Fossil Discoveries in Niger with Dr. Ralf Kosma

“I often wrapped wet clothes around my head in order to cool my brain during digging.”

Dr. Ralf Kosma, curator of paleontology at the State Museum of Natural History in Braunschweig, Germany, was part of an international team that excavated fossils in Niger during the late 2000s.

“[T]he heat was incredible,” he wrote in an email, “especially in April/May. Usually I can stand the heat, and I did in Niger, but many colleagues in our team (both German and Nigerien) became ill as a result of the horrifying heat.”

Embed from Getty Images

 

Much of the country—particularly in the northern region, which is where Dr. Kosma and team excavated–is in the Sahara desert.  In an area devoid of many trees (hence, shade), where temperatures are regularly above 100 degrees Fahrenheit and where water is in short supply, heat is a crucial concern.

Word of a large dinosaur bone traveled from Niger to Germany by way of Edgar Sommer, both a friend of State Museum of Natural History Director Dr. Ulrich Joger and someone with ties to an educational organization in Niger.

Paleontologists from the museum worked together with those from the local Aderbissinat community: a people comprised—like the country (and the continent!) entire—of various cultures.  Among those cultures are the Tuareg, the Hausa, and the Fulani people.

“This was organized,” Dr. Kosma wrote, describing who they hired from the community, “by Ahmad Bahani, our local Tuareg partner, and Mohammed Echika, Tuareg Chief and Mayor of the village Tadibene…”

Photo courtesy of Dr. Ralf Kosma

Photo courtesy of Dr. Ralf Kosma

 

Photo courtesy of Dr. Ralf Kosma

Photo courtesy of Dr. Ralf Kosma

Back row from left to right: Sidi Bahani, Dr. Ralf Kosma (Braunschweig), Abdul Khader, Achim Ritter (Braunschweig, technican and artist), Prof. Dr. Ulrich Joger (Director of our museum, the State Museum of Natural History in Braunschweig, Germany), Hanna Joger (daughter of Ulrich Joger) from Darmstadt, Germany, Jannis Joger (with colorful turban; son of Ulrich Joger from Darmstadt, Germany), Fritz J. Krüger (Braunschweig, paleontological volunteer of the SNHM), Michel Rabe (with hat, Braunschweig, also museum volunteer), Azziz Bahani.

Front row from left to right: Moussa, Aghali, Abdul Raman, Mohammed, Dr. Alexander Mudroch (Paleontologist, Hannover, Germany), Jörg Faust (camera assistant, from Berlin)

Picture was taken in spring 2007 in Aderbissinat at our field camp at the Spinophorosaurus site.

Photo and caption courtesy of Dr. Ralf Kosma

 

Proud Tuareg camel riders celebrating the “Festival of Salt” in Agadez, 2007. Photo and caption courtesy of Dr. Ralf Kosma

Photo courtesy of Dr. Ralf Kosma

 

They camped in the field—using a campfire to cook food, some of it local, some of it brought with them in tins from Germany.  Along with the heat, they dealt with several sandstorms.

“It was peeling our skin. One was really hard and we took shelter in our laboratory truck.”

But they were also excavating at a time when civil war broke out within the country.

“We were,” he wrote, “protected by the army and by Mayor Mohammed Echika.”

 

“We encountered snakes, scorpions, a monitor lizard, geckoes, skinks and a variety of toads, birds and mammals. Due to our director being a herpetologist we were well prepared against bites of venomous snakes. At night we went snake hunting with [flashlights].” – Dr. Ralf Kosma.  Caption and photo courtesy of Dr. Ralf Kosma

 

Between 2005 and 2008, the team excavated several places near Aderbissinat.  Petrified wood fossils of Taxodioideae amongst other conifers, fossil crocodile teeth, and ganoid fish scales indicate that the arid area of today was actually swampy and wet in the Jurassic.  Perhaps their most exciting finds: a partial sauropod skeleton and 5 individual theropod trackways.

Excavation of the sauropod took place in 2007; removal of the fossil occurred in 2008, when it was taken to the State Museum of Natural History in Braunschweig. Now on permanent display in its dinosaur hall, the partial sauropod is 8 meters long: 37 caudal vertebrae and 5 fused sacral vertebrae.

Specimen 1 from Spinophorosaurus nigerensis [a different fossil and species from the one discussed in this blog], directly after excavating in November 2006. The specimen was almost completely articulated. This specimen was later taken by a Spanish team and brought to the paleontological museum of Elche in the vicinity of Alicante in Spain. The person on the picture is Ahmed Bahani, our Tuareg coordinator. Photo and caption courtesy of Dr. Ralf Kosma

Photo courtesy of Dr. Ralf Kosma

Photo courtesy of Dr. Ralf Kosma

Fossilized tree trunk on top of the cliffs of Tiguidit. 2008. Probably Cretaceous. (Attention! If you thought this is a sauropod vertebrae – it is not!) Photo and caption courtesy of Dr. Ralf Kosma

 

Further study by Dr. Emanuel Tschopp and team indicates the sauropod might be Jobaria tiguidensis.  Research undertaken by Florian Witzmann, Oliver Hampe, Bruce Rothschild, Ulrich Joger, Ralf Kosma, Daniela Schwarz and Patrick Asbach reveals that the poor Jobaria may have suffered from a painful bone pathology.

