The Kem Kem beds in Morocco are famous for the spectacular fossils found there, including at least four large-bodied non-avian theropods, several large-bodied pterosaurs and crocodilians.

Now, in a new geology and paleontology monograph, that reveals much more about the famous Kem Kem beds in Morocco, Dr. Nizar Ibrahim from the University of Detroit Mercy, Prof. Paul Sereno from the University of Chicago, and a team of international scholars from the United States, Europe and Morocco, have put together a comprehensive story that is published in the open-access journal ZooKeys.

The aim of the new research is to provide the international community with an in-depth review of the rocks and fossils of the region. It reviews the geology and paleontology of this famous but surprisingly understudied area, describing and formally naming the strata and summarizing all of the preserved life forms, from fragile plants and insects to massive dinosaurs. The monograph also paints a picture of life as it once was some 95 million years ago by describing the paleoenvironments of the region, and the unusual predator-dominated fauna.

In 1996 Prof. Sereno and colleagues introduced the informal term “Kem Kem beds” for this fossil-rich escarpment. In this monograph, the authors review the original tri-level proposal for the region by French geologist Choubert (his informal “trilogie mésocretacée”) and propose the Kem Kem Group for the entire package of rock with two new names for the dinosaur-bearing layers based on the richest fossil sites, the Gara Sbaa and Douira formations.

The region is famous for the prodigious fossils found in all of these units, many derived from commercial fossil collecting, which obscures the precise location and level of the specimens. The monograph is the first work to pinpoint where many of the most important finds were made. Over the last 25 years in particular, paleontologists have brought to light a diverse array of new vertebrate fossils including at least four large-bodied non-avian theropods, several large-bodied pterosaurs, crocodilians, turtles and an array of sharks and bony fish.

To put a comprehensive story together on the Kem Kem, the authors of the monograph visited collections of Kem Kem fossils around the world and led many expeditions to the region. Fossil and geological data reviewed in the monograph is derived from a number of different sources. A University of Chicago-led major expedition in 1995 generated a wealth of geological and paleontological data, as did later expeditions involving teams from the University College Dublin, the University of Portsmouth, the Faculté des Sciences Aïn Chock, the Muséum national d’Histoire naturelle, the University Cadi Ayyad, the Museo Civico di Storia Naturale (Milan), and the University of Detroit Mercy.

One of the key features of the Kem Kem assemblage is the presence of several large-bodied theropods, a group of dinosaurs that includes all of the meat-eaters. Most famous among these from the Kem Kem include the sail-backed Spinosaurus and the sabre-toothed Carcharodontosaurus.

Most fossils in the Kem Kem region are discovered as isolated fragmentary pieces weathered from sandstones. Only four partial dinosaur skeletons or skulls have been recovered, which include the long-necked sauropod Rebbachisaurus garasbae and the theropods Deltadromeus agilis, Carcharodontosaurus saharicus and Spinosaurus aegyptiacus. These Kem Kem theropods are among the largest known dinosaurian predators on record reaching adult body lengths in excess of 12 meters.

“Given the continued input of new specimens and the continuing expansion of paleontological research, we predict that diversity in the Kem Kem Group will increase substantially in the coming decades. Based on our review of existing collections, this increase will include scores of taxa from the pond locality Oum Tkout including nonvertebrates, such as plants, insects, and ostracods, as well as an array of actinopterygian fish. We also anticipate a continuing trickle of new terrestrial vertebrates that will be named on better-preserved specimens that are diagnostic at present only at the familial level, including turtles and various kinds of archosaurs. As nearly half of the reptilian families listed are indeterminate, better-preserved specimens will offer future opportunities to recognize new reptilian genera,” share the authors.

“In summary, the Kem Kem assemblage of non-vertebrates and vertebrates is likely to continue to show dramatic increase in diversity in the coming decades. Nonetheless, the array of taxa currently known, which extends from plants across a range of aquatic and terrestrial vertebrates, is sufficiently mature to allow a summary of the vertebrate assemblage and a discussion of its paleoecological context,” conclude the researchers.

In his earlier research, a famous paleontologist from the University of Chicago Prof. Paul Sereno has described many outstanding dinosaur discoveries, including new Cretaceous crocodilians from the Sahara and two new fanged vegetarian dinosaur dwarfs (called heterodontosaurids).

Reference:
Nizar Ibrahim, Paul C. Sereno, David J. Varricchio, David M. Martill, Didier B. Dutheil, David M. Unwin, Lahssen Baidder, Hans C. E. Larsson, Samir Zouhri, Abdelhadi Kaoukaya. Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco. ZooKeys, 2020; 928: 1 DOI: 10.3897/zookeys.928.47517

Note: The above post is reprinted from materials provided by Pensoft Publishers.

In 1996, palaeontologists found skeletal remains of a giant shark at the northern coast of Spain, near the city Santander. Here, the coast comprises meter high limestone walls that were deposited during the Cretaceous period, around 85 million years ago, when dinosaurs still roamed the world. Scientists from the University of Vienna examined this material now and were able to assign the remains to the extinct shark family, Ptychodontidae, a group that was very specious and successful in the Cretaceous but suddenly vanished mysteriously before the infamous end-Cretaceous extinction event.

