PALEONTOLOGY
Archaic dolphin could hear high frequency sounds
Staatliche Naturwissenschaftliche Sammlungen Bayerns
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Fossil dolphin Romaleodelphis pollerspoecki
view moreCredit: M. Schellenberger, SNSB-BSPG
The shallow inland sea in which the newly described dolphin lived some 22 million years ago together with many other organisms, including a variety of microorganisms, algae, snails, mussels, relatives of squid, and fishes, stretched north of the just emerging Alps. The only fossil known of this dolphin to date comes from a site near Linz in Upper Austria. It was assigned to a new, previously unknown species and genus, and scientifically named Romaleodelphis pollerspoecki by researchers from the Bavarian State Collection of Palaeontology and Geology (SNSB-BSPG) and the Ludwig-Maximilians-University in Munich, as well as the Senckenberg Research Institute and Natural History Museum Frankfurt.
"All that remains of Romaleodelphis pollerspoecki is its fragmented and incomplete skull with an elongated snout and 102 uniform teeth" reports first author Catalina Sánchez Posada who examined the fossil as part of her master's thesis. The animal belongs to the toothed whales, but differs significantly from all previously known prehistoric representatives of this lineage. Comparisons and a complex computer-based analysis of the relationships to other fossil dolphins revealed that Romaleodelphis was probably related to the already extinct, very archaic dolphins of the so-called Chilcacetus clade. "All previously known fossils of this dolphin lineage come from the north-eastern Pacific and the coasts of South America. The discovery of Romaleodelphis pollerspoecki, a putative European relative of this lineage, could therefore provide important new insights into the origin and evolution of the lineage in the earliest Miocene," says PD Dr. Gertrud Rößner, curator of fossil mammals from the Bavarian State Collection of Palaeontology and Geology, senior author of the study.
The fossil of the skull is severely compressed and distorted, which made the examination of the skull anatomy particularly challenging. Computed tomography images taken at the Department of Radiology at the Ludwig Maximilians University Hospital in Munich made it possible to examine and reconstruct internal features.
The anatomical reconstruction of the fossil's inner ear using micro-computed tomography images also yielded astonishing results. "The shape of the well-preserved bony labyrinth in the skull indicates that Romaleodelphis pollerspoecki was able to hear high-frequency signals," explains co-author Dr. Rachel Racicot from Senckenberg Research Institute and Natural History Museum. This makes this dolphin one of the oldest known toothed whales that already had a similarly developed sense of hearing as modern porpoises, for example. These animals are able to communicate in frequency ranges that are beyond the hearing range of their predators. There may also be a connection in the development with the ability of orientation through echolocation, which is typical for dolphins.
The dolphin fossil was unearthed in 1980 by the private collector Jürgen Pollerspöck, who later gave it to the Bavarian State Collection of Palaeontology and Geology for restoration and proper storage. The study has now been published in the Journal of Vertebrate Paleontology.
Fossil dolphin Romaleodelphis pollerspoecki. View from above
Fossil dolphin Romaleodelphis pollerspoecki. View from above
Caption
Fossil dolphin Romaleodelphis pollerspoecki. Lateral view
Fossil dolphin Romaleodelphis pollerspoecki. Lateral view
Credit
Manuela Schellenberger, SNSB-BSPG
Manuela Schellenberger, SNSB-BSPG
The skull of Romaleodelphis pollerspoecki in the CT of the Clinic and Polyclinic for Radiology at the LMU Munich Hospital
The skull of Romaleodelphis pollerspoecki in the CT of the Clinic and Polyclinic for Radiology at the LMU Munich Hospital
Credit
Catalina Sánchez Posada
Catalina Sánchez Posada
Journal
Journal of Vertebrate Paleontology
Subject of Research
Animals
Article Title
Romaleodelphis pollerspoecki, gen. et sp. nov., an archaic dolphin from the Central Paratethys (Early Miocene, Austria)
Article Publication Date
5-Nov-2024
Fossil of huge terror bird offers new information about wildlife in South America 12 million years ago
Johns Hopkins Medicine
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The end of a terror bird’s left tibiotarsus, a lower leg bone in birds equivalent to that of a human tibia or shin bone, dates back to the Miocene epoch around 12 million years ago.
view moreCredit: Degrange et al.
Researchers including a Johns Hopkins University evolutionary biologist report they have analyzed a fossil of an extinct giant meat-eating bird — which they say could be the largest known member of its kind — providing new information about animal life in northern South America millions of years ago.
The evidence lies in the leg bone of the terror bird described in new paper published Nov. 4 in Palaeontology. The study was led by Federico J. Degrange, a terror bird specialist, and included Siobhán Cooke, Ph.D., associate professor of functional anatomy and evolution at the Johns Hopkins University School of Medicine. The bone, found in the fossil-rich Tatacoa Desert in Colombia, which sits at the northern tip of South America, is believed to be the northernmost evidence of the bird in South America thus far.
The size of the bone also indicates that this terror bird may be the largest known member of the species identified to date, approximately 5%–20% larger than known Phorusrhacids, Cooke says. Previously discovered fossils indicate that terror bird species ranged in size from 3 feet to 9 feet tall.
“Terror birds lived on the ground, had limbs adapted for running, and mostly ate other animals,” Cooke says.
The bird’s leg bone was found by Cesar Augusto Perdomo, curator of the Museo La Tormenta, nearly 20 years ago, but was not recognized as a terror bird until 2023. In January 2024, researchers created a three-dimensional virtual model of the specimen using a portable scanner from Johns Hopkins Medicine, allowing them to analyze it further.