There is a debate—since soft-tissues rarely fossilize—about what existed between vertebrae in dinosaurs.  What connected the bones, of what did that connection consist, and how exactly did it make that connection to the bone?  We don’t know.  But research gives us insightful clues.

Dr. Witzmann and team, in their 2016 paper (Subchondral cysts at synovial vertebral joints as analogies of Schmorl’s nodes in a sauropod dinosaur from Niger), looked to the work of Steve Salisbury and Eberhard Frey.  Comparing extant and extinct crocodile vertebrae with that of mammalian vertebrae, they found evidence pointing to synovial joints in dinosaurs.  This is in direct contrast to the discovertebral junctions known in mammals. The two are shaped differently, enable different range of movement within the joints, and are comprised of different substances.

Ultimately, we don’t know for certain whether dinosaurs had a discovertebral junction or whether they had synovial joints. This is important because these distinctions impact our understanding of the Nigerien sauropod’s pathology.

A 1978 paper by Resnick and Niwayama suggests subchondral cysts near synovial joints result in the same pathology as “Schmorl’s nodes,” a pathology that presents as holes or lesions in the bone. This is particularly interesting, as, thus far, only extant mammals (animals with discovertebral junctions) have exhibited traces of Schmorl’s nodes. (Only one case of possible Schmorl’s nodes in a reptile was published in 2001.)

Schmorl’s Nodes from Wikipedia credit: By J. Lengerke 22:47, 12. Jan. 2010 (CET) (Praxis Dr. Jochen Lengerke) [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0), CC BY-SA 3.0 de (https://creativecommons.org/licenses/by-sa/3.0/de/deed.en) or GFDL (http://www.gnu.org/copyleft/fdl.html)%5D, via Wikimedia Commons

 

CT scanning provided further insight into the sauropod vertebrae.  While the team wondered whether the holes might be the work of ancient insects, this was discounted because there are no traces of insect mandibles and the holes are too large.  As the vertebrae were articulated when they were discovered, it was determined the space was too small for tiny mammals to make any impact postmortem.  The team therefore suggests that the lesions on the sauropod vertebrae are subchondral cysts, perhaps an analog to Schmorl’s nodes.

 

Photo courtesy of Dr. Ralf Kosma

 

Photo courtesy of Dr. Ralf Kosma

Photo courtesy of Dr. Ralf Kosma

Preparing the ribs of Spinophorosaurus nigerensis, specimen 2, for transportation in spring 2007. Aderbissinat. Constructing plaster jackets. Persons from left to right: Tuareg helper Aghali, our museum volonteer Fritz J. Krüger (from Braunschweig, Germany), and me (Dr. Ralf Kosma, Staatliches Naturhistorisches Museum, Braunschweig, Germany). Photo and caption courtesy of Dr. Ralf Kosma

 

The fossil footprints—120 tracks thus far, all of which remain in-situ in Niger—were discovered in 2007 and 2008.  Researchers from the Archaeological Institute of the University Abdou Moumouni (Institut de Recherches en Sciences Humaines, Niamey) and paleontologists from the German Museum worked together to both find and study them (Alexander Mudroch, Ute Richter, Ulrich Joger, Ralf Kosma, Oumarou Idé, Abdoulaye Maga in their 2011 paper: Didactyl Tracks of Paravian Theropods (Maniraptora) from the ?Middle Jurassic of Africa).

Casts and molds were taken of the tracks, of which, it was determined there are 5 distinct trackways.  Their unique shape gave rise to a new ichnotaxon: Paravipus didactyloides.

Although found in an area believed to be by a stream or lake during the Jurassic, the footprints are not believed to be swim traces.  Nothing in the sediment supports this.

There is, however, indication that two individual dinosaurs walked together at one point.  The size and shape of the footprints suggest those dinosaurs were theropods, possibly Deinonychus.

Figure 2. Map of dinosaur localities in the vicinity of Agadez, Rep. Niger. Generated with GoogleEarth MapMaker Utility 2009. https://doi.org/10.1371/journal.pone.0014642.g002
Taking casts of the perfectly preserved Paravipus didactyloides trackways. About 1 mile SE of the Spinophorosaurus site, Aderbissinat. These tracks were later scientifically described in PlosOne by our team. They were caused by rather large dromaeosaurids (“raptors”). The tracks are numerous, large, perfectly preserved, the first proof for this group from rocks as old als middle Jurassic and, last but not least, the first proof for this group in subsaharan Africa. The person with hat is Michel Rabe, volunteer at our museum. The three guys to the right are Tuareg and Hausa helpers. Photo and caption courtesy of Dr. Ralf Kosma
Photo courtesy of Dr. Ralf Kosma

After removing the silicone mould of the Paravipus tracks. Michel Rabe (with hat) and me (with turban). Photo and caption courtesy of Dr. Ralf Kosma

 

In 2009, the State Museum of Natural History in Braunschweig opened “Projekt Dino,” an exhibition highlighting dinosaurs from West Africa.

