Interview: description of two African shovel-snout snakes from Angola

The small number of collected samples, coupled with the animals’ curious skull structure and anomalous ecology, has puzzled scientists for decades.

Recently, our journal ZooKeys published a paper describing two new species of African Shovel-snout snakes: Prosymna confusa, endemic to dry habitats in southwestern Angola, and P. lisima, associated with the Kalahari sands.

We interviewed the authors of the study to find out how they made this discovery and what it means for biodiversity. Werner Conradie (South Africa), the leader of the project, collected most of the specimens and did all the morphological examinations and taxonomy work. Chad Keates (South Africa) conducted the molecular analysis, Javier Lobon-Roviara (Spain) did the CT-scanning skull reconