Naming Nature

The naming of animals plants is not an easy task, yet it is probably one of the most important ones in science (even though there is little money available for it). We need to understand the unique biodiversity on our planet so we can protect it. Individual species have prevented construction work, protected wetlands, and even stopped a certain former President’s golf course from being built.  

Those scientists who name nature (taxonomists) are specialists in their field, and work on a specific group of organisms. When a new animal or plant is found, it is carefully, and meticulously, compared to others, which will help work out where it belongs on the tree of life. For example, a fly is a fly which is an insect, and a frog is a frog, which is an amphibian, so these are good starting points. Comparing to other groups and looking for similarities helps the taxonomists to see which species they are closely related to. It sounds complicated, and there are a lot of different steps (and Latin!), but if you understand the basics, it’s fairly simple. The system of taxonomy was devised by the Sweedish naturalist, Carolus Linnaeus, also known as Carl von Linné, (1707-1778). He wanted to organise animals and plants into groups based on their similarities, which indirectly shows how closely related species are.

A page from Linnaeus’ 10th Edtition of Systema Naturar in 1758. (Image Public Domain)

If we look at humans as an example, we can look at where we fit on the taxonomic tree. At the top, humans belong to the Kingdom Animalia (which includes all animals from worms to wombats). Next, humans are classed into the Phylum Chordata (all animals with a nerve chord running through their spines, also known as vertebrates). The next group is the Class, and humans belong in the Class Mammalia (all animals with fur or hair, secreting milk for their young, and have three ear bones). There are a lot of different types of mammals, and there are several groups (Orders) in the Class Mammalia, rats belong in the Order Rodentia which includes mice and shrews. Humans are placed in the Order Primates (animals that have a rotating shoulder joint and separate big toes and thumbs for holding onto things). Humans belong in the Family Hominidae, which includes all the great apes (chimpanzees, gorillas, and orangutans), primates that don’t have a tail. Within the Family Hominidae, humans belong to the Genus Homo, which is classified by walking on two legs and brain size. Finally, humans belong to the species sapiens, the individual species name for all humans, so our species is called Homo sapiens. This hierarchy of classification can be carried out for all organisms from jellyfish to whales.

Taxonomy can be taxing. Classification can be confusing. But it’s a way of understanding how all life on our beautiful planet is related, and how rich biodiversity is, and has been, and the job of the taxonomist is to unravel the mysteries of life.

Researchers use computer programs, which is known as cladistics, to work out the relationships between organisms. They input numerous characteristics, and the programme works out possible relationships. This example is looking at different species of moss. It can be done with anything, from ants to antelopes. (Image Public Domain)

For taxonomists studying life on Earth today, from the deepest rainforests to the cold, dark ocean floor, they have preserved specimens in museums they can use to work out where this creature of plant fits. They will compare the specimen they have found with many other species, and if it is new, then the specimen they describe is the type specimen of this new species (the specimen which defines that species). And with specimens in museums, there are a lot of features that can be compared, helping identify the organism, or seeing if it is a new species. Palaeontologists have a much more difficult time. Often all they have is a single bone, or a single tooth. But they do use the same techniques to identify the long dead animal. And an enormous number of different species have been identified and named increasing our understanding of life during the past.

Most of the time, palaeontologists will look at modern species and work out who their fossil is most closely related to. So cave lions, for example, are closely related to modern African lions (Panthera leo), so they are placed in the same Genus (Panthera) as a different species, Panthero spelaea. It gets more tricky with extinct beasts, because sometimes are no modern species closely related. Their entire line has vanished (Think of the weird Macrauchenia and Toxodon which were anomalies for decades, until research into their DNA finally unravelled their true relationships to other animals). The same principles still apply, and the scientists look characteristics in the bones to help identify closely related Families, and propose a new Genus and species. Or in the case of Dinosaurs for example, a completely new Order.

Sometimes things go the opposite way! An interesting, and little-known, beast was discovered in a cave in Brazil in the 1830s, by the Danish palaeontologist Peter Wilhelm Lund. A new Genus and new species to science. There were, at the time, no other animals like it. It was a dog, so the researched placed it in the Family Canidae, and gave a new Genus for it, Speothos venaticus. The Bush Dog. This was the type specimen for this species (the first specimen to be described and published, defining that species). It was until decades later that this extinct creature was found alive and well! It is very rare for an animal around to day to be scientifically named from fossils.

The living Bush Dog is a beautiful little animal. They are small, reaching just 12 inches at the shoulders, with beautiful soft brown fur, with orange tinges around their heads. It is actually divided into two sub-species: the South American Bush Dog (S. venaticus venaticus) and the Panamanian Bush Dog (S. venaticus panamensis). The two are similar enough to be the same species, but a few differences to separate them into sub-species.

The beautiful South American Bush Dog Speothos venaticus. (Image Public Domain)

They are rare little creatures, living in South and Central America, with habitat destruction is pushing them to the brink of extinction. Living in wetland areas, these incredible animals have webbed feet, and are extremely good swimmers. For such a small dog, they are pretty gutsy hunters. Mostly feeding on small rodents, they will sometimes attack capybaras or even the large flightless rea!

In 1984, another cave in Brazil was excavated and more fossils of Speothos were discovered. These fossils were larger than the living bush dog, and had slightly different molars, so a new species was described, Speothos pacivorus, the Pleistocene Bush Dog. The teeth show it was a carnivore, but as the soft parts of the body were not fossilised, we will never know if it had webbed feet. The Pleistocene Bush Dog is a mysterious beast.

It was a different environment for this ‘giant’. There were much larger creatures around, like mastodons and giant sloths, but these were much to big for this little predator, and it is more likely they preyed on smaller rodents, like pacas which were also found in the caves.. The Pleistocene Bush Dog would have faced competition from other, larger carnivores, such as the large canids Theriodictus and Protocyon, two much larger carnivores. Like the South American Bush Dog, this beast very likely created dens in burrows, to bring up their young and for safety against potential large predators.

Very little is known about the Pleistocene Bush Dog, and it is tempting to make assertions based on the living South American Bush Dog. But different species in the same Genus can have very different lifestyles and live in very different environments (think of the modern lion and the cave lion we mentioned earlier). We don’t actually know a lot about this captivating canid. More cave sites holding fossils will be able to tell us more about the habitat it lived in and even more about its lifestyle. For now, we have the Pleistocene Bush Dog. Enigmatic, yes. But for the time being, this is one more species added to the ever-growing list of incredible animals that have walked, or in this case, slightly waddled, on Earth.

Written by Jan Freedman (@JanFreedman)

Further reading:

Berta, A. (1984). ‘The Pleistocene Bush Dog, Speothos pacivorus (Canidae) from the Lago Santa Caves, Brazil’. Journal of Mammalogy. 65. pp.549-559. [Abstract only]

De Mello Beisiegel, B., and Zuercher, G. L. (2005). ‘Speothos venaticus’. Mammalian Species. 783. pp.1-6. [Abstract only]

Lagoa Santa Caves. In: Encyclopedic Dictionary of Archaeology. Springer. Cham.

Mayer, E. L., et al. ‘Taxonomic, biogeographic, and taphonomic reassessment of a large extinct species of paca from the Quaternary of Brazil.’ Acta Palaeontol. Pol.  61(4). pp.743-758. [Full article]

Nascimento, R., and Silveira, L. F. (2020). The fossil birds of Peter Lund. Zootaxa. 4743(4). [Abstract only]

Owens, P. (2001). ‘Speothos venaticus (South American Bush Dog)’. Digital Morphology. [Full article]

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