“It was open to public for 4 months until March 2010, as far as I remember,” wrote Dr. Kosma. “Afterwards Spinophorosaurus [nigerensis—another sauropod from Niger] and Jobaria [tiguidensis] were moved to our main building.  Since 2010, the Niger-story is represented in our permanent exhibition…[W]e dedicated a complete hall–our dinosaur hall–to that topic.  Visitors of all ages are very fascinated by these skeletons. They are a central point of interest and strongly help the understanding of Earth history…Many school classes come here to learn about the giants of the Mesozoic.”

Photo courtesy of Dr. Ralf Kosma

The acknowledgments at the end of “Subchondral cysts at synovial vertebral joints as analogies of Schmorl’s nodes in a sauropod dinosaur from Niger” state: “We also thank the people of Aderbissinat, Niger, for all the support and help they have offered us during our field campaigns.”

At the beginning of “Didactyl Tracks of Paravian Theropods (Maniraptora) from the ?Middle Jurassic of Africa,” it is noted that in exchange for paleontological work and recovery of fossils, part of the funds donated for the research were given toward building a local school, providing food for the children and 20,000 school books.

In corresponding with Dr. Kosma, one of his comments struck a personal chord with me:

“We all miss Niger very much: the country, the people, the desert, and would like to go there again digging for dinosaurs. We are still in contact with the local people, and they tell us the situation of the civil war is getting better right now.”

 

 

References:

  1. Florian Witzmann, Oliver Hampe, Bruce M. Rothschild, Ulrich Joger, Ralf Kosma, Daniela Schwarz & Patrick Asbach (2016) Subchondral cysts at synovial vertebral joints as analogies of Schmorl’s nodes in a sauropod dinosaur from Niger, Journal of Vertebrate Paleontology, 36:2, DOI: 10.1080/02724634.2016.1080719
  2. Mudroch A, Richter U, Joger U, Kosma R, Idé O, Maga A (2011) Didactyl Tracks of Paravian Theropods (Maniraptora) from the ?Middle Jurassic of Africa. PLoS ONE 6(2): e14642. https://doi.org/10.1371/journal.pone.0014642
  3. Salisbury, S, and E. Frey.  2001. A biomechanical transformation model for the evolution of semi-spheroidal articulations between adjoining vertebral bodies in crocodilians; pp. 85 – 134 in G. C. Grigg, F. Seebacher, and C. E. Franklin (eds.), Crocodilian Biology and Evolution. Surrey Beatty and Sons, Chipping Norton, England.

 

An absolutely tremendous and heartfelt thank you to Dr. Ralf Kosma, who was not only very generous with the pictures he provided of his experiences, but with his help and patience with this blog.  It took much longer to write this post than normal; he was exceedingly kind throughout the process.

An equally heartfelt thank you to Dr. Florian Witzmann, who not only put me in touch with Dr. Kosma, but helped clarify some points on his research.

A special thank you to Dr. Emanuel Tschopp who kindly confirmed the species of sauropod to be Jobaria tiguidensis (so far!)

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Researching Fossil Ungulate Communities

alces-alces-porkkala-finland

Alces alces (moose), Porkkala, Finland; photo courtesy of Juha Saarinen

In their paper “Patterns of diet and body mass of large ungulates from the Pleistocene of Western Europe, and their relation to vegetation,” published this past September in Palaeontologia Electronica, Juha Saarinen, Jussi Eronen, Mikael Fortelius, Heikki Seppä, and Adrian Lister investigate fossil ungulate communities found in England, Ireland, and Germany.

Not fossil ungulates, fossil ungulate communities.

The variety of fossils studied is just one of the exciting elements of their research.  Rather than focusing on a single species—which, given the limitations of the fossil record, is usually the case—they studied groups of fossils from at least 14 different ungulate species from the Middle to Late Pleistocene.

“[W]e are now at a point,” wrote Juha Saarinen, lead author of the paper, in an email, “where enough fossil material of ungulates and pollen records have accumulated to enable such a large scale quantitative comparison of body size and diets of ungulate with local vegetation patterns in the past as we did. Comparing vegetation proxies and mammal ecometrics from fossil data using such quantitative statistical analyses as we did has, to our knowledge, never been attempted before, so that is probably the most novel achievement of this study.”

The ungainly name of ‘ungulate’ refers to hooved animals: even-toed and odd-toed (Artiodactyla and Perissodactyla, respectively). Examples include horses, deer, moose, rhinoceros, bison, pigs and hippopotamuses.

beneski-brontops-tyleri-brontothere-view-from-skull

Brontops tyleri (a type of brontothere and a Perissodactyl) at the Beneski Museum at Amherst College, Massachusetts.   Brontotheres survived until the Eocene, an era that ended approximately 30+ million years BEFORE the Pleistocene, so this animal–although an ungulate–was not part of this study. Picture taken by the author of this blog

 

Using mesowear on the fossil teeth, they were able to determine information about their diets (from browsing to grazing), and by comparing this data with the pollen record associated with the areas in which these fossils were found, they were able to tell whether they ate more browse or grass in either open or closed environments. Body mass for these fossils was calculated and then compared to the diet of these animals.

