Often quite different from their more familiar North American counterparts and adorned with bizarre frills, bumps, dorsal sails, and crests, these new southern “terrible lizards” are changing many of our perceptions about dinosaurs. As an example, consider the now-diminished status of the iconic Tyrannosaurus rex, the fiercest North American predator. The most widely recognized of all dinosaurs, T. rex had long been considered the biggest, baddest carnivore ever to walk the Earth. But now it seems that T. rex, whose name loosely means “king of the tyrant lizards,” is not really the king after all. It has recently been surpassed in both size and probable ferocity by Giganotosaurus from South America and Spinosaurus from Africa. This discussion about southern dinosaurs was inspired by my opportunity to view the spectacular traveling exhibition, Ultimate Dinosaurs. In the presentation, seventeen of these strange southern dinosaurs are displayed. The collection was created and produced by the Royal Ontario Museum, Toronto, Canada, and presented by the Science Museum of Minnesota. The exhibition explains the southern dinosaurs as products of continental drift and subsequent evolutionary isolation through spectacular skeletal mounts and outstanding interpretive displays.
DYNAMIC DINOSAUR DISCOVERIES
Southern dinosaurs are the latest chapter in dinosaur paleontology, a discipline that began in the late 1800s when dinosaur fossils were discovered in the American West. At that time, the United States, as a rapidly developing nation, was ready and eager to fully exploit its dinosaur-fossil resources. It had paleontologists available to excavate the bones, museums, and universities to display them, and newspapers and magazines to publicize them.
Attracting worldwide attention, these fossil recoveries established the United States as the center of dinosaur excavation and research. During the following decades, many Americans grew up believing that such familiar North American dinosaurs as Tyrannosaurus, the long-necked sauropod Brontosaurus (now Apatosaurus), and the duckbilled hadrosaurs were representative of dinosaurs worldwide. But now, the plethora of recent southerndinosaur discoveries are revealing that dinosaur diversity is far greater than previously realized.
When the first dinosaurs appeared during the early Triassic Period some 240 million years ago, the Earth’s continental geography was radically different. Each a large, solid tectonic plate, the continents were grouped together into a supercontinent called Pangaea. Dinosaurs roamed freely across this vast landmass, shared many of the same genes, and exhibited relatively little diversity.
But after dinosaurs had become well-established, Pangaea’s tectonic plates began to separate. By the dawn of the Cretaceous Period 145 million years ago, Pangaea had broken apart into two large landmasses: Laurasia to the north, consisting of the stillgrouped, future continents of North America, Europe, and Asia; and Gondwana to the south, which included the future continents of Africa, South America, Australia, and Antarctica.
The breakup of Pangaea into Laurasia and Gondwana, and the subsequent separation into the individual continents we know today, divided dinosaur communities into groups isolated by oceans. With gene-sharing no longer possible, these dinosaur groups began to evolve independently, developing features and traits suited to their specific environments.
Although the idea that continents could shift geographically had been suggested as early as 1600, it was not considered seriously until 1910 when German geophysicist Alfred Wegener observed that the coastal outlines of western Africa and eastern South America fit together as if they had once been joined. Citing similarities in particular African and South American plant and animal fossils, Wegener concluded that these two continents had once formed a single landmass, and, prior to this, all the continents had been consolidated into a single “supercontinent.” Wegener named this supercontinent “Pangaea” from the Greek words for “all earth.”
But becaute geologists could not yet explain the mechanics of continental movement, Wegener’s idea remained controversial. Finally, a half-century later, geologists realized that slowly circulating currents within the Earth’s semisolid mantle did indeed move the continents. This discovery of currents validated Wegener’s theory and led to the now-accepted principle of continental drift.
Perhaps the best-known South American dinosaur that developed through continental drift and subsequent isolated evolution is the carnivore Giganotosaurus (jig-a-NOT-a-SOR-us), a name meaning “giant southern lizard.” An amateur fossil hunter discovered Giganotosaurus’s bones in 1993 in the badlands of southern Argentina’s Neuquén Province.
Despite their similar appearance, Giganotosaurusand T. Rex are not closely related. These two predators arose independently after the breakup of Pangaea. Giganotosaurus lived about 98 million years ago in South America, while T. rex existed some 30 million years later in North America.
Continue reading your story on the app
Continue reading your story in the magazine
Filling an Empty Space and Enhancing a Cabochon
I often look for a special feature within a slab when choosing the shape to cut into a cab.
Pterodactyls No Longer Birds of a Feather?
For a couple of decades now, feathered dinosaurs have been all the rage.
