A slab of sandstone discovered at NASA’s Goddard Space Flight Center contains at least 70 mammal and dinosaur tracks from more than 100 million years ago, according to a new paper published Jan. 31 in the journal Scientific Reports. The find provides a rare glimpse of mammals and dinosaurs interacting.

The tracks were discovered by Ray Stanford — a local dinosaur track expert whose wife, Sheila, works at Goddard. After dropping off Sheila at work one day in 2012, Stanford spotted an intriguing rock outcropping behind Shelia’s building on a hillside. Stanford parked his car, investigated, and found a 12-inch-wide dinosaur track on the exposed rock. Excavation revealed that the slab was the size of a dining room table and examination in the ensuing years found that it was covered in preserved tracks.

The remarkable Goddard specimen, about 8 feet by 3 feet in size, is imprinted with nearly 70 tracks from eight species, including squirrel-sized mammals and tank-sized dinosaurs. Analysis suggests that all of the tracks were likely made within a few days of each other at a location that might have been the edge of a wetland, and could even capture the footprints of predator and prey.

“The concentration of mammal tracks on this site is orders of magnitude higher than any other site in the world,” said Martin Lockley, paleontologist with the University of Colorado, Denver, a co-author on the new paper. Lockley began studying footprints in the 1980s, and was one of the first to do so. “I don’t think I’ve ever seen a slab this size, which is a couple of square meters, where you have over 70 footprints of so many different types. This is the mother lode of Cretaceous mammal tracks.”

After Stanford’s initial find, Stephen J. Godfrey, curator of paleontology at the Calvert Marine Museum, coordinated the excavation of the slab and produced the mold and cast that formed the basis of the scientific work.

The first track Stanford found was of a nodosaur — “think of them as a four-footed tank,” Stanford said. Subsequent examination revealed a baby nodosaur print beside and within the adult print, likely indicating that they were traveling together. The other dinosaur tracks include: a sauropod, or long-necked plant-eater; small theropods, crow-sized carnivorous dinosaurs closely related to the Velociraptor and Tyrannosaurus rex; and pterosaurs, a group of flying reptiles that included pterodactyls.

“It’s a time machine,” Stanford said. “We can look across a few days of activity of these animals and we can picture it. We see the interaction of how they pass in relation to each other. This enables us to look deeply into ancient times on Earth. It’s just tremendously exciting.”

The dinosaur tracks are impressive, but it is the collection of mammal tracks that make the slab significant. At least 26 mammal tracks have been identified on the slab since the 2012 discovery — making it one of two known sites in the world with such a concentration of prints. Furthermore, the slab also contains the largest mammal track ever discovered from the Cretaceous. It is about four inches square, or the size of a raccoon’s prints.

Lockley and Stanford said most of these ancient footprints belong to what we would consider small mammals — animals the size of squirrels or prairie dogs. Most Cretaceous mammals discovered to date have been the size of rodents, their size usually determined only from their teeth. “When you have only teeth, you have no idea what the animals looked like or how they behaved,” Lockley said.

Lockley and Stanford believe the wide diversity and number of tracks show many of the animals were in the area actively feeding at the same time. Perhaps the mammals were feeding on worms and grubs, the small carnivorous dinosaurs were after the mammals, and the pterosaurs could have been hunting both the mammals and the small dinosaurs.

The parallel trackway patterns made by four crow-sized carnivorous dinosaurs suggests they were hunting or foraging as a group. “It looks as if they were making a sweep across the area,” Lockley said.

Several of the mammal tracks occur in pairs, representing hind feet. “It looks as if these squirrel-sized animals paused to sit on their haunches,” Lockley said. The team gave the new formal scientific name of Sederipes goddardensis, meaning sitting traces from Goddard Space Flight Center, to this unusual configuration of tracks.

“We do not see overlapping tracks — overlapping tracks would occur if multiple tracks were made over a longer period while the sand was wet,” said Compton Tucker, a Goddard Earth scientist who helped with the excavation, coordinated bringing in multiple scientists to study the tracks, and has worked to create a display of the cast in Goddard’s Earth science building. “People ask me, ‘Why were all these tracks in Maryland?’ I reply that Maryland has always been a desirable place to live.”

What is now Maryland would have been a much hotter, swampier place in the Cretaceous, when sea levels would have been hundreds of feet higher than today. As scientists continue to study the slab and compare the tracks to others found in the area and around the world, they will continue to discover more about prehistoric life that existed here.

“This could be the key to understanding some of the smaller finds from the area, so it brings everything together,” Lockley said. “This is the Cretaceous equivalent of the Rosetta stone.”

Note: The above post is reprinted from materials provided by NASA/Goddard Space Flight Center. Original written by Ashley Hume and Patrick Lynch.