They were searching for answers to how these species adapted to the environment in which they lived.  How did their body size relate to the vegetation available? Was their body size influenced by possible predators or by other members of their species? (In other words, were they bigger to intimidate predators or were they smaller because they lived in expansive herds?) Or was thermoregulation the single determining factor in how big these animals became, as has been proposed in earlier studies?

 

Beneski - Irish elk

Megaloceros giganteus (otherwise known as Irish Elk and an Artiodactyl) in between a mastodon and a mammoth fossil at the Beneski Museum at Amherst College, Massachusetts; picture taken by the author of this blog

 

It interested me to learn that they relied on what I rather simplistically referred to as the ‘physical observation’ of fossils.

Mesowear analysis looks at the wear and shape of fossil teeth.  Various plant material affects tooth-wear in distinctly different ways, which can be seen both on the teeth themselves and in the way the teeth have evolved.

To be clear, “this is specifically wear-induced shape, not the original shape of the unworn teeth,” Juha added. “In other words, mesowear is the change in the shape of the teeth as they get worn, and different food items cause different worn shape to develop (browse maintains high and sharp features on the tooth surface, whereas grass “grinds” them down leading to them to progressively wear down lower and more blunted the more there is grass in the diet).”

hmnh-mammoth-and-mastodon-teeth

Examples of a mammoth tooth — used to eat mostly grasses and sedges — and a mastodon tooth — used to eat trees and shrubs. Notice the very different shape of these teeth for very different types of vegetation. Proboscideans such as mammoths and mastodons were once grouped in with ungulates, but this has changed. Picture taken at the Harvard Museum of Natural History by the author of this blog.

 

Obtaining data about the pollen record (non-arboreal pollen percentages, or NAP %) meant researching published information and connecting that information with the related fossil sites.

The mathematical work behind all of this–determining mesowear, animal body size, and then relating this to the available pollen record—is staggering.

Surely, I thought, isotopic analysis would have been a much easier way to obtain information about each fossil’s diet at least.  Especially given that the pollen record isn’t always available, or—in one case—runs the risk of being skewed by the defecation of Pleistocene hippopotamuses that grazed in the area.  Why, I wondered, did they rely on methods that seemed considerably more labor-intensive and potentially (to my understanding) less accurate?

“There are a number of reasons for this,” Juha explained. “First, we wanted to obtain as much palaeodietary data as possible, comprising as complete ungulate communities as possible, and this meant dealing with very large samples of fossil molar teeth. Taking isotope samples from all those teeth would have been laborious, time consuming and expensive, not to mention also slightly destructive to the fossil specimens.

cervus-elaphus-richmond-park-london-uk

Cervus elaphus (Red Deer, Artiodactyl) at Richmond Park, London; photo courtesy of Juha Saarinen. Red Deer are one of the most extensively studied animals today. You can read about another study that references Red Deer in this post.

 

“Second, stable isotopes work best at resolving herbivore diet compositions in tropical areas where carbon isotope composition reflects roughly the proportions of C4/C3 –photosynthesizing plants (roughly grass vs. browse) in diet, but outside tropical areas all plants, grasses included, are C3 photosynthesizing and the carbon isotope composition varies also considerably according to so called canopy effect (open vs. closed environment), not just according to diet, and thus isotopes would not have allowed us to estimate the amount of grass vs. browse in the Pleistocene European ungulates as consistently and quantitatively as we could with mesowear analysis.

“Third, mesowear has been specifically shown to reflect average grass vs. browse compositions in the diets of ungulate populations, without being significantly obscured by other environmental variables, such as climate or environmental openness (e.g. Louys et al. 2012, Kaiser et al. 2013). Even if mesowear is a ‘physical observation’ as you say, it has been shown to specifically reflect the amount of abrasive dietary items (mostly grass) in herbivore diets.”

The authors focused on fossil-rich sites, where they could study between 3 – 10 fossils of each species.  They made sure to include species that were browsers, grazers and mixed-feeders.

figure-1-saarinen-et-al

Screenshot of Figure 1 from “Patterns of diet and body mass of large ungulates from the Pleistocene of Western Europe, and their relation to vegetation.” Palaeontologia Electronica19.3.32A: 1-58

 

“I owe thanks to my co-authors who knew much of the available European Pleistocene mammal collections already, having experience on working on them for many years,” Juha responded when asked how they knew of or had access to so many fossils.

Adrian Lister from the Natural History Museum of London in particular has a huge amount of knowledge and experience about Pleistocene mammal collections.

“I was also in contact with the curators of the museum collections, who gave me valuable information about the how much and what kind of material they have. Also, information about important fossil finds and numbers of specimens found have often been published before in scientific journals.

“The authors of this paper represent different fields of research experience on the various aspects of the study. I started to work on this research as a part of my PhD work, and I originally planned it with my PhD thesis supervisors Mikael Fortelius, Jussi Eronen and Heikki Seppä from the University of Helsinki.