The Saga of COLORADO GOLD - 53 Million Troy Ounces and Counting
Colorado has been mining gold even before the region became a territory and is still mining it today.
SPECTACULAR NATIVE SILVER - Rarer Than Gold in Specimen Form
When it comes to naturally occurring precious metal specimens on Earth, finding native silver is not as easy as finding native gold.
PEARL OF THE PACIFIC - San Diego's Pacific Rim Park
Did you know, the Pearl of the Pacific was created in 1998 as a symbol of friendship and unity between the United States, Mexico, China and Russia?
POPULAR PSEUDOMORPHS - More Common Varieties Enhance Any Collection
In part one of this two-part series, which appeared in the December 2020 issue of Rock & Gem, we explained pseudomorphs as minerals whose normal form has changed, so they may look like the original but are now another mineral.
New Era Gems - CARVING A PATH AND CREATING A LEGACY
Think back to your 20th birthday; what were you doing? How did you celebrate?
DIAMONDS - A Luxury Gem Steeped in Fact & Fable
The diamond is one fabled gemstone! For example, google “Hope Diamond” to see all the legends associated with just this one stone said to bring misfortune to its owners.
Cleaning Without Chemicals
Do you have specimens like desert roses, quartz crystal clusters, or geode halves that sat for eons in the open before being collected?
Black Ilmenite and “Titanium White”
The bright-white color that we see in everything from highway lines, donut icing, and tooth-paste to paint, paper, plastics, and ceramics comes mostly from titanium dioxide, the world’s most widely used pigment.
Pittsburgh's August Wilson African American Cultural Center
LOCATED IN THE HEART of downtown Pittsburgh, on Liberty Avenue close to Union Station and the David Lawrence Convention Center, the sleek and elegant but unpretentious August Wilson African American Cultural Center (awaacc) cannot fail to capture the eye and the imagination of anybody who is visiting Pittsburgh or, for that matter, of anybody who lives in the city.
Bishop Stephen Masilela is the general presbyter for the COGOP in Africa. He is also a counselor and registered marriage officer and currently serves as president for Evangelical and Pentecostal churches in Africa. He holds a diploma in Personnel Management and Training (IPM) from Bible Training Institute and is enrolled with the Gordon Conwell/COGOP Leader of Leaders Master’s Degree program and the Extension School of Ministry of Swaziland College of Theology for a theology degree. He is married to Sibongile and they are blessed with three children.
NICOLE PATTON-TERRY READING RESEARCHER
Nicole Patton-Terry loves helping kids learn to read. She is associate director of the Florida Center for Reading Research at the Florida State University. Patton-Terry works on teams with researchers, students, teachers, designers, parents, and community members. Together they study reading and develop tools that help children read.
THE MOST Surreal RIFE OF OUR LIVES
National Route 40 is not only the longest road in Argentina, but also the world. Parallel to the Andes, it crosses 11 provinces, connecting some of the most prominent places of natural beauty and cultural interest in the country. We’d planned to take our time and enjoy the seemingly endless points of interest in the southern part of RN40, but just before reaching the province of Mendoza, we realized that our visas would soon need renewing. The least complicated way to extend them was a “border run,” which meant a ride out of and back into the country from the nearest border crossing to obtain the passport stamps.
‘THE 24TH' IS A SOBERING HISTORY LESSON FOR TODAY
On Aug. 23, 1917, four months after the U.S. had entered World War I, the all-Black 3rd battalion of the U.S. Army’s 24th Infantry Regiment mutinied in Houston.
BEYONCÉ'S ‘BLACK IS KING' IS SUPREME BLACK ART
King Beyoncé’s new film takes you on a journey of Black art, music, history and fashion as the superstar transports you to Africa to tell the story of a young man in search of his crown, matched to epic songs she created while inspired by “The Lion King.”
CAN WE TRAVELERS ADAPT IN THE TIME OF A PANDEMIC?
Being housebound in a small apartment in a random town during a pandemic with expired visas and a half-dead scooter in a country that until recently Wikipedia had under the category “Third World,” is not exactly the ideal situation. And it’s more than obvious that this part of our journey is not what we originally had in mind. However, this is how things are at the moment (April 2020) and no one knows how or when it’ll be over.
BY THE SEAT OF OUR PANTS
My Africa Twin Adventure Sports was buried belly pan-deep in mud.
Giant Loop Round the World Panniers and Pannier Mounts
Walk on The Wildside
Most visitors to Africa experience its wildlife from the safety of a Land Rover. But on a walking safari, things get real fast.