fossil is more dense and heavier than the wood of the original tree; this half alone weighs about 30 pounds! The smaller specimen is a horizontal slice of another palm. The slice cuts through the internal vessels of the plant and we can see the “dot” pattern common to all petrified palms.

When you’re out exploring keep your eyes open to the world around you. Boy Scout Eric Mills of Webelos Den 534 discovered this fossil near Dimebox. Petrified palm wood is often found in east Texas and along the Gulf Coast. It is the official state stone of Texas.

“Sarah's Dinosaur from Gold Spring”

Sarahsaurus aurifontanalis
TMM 43646-2

Long before giant sauropod dinosaurs left their tracks along muddy tidal flats in Texas, the ancestors of Sarahsaurus moved northward from the Southern Hemisphere into what is now North America. These dinosaur dispersals occurred multiple times once the supercontinent Pangaea began to split apart 200 million years ago. Mass extinctions resulted from the effects of volcanic activity associated with the break-up of Pangaea. These extinctions emptied many land-based ecological niches, setting the stage for the evolution of Sarahsaurus and other early dinosaurs.

Sarahsaurus was discovered by Dr. Timothy Rowe and his field team from TNSC’s Vertebrate Paleontology Laboratory. The fossilized skeleton was preserved in 190 million year old rocks of the Kayenta Formation in northeastern Arizona and was collected under a permit granted by the Navajo Nation. The scientific name of this new dinosaur, Sarahsaurus aurifontanalis, was given in honor of Mrs. Sarah Butler, Austin philanthropist and supporter of the arts and sciences, and also references Gold Spring (aurum, Latin for gold and fontanalis, Latin for “of the spring”), the locality where the dinosaur was found.

After years of painstaking preparation of the skeleton of Sarahsaurus, Dr. Rowe and colleagues have learned much about this intriguing new dinosaur. Sarahsaurus was 14 feet (4.3 meters) long and estimated to weigh 250 lbs (113 kg). Its long neck supported a small head. Sarahsaurus had large hind limbs with column-like thigh bones, a characteristic that would be an advantageous adaptation inherited by its descendants, the gigantic sauropod dinosaurs. But unlike its massive relatives, Sarahsaurus did not always support its body on all four limbs. Sarahsaurus may have utilized its clawed powerful hands to tear into downed trees or other places to find small animal prey. The elongated leaf-shaped teeth of Sarahsaurus were serrated, which also suggests this dinosaur was an omnivore.

bison skull

Steppe bison

Bison priscus
TMM 962-1
Lived from 500,000 to 10,000 years ago
Found near Fairbanks, Alaska

Steppe bison lived in the dry grasslands of Canada, the United States and Mexico 500,000 to 10,000 years ago. The steppe bison was a large animal whose horns could span up to four feet across. This is the “skull cap” of one animal, including part of the horns. This is a special specimen to scientists because the horn sheath, or outside covering, is preserved in the fossil. Horn sheaths break down quickly after an animal dies, so they are not often found in fossils. Horn sheaths are made of keratin, the same material in your hair and fingernails.

Can you see the ridges on the dark brown horn sheath to the right? Those ridges helped prevent twisting when one bison locked horns with another. Steppe bison did not clash heads like sheep. Instead, the males fought a battle of strength by locking horns and pushing and twisting!

horn fossil

Torosaurus horn core

Torosaurus utahensis
TMM 41835-1
Lived about 65 million years ago
Found in Big Bend National Park, Brewster County, Texas

This massive horn core belonged to Torosaurus, a very rare ceratopsian dinosaur. Ceratopsians were plant-eating dinosaurs with enormous horned and frilled skulls. The late Bob Rainey, who served as head preparator of TNSC's Vertebrate Paleontology Lab, found this specimen in Big Bend National Park in 1976. Its discovery reveals that Torosaurus ranged as far south as present-day West Texas during its time on Earth.

This bone horn core is about two feet long, and supported the horn from inside. Can you see the curved eye socket at the base of the horn? Large horns and frills helped protect Torosaurus from predators like Tyrannosaurus rex. Amazingly, Torosaurus skulls have been found that measure up to nine feet from nose to frill—the largest skull of any terrestrial animal ever on Earth!