“During the work, I visited the Natural History Museum of London, where I worked together with Professor Adrian Lister, whose expertise on British Pleistocene mammals, the NHM fossil mammal collections and mammal palaeoecology in general were very important for this work.”

NHM-DrListerLyuba

Image of Professor Adrian Lister, Natural History Museum of London, with the mummified baby mammoth, Lyuba; photo courtesy of the Natural History Museum of London for this post.

 

This work was not without its challenges.  As with any study of fossils, there are limits to the number of fossils available.  While pollen record availability has increased, there is still so much more to be discovered.  And although some species–based on extant examples–do not exhibit sexual dimorphism in body size, the sex of most of the fossils they studied was indeterminate.

“Indeed, these were some of biggest challenges in this study,” Juha acknowledged, “but they were expected and nothing much could be done to completely avoid them. I would add that it was often challenging to connect the fossil mammals with associated pollen records, especially when the fossil pollen was not obtained directly from the mammal fossils. To succeed in this study, it was important to analyze lots of data in order to overcome these problems, and to ensure that the main results and conclusions of this study are robust despite of them.”

The authors of this paper considered numerous variables in their research, and they suggest that ungulate size has a lot to do with a number of factors.  This might seem obvious, but such has not been the result of past studies.  In particular, Bergmann’s rule, which stipulates that body size corresponds largely to thermoregulation (i.e.: big body size is the result of living in colder environments), has been supported before.

bison-bonasus-kraansvlak-netherlands

Bison bonasus (Artiodactyla), Kraansvlak, Netherlands;photo courtesy of Juha Saarinen. 

 

“[T]here has been a lot of discussion as to what ultimately explains the tendency of some (but not all) organisms to be larger in cold climate. This was actually one of the main questions I discussed in my PhD thesis,” wrote Juha. “Already in 1950s some researchers (e.g. Scholander 1955, Irving 1957, Hayward 1965) pointed out that increase in size alone would not give a large enough benefit for thermoregulation in cold climates, especially considering that mammals have far more effective mechanisms of keeping warm, such as thick fur.

“Since then, many authors have noted that while there is a tendency of mammals being larger in higher latitudes, there are a number of exceptions to this ‘rule’ and heat conservation alone would not explain it.

“However, body size in mammals does correlate with food quality and availability and this seems to explain most of the body size patterns observed in mammals (e.g. Rosenzweig 1968, Geist 1987, Meiri et al. 2007, McNab 2010). For example, many herbivorous mammals tend to be larger at higher latitudes because food quality is better there (e.g. because of fertile soils created by glacial erosion and because plant defense mechanisms are lower), and thus predators eating them also tend to be larger there, but for example brown bear body mass does not correlate with latitude but with distance to nearest salmon spawning areas. On the other hand, population density also affects body size through resource availability: individual body size has been noted to decrease in many species of mammals when population densities are high leading to increased intraspecific resource competition (e.g. Wolverton et al. 2009).”

The authors of this paper argue that environment–climate, open or closed vegetation, food availability and quality–and species social structure–large or small herds–affect body size.

“[T]here are many (often interconnected) factors which together affect body size,” Juha explained. “This makes it quite complicated and challenging to study what ultimately regulates body size in mammals (and other organisms).

“In fact, our results do not support Bergmann’s rule as such, because even if our analyses show that larger sizes seem to occur in some species in open environments, this is not because of low temperature, as some of the open environments were in fact quite warm. Also, we often see that when one species was particularly large in an environment, another species was particularly small under those same conditions. E.g., we found out that red deer (Cervus elaphus) tends to be large in open environments, but wild horse (Equus ferus) tends to be small in those same environments. Thus, our results do not support the assumption of Bergmann’s rule or any other “single-cause” explanation for ungulate body size variation.

“What ultimately regulates ungulate body size is primarily food quality and availability, which is affected by the interplay of vegetation structure (regulated by environmental temperature, precipitation and soil fertility), interspecific resource competition (depending on the presence of competing species) and intraspecific resource competition (depending on population density). For example, species with large population densities in open environments, such as reindeer, bison and wild horses, could be small under those conditions because of increased intraspecific resource competition, whereas species with smaller population densities in open environments, such as red deer are large under such conditions, e.g. because of abundant, high-quality food and diminished plant defense mechanics. This is also the main conclusion concerning our results of Pleistocene European ungulate body size variation.”

“I think that studying how mammals in the past interacted with their environments is important for understanding how these interactions work in general,” he concluded. “At present, environments and their mammal faunas are so heavily influenced by human activities, and they have lost so much of their original diversity, that I believe that we simply need to study fossil mammals and their palaeoenvironments to better understand how these things have worked and ‘should usually work’ in nature.”

equus-ferus-mongolian-wild-horse-lippeaue-germany

Equus ferus (Mongolian wild horse and Perissodactyl), Lippeaue, Germany;photo courtesy of Juha Saarinen. 

It was a great honor and pleasure connecting with Dr. Juha Saarinen!  Reading this paper and gaining more insight about it from him was absolutely fascinating!  An enormous thank you to him for all of his generous help!!

