Research: Whale fossil provides key to unlock date of East Africa’s mysterious uplift

paleontology

Research: Whale fossil provides key to unlock date of East Africa’s mysterious uplift

A 17 million-year-old Turkana ziphiid beaked whale fossil from the Great Rift Valley, East AfricaPaleontologists have used a fossil from the most precisely dated beaked whale in the world to pinpoint for the first time a date when East Africa’s mysterious elevation began.

The 17 million-year-old fossil is from the Ziphiidae family. It was discovered 740 kilometers inland at a elevation of 620 meters in modern Kenya’s harsh desert region and is the only stranded whale ever found so far inland on the African continent, said SMU vertebrate paleontologist Louis Jacobs.

Uplift associated with the Great Rift Valley of East Africa and the environmental changes it produced have puzzled scientists for decades because the timing and starting elevation have been poorly constrained. Determining ancient land elevation is very difficult, but the whale provides one near sea level.

“It’s rare to get a paleo-elevation,” Jacobs said, noting only one other in East Africa, determined from a lava flow.

At the time the whale was alive, it would have been swimming far inland up a river with a low gradient ranging from 24 to 37 meters over more than 600 to 900 kilometers, said Jacobs. He is co-author of a study, published in the Proceedings of the National Academy of Sciences, that provides the first constraint on the start of uplift of East African terrain from near sea level.

“The whale was stranded up river at a time when east Africa was at sea level and was covered with forest and jungle,” Jacobs said. “As that part of the continent rose up, that caused the climate to become drier and drier. So over millions of years, forest gave way to grasslands. Primates evolved to adapt to grasslands and dry country. And that’s when – in human evolution – the primates started to walk upright.”

Identified as a Turkana ziphiid, the whale would have lived in the open ocean, like its modern beaked cousins. Ziphiids, still one of the ocean’s top predators, are the deepest diving air-breathing mammals alive, plunging to nearly 10,000 feet to feed, primarily on squid.

In contrast to most whale fossils, which have been discovered in marine rocks, Kenya’s beached whale was found in river deposits, known as fluvial sediments, said Jacobs, a professor in the Roy M. Huffington Department of Earth Sciences of SMU’s Dedman College of Humanities and Sciences.

The whale, probably disoriented, swam into the river and could not change its course, continuing well inland.

“You don’t usually find whales so far inland,” Jacobs said. “Many of the known beaked whale fossils are dredged by fishermen from the bottom of the sea.”

The beaked whale fossil was discovered in 1964 by J.G. Mead in what is now the Turkana region of northwest Kenya. Mead, an undergraduate student at Yale University at the time, made a career at the Smithsonian Institution, from which he recently retired. Over the years, the Kenya whale fossil went missing in storage.

Jacobs, who was at one time head of the Division of Paleontology for the National Museums of Kenya, spent 30 years trying to locate the fossil. His effort paid off in 2011, when he rediscovered it at Harvard University and returned it to the National Museums of Kenya.

The fossil is only a small portion of the whale, which Mead originally estimated was 7 meters long during its life. Mead unearthed the beak portion of the skull, 2.6 feet long and 1.8 feet wide, specifically the maxillae and premaxillae, the bones that form the upper jaw and palate.

The researchers reported their findings in “A 17-My-old whale constrains onset of uplift and climate change in east Africa” online at the PNAS web site. Besides Jacobs, other authors from SMU are Andrew Lin, Michael Polcyn, Dale Winkler and Matthew Clemens.

From other institutions, authors are Henry Wichura and Manfred R. Strecker, University of Potsdam, and Fredrick K. Manthi, National Museums of Kenya.

Funding for the research came from SMU’s Institute for the Study of Earth and Man and the SMU Engaged Learning program.

Written by Margaret Allen

> Read the full story from the SMU Research blog

March 19, 2015|For the Record, News, Research|

Research: SMU paleontologist identifies new Texas fossil species

A new species of coelacanth fish has been discovered in Texas. Pieces of tiny fossil skull found in Fort Worth have been identified as 100 million-year-old coelacanth bones, according to SMU paleontologist John Graf.

The coelacanth has one of the longest lineages — 400 million years — of any animal. It is the fish most closely related to vertebrates, including humans.

The SMU specimen is the first coelacanth in Texas from the Cretaceous, said Graf, who identified the fossil. The Cretaceous geologic period extended from 146 million years ago to 66 million years ago.

Graf named the new coelacanth species Reidus hilli. It is now the youngest coelacanth identified in the Lone Star State, a distinction previously belonging to a 200 million-year-old coelacanth from the TriassicReidus hilli is also the first coelacanth ever identified from the Dallas-Fort Worth area.

Coelacanth fossils have been found on every continent except Antarctica. Few have been found in Texas, said Graf, a paleontology graduate student in the Huffington Department of Earth Sciences of SMU’s Dedman College.

The coelacanth has eluded extinction for 400 million years. Scientists estimate it reached its maximum diversity during the Triassic. The fish was thought to have gone extinct about 70 million years ago. However, the fish rose to fame in 1938 after live specimens were caught off the coast of Africa. Today coelacanths can be found swimming in the depths of the Indian Ocean.

