New ancient shark discovered
This rare fossil find comes from the Kimmeridge Clay Formation in England, a series of sedimentary rocks that was formed in a shallow, tropical-subtropical sea during the Upper Jurassic, about 150 million years ago. The fossil shark skeleton was found more than 20 years ago on the southern coast of England and is now held in the Etches Collection. Additional fossil shark specimens from it will be investigated in the years to come.
Due to their life-long tooth replacement shark teeth are among the most common vertebrate finds encountered in the fossil record. The low preservation potential of their poorly mineralized cartilaginous skeletons, on the other hand, prevents fossilization of completely preserved specimens in most cases.
The new study published in the journal PeerJ and led by Sebastian Stumpf from the University of Vienna now presents the fossil skeleton of a new ancient shark from the Kimmeridge Clay Formation of England, a fossiliferous rock sequence that was formed during the Late Jurassic in a shallow, tropical-subtropical sea.
The new shark fossil, which is about 150 million years old, is assigned to a previously unknown genus and species of hybodontiform sharks named Durnonovariaodus maiseyi. This extremely rare fossil find was made almost 20 years ago on the southern coast of England and is now held and curated in the Etches Collection, which houses one of the most scientifically significant fossil collections in England.
Hybodontiform sharks are one of the most species-rich groups of extinct sharks and represent the closest relatives to modern sharks. They first appeared during the latest Devonian, about 361 million years ago, and went extinct together with dinosaurs at the end of the Cretaceous, about 66 million years ago. The new genus and species Durnonovariaodus maiseyi differs from all other previously described hybodontiform sharks, including those that are characterized by having similarly shaped teeth. “Durnonovariaodus maiseyi represents an important source of information for better understanding the diversity of sharks in the past as well as for new interpretations of the evolution of hybodontiform sharks, whose relationships are still poorly understood, even after more than 150 years of research,” says Stumpf.
The scientific importance of the Kimmeridge Clay Formation is underlined by additional, but still undescribed hybodontiform shark skeletons, which are also held in the Etches Collection. The research of fossil sharks from the Kimmeridge Clay Formation of England, which will be continued in the years to come, will certainly contain further surprises to be yet discovered.
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Materials provided by University of Vienna. Note: Content may be edited for style and length.
Journal Reference:
- Sebastian Stumpf, Steve Etches, Charlie J. Underwood, Jürgen Kriwet. Durnonovariaodus maiseyi gen. et sp. nov., a new hybodontiform shark-like chondrichthyan from the Upper Jurassic Kimmeridge Clay Formation of England. PeerJ, 2021; 9: e11362 DOI: 10.7717/peerj.11362
Newly described horned dinosaur from New Mexico was the earliest of its kind
A newly described horned dinosaur that lived in New Mexico 82 million years ago is one of the earliest known ceratopsid species, a group known as horned or frilled dinosaurs. Researchers reported their find in a publication in the journal PalZ (Paläontologische Zeitschrift).
Menefeeceratops sealeyi adds important information to scientists’ understanding of the evolution of ceratopsid dinosaurs, which are characterized by horns and frills, along with beaked faces. In particular, the discovery sheds light on the centrosaurine subfamily of horned dinosaurs, of which Menefeeceratops is believed to be the oldest member. Its remains offer a clearer picture of the group’s evolutionary path before it went extinct at the end of the Cretaceous.
Steven Jasinski, who recently completed his Ph.D. in Penn’s Department of Earth and Environmental Science in the School of Arts & Sciences, and Peter Dodson of the School of Veterinary Medicine and Penn Arts & Sciences, collaborated on the work, which was led by Sebastian Dalman of the New Mexico Museum of Natural History and Science. Spencer Lucas and Asher Lichtig of the New Mexico Museum of Natural History and Science in Albuquerque were also part of the research team.
“There has been a striking increase in our knowledge of ceratopsid diversity during the past two decades,” says Dodson, who specializes in the study of horned dinosaurs. “Much of that has resulted from discoveries farther north, from Utah to Alberta. It is particularly exciting that this find so far south is significantly older than any previous ceratopsid discovery. It underscores the importance of the Menefee dinosaur fauna for the understanding of the evolution of Late Cretaceous dinosaur faunas throughout western North America.”