The fossil, the end of a left tibiotarsus, a lower leg bone in birds equivalent to that of a human tibia or shin bone, dates back to the Miocene epoch around 12 million years ago. The bone, with deep pits unique to the legs of all Phorusrhacids, is also marked with probable teeth marks of an extinct caiman — Purussaurus — a species that is thought to have been up to 30 feet long, Cooke says.
“We suspect that the terror bird would have died as a result of its injuries given the size of crocodilians 12 million years ago,” she says.
Most terror bird fossils have been identified in the southern part of South America, including Argentina and Uruguay.
The Phorusrhacid fossil discovery as far north as Colombia suggests that it was an important part of predatory wildlife in the region. Importantly, this fossil helps the researchers better understand the animals living in the region 12 million years ago. Now a desert, scientists believe this region was once an environment full of meandering rivers. This giant bird lived among primates, hoofed mammals, giant ground sloths and armadillo relatives, glyptodonts, that were the size of cars. Today, the seriema, a long-legged bird native to South America that stands up to 3-feet-tall, is thought to be a modern relative of Phorusrhacid.
“It’s a different kind of ecosystem than we see today or in other parts of the world during a period before South and North America were connected,” Cooke says
Believed to be the first of its kind from the site, the fossil indicates that the species would have been relatively uncommon among the animals there 12 million years ago, Cooke says.
“It’s possible there are fossils in existing collections that haven’t been recognized yet as terror birds because the bones are less diagnostic than the lower leg bone we found,” she says.
For Cooke, the finding helps her imagine an environment one can no longer find in nature.
“It would have been a fascinating place to walk around and see all of these now extinct animals,” she says.
In addition to Cooke and Perdomo, the study’s authors include first author Federico Javier Degrange of Centro de Investigaciones en Ciencias de la Tierra; Luis G. Ortiz-Pabon of Universidad de Los Andes, Carrera, Bogotá, Colombia and Universidad Nacional de Colombia, Carrera, Bogotá; Jonathan Pelegrin of Universidad del Valle, Colombia, and Universidad Santiago de Cali, Colombia; Rodolfo Salas-Gismondi of Universidad Nacional Mayor de San Marcos, Avenida Arenales, Perú; and Andrés Link of Universidad de Los Andes, Carrera Bogotá, Colombia.
DOI: doi.org/10.1002/spp2.1601
Journal
Palaeontology
Reconstructing plesiosaur swimming styles with bio-mimetic control
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The plesiosaur-like robot that uses the bio-inspired control system.
view moreCredit: Akira Fukuhara
A research group may have unraveled the mystery behind the locomotion of the ancient marine reptile, the plesiosaur, by recreating a bio-inspired control system that accounts for motion adjustment.
Extinct animals have vastly different body shapes from animals still around today, making it difficult to determine how they moved by comparing them to living species. Additionally, fossils rarely preserve the soft limb tissues that scientists need to study locomotion and gain key insights into their lifestyles.
Plesiosaurs roamed Earth's prehistoric oceans, propelled by their unique body structure, which featured four large, equally sized flippers. Yet how plesiosaurs used these flippers to swim has long baffled paleontologists. This so-called 'four-wing problem' has been a topic of heated debate for years.
But now, a research group comprising researchers from Tohoku University, Kanagawa University, and the University of Manchester has developed a novel approach to tackle this mystery.
"Instead of focusing solely on how water interacts with plesiosaur bodies - that is, the hydrodynamics of swimming - we decided to examine how these animals controlled their movement," says Akio Ishiguro, a professor at the Research Institute of Electrical Communication (RIEC) at Tohoku University. "This is because plesiosaurs must have been able to swim at different speeds and in varied conditions."
Akio and his colleagues drew inspiration from inter-limb coordination mechanics underlying the flexible gait patterns used by other four-legged vertebrates, such as dogs and cats. They developed an autonomous decentralized control system for a plesiosaur-like robot.
Experimental results showed that the control system successfully generated coordinated patterns between the fore and hind flippers in response to changes in the flapping cycle and morphology.
"Our new approach reconstructs the way extinct animals can adjust their movement patterns in a flexible, situation-dependent manner," says Akira Fukuhara, an assistant professor at RIEC and the lead/first author of the paper. "It also means we can start investigating the complete locomotion repertoires of other extinct animals and learn more about their lifestyles."
Details of the finding were published in the journal Scientific Reports on October 28, 2024.
Also involved in the study were Mtsutoshi Sato and Hisayuki Ogawa, two former graduate students from RIEC; along with Tamaki Sato, a professor at Kanagawa University; and William Sellers, a professor at the University of Manchester.
Looking ahead, the research group hopes to make motion reconstructions that factor in other aspects of plesiosaur bodies. "Plesiosaurs notoriously possessed elongated necks, but these lengths varied considerably from creature to creature," adds Ishiguro. "We hope to create models that incorporate the roles of the neck, head, and torso in controlling these ancient creatures' movements."
A plesiosaur with a unique morphology. Modern animals that swim using their fins propel themselves using their front fins, but plesiosaurs have very large front and hind fins, and it is thought that they could use both to propel themselves. The problem of the coordination of the limbs of plesiosaurs is discussed as the 'four-wing problem,' and it is one of the long-standing movement reconstruction issues in paleontology.
Credit
Akira Fukuhara
Journal
Scientific Reports
Article Title
Rethinking the four-wing problem in plesiosaur swimming using bio-inspired decentralized control
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