When it comes to the final days of the dinosaurs, Africa is something of a blank page. Fossils found in Africa from the Late Cretaceous, the time period from 100 to 66 million years ago, are few and far between. That means that the course of dinosaur evolution in Africa has largely remained a mystery. But in the Sahara Desert of Egypt, scientists have discovered a new species of dinosaur that helps fill in those gaps: Mansourasaurus shahinae, a school-bus-length, long-necked plant-eater with bony plates embedded in its skin.

The fossilized remains of Mansourasaurus were unearthed by an expedition undertaken by the Mansoura University Vertebrate Paleontology (MUVP) initiative, an effort led by Dr. Hesham Sallam of the Department of Geology at Mansoura University in Mansoura, Egypt. Sallam is the lead author of the paper published today in the journal Nature Ecology and Evolution that names the new species. The field team included several of his students, many of whom — Ms. Iman El-Dawoudi, Ms. Sanaa El-Sayed, and Mrs. Sara Saber — also participated in the study of the new dinosaur. The creature’s name honors both Mansoura University and Ms. Mona Shahin for her integral role in developing the MUVP. According to Sallam, “The discovery and extraction of Mansourasaurus was such an amazing experience for the MUVP team. It was thrilling for my students to uncover bone after bone, as each new element we recovered helped to reveal who this giant dinosaur was.”

“Mansourasaurus shahinae is a key new dinosaur species, and a critical discovery for Egyptian and African paleontology,” says Dr. Eric Gorscak, a postdoctoral research scientist at The Field Museum and a contributing author on the study. Gorscak, who began work on the project as a doctoral student at Ohio University, where his research focused on African dinosaurs, adds, “Africa remains a giant question mark in terms of land-dwelling animals at the end of the Age of Dinosaurs. Mansourasaurus helps us address longstanding questions about Africa’s fossil record and paleobiology — what animals were living there, and to what other species were these animals most closely related?”

Late Cretaceous dinosaur fossils in Africa are hard to come by — much of the land where their fossils might be found is covered in lush vegetation, rather than the exposed rock of dinosaur treasure troves such as those in the Rocky Mountain region, the Gobi Desert, or Patagonia. The lack of a Late Cretaceous fossil record in Africa is frustrating for paleontologists since, at that time, the continents were undergoing massive geological and geographic changes.

During the earlier years of the dinosaurs, throughout much of the Triassic and Jurassic periods, all the continents were joined together as the supercontinent of Pangaea. During the Cretaceous Period, however, the continents began splitting apart and shifting towards the configuration we see today. Historically, it hasn’t been clear how well-connected Africa was to other Southern Hemisphere landmasses and Europe during this time — to what degree Africa’s animals may have been cut off from their neighbors and evolving on their own separate tracks. Mansourasaurus, as one of the few African dinosaurs known from this time period, helps to answer that question. By analyzing features of its bones, Sallam and his team determined that Mansourasaurus is more closely related to dinosaurs from Europe and Asia than it is to those found farther south in Africa or in South America. This, in turn, shows that at least some dinosaurs could move between Africa and Europe near the end of these animals’ reign. “Africa’s last dinosaurs weren’t completely isolated, contrary to what some have proposed in the past,” says Gorscak. “There were still connections to Europe.”

Mansourasaurus belongs to the Titanosauria, a group of sauropods (long-necked plant-eating dinosaurs) that were common throughout much of the world during the Cretaceous. Titanosaurs are famous for including the largest land animals known to science, such as Argentinosaurus, Dreadnoughtus, and Patagotitan. Mansourasaurus, however, was moderate-sized for a titanosaur, roughly the weight of an African bull elephant. Its skeleton is important in being the most complete dinosaur specimen so far discovered from the end of the Cretaceous in Africa, preserving parts of the skull, the lower jaw, neck and back vertebrae, ribs, most of the shoulder and forelimb, part of the hind foot, and pieces of dermal plates. Says study coauthor and dinosaur paleontologist Dr. Matt Lamanna of Carnegie Museum of Natural History, “When I first saw pics of the fossils, my jaw hit the floor. This was the Holy Grail — a well-preserved dinosaur from the end of the Age of Dinosaurs in Africa — that we paleontologists had been searching for for a long, long time.”

Also contributing to the Mansourasaurus research were experts on African paleontology from other institutions in Egypt and the US. MUVP student Iman El-Dawoudi played a particularly important role in the analysis of the new titanosaur, making numerous observations on its skeleton. “The combined effort of multiple institutions across the globe, not to mention the absolutely key role played by students on the project from the field, to the laboratory, to the final analysis and writeup of the results, exemplifies the collaborative nature of expeditionary sciences today,” notes Dr. Patrick O’Connor, study coauthor and professor of anatomy at the Ohio University Heritage College of Osteopathic Medicine.