Shark vertebrae are rare in the fossil record, but precious

Ptychodontid sharks are mainly known from their teeth, which are flattened and allowed them to crush hard-shelled prey, like bivalves or ammonites, similar to some of today’s ray species. However, the find of Spain consists only of parts of the vertebral column and placoid scales (teeth-like scales), which are much rarer than teeth in the fossil record.

In contrast to teeth, shark vertebrae bear important information about a species’ life history, such as size, growth and age, which are saved as growth rings inside the vertebra, like in the stem of trees. Statistical methods and the comparison with extant species, allowed the scientists to decode these data and reconstruct the ecology of this enigmatic shark group.

Ptychodontid sharks grew big and old

“Based on the model, we calculated a size of 4-7m and an age of 30 years for the examined shark. Astonishing about this data is the fact that this shark was not yet mature when it died despite its rather old age.” states Patrick L. Jambura, lead author of the study. Sharks follow an asymptotic growth curve, meaning that they grow constantly until maturation and after that, the growth curve flattens resulting from a reduced growth rate. “However, this shark doesn’t show any signs of flattenings or inflections in the growth profile, meaning that it was not mature, a teenager if you want. This suggests that these sharks even grew much larger (and older)!”

The study suggests that ptychodontid sharks grew very slow, matured very late, but also showed high longevity and reached enormous body sizes. “This might have been a main contributor to their success, but also, eventually, demise.”

Do modern sharks face a similar fate?

Many living sharks, like the whale shark or the great white shark, show very similar life history traits, a combination of low recruitment and late maturation, which makes them vulnerable to anthropogenic threats, like overfishing and pollution.

“It might be the case that similar to today’s sharks, ptychodontid sharks faced changes in their environment, to which they could not adapt quick enough and, ultimately, led to their demise before even dinosaurs went extinct. However, unlike in the Cretaceous period, it is up to us now, to prevent this from happening to modern sharks again and to save the last survivors of this ancient and charismatic group of fishes!”

Reference:
Patrick L. Jambura, Jürgen Kriwet. Articulated remains of the extinct shark Ptychodus (Elasmobranchii, Ptychodontidae) from the Upper Cretaceous of Spain provide insights into gigantism, growth rate and life history of ptychodontid sharks. PLOS ONE, 2020; 15 (4): e0231544 DOI: 10.1371/journal.pone.0231544

Note: The above post is reprinted from materials provided by University of Vienna.

You might own something made from mahogany like furniture, paneling or a musical instrument.

Mahogany is a commercially important wood, valued for its hardness and beauty. The United States is the world’s top importer of the tropical timber from leading producers like Peru and Brazil. Unfortunately, mahogany is harvested illegally a lot of the time.

For science, mahogany is important, too — the fossil presence of the mahogany family is a telltale of where tropical forests once stood. Until recently, paleobotanists had only found evidence the mahogany family extended back to the Paleocene (about 60 million years ago).

Now, a new paper written by University of Kansas researcher Brian Atkinson in the American Journal of Botany shows the mahogany family goes back millions of years more, to the last hurrah of the dinosaurs, the Cretaceous.

“For understanding when many of the different branches of the tree of life evolved, we’re primarily dependent on the fossil record,” said Atkinson, an assistant professor of ecology & evolutionary biology and curator in the Biodiversity Institute’s Division of Paleobotany. “In this case, Meliaceae, the mahogany family, is an ecologically and economically important group of trees. A lot of researchers have used this group as a study system to better understand the evolution of tropical rainforests. This work is the first definitive evidence that the tropically important trees were around during the Cretaceous period, when we first start to see the modernization of ecosystems and modern groups of plants.”

Atkinson’s new work pushes back the fossil record for Meliaceae by 15 to 20 million years, the Campanian stage of the Late Cretaceous, from between 72-79 million years ago. The well-preserved mahogany specimen Atkinson analyzed was discovered just off Vancouver Island in Canada.

“The rock that contained the specimen was collected by a local fossil collector, Graham Beard, who is the director of the Qualicum Beach Museum of Natural History,” Atkinson said. “He collected it years ago, but I was actually interested in the rock that has this fossil in it for something else. And as I kept preparing this rock, more for the other fossils were in there, this thing showed up by surprise. So, it was kind of found by accident.”

To pinpoint the fossil’s identity, Atkinson carefully studied the structure of the fossilized fruit and also analyzed phylogenetic information to figure out its relationship to other species in the mahogany family.

“I combined the molecular data from living representatives of the mahogany family with the morphology of the fossil, as well as the morphology of living species,” he said. “And then I subjugated that combined dataset to phylogenetic analyses, which allows us to reconstruct evolutionary relationships. Based on this analysis, we found the fossil is closely related to this genus called Melia, which is living today.”