Additionally, Dr. Saarinen was extraordinarily kind and helpful in clarifying points about the research that I had misunderstood.  That is always appreciated.  THANK YOU!!

Reference:

  1. Saarinen, Juha, Eronen, Jussi, Fortelius, Mikael, Seppä, Heikki, and Lister, Adrian M. 2016. Patterns of diet and body mass of large ungulates from the Pleistocene of Western Europe, and their relation to vegetation. Palaeontologia Electronica 19.3.32A: 1-58 palaeo-electronica.org/content/2016/1567-pleistocene-mammal-ecometrics

Dick Mol – Renowned Mammoth Expert: Fossil Hunting in the Sea

‘Fossil-hunting’ often brings to mind remote locations filled with rocks, sparse vegetation and a bright, merciless sun.

But Dick Mol–an internationally renowned paleontologist–is part of a team that regularly uncovers fossils in an unusual place: the ocean.

Dick MolDick Mol holding Ice Age bison skull found in the North Sea, image courtesy of Rene Bleuanus and Dick Mol

 His expeditions take place upon the North Sea, a large expanse of ocean between the East coast of the United Kingdom and the coasts of several other European countries such as the Netherlands, Belgium, and Germany up through to Norway.

 

Embed from Getty Images
“The North Sea is very rich,” wrote Dick Mol in an email. “Ever since 1874, fishermen have brought large quantities of bones and molars ashore.”

He himself has written articles about these finds, describing how the area is routinely dredged, enabling large ships passage on this navigational route. This dredging is what helps uncover fossils deposited there so many thousands of years ago. Coupled with trawling—a method of fishing that pulls weighted nets along the sea floor—these fossils are then brought to the surface.

“I learned about the Ice Age mammal remains, trawled by fishermen,” he explained, “from the curator of the Geological and Mineralogical Museum in Leiden, now the NCB Naturalis (Netherlands Center for Biodiversity). At that time, the attic of the museum was full of large bones of trawled mammoth bones, skulls and lower jaws. It was very impressive.”

Trawling boat, Stellendam harborFisherman preparing trawling nets as the ship leaves Stellendam harbor for the North Sea, image courtesy of Hans Wildschut and Dick Mol

“I remember,” he continued, “that in November 1992 I brought the late Dr. Andrei Sher, a renowned mammoth expert from Moscow, to the museum. When he entered the large attic, he didn’t believe what he was seeing: perhaps one of the largest collections of isolated mammoth bones in the world. This was recorded by a film crew making a documentary on mammoths in the Netherlands. Once in a while, I rewatch this brief documentary again, and it gives me very good memories of a longtime ago.”

“When he entered the large attic, he didn’t believe what he was seeing: perhaps one of the largest collections of isolated mammoth bones in the world.” — Dick Mol, describing the reaction of Dr. Andrei Sher to a collection of mammoth fossils from the North Sea at the NCB Naturalis in the Netherlands

Known to the world as Dick Mol, his name is actually Dirk Jan Mol, and he has been researching mammoths and other Pleistocene fauna for decades. One cannot study mammoths without becoming acquainted with his name and his work.

In response to what prompted his career in mammoths, he wrote, “I grew up on the border with Germany. Around the town of Winterswijk a lot of different geological sediments and fossils can be found from the Triassic, Cretaceous, Oligocene, Miocene, Pliocene and Holocene eras. In different quarries and clay-pits you could collect fossils, but none were of mammoths or remains of other Ice Age creatures.”

“I have been, since 1968, fascinated by mammoths. In the literature, you could read that these prehistoric animals stood up to 5 meters at shoulder (which was exaggerated, of course). I wanted to know more about mammoths and their ancestors. I wanted to find my own mammoths, but it seems that the mammoth has found me!”

“I wanted to find my own mammoths, but it seems that the mammoth has found me!” — Dick Mol

His enthusiasm for the topic has lead him to become a visiting scientist in 1990 and 1994 at the Mammoth Site in Hot Springs, South Dakota—part of the “Visiting Scholar” program designed by Dr. Larry Agenbroad. He has co-authored numerous papers over the years, and his books include Mammoths (published 1993) and, more recently, Mammoths and Mastodons of the Haute-Loire (published 2010), a bilingual book he co-authored with French paleontologist, Frédéric Lacombat.

Scientists and explorers from all over the world have invited him to help excavate their discoveries: some of the most notable finds include the Jarkov woolly mammoth in Russia (Mammuthus primigenius), the Nolhac steppe mammoth in France (Mammuthus trogontherii), and parts of a mastodon skeleton in Greece (Mammut borsoni), in which the longest tusks found to-date were uncovered (502 cm in length).

Queen Beatrix of the Netherlands knighted him for his work in paleontology in 2000. In addition, he is President of Mammuthus Club International and has been involved in the international conference related to mammoth research for years.

His family’s personal collection of fossils exceeds 30,000 specimens that have been used for educational purposes and scientific studies.