Funding for the Mansourasaurus study was provided by grants from Mansoura University, the Jurassic Foundation, the Leakey Foundation, the National Geographic Society/Waitt Foundation, and the National Science Foundation (NSF).

“The discovery of rare fossils like this sauropod dinosaur helps us understand how creatures moved across continents, and gives us a greater understanding of the evolutionary history of organisms in this region,” says Dena Smith, a program director in NSF’s Division of Earth Sciences, which partially funded the laboratory portion of the research.

Scientific discoveries are often compared to finding the last missing puzzle piece to complete a picture; Gorscak says that since so little is known about African dinosaurs, Mansourasaurus is better likened to an earlier step in the puzzle-solving process. “It’s like finding an edge piece that you use to help figure out what the picture is, that you can build from. Maybe even a corner piece.”

“What’s exciting is that our team is just getting started. Now that we have a group of well-trained vertebrate paleontologists here in Egypt, with easy access to important fossil sites, we expect the pace of discovery to accelerate in the years to come,” says Sallam.

Reference:
Hesham M. Sallam, Eric Gorscak, Patrick M. O’Connor, Iman A. El-Dawoudi, Sanaa El-Sayed, Sara Saber, Mahmoud A. Kora, Joseph J. W. Sertich, Erik R. Seiffert, Matthew C. Lamanna. New Egyptian sauropod reveals Late Cretaceous dinosaur dispersal between Europe and Africa. Nature Ecology & Evolution, 2018; DOI: 10.1038/s41559-017-0455-5

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

The story of the Mansourasaurus discovery began in December of 2013, when I received an invitation to give a talk about vertebrate paleontology at New Valley University in Kharga Oasis in southern Egypt. To get there I drove 12 hours with my graduate students from Mansoura University, Sanaa El-Sayed and Iman El-Dawoudi, who had just graduated and were eager to reach out to other Egyptian students about fossil vertebrates. On the way there we also picked up my third student, Sara Saber, from Assiut University. After the talk, we drove out to quickly have a closer look at the dinosaur-bearing rock exposures around Dakhla Oasis that I had been working in since 2008, with American colleagues from Ohio University, the University of Southern California, and the Denver Museum of Nature and Science. Our project aims to fill a ~30 million year gap in the Late Cretaceous fossil record of Africa, from which very few fossils of land-living vertebrates are known.

As the sun was going down, I noticed a new road that could give us a view of some unexplored exposures, so the next morning we drove all the way to its end and found a gravel quarry. We had only half an hour to look at the rocks before the long drive back to Mansoura. Sara and I walked in the same direction, while the others headed off in different directions to cover as much ground as possible. Only a few minutes later, I looked over my shoulder to see that Sara was brushing something, which I assumed was probably a rock. I kept walking and a few minutes later my cell phone rang. It was Sara. I picked up the phone to hear her excitedly telling me to please come back, because there were fossil bones all over the place. I quickly returned to find that the area was indeed full of bones… the remains of an associated partial skeleton of a sauropod dinosaur. I noticed my footprints all over the site, and joked with Sara, saying “by the way, I saw it first but left it for you as a test.” She replied quickly, saying “no, professor, you stepped all over the bones!,” and we had a good laugh. It was one of those wonderful moments in paleontology when you know that something really important has just been discovered.

I knew that we needed at least two weeks of fieldwork to properly excavate the skeleton, so we made the difficult decision to come back later and better prepared. Leaving such an important discovery behind made everyone incredibly anxious, because all of the bulldozers moving through the area could destroy the fossils in an instant. After two long months of preparation, we returned to the site with Sanaa, Iman, Sara, and two of my other colleagues, Mai El-Amir and Farahat Ibrahim. The excavation was difficult as the area is extremely hot, and we were hit with sandstorms and even pouring rain, but our enthusiasm kept us going, as we knew that we were writing a new chapter in the history of Egyptian vertebrate paleontology. Every evening, we went to the highest point in the area to get access to the Internet to learn more about dinosaur anatomy. On the third day we found the most diagnostic bone, the left dentary, from which it was clear that the lower jaw of this sauropod had a pronounced ‘chin.’ We were in close contact with our friends and colleagues in Egypt and the U.S.A., who were following the action daily. As time passed it became clear that we had skull bones, much of the shoulder girdle and forelimb, multiple vertebrae and ribs, part of the foot, and pieces of several dermal plates – more than was known for any dinosaur of this age from the entire African continent. While chatting with my American colleague Joe Sertich, he suggested the name Mansourasaurus, and it stuck.