The KU researcher gave the oldest-known mahogany fossil the scientific name Manchestercarpa vancouverensis — the species name signifies where the specimen was discovered, and the genus is named after an esteemed colleague in the field.

“I named it after a prolific paleobotanist who’s really improved our understanding of the evolution of flowering plants through the fossil record,” Atkinson said. “So, I named it in honor of Steve Manchester, who’s at the University of Florida Museum of Natural History.”

While it’s noteworthy that Atkinson has pushed back the origin story of mahogany, he stressed it also helps improve our understanding of the rate of early flowering plant evolution and, in turn, our grasp of larger modern ecosystems.

“They’re our most diverse group of plants on Earth, and so there’s a whole lot to explore,” he said. “And there are some cool things you can do methodologically that you might not be able to do with other groups of plants. I can really ask some exciting paleontological and general evolutionary questions with this group.”

Reference:
Brian A. Atkinson. Fossil evidence for a Cretaceous rise of the mahogany family. American Journal of Botany, 2020; 107 (1): 139 DOI: 10.1002/ajb2.1416

Note: The above post is reprinted from materials provided by University of Kansas.

Pterosaurs were the largest animals ever to fly. They soared the skies for 160 million years — much longer than any species of modern bird. Despite their aeronautic excellence, these ancient flyers have largely been overlooked in the pursuit of bioinspired flight technologies. In a review published April 15 in the journal Trends in Ecology and Evolution researchers outline why and how the physiology of fossil flyers could provide ancient solutions to modern flight problems, such as aerial stability and the ability of drones to self-launch.

“There’s a lot of really cool stuff in the fossil record that goes unexplored because engineers generally don’t look to paleontology when thinking about inspiration for flight,” says first author Liz Martin-Silverstone (@gimpasaura), a post-doctoral researcher and paleontologist at the University of Bristol. “If we’re only looking at modern animals for inspiration, we’re really missing a large degree of the morphology out there and ignoring a lot of options that I think could be useful.”

Previously, engineers have largely focused on the physiology of modern birds and insects when designing aeronautic technology like drones and planes; they might not think to examine fossils that — by their nature — are often incomplete. However, Martin-Silverstone says there are a select few pterosaur fossils that provide extraordinarily deep insight into the anatomy of their wings, which is essential for understanding their flight capabilities.

“There are two or three absolutely amazingly preserved pterosaur fossils that let you see the different layers within the wing membrane, giving us insight into its fibrous components. Also, some fossils are preserved enough to show the wing attachments beneath the hip,” she says. “While you don’t know exactly the shape of the wing, by knowing the membrane attachments you can model the effectiveness of different wing shapes and determine which would have performed best in natural conditions.” Analyzing the morphology and predicted flight mechanics of these ancient creatures has revealed novel tactics that don’t exist in modern flyers.

Becoming airborne is one example. Launching into the air through a leap or jump, also known as ballistic launch, is standard throughout the animal kingdom. However, larger birds require a running start to gain enough momentum for lift-off. Pterosaurs, on the other hand, may have developed a method to launch from a stationary position despite some specimens weighing nearly 300 kilograms. One hypothesis, proposed by review co-author Mike Habib (@aeroevo) of the Dinosaur Institute at the Natural History Museum of Los Angeles County, suggests that the wing membrane and the robust muscle attachments in the wings allowed pterosaurs to generate a high-powered leap off of their elbows and wrists, giving them enough height to become airborne.

“Today, something like a drone requires a flat surface to launch and is quite restricted on how it actually gets into the air. The unique launch physiology of pterosaurs might be able to help solve some of these problems,” Martin-Silverstone says.

Pterosaurs can also provide insights on how to prevent flight instability once in the air. Contrary to how sails can become unstable in a strong wind, pterosaurs evolved strategies to resist flutter of their broad wings. “So far we’ve struggled to design things like flight suits that can resist the pressures of flight. If we can understand how pterosaurs did it, for instance by understanding how their wing membrane was actually structured, then that’s something we can use to answer modern engineering questions,” she says.

These unique physiological elements aren’t limited to pterosaurs, either. Other ancient flyers, like Microraptor, had feathered wings on both their arms and legs, while newly discovered dinosaur, Yi qi, had wings that combine feathers with a bat-like membrane — a body plan that has never been repeated since their extinction. As such, the authors say many flight strategies remain to be properly explored.

Martin-Silverstone suggests that if we combine our knowledge from flyers both living and extinct, we will have a much better chance of overcoming the hurdles still hindering human-made flight. She says: “We want biologists and engineers alike to reach out to paleontologists when they are looking to solving flight problems, as there might be something extinct that could help. If we limit ourselves to looking at the modern animals, then we’re missing out on a lot of diversity that might be useful.”

Reference:
Elizabeth Martin-Silverstone, Michael B. Habib, David W.E. Hone. Volant Fossil Vertebrates: Potential for Bioinspired Flight Technology. Trends in Ecology & Evolution, 2020; DOI: 10.1016/j.tree.2020.03.005

Note: The above post is reprinted from materials provided by Cell Press.