Today, he is a Research Associate at the following institutions:

For all of his accolades and accomplishments, Dick Mol is a very accessible and kind man. One witnesses his infectious enthusiasm in these two videos about his work in the North Sea:

 

Trawling for Mammoths: http://www.bbc.co.uk/programmes/p01q0gfr

A Mammoth Task: http://www.bbc.co.uk/programmes/p01q29mg

 

“Over the years, tons and tons of bones have been trawled by fishermen in their nets,” he reiterated. “Between 1997 and 2003, we weighed the mammoth bones: 57 tons, not including 8000 mammoth molars (!) of woolly mammoths. The southern bight of the North Sea between the British Islands and the Netherlands is very rich in Pleistocene mammal remains. It is a real treasure trove.”

“Between 1997 and 2003, we weighed the mammoth bones: 57 tons, not including 8000 mammoth molars (!) of woolly mammoths. The southern bight of the North Sea between the British Islands and the Netherlands is very rich in Pleistocene mammal remains. It is a real treasure trove.”–Dick Mol

“In the meantime, I have organized 43 mammoth fishing expeditions on the North Sea using big beam trawlers. Quite spectacular and always a good catch. Doing these expeditions gave us very good insight into those areas that are very productive and those areas in which Pleistocene fossils are scarce.”

Given the enormous number of fossils brought up from dredging, it doesn’t take a lot of imagination to wonder whether there might be exciting fossil discoveries just waiting to be found if one could go even deeper.

“Yes, for sure,” he agreed. “Most of the bones trawled by the fishermen have been washed out of the seabed by currents. The Eurogully area, off the coast of the province of South-Holland, was dredged from 13 to 40 meters below sea level. At approximately 23-26 meters, there is a rich layer with bones and teeth from the Late Pleistocene. Deeper, there is a layer containing an interglacial fauna (110.000-130.000 BP) including Hippopotamusses and straight-tusked elephants. This is true for the entire southern bight of the North Sea.”

Private collector with femur of the so-called straight-tusked elepahnt, North Sea

Private collector with the femur of the so-called straight-tusked elephant from the North Sea,image courtesy of Hans Wildschut and Dick Mol

But the cost of such an underwater excavation might be prohibitive.

“Once, I used a diver on one of the expeditions. Visibility was very poor, and it was not successful. But some divers in the past have found some mammoth remains. Amongst others, a diver brought up a complete mammoth tusk.”

Aside from the need to desalinate fossils found in the North Sea, they are not physically treated any differently than fossils one finds on land. And despite the wealth of fossils found thus far, Dick Mol does not have any favorites.

“For me,” he wrote, “every bone, bone fragment or remnant is unique and tells us a story….”

Mammoth tibia, freshly trawled, with fish... (1)

Mammoth tibia freshly trawled from the North Sea with fish, image courtesy of Hans Wildschut and Dick Mol

Keep in mind, however, that these fragments and bones are not found together.

Paleontology is like detective work: terrestrial excavations include mapping by grid, pictures, and notes related to where each bone is found. All of these details help paleontologists better understand what species it is and what happened to that animal before and after it died.

The bones found in the North Sea are pulled up individually in a mass of fish and other debris.

Without any of the clues available to someone digging on land, this begs the question: can one determine to which species a bone belongs in isolation?

“[A]fter spending more than 40 years of my life identifying isolated skeletal elements (we have never retrieved a complete skeleton from the North Sea bed) again and again, using comparative collections, it is possible to identify the specimens as soon as they are on the deck of the vessel.”

“Sometimes,” he added, “I need to use literature, but in most cases, an experienced anatomist can do it right away.”

And what about the isolated teeth that have been found in abundance?

“[A]t least three different species of mammoths are well-documented: from the Early Pleistocene the southern mammoth, (Mammuthus meridionalis); from the Middle Pleistocene the steppe mammoth, (Mammuthus trogontherii); and from the Late Pleistocene the woolly mammoth, the icon of the Ice Age, (Mammuthus primigenius). The molars of these species are quite different and easy to tell apart from each other by an experienced specialist.”

Grooves and marks upon the bones give rise to questions about who or what caused them: humans or other Pleistocene animals? And how can one tell the difference?

“Hyena gnawing marks and other predators are well-known and, in general, easy to recognize. Of course, you need some training and experience. Sometimes, especially in large bones, one can see the deep grooves in the so-called material spongiosa caused by hyena (pre)molars. Hyena gnawing marks are very often found in the skeletal remains of woolly mammoths and woolly rhinoceroses. The ice-aged hyena was very common on the Late Pleistocene mammoth steppe environment. Cut marks caused by human activity are completely different from those of predators.”

The “quality and quantity” of the fossils in the North Sea are two things that surprise him the most.

“We have huge collections, and we are constantly learning from them.”

Storage private collection Urk (1)

Private fossil collection storage, image courtesy of Hans Wildschut and Dick Mol (Dick Mol is pictured on the left)

Highlighting mammoth teeth

Please click on this (or any) image to see it in more detail, image courtesy of Hans Wildschut and Dick Mol; highlighting by author

“Recently, many collectors are also focusing on small mammal remains (micro-mammals like voles and lemmings). These remains can be found on the beaches of the North Sea where Pleistocene sediments have been added to strengthen the coastline. Some collectors have hundreds and hundreds of small molars of the entire small mammal fauna. These small mammal remains provide very interesting data to complete the picture of the woolly mammoth and its Ice Age world. In other words, it gives us a window into the small animal community that coexisted with the megafauna.”

“These small mammal remains provide very interesting data to complete the picture of the woolly mammoth and its Ice Age world. In other words, it gives us a window into the small animal community that coexisted with the megafauna.”–Dick Mol

There are two questions that come to mind regarding the volume of fossils collected so far: where are these fossils stored and how long does it take to catalog and study such collections?

“It is a continuous process,” he stated, referring to the length of time needed to catalog and study the fossils.

But in terms of where they are stored, he wrote, “[t]he NCB Naturalis (Netherlands Center of Biodiversity Naturalis in Leiden) has a huge collection of fossil bones from both the North Sea, as well as from dredging operations in the floodplain of our rivers like Rhine, Meuse and IJssel. Really, a huge collection.”

“Using about 200 skeletal elements of mammoths of almost the same size, same age and same gender, we compiled a skeleton for museum display, a huge male individual. Another extensive collection is housed at the Natural History Museum in Rotterdam. Here, a huge collection of Pliocene and Pleistocene marine mammals is stored. Most of these marine mammal remains have been trawled from the seabed as well, and some of these animals coexisted together with terrestrial mammals like mammoths and other large animals. The marine mammals were living in the paleodeltas.”

Compilation skeleton woolly mammoth, NCB Naturalis Leiden (1)

 

Woolly mammoth skeleton at the NCB Naturalis Leiden Museum, the Netherlands, composed of individual fossils found within the North Sea, image courtesy of Hans Wildschut and Dick Mol

“And there are some private collections. Some of them are very well documented. They are like professional collections, and they are available and often used for scientific studies.”

“The co-operation between non-professional and professional paleontologists is extremely good in the Netherlands. For more than three decades, both groups have been working closely together on mammoths and mammoth fauna, scoring very interesting results like 14C, stabile isotopes, new species, etc.”

Dick Mol himself posed the final question: “What can we learn from the mammoth bones trawled from the North Sea between the British Islands and the Netherlands?

“The rich terrestrial mammal remains trawled teach us that the North Sea between Britain and the Netherlands was once dry land,” he explained. “The British Islands were connected with the mainland of Europe during the entire Pleistocene or Ice Age (2.580.000 – 11.500 BP). That area was inhabited by different faunas.”

“In the Early Pleistocene, it was a savannah-like environment, dominated by the southern or ancestral mammoths, (Mammuthus meridionalis). In the Middle Pleistocene, it was a steppe-like environment dominated by the steppe mammoth, (Mammuthus trogontherii), and in the Late Pleistocene, it was a cold, dry and almost treeless steppe dominated by woolly mammoths, (Mammuthus primigenius).”

Dick Mol - compilation skeleton

Woolly mammoth skeleton at the Hellevoetsluis Museum, the Netherlands, composed of individual fossils found within the North Sea, image courtesy of Hans Wildschut and Dick Mol

“At the end of the Pleistocene, this landscape disappeared, caused by dramatic change of climate. It became warmer and warmer, and ice–which blanketed the northern hemisphere–started to melt. Melted water filled up lower countries, and the vast plain became ocean. We know this area today as the ‘North Sea’, and it reached its present sea level about 8,000 years ago. The mammoth steppe disappeared and the mammoth fauna became extinct. This extinction is what we need to accept; it is not dramatic.”

“These events—of which we can learn from the North Sea fossils–show us that we are on a living planet and extinction belongs to it.”
————-

A Mammuthus trogontherii-sized THANK YOU to Dick Mol for his generous and detailed answers to my many, many questions; for his time, his wisdom and his thoughtfulness! What a truly great honor and a great pleasure!!

Dick Mol

 

Dick Mol, image courtesy of Hans Wildschut and Dick Mol

Dick Mol’s papers and research: http://hetnatuurhistorisch.academia.edu/DickMol

The Eurogeul—first report of the palaeontological, palynological and archaeological investigations of this part of the North Sea:  http://www.sciencedirect.com/science/article/pii/S1040618205000649

For fascinating pictures and in-depth descriptions of mastodons and mammoths, Mammoths and Mastodons of the Haute-Loire is a great book (published 2010, in English and in French):  http://www.amazon.fr/Mammouths-Mastodontes-Haute-Loire-Dick-Mol/dp/2911794974/

If you are interested in seeing more of Hans Wildschut’s exciting work, here are links provided by Dick Mol:

Trawling and fossils:

Hans Wildschut – trawling for fossils

Hans Wildschut – fossil finds

Hans Wildschut – trawling for fossils, December 2010

Hans Wildschut – exciting fossil finds and collection (Urk)

Remie Bakker and the creation of the life-sized model of the Mastodon of Auvergne:

Hans Wildschut – Remie Bakker’s work