The fossil specimen of the new species, including multiple bones from one individual, was originally discovered in 1996 by Paul Sealey, a research associate of the New Mexico Museum of Natural History and Science, in Cretaceous rocks of the Menefee Formation in northwestern New Mexico. A field crew from the New Mexico Museum of Natural History and Science collected the specimen. Tom Williamson of the New Mexico Museum of Natural History and Science briefly described it the following year, and recent research on other ceratopsid dinosaurs and further preparation of the specimen shed important new light on the fossils.
Based on the latest investigations, researchers determined the fossils represent a new species. The genus name Menefeeceratops refers to the rock formation in which it was discovered, the Menefee Formation, and to the group of which the species is a part, Ceratopsidae. The species name sealeyi honors Sealey, who unearthed the specimen.
Menefeeceratops is related to but predates Triceratops, another ceratopsid dinosaur. However Menefeeceratops was a relatively small member of the group, growing to around 13 to 15 feet long, compared to Triceratops, which could grow to up to 30 feet long.
Horned dinosaurs were generally large, rhinoceros-like herbivores that likely lived in groups or herds. They were significant members of Late Cretaceous ecosystems in North America. “Ceratopsids are better known from various localities in western North America during the Late Cretaceous near the end of the time of dinosaurs,” says Jasinski. “But we have less information about the group, and their fossils are rarer, when you go back before about 79 million years ago.”
Although bones of the entire dinosaur were not recovered, a significant amount of the skeleton was preserved, including parts of the skull and lower jaws, forearm, hindlimbs, pelvis, vertebrae, and ribs. These bones not only show the animal is unique among known dinosaur species but also provide additional clues to its life history. For example, the fossils show evidence of a potential pathology, resulting from a minor injury or disease, on at least one of the vertebrae near the base of its spinal column.
Some of the key features that distinguish Menefeeceratops from other horned dinosaurs involve the bone that make up the sides of the dinosaur’s frill, known as the squamosal. While less ornate than those of some other ceratopsids, Menefeeceratops’ squamosal has a distinct pattern of concave and convex parts.
Comparing features of Menefeeceratops with other known ceratopsid dinosaurs helped the research team trace its evolutionary relationships. Their analysis places Menefeeceratops sealeyi at the base of the evolutionary tree of the centrosaurines subfamily, suggesting that not only is Menefeeceratops one of the oldest known centrosaurine ceratopsids, but also one of the most basal evolutionarily.
Menefeeceratops was part of an ancient ecosystem with numerous other dinosaurs, including the recently recognized nodosaurid ankylosaur Invictarx and the tyrannosaurid Dynamoterror, as well as hadrosaurids and dromaeosaurids.
“Menefeeceratops was part of a thriving Cretaceous ecosystem in the southwestern United States with dinosaurs that predated a lot of the more well-known members closer to end of the Cretaceous,” says Jasinski.
While relatively less work has been done collecting dinosaurs in the Menefee Formation to date, the researchers hope that more field work and collecting in these areas, together with new analyses, will turn up more fossils of Menefeeceratops and ensure a better understanding of the ancient ecosystem of which it was part.
Peter Dodson is a professor of anatomy in the School of Veterinary Medicine and a professor of earth and environmental science in the School of Arts & Sciences at the University of Pennsylvania.
Steven E. Jasinski is a curator of paleontology and geology at the State Museum of Pennsylvania and corporate faculty at Harrisburg University of Science and Technology. He earned his doctoral degree in the Department of Earth and Environmental Science in the University of Pennsylvania’s School of Arts & Sciences.
Sebastian G. Dalman is a research associate at the New Mexico Museum of Natural History and Science in Albuquerque.
Spencer G. Lucas is a curator of paleontology at the New Mexico Museum of Natural History and Science in Albuquerque.
Asher J. Lichtig is a research associate at the New Mexico Museum of Natural History and Science in Albuquerque.
Jasinski was supported by Geo. L. Harrison and Benjamin Franklin fellowships while attending the University of Pennsylvania. The research was also partially funded by a Walker Endowment Research Grant and a University of Pennsylvania Paleontology Research Grant.
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Materials provided by University of Pennsylvania. Note: Content may be edited for style and length.