“These animals have one of the longest lineages of any vertebrates that we know,” Graf said.

The SMU specimen demonstrates there was greater diversity among coelacanths during the Cretaceous than previously known.

“What makes the coelacanth interesting is that they are literally the closest living fish to all the vertebrates that are living on land,” he said. “They share the most recent common ancestor with all of terrestrial vertebrates.”

Coelacanths have boney support in their fins, which is the predecessor to true limbs. “Boney support in the fins allows a marine vertebrate to lift itself upright off the sea floor,” Graf said, “which would eventually lead to animals being able to come up on land.”

Written by Margaret Allen

> Read the full story at the SMU Research blog

October 31, 2012|Research|

Research: New insight into a 19th-century fossil feud

In the late 1800s, a flurry of fossil speculation across the American West escalated into a high-profile national feud called the Bone Wars. Drawn into the spectacle were two scientists from the Lone Star State: geologist Robert T. Hill, now acclaimed as the Father of Texas Geology, and naturalist Jacob Boll, who made many of the state’s earliest fossil discoveries.

Hill and Boll had supporting roles in the Bone Wars through their work for one of the feud’s antagonists, Edward Drinker Cope, according to a new study by SMU’s Louis Jacobs, a vertebrate paleontologist in the Huffington Department of Earth Sciences, Dedman College.

The study by Jacobs expands knowledge about Cope’s work with Hill and Boll. It also unveils new details about the Bone Wars in Texas that Jacobs deciphered from 13 letters written by Cope to Hill. Jacobs discovered the letters in an archive of Hill’s papers at SMU’s DeGolyer Library. The letters span seven years, from 1887 to 1894.

Hill, who worked for the U.S. Geological Survey, not only provided Cope with fossils of interest but also shared geological information about fossil locales.

Boll, who was a paid collector for Cope — as was the practice at the time — supplied the well-known paleontologist with many fossils from Texas. More than 30 of the taxa ultimately named by Cope were fossils collected by Boll.

“Fossils collected by Boll and studied by Cope have become some of the most significant icons in paleontology,” said Jacobs, president of SMU’s Institute for the Study of Earth and Man. His study, “Jacob Boll, Robert T. Hill, and the Early History of Vertebrate Paleontology in Texas,” is published in the journal Historical Biology as part of the conference volume of the 12th International Symposium on Early Vertebrates/Lower Vertebrates.

Jacobs describes the late 1800s as a period of intense fossil collecting. The Bone Wars were financed and driven by Cope and his archenemy, Othniel Charles Marsh. The two were giants of paleontology whose public feud brought the discovery of dinosaur fossils to the forefront of the American psyche.

Over the course of nearly three decades, however, their competition evolved into a costly, self-destructive, vicious all-out war to see who could outdo the other. Despite their aggressive and sometimes unethical tactics to outwit one another and steal each other’s hired collectors, Cope and Marsh made major contributions to the field of paleontology, Jacobs said.

Written by Margaret Allen

> Read the full story at the SMU Research blog

September 11, 2012|Research|

Research Spotlight: Digital dino track a roadmap for saving at-risk natural history resources

Portable laser scanning technology allows researchers to tote their latest fossil discovery from the field to the lab in the form of lightweight digital data stored on a laptop. But sharing that data as a 3D model with others requires standard formats that are currently lacking, say SMU paleontologists.

University researchers used portable laser scanning technology to capture field data of a huge 110 million-year-old Texas dinosaur track and then create to scale an exact 3D facsimile. They share their protocol and findings with the public – as well as their downloadable 145-megabyte model – in the online scientific journal Palaeontologia Electronica.

The model duplicates an actual dinosaur footprint fossil that is slowly being destroyed by weathering because it’s on permanent outdoor display, says SMU paleontologist Thomas L. Adams, lead author of the scientific article. The researchers describe in the paper how they created the digital model and discuss the implications for digital archiving and preservation. Click here for the download link.

“This paper demonstrates the feasibility of using portable 3D laser scanners to capture field data and create high-resolution, interactive 3D models of at-risk natural history resources,” write the authors.

“3D digitizing technology provides a high-fidelity, low-cost means of producing facsimiles that can be used in a variety of ways,” they say, adding that the data can be stored in online museums for distribution to researchers, educators and the public.

SMU paleontologist Louis L. Jacobs is one of the coauthors on the article. “The protocol for distance scanning presented in this paper is a roadmap for establishing a virtual museum of fossil specimens from inaccessible corners across the globe,” Jacobs said.

The full-resolution, three-dimensional digital model of the 24-by-16-inch Texas footprint is one of the first to archive an at-risk fossil, the SMU paleontologists say. They propose the term “digitype” for such facsimiles, writing in their article “High Resolution Three-Dimensional Laser-scanning of the type specimen of Eubrontes (?) Glenrosensis Shuler, 1935, from the Comanchean (Lower Cretaeous) of Texas: Implications for digital archiving and preservation.”

Laser scanning is superior to other methods commonly used to create a model because the procedure is noninvasive and doesn’t harm the original fossil, the authors say. Traditional molding and casting procedures, such as rubber or silicon molds, can damage specimens.

