Podcasts: Hall of Geology and Paleontology

Dr. Ann Molineux, Former Curator of NPL Collections
Time length: 44 seconds

Transcript: Sea urchins are found in all oceans of the world and are even ‘farm raised’ in New England for their gonads which are used in some Asian delicacies such as Japanese sushi. They cannot survive in brackish water and are very sensitive to changes in the sea water salinity. Sea urchins main food source is algae, such as kelp, although crinoids, brittle stars and sponges provide variety. They, themselves, are the favorite food of sea otters. Where the otters are in decline rampant sea urchins can destroy the kelp beds by eating the holdfasts of the kelp.

Dr. Pamela R. Owen, Associate Director of TMM
Time length: 41 seconds

Transcript: Mosasaurs, marine lizards that were closely related to snakes and monitor lizards, were completely adapted for life in the oceans of the Late Cretaceous. They were the top predators, feeding on other marine reptiles, fish, and ammonites. Mosasaurs were equipped with several sharp conical teeth that were used to capture and hold prey, but not to chew it into pieces. To assist in the eating of large slippery prey, mosasaurs had a set of teeth on the pterygoid bones in the roof of the mouth. Using these pterygoid teeth and flexible lower jaws, mosasaurs could swallow their prey whole, a fashion similar to that of snakes.

Dr. Ann Molineux, Former Curator of NPL Collections
Time length: 1 minute 1 second

Transcript: What do engine blocks, train tracks, ships and bridges have in common?—IRON. Iron makes up about 5% of the Earth’s crust. We often see it in Cretaceous aged rocks around central Texas as flecks of red or yellow, or the glinting grains of ‘fool's gold’—iron pyrite. Most of the world’s iron ore, however, was formed in the middle Precambrian around 2 billion years ago. The great banded iron deposits are the richest source of iron ore; some of the Australian Pilbara deposits, such as this specimen, have as much as 65% iron ore, while the Mesabi Range in Minnesota has 70%. The Australian banded iron formations are sometimes termed tiger iron because of the amount of bright yellow tiger’s eye in the rock.

Dr. Ann Molineux, Former Curator of NPL Collections
Time length: 1 minute 5 seconds

Transcript: The oldest rock on Earth is 4.02 billion years old. That's the oldest one ever found. Meteorites are usually around 4.55 billion years old. The solar system formed about 4.5 billion years ago. If you want to study the first half billion years of Earth’s history meteorites are the rocks to investigate. Meteorites have been called the “poor man’s space probe” because they allow us to sample places from which no rocks have yet been brought back by spacecraft, such as parts of the Moon, Mars and asteroids. How can you recognize a meteorite? That can be quite tricky because many stony meteorites look just like Earth rocks. The ones that are more commonly noticed are iron meteorites which are abnormally heavy for their size, highly magnetic, and very dense with no internal holes.

Dr. Pamela R. Owen, Associate Director of TMM
Time length: 44 seconds

Transcript: This jaw is from the gomphothere Amebelodon, an extinct relative of mammoths, elephants, and mastodons. The elongate jaw supports tusks that are flattened and shovel-like. Amebelodon used its jaws and trunk to strip bark, leaves, and twigs from trees as well as to scoop up aquatic vegetation. Not all gomphotheres were “shovel-tuskers” like Amebelodon, but all possessed molars that developed a cloverleaf pattern on the chewing surface during wear. Over its lifetime, a gomphothere used six sets of grinding teeth in each side of both the upper and lower jaws. As the previous set was worn, it was pushed forward by the eruption of the next larger, unworn set of teeth.

Dr. Edward Theriot, Director of TMM
Time length: 42 seconds

Transcript: The Glen Rose Dinosaur Tracks are probably the most famous such tracks in the world. Taken from what is now Dinosaur Valley State Park on the Paluxy River just northwest of Glen Rose, Texas, these tracks are only a small part of the thousands of dinosaur footprints you can see and touch. They are about 113 million years old. Our tracks are thought to show a meat eating dinosaur trailing a plant eating dinosaur. In what is roughly the middle of the track, you can see a three-toed meat-eater footprint inside of the round plant eater footprint, meaning that the meat-eater had to step there after the plant-eater. No one knows whether or not the two dinosaurs struggled or how that struggle might have ended.

Dr. Pamela R. Owen, Associate Director of TMM
Time length: 44 seconds

Transcript: Before the appearance of dinosaurs, Texas was home to a type of vertebrate commonly called “sailback”. Sailbacks, such as Dimetrodon and Edaphosaurus have backbones with very long upward-extending spines. Grooves at the base of these spines probably held blood vessels, which would have carried blood through the skin that covered the spines in life. This anatomical arrangement is thought to provide the sailback with a way to regulate its body temperature. By standing with the broad surface of the sail facing the sun, a sailback would absorb heat and transport it through its circulatory system, warming its whole body. If a sailback needed to cool off, it could radiate heat from the sail as it stood in the shade.

