At the intersection of the present day
and Earth’s history

LIB: Mr Harms, Mr Kotthoff – you are a spider researcher and a palaeontologist. When did you first find out that your two fields of research are rather complementary?

Dr Danilo Harms: Ulrich and I share an interest in palaeontology. I used to research extinct tarantulas preserved in amber. Ulrich and I first met and started our collaboration when I joined the Museum of Nature in Hamburg. We wanted to use amber and the organisms enclosed in it to learn what the fauna in amber can tell us about changes that the habitats and fauna in Europe went through over the last 50 million years.

Dr Ulrich Kotthoff: I was also researching fossil insects for my diploma thesis. In spite of my arachnophobia, I’ve always found arachnids quite fascinating. (Laughs.) I still remember when my brother showed me a pseudoscorpion when we were children. Danilo told me that he was working with pseudoscorpions, and I immediately went: “Oh, how cool is that?”

LIB: What are pseudoscorpions anyway?

D. Harms: They are creatures that look like miniature scorpions. They have no stingers and are also arachnids. Some of them have venom glands in their pincers. Pseudoscorpions live in the leaf litter or under bark. Some species can also be found in caves, beehives, or even in libraries.

LIB: Why is the study of spiders or long-extinct organisms relevant?

D. Harms: Spiders are a central element of the cycle of nature. Without spiders to eat insects, our world would look very different today. We would probably be wading through hordes of grasshoppers or flies. Spiders maintain the balance in many systems. Our research targets the biodiversity of spiders, looking at how many species there are, where they live, how to distinguish them or what they can teach us about evolution or changing ecosystems.

U. Kotthoff: Many problems that we are facing today are connected to geological processes: scarcity of raw materials, climate change, or the changes to biodiversity. Due to this, our research is looking at past diversity, or palaeodiversity to give us a better understanding of current developments and to show what can be considered “natural” and what cannot.

LIB: In what way?

U. Kotthoff: The Earth is about 4.6 billion years old. As humans, we can only perceive a tiny fraction of that. Our view of processes that are vital to understand is highly limited. Today’s biodiversity can only be partly explained when looking only at the present day. A strictly genetic look into the past makes it seem as if diversity were constantly growing. In fact, however, a great many body plans have since disappeared entirely. We can see how organisms needed to change under the pressure posed, for example, by changes in our planet’s system. On top of this, there are some factors such as continental drift, the distance between the Earth and the sun, the tilt of the Earth’s axis, and others. If we do not study the past, we will hardly be able to forecast anything about the future. Europe, in particular, is a complex continent with a unique climate history. 20,000 years ago, there even was a glacier that basically came right up to our doorstep here in Hamburg.

LIB: Mr Harms, what is a common misconception that you keep hearing about?

D. Harms: Many people think that we know every species in the world at this point. Nothing could be further from the truth: we only know a small fraction of them, in fact. That doesn’t just include the arachnids. Small insects in particular are an area where hundreds of new species are discovered every year. We may not know more than 20 or 30 percent of all small animal species so far, which has the potential for some very practical and far-reaching consequences, e.g., for the development of medicines.

LIB: You have already described many new species yourself. How does that process work from discovery to publication?

D. Harms: Approaches can differ. Our own research, for example, involves travelling to the tropics and collecting specimens, either in the scope of ecological projects or specifically targeted at particular animals. We bring the collected arachnids to the lab and analyse them there. Animals may be identified based on morphological characteristics then. We use identification keys and try to work our way from the family to the genus to the species. Another road to identification may be molecular biology and analysing the animals’ DNA strands to compare them to databases. Many species are neither genetically nor morphologically documented once we go through these items.

LIB: It sounds like detective work.

D. Harms: It does. You end up digging through research databases, bringing together molecular and morphological information, sequencing, and studying animal morphology and ecology. Then you need to start documenting your new species and distinguishing them from known ones by taking pictures, measuring, drawing, and writing descriptions. You need to work according to some specific protocols that differ by animal group but generally follow standardised patterns. In the end you publish your work in a scientific journal. Reference specimens also must be deposited in museum collections as physical preservation for posterity.

U. Kotthoff: That’s why collections like the one Danilo and I curate really can be called libraries of life. They are both a privilege and a great responsibility.

LIB: A library like this needs to be populated with exhibits, too. Can you tell us about some memorable expeditions you went on?

U. Kotthoff: I was part of an expedition in the eastern Mediterranean back in 2017 where we were planning to extract sediment cores from across the Aegean Sea. At the time, we had the problem that tensions between Turkey and Greece were rife. Our research vessel’s crew were growing nervous whenever Turkish or Greek warships came near us. There were apparently some diplomatic talks. We eventually had to abandon our research in the Aegean and move on to the Adriatic. Even today I think that being surrounded by warships on a research vessel and being forced to abandon our project right in Europe really is a shame.

LIB: What about you, Mr Harms?

D. Harms: I visited Tasmania as a doctoral student, searching for endemic pseudoscorpions – species that cannot be found anywhere else. I spent hours hiking the rainforest in full safety gear, carrying all the equipment I needed with me. We rappelled several hundred metres down into a cave, with a waterfall plunging into the depths inside. I was forced to move through that horrendously cold water and spent hours sitting at the bottom, wet and shivering in the dark, turning over stone after stone without anything to show for my pain in the end. As I was making my slow way back up, I kept asking myself why I had ever agreed to go on that trip. Then, right by the waterfall, I turned over a stone – and there it was: a blind pseudoscorpion. A new species that had probably lived in this cave for millions of years, and of which only this one individual is known to us. Unfortunately, I haven’t yet managed to record it scientifically.