Earth Science Club of Northern Illinois - ESCONI

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Meet the giant dinosaur that roamed southern Africa 200 million years ago

Kayentapus ambrokholohali footprints belong to an animal of about 26 feet long, dwarfing all the life around it. Theropod image adapted by Lara Sciscio, with permission, from an illustration by Scott Hartman

Lara Sciscio, University of Cape Town

Globally at around 200 million years ago, in what’s known as the Early Jurassic, small and agile two-legged carnivorous dinosaurs called theropods roamed the ancient landscapes. In southern Africa, we know of their existence from their rare body fossils but also, importantly, from their fossil footprints.

Now our team’s new discovery, published in PLOS ONE, unexpectedly reveals that very large carnivorous dinosaurs with an estimated body length of between 8 to 9 meters (or 26 feet) – that’s a two-story building or two adult rhinos nose to tail – lived in southern Africa too.

Miengah Abrahams, a PhD student from the University of Cape Town, lying next to the dinosaur’s tracks. She is 1.6m tall. Lara Sciscio

Evidence for this massive beast comes from a set of three-toed, 57cm long and 50cm wide footprints recently found in western Lesotho. This is a first for Africa. It places a huge carnivorous dinosaur in what was then the southern part of the supercontinent Gondwana during Early Jurassic times.

Until this discovery, theropod dinosaurs were thought to be considerably smaller, at three to five metres in body length, during the Early Jurassic.

There has only been one other report of large carnivorous dinosaurs occurring as early as 200 million years ago. This also came from fossil footprint evidence in Poland’s Holy Cross Mountains. Such giants are rare. The iconic and enormous (about 12 metres long) Tyrannosaurus, for instance, only emerged around 128 million years later during the Late Cretaceous.

The dimensions of the trackmaker with the 57cm long feet, although slightly smaller, come close to those of the well-known and younger Late Cretaceous theropod dinosaurs such as Tyrannosaurus rex or the similarly huge North African Spinosaurus.

The unanticipated footprint size of this Lesotho giant considerably expands the body size range of theropods in the Early Jurassic. Now the hunt is on to track down more theropod footprints – and perhaps even their body fossils.

Lesotho’s giant carnivore

Our team of scientists from South Africa’s University of Cape Town, the University of Manchester in the UK, Fundación Conjunto Paleontológico de Teruel-Dinópolis in Spain, and Brazil’s Universidade de São Paulo discovered the 200 million year old megatheropod trackway during recent fieldwork in Lesotho.

The footprints were found on a small dirt road approximately 2km from the National University of Lesotho at Roma (Maseru District) in the western part of the country. They are on a palaeosurface, an ancient land surface that has been preserved in time.

Once the dinosaur’s tracks had been identified and cleaned of rock debris, the team photographed and took silicon rubber impressions of them. Lara Sciscio

The ancient surface is also covered in the footprints of other theropod dinosaurs. Even their footprint impressions are relatively large (30-40cm long) for the time period.

The 57 cm long Lesotho footprints have been named Kayentapus ambrokholohali. The trackmaker falls into an informal grouping of very large dinosaurs, called “megatheropods”, with footprints exceeding 50 cm in length and calculated hip heights greater than 2 m.

The new species name ambrokholohali was given to identify this particular footprint. It was derived in honour of Emeritus Professor David Ambrose, a now retired professor and Head Research Fellow at National University of Lesotho, for his detailed recording of the trace fossil heritage within Roma.

We were following in Ambrose’s footsteps, trying to relocate one of his documented sites, when we discovered the freshly exposed megatheropod footprints.

The latter part of the name, kholohali, is derived from two Sesotho words: “kholo”, meaning big, large or great and “hali”, meaning much or very. This was to describe its unexpectedly large size.

Size matters

The main bipedal predators during the Mesozoic (the “Dinosaur Era”) were large theropod dinosaurs. They included the Allosaurus (from the late Jurassic) and Tyrannosaurus (Upper Cretaceous). But early in the Mesozoic, theropod dinosaurs were usually relatively small (3–5 m body length). Truly large forms of theropods only started making their appearance around 100 million years later, within the Late Jurassic and Early Cretaceous.

In light of this, the new discovery of these impressively large tracks expands the range of body size for theropods in the Early Jurassic at the very onset of their diversification. But, why were these theropods so much larger than anything else around at the time? An answer could lie in the timing of their evolution.

The megatheropod tracks appear after the end-Triassic mass extinction event. This mass extinction event was the result of a biotic crisis that significantly affected animals both on land and sea. The biotic crisis allowed for the main competitors of theropod dinosaurs to be completely eradicated. Killing off the competition, coupled with changes in ecosystem composition, probably gave theropod dinosaurs “free reign” to dominate the Early Jurassic landscape and resources.