Dr. Pamela R. Owen, Associate Director of TMM
Time length: 44 seconds

Transcript: Tyrannosaurus was one of the largest of the theropod dinosaurs, the carnivorous and bipedal branch of the dinosaur family tree. Most Tyrannosaurus fossils have been found in the foothills of the central and northern Rocky Mountains, including the specimen from which this cast was made. To your right, in a special exhibit case, is part of the upper jaw of a Tyrannosaurus collected in Big Bend National Park. This rare fossil shows us that Tyrannosaurus once ranged as far south as present-day West Texas. Tyrannosaurus was one of the last dinosaurs in Texas, becoming extinct 65 million years ago, along with other dinosaurs such as Alamosaurus and Chasmosaurus.

Dr. Pamela R. Owen, Associate Director of TMM
Time length: 44 seconds

Transcript: Plesiosaurs are an extinct group of large aquatic reptiles that were among the largest predators in the Mesozoic oceans. Adaptations for powerful swimming are seen in the shield-like pectoral and pelvic bones and large paddle-like limbs. This plesiosaur was found by a local dentist exploring Shoal Creek. The fossil remains are exhibited in the position in which they were found and excavated. The skull was not attached to the skeleton, but discovered next to it. Unfortunately, it was very poorly preserved and broken into many pieces – too fragile to be put on exhibit. Despite the condition of its skull, this plesiosaur is still an important and fascinating part of Austin’s ancient history.

Dr. Pamela R. Owen, Associate Director of TMM
Time length: 46 seconds

Trancript: Scimitar-toothed cats were about the size of modern African lions, but had a lighter build with long forelimbs and relatively shorter hindlimbs. These cats used their sharp, retractile claws to help pull down large prey. Scimitar-toothed cats, as did other saber-toothed cats, possessed flattened and serrated upper canine teeth that were effective weapons. The elongate canines were used in killing bites to the throat or abdomen of large Pleistocene herbivores such as bison, mammoth, horse, and camel. The adult and kitten skeletons on exhibit were excavated from Friesenhahn Cave, near San Antonio. This cave was used as a den by these extinct cats about 20,000 years ago.

Dr. Pamela R. Owen, Associate Director of TMM
Time length: 41 seconds

Transcript: Glyptodonts are an extinct type of mammal related to armadillos, sloths and anteaters. Glyptodont skeletons include thick protective armor that covered them from head to tail. Their 5 foot long “shell” (called a carapace) is like that of an armadillo, but lacks the “bands” seen in the midsection of armadillos. The tail, clad in armor, could serve as a club, but it was mostly used for balance during locomotion. Glyptodonts had short square skulls and chewed the plants they ate with a forward-grinding motion. The name “glyptodont” means “carved tooth” in Greek, named for the grooves found on the outside of their teeth.

Dr. Pamela R. Owen, Associate Director of TMM
Time length: 41 seconds

Transcript: Xiphactinus is often called the “bulldog fish”, given its large conical teeth in the front of its mouth. This extinct predatory fish swallowed its prey whole. The strange bones found along the bottom of this fish’s belly are not the remains of its last meal, but actually its paired pelvic bones. These bones make up what is called the pelvic girdle, to which a pair of pelvic fins attaches. As in many bony fish, the pelvic fins, in addition to the pectoral fins, are used for maneuvering in the water. Because the pelvic girdle is embedded in muscle in life, the bones look like they are floating in the belly in fossilized fish skeletons.

Dr. Pamela R. Owen, Associate Director of TMM
Time length: 1 minute

Transcript: Sloths are a fascinating and diverse group of mammals with a rich fossil record that dates back 28 million years. Two species of 2-toed sloths and four species of 3-toed sloths currently make their homes in tropical rainforests of Central and South America. Prehistoric sloths were not limited to life in the trees, for there were many forms with different adaptations for locomotion and feeding. Paramylodon harlani is an extinct Pleistocene sloth that unlike the arboreal leaf-eating sloths of today, did not climb trees, and lived in open woodland and plains regions of North America, including Texas. This might not be too surprising, given this sloth’s large body size and estimated weight of 2300 pounds! Paramylodon had large claws on the second and third digits of its hand that were useful not only as defensive weapons, but may have been used to dig up roots and other vegetation, for this sloth had a diet of mixed plants dominated by grasses.

Dr. Pamela R. Owen, Associate Director of TMM
Time length: 1 minute 1 second

Transcript: Equus simplicidens, often called the American “zebra”, was the earliest member of the equid family, which includes the zebras, horses and wild asses of today. It was not the direct ancestor of zebra species living in Africa, but an even older ancestor to both the zebra and wild ass groups. About the size of an Arabian horse, this extinct equid had a narrow skull and features of its teeth that are similar to those of zebras, especially the endangered Grevy’s zebra. Did Equus simplicidens have stripes? Unfortunately, coat colors and patterns do not fossilize, but we can imagine American zebras with stripes on the legs and one down the back – just like many of its living relatives, the wild asses and zebras. This 3.7 million year old skeleton was found in Idaho, but teeth and partial skeletons of American “zebras” have also been found in Crosby and Hudspeth counties in West Texas.