But the paleontologists call for development of standard formats to help ensure data accessibility. “Currently there is no single 3D format that is universally portable and accepted by all software manufacturers and researchers,” the authors write.

SMU’s digital model archives a fossil that is significant within the scientific world as a type specimen – one in which the original fossil description is used to identify future specimens. The fossil also has cultural importance in Texas. The track is a favorite from well-known, fossil-rich Dinosaur Valley State Park, where the iconic footprint draws tourists.

The footprint was left by a large three-toed, bipedal, meat-eating dinosaur, most likely the theropod Acrocanthosaurus. The dinosaur probably left the footprint as it walked the shoreline of an ancient shallow sea that once immersed Texas, Adams said. The track was described and named in 1935 as Eubrontes (?) glenrosensis. Tracks are named separately from the dinosaur thought to have made them, he explained.

“Since we can’t say with absolute certainty they were made by a specific dinosaur, footprints are considered unique fossils and given their own scientific name,” Adams said.

The fossilized footprint, preserved in limestone, was dug up in the 1930s from the bed of the Paluxy River in north central Texas about an hour’s drive southwest of Dallas. In 1933 it was put on prominent permanent display in Glen Rose, Texas, embedded in the stone base of a community bandstand on the courthouse square.

The footprint already shows visible damage from erosion, and eventually it will be destroyed by gravity and exposure to the elements, Adams said. The 3D model provides a baseline from which to measure future deterioration, he said.

Besides Adams and Jacobs, other co-authors on the article are paleontologists Christopher Strganac and Michael J. Polcyn in the Roy M. Huffington Department of Earth Sciences at SMU.

The research was funded by the Institute for the Study of Earth and Man at SMU. – Margaret Allen

> Find more information, photos and links at the SMU Research blog

February 15, 2011|Research|

Research Spotlight: Texas dinosaur reveals new biology

Paluxysaurus jonesi skeletal mountThe Early Cretaceous sauropod Paluxysaurus jonesi weighed 20 tons, was 60 feet long and had a neck 26 feet long, according to the scientists who have prepared the world’s first full skeletal mount of the dinosaur.

The massive mount, prepared for the Fort Worth Museum of Science and History in Fort Worth, was unveiled Nov. 20 when the museum opened in a new $80 million facility. It enables Texans to see their state dinosaur in three dimensions for the first time.

The reconstructed skeleton is yielding clues to the biology of the animal and its relationship to other similar dinosaurs, says Dale Winkler, lead consultant for anatomy and posture on the skeletal mount. Winkler is director of SMU’s Shuler Museum of Paleontology and a research professor in the Roy M. Huffington Department of Earth Sciences, Dedman College.

Winkler has worked with Paluxysaurus bones since crews from SMU and the Fort Worth museum began to unearth them in the early 1990s. The bones assembled for Fort Worth’s Paluxysaurus mount were recovered by students, faculty, staff and hundreds of volunteers over the past 16 years.

In preparing the mount, Winkler said he was surprised at how extremely long the neck was – at 26 feet – compared to the tail, and he found the head especially striking.

“It was really exciting to see what the head looked like,” Winkler says. “Paluxysaurus had very high cheeks compared to its relatives. Once the bones defining the opening of the nose were connected, it showed that the nostrils were turned up on top of the snout, instead of out like Brachiosaurus.”

A relative of Brachiosaurus and Camarasaurus, Paluxysaurus lived about 110 million to 115 million years ago. The dinosaur was identified and named in 2007 by Peter J. Rose. The Fort Worth skeleton was assembled from a combination of actual fossil bones from at least four different dinosaurs found on private ranch land in North Central Texas and from cast lightweight foam pieces modeled on original bones. The mount enables scientists to better understand the animal’s anatomy, size and stature on questions like “How were the legs situated, and how did the shoulders relate to the hips?”

From the skeletal mount, the scientists learned that Paluxysaurus was more than 6 feet wide and nearly 12 feet tall at the shoulder, although built fairly light, Winkler says. Its teeth are a lot slimmer than those of its closest relatives, indicating Paluxysaurus gathered and processed food differently, using its teeth not for chewing, but to grab food, he says.

Paluxysaurus had a long neck like Brachiosaurus, and a tail almost as long, but wasn’t quite so gigantic. Scientists also learned Paluxysaurus had relatively long front arms, making its back more level. The dinosaur’s shoulder turned out fairly high, and the hips were wide, Winkler says, and it had reached a more advanced stage of evolution than Late Jurassic sauropods.

Paluxysaurus’ massive pelvis and its sacrum have never before been viewed by the public, he says. Its ilium, the largest bone in the pelvis, is similar to that of titanosaurids of the Late Cretaceous, mainly found in South America. However, one titanosaurid, called Alamosaurus, entered North America and is known from Big Bend National Park in southwest Texas.

(Above, the skeletal mount of Paluxysaurus jonesi. Photo courtesy of Ralph Lauer Images.)

Read more from the SMU Research blog

December 15, 2009|Research|
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