We ended up working at the site for three weeks, and by the time we were finished we had made 19 plaster jackets and collected loads of isolated bone fragments. When we returned to Mansoura, we brought the jackets to be CT scanned at the university hospital. Never having seen plaster jackets in the hospital before, some of the staff stopped us and asked what we were pushing around on a gurney. I told them it was a dinosaur. They were astonished! One man asked if it was sick… to which I replied that it had been dead for at least 75 million years!

As time went on we would regularly meet up with our American colleagues over Skype, particularly the sauropod experts Eric Gorscak of Ohio University and later The Field Museum, Matt Lamanna of the Carnegie Museum, and Patrick O’Connor of Ohio University. Slowly the picture started to come together of just what we were dealing with. I think most of us initially expected Mansourasaurus to have been a member of a very ancient African lineage, given that continent’s hypothesized isolation during the Cretaceous, but it turned out that its closest affinities were instead with European sauropods, providing some of the first compelling evidence for the movement of dinosaurs between Africa and Europe in the later part of the Cretaceous. A find like this shows how little we still know about the Late Cretaceous of Africa, and has motivated us all to keep up the search for new fossils in Egypt.

Note: The above post is reprinted from materials provided by Nature. The original article was written by Hesham Sallam.

Researchers from Ludwig-Maximilians-Universitaet (LMU) in Munich report the first description of the geologically oldest fossil securely attributable to the genus Archaeopteryx, and provide a new diagnostic key for differentiating bird-like dinosaurs from their closest relatives.

Some 150 million years ago in what is now Northern Bavaria, Archaeopteryx — the oldest bird species yet discovered — inhabited a subtropical environment characterized by reef islands and lagoons set in a shallow sea that was part of the primordial Mediterranean. All the specimens of Archaeopteryx so far recovered were found in the valley of the Altmühl River, in geological settings that represent this habitat — the Jurassic Solnhofen Archipelago. The latest find was made there in 2010, and this new specimen has now been analyzed by a team of researchers led by LMU paleontologist Oliver Rauhut, a professor in the Department of Earth and Environmental Sciences who is also affiliated with the Bavarian State Collections for Paleontology and Geology in Munich. Stratigraphic analysis of the find locality reveals that the fossil is the oldest known representative of the genus Archaeopteryx.

“Specimens of Archaeopteryx are now known from three distinct rock units, which together cover a period of approximately 1 million years,” Rauhut explains. Notably, the oldest example exhibits features that were so far not known from the other specimens. “Among other things, they reveal that Archaeopteryx was very similar to advanced predatory dinosaurs in many respects,” says Rauhut. Moreover, in the new study, he and his colleagues provide a diagnosis that allows to reliably distinguish Archaeopteryx from its closest relatives, both non-avialan theropod dinosaurs and basal birds. This key will be very valuable, as a whole series of bird-like predatory dinosaurs has been described in recent years, mainly from China, which has greatly complicated the taxonomical classification of the group.

The new specimen is the 12th fossil to be attributed to the genus. However, in a study published in the online journal BMC Evolutionary Biology last year, Rauhut’s group reported that the first of these to come to light — the so-called Haarlem specimen discovered in 1861 — does not actually belong to the group. This result thus reduces the number of Archaeopteryx fossils to 11, although some doubts remain concerning the assignment of two of these. This underlines the necessity for a diagnosis to clearly identify Archaeopteryx.

Moreover, the investigation of the 11th specimen demonstrates that the known specimens span a remarkable range of anatomical variation. Potential explanations for the broad spectrum of variation extend from intraspecific developmental polymorphism to evolutionary differentiation, i.e., the possibility that the fossil material so far recovered represents more than one species. “The high degree of variation in the teeth is particularly striking — none of the specimens shows the same pattern of dentition as any other, which could reflect differences in diet,” Rauhut points out. “This is very reminiscent of the famous case of Darwin’s finches on the Galapagos, which show remarkable variation in their beak shapes. It is even conceivable that this primeval bird genus might, in a similar fashion, have diversified into several specialized forms on the islands of the Solnhofener Archipelago. In that case, the Archaeopteryx fossils could represent a species flock, a Jurassic analog of Darwin’s finches.”

Reference:
Oliver W.M. Rauhut, Christian Foth, Helmut Tischlinger. The oldest Archaeopteryx (Theropoda: Avialiae): a new specimen from the Kimmeridgian/Tithonian boundary of Schamhaupten, Bavaria. PeerJ, 2018; 6: e4191 DOI: 10.7717/peerj.4191

Note: The above post is reprinted from materials provided by Ludwig-Maximilians-Universität München.