Journal Reference:
- Sebastian G. Dalman, Spencer G. Lucas, Steven E. Jasinski, Asher J. Lichtig, Peter Dodson. The oldest centrosaurine: a new ceratopsid dinosaur (Dinosauria: Ceratopsidae) from the Allison Member of the Menefee Formation (Upper Cretaceous, early Campanian), northwestern New Mexico, USA. PalZ, 2021; DOI: 10.1007/s12542-021-00555-w
18.5 million year old vine fossil identified as new species
An 18.5 million-year-old fossil found in Panama provides evidence of a new species and is the oldest reliable example of a climbing woody vine known as a liana from the soapberry family. The discovery sheds light on the evolution of climbing plants.
The new species, named Ampelorhiza heteroxylon, belongs to a diverse group of tropical lianas called Paullinieae, within the soapberry family (Sapindaceae). More than 475 species of Paullinieae live in the tropics today.
Researchers identified the species from fossilized roots that revealed features known to be unique to the wood of modern climbing vines, adaptations that allow them to twist, grow and climb.
The study, “Climbing Since the Early Miocene: The Fossil Record of Paullinieae (Sapindaceae),” was published April 7 in the journal PLOS ONE.
“This is evidence that lianas have been creating unusual wood, even in their roots, as far back as 18 million years ago,” said wood anatomist Joyce Chery ’13, assistant research professor in the School of Integrative Plant Science, Plant Biology Section, in the College of Agriculture and Life Sciences, and a corresponding author of the paper.
“Before this discovery, we knew almost nothing about when or where these lianas evolved or how rapidly they diversified,” said first author Nathan Jud, assistant professor of plant biology at William Jewell College and a former Cornell postdoctoral researcher.
Panama was a peninsula 18.5 to 19 million years ago, a volcanic landscape covered with tropical forest in North America and separated from South America by a Central American seaway. While these forests contained North American animals, the plants mostly descended from South American tropical plants that had dispersed across the seaway, Jud said.
“The fossil we described is the oldest macrofossil of these vines,” he said, “and they were among the plants that made it to North America long before the Great American Biotic Interchange when large animals moved between the continents some 3 million years ago.”
In the study, the researchers made thin slices of the fossil, examined the arrangements and dimensions of tissues and water conducting vessels under a microscope and created a database of all the features. They then studied the literature to see how these features matched up with the living and fossil records of plants.
“We were able to say, it really does look like it’s a fossil from the Paullinieae group, given the anatomical characteristics that are similar to species that live today,” Chery said.
During their analyses, the researchers identified features that are characteristic of lianas. Most trees and shrubs have water-conducting tissues (which transport water and minerals from roots to leaves) that are all roughly the same size when viewed in a cross-section; in vines, these conduits come in two sizes, big and small, which is exactly what the researchers discovered in the fossil.
“This is a feature that is pretty specific to vines across all sorts of families,” Chery said.
The two vessel sizes provide insurance for a twisting and curving plant, as large vessels provide ample water flow, but are also vulnerable to collapse and develop cavities that disrupt flow. The series of smaller vessels offers a less vulnerable backup water transport system, Chery said.
Also, cross-sections of the wood in trees and shrubs are circular, but in the fossil, and in many living vines, such cross-sections are instead irregular and lobed.
Thirdly, on the walls of those vascular vessels, they found long horizontal perforations that allow for water to flow in lateral directions. That is a distinguishing feature of lianas in the soapberry family, Chery said.
In future work, now that they can place the lianas of Sapindaceae to 18.5 million years ago, the researchers intend to continue their investigation of the evolutionary history and diversification of this family. Chery also plans to investigate how wood has evolved in this group of vines, including identifying the genes that contribute to lobe-shaped stems.
The study was partly funded by the National Science Foundation.
Story Source:
Materials provided by Cornell University. Original written by Krishna Ramanujan. Note: Content may be edited for style and length.
Journal Reference:
- Nathan A. Jud, Sarah E. Allen, Chris W. Nelson, Carolina L. Bastos, Joyce G. Chery. Climbing since the early Miocene: The fossil record of Paullinieae (Sapindaceae). PLOS ONE, 2021; 16 (4): e0248369 DOI: 10.1371/journal.pone.0248369