Another possible driver for larger theropod body size was the increased size of the herbivorous dinosaurs – like the Highland Giant sauropodomorph – within the same ancient landscape.

It’s most likely that both factors lead to theropods in southern Africa being able to evolve into numerous forms and increase in abundance. But these are questions we can’t answer conclusively.

Giant footprints, but still no fossils

The body fossil evidence for theropod dinosaurs in southern Africa is slim. Luckily the footprints they left behind are not. By studying these and other tracks as well as the bone fossil record, scientists are able to tentatively link footprints to potential trackmakers.

To date, we have no body fossil material to match the K. ambrokholohali‘s footprints. Hopefully we’ll soon discover more unusual footprints and, from there, body fossils that will help add to our understanding of the complex ancient world.

Lara Sciscio, Postdoctoral Research Fellow in Geological Sciences, University of Cape Town

This article was originally published on The Conversation. Read the original article.

General Meeting November 10th, 2017: What do we know about life on early Earth?

The title of Dr. D'Arcy Meyer-Dombard's program at our November 2017 meeting is "What do we know about life on early Earth?"

 

The speaker at our February 9, 2018 meeting will be Dr. Dan Gebo from the Department of Anthropology at NIU. His research focuses

on understanding locomotor adaptation and evolution in living and fossil primates, particularly the haplorhines (the clade that includes humans).

You can read more about him at http://www.niu.edu/anthro/faculty_staff/faculty/gebo.shtml

 

ESCONI 2017 Holiday Dinner Friday, December 1st, 2017

The ESCONI 2017 Holiday Dinner is scheduled for Friday, December 1st, 2017 at Cozymel's in Wheaton, starting at 5:30-7:30 PM. The room has been reserved for 30 people but we can handle a few more if needed. I have asked them to set up the tables in a different configuration than the "L" shape from the last two years, since it creates a space problem for those sitting at the inside corner.

 

The December speaker is Dr. Kerry Sagebiel from NIU. The title of her program is "In the Realm of the Submerged Crocodile: Archaeology at the Maya City of Ka'kabish, Belize". Here's a link to a video on Facebook that shows the project there:

 

https://www.facebook.com/727575807282024/videos/vb.727575807282024/801143663258571/?type=2&theater

 

ESCONI Field Trip: Saturday, November 4th, 2017 to Thornton Quarry

There will an ESCONI field trip to the Thornton Quarry on Saturday November 4, 2017 from 8 AM to 12 noon.  The weather can be challenging in November, so think nice warm thoughts, and we'll give it a try!

 

I don't have all the details but here is what I have so far:

 

1. Everyone in your party must be an ESCONI member.

 

2. Everyone in your party must be at least 18 years of age.

 

3. Maximum of 30 people total.

 

4. Standard safety equipment required - hard hat (no bike helmets), boots, safety glasses and safety vest.

 

5. I will distribute the ESCONI waiver by email prior to the trip. There will be safety training at the quarry.

 

6. Once there we will need to share cars to minimize the number of vehicles actually going into the quarry.

 

This will be a geological "tour" with at least one stop specifically for collecting.

 

I do not yet know where we are to meet. I will update that as soon as I get it.

 

To sign up, send me (Dave) an email at [email protected]. I will reply by email within 24 hours. If I don't reply, send it again.

Humans Today Have Even More Neanderthal DNA Than We Realised

George Dvorsky

Oct 6, 2017, 6:00pm

A international team of researchers has completed one of the most detailed analyses of a Neanderthal genome to date. Among the many new findings, the researchers learned that Neanderthals first mated with modern humans a surprisingly long time ago, and that humans living today have more Neanderthal DNA than we assumed.

Before this new study, only four Neanderthal specimens have had their genomes sequenced. Of these, only one — an Altai Neanderthal found in Siberia — was of sufficient quality, where scientists were able to accurately flag variations in the genome. The new analysis, enabled by a remarkably well-preserved genome taken from a 52,000 year old bone fragment, is now the second Neanderthal genome to be fully sequenced in high fidelity. The resulting study, now published in Science, confirms a bunch of things we already knew about Neanderthals, while also revealing some things we didn't know.

The international research team that conducted this study — a group led by Kay Prüfer and Svante Pääbo from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany — sequenced the genome of a female Neanderthal, dubbed Vindija 33.19, whose remains were uncovered at Vindija Cave in northern Croatia. By studying Neanderthal genomes in detail, and by comparing their DNA to those of modern humans, scientists can learn more about our evolutionary history and biology. And indeed, the researchers made some interesting discoveries.

Based on previous archaeological and genetic evidence, archaeologists and anthropologists suspected that Neanderthals were thinly dispersed across Europe and Asia. The lack of genetic diversity (low heterozygosity) in the Vindija 33.19 specimen affirms these earlier findings, showing that Neanderthals "lived in small and isolated populations" and "with an effective population size of around 3000 individuals," the researchers write in their study.

The earlier genomic analysis of the female Altai Neanderthal showed that her parents were half-siblings, which got scientists thinking that Neanderthals made it a habit of breeding with immediate family members. But the Vindija 33.19 genome is different; her parents were not as closely related, so we can no longer say that extreme inbreeding is a common fixture of the Neanderthals. That said, the Croatian Neanderthal shared a maternal ancestor with three other individuals found in the Vindija Cave (whose genomes aren't nearly as complete).

The previous Altai Neanderthal study also suggested that Neanderthals starting breeding with archaic modern humans around 100,000 years ago, but the new analysis pushes that back even further to between 130,000 to 145,000 years ago. The location of these sub-species encounters probably happened in the Middle East or the Arabian Peninsula, but before modern humans spread en masse into Europe and Asia.

A comparative analysis of the Vindija 33.19 DNA to living humans resulted in an uptick in the amount of genes retained by Homo sapiens. When our ancestors mated with Neanderthals, we absorbed and retained some of their genes — some good, and some bad (more on this in just a second). Some of these genes have been lost forever (due to natural selection weeding out unfavourable inherited traits), but some have stuck around. Prüfer and Pääbo say that, based on the new high-quality genome, modern populations carry between 1.8 to 2.6 per cent Neanderthal DNA — that's higher than the previous estimates of about 1.5 to 2.1 per cent. More specifically, East Asians have about 2.3 to 2.6 per cent Neanderthal DNA, while people from western Europe and Asia have retained about 1.8 to 2.4 per cent DNA. African populations have virtually none because their ancestors did not mate with Neanderthals.

Finally, the researchers were able to identify the functions of the gene variants that are still exerting a force on humans today. These include genes associated with plasma levels of LDL cholesterol and vitamin D, eating disorders, visceral fat accumulation, rheumatoid arthritis, schizophrenia, and response to antipsychotic drugs. "This adds to mounting evidence that Neanderthal ancestry influences disease risk in present-day humans, particularly with respect to neurological, psychiatric, immunological, and dermatological phenotypes [disease of skin, nails, hair]," write the researchers. Some of these inherited characteristics allowed modern humans to survive outside of Africa, but now make us susceptible to diseases today.

Anne Stone, an anthropological geneticist at Arizona State University who wasn't involved in the study, says the most surprising thing about the new research is that the scientists were able to acquire such a beautifully preserved genetic sequence.

"From that information, however, I think what was most interesting to me was the evidence that ancient modern humans interbred with Neanderthals really early (we see this in the Neandertal genomes) during a time that was prior to when we think the big movement out of Africa occurred (that resulted in the colonization of the rest of the world by modern humans)," Stone told Gizmodo. "The other surprising aspect was that the level of genetic diversity was similar to that seen in some isolated modern human populations. This is different from what was seen in the Altai Neandertal who was quite inbred."

An aspect of the study that did not surprise Stone — but one she found cool nonetheless — was that the Vindija 33.19 individual was more closely related to the population of Neanderthals that interbred with ancient modern humans who had moved out of Africa. "This is not surprising given the location of the cave [which is] much closer to the area where we think this happened," she said.

Pretty amazing what scientists can learn from a 52,000-year-old strand of DNA.

Earth Science Week is October 8th-14th, 2017

Earth Science Week 2017 is October 8th-14th.  It includes National Fossil Day on Wednesday, October 11th, 2017.  Here is a link with events near you!

 

ESCONI Events October 2017

Field trips require membership, but visitors are welcome at all meetings!

Sun, Oct 8th	Field Trip - Irene Quarry - see here for details.
Fri, Oct 13th	ESCONI General Meeting, 8:00 PM College of Dupage - Tech Ed (TEC) Building, Room 1038B (Map) - Topic: "Fluorite and Rare Earth Elements in the Illinois-Kentucky Fluorspar District" by Brett Denny, with the Illinois State Geological Survey
Sat, Oct 14th	ESCONI Minerology Study Group Meeting, 7:30 PM College of Dupage - Tech Ed (TEC) Building, Room 1038B (Map) - Topic: "Discussion of Fluorites"
Wed, Oct 11th	Happy National Fossil Day! - see here for details.
Sat, Oct 21th	ESCONI Paleontology Study Group Meeting, 7:30 PM College of Dupage - Tech Ed (TEC) Building, Room 1038B (Map) - Topic: "Devonian Cephalopods" by John Catalani
	ESCONI Archaeology Study Group Meeting - Open at this time, seeking a chair
	ESCONI Junior Meeting - Open at this time, seeking to restart the group.  Contact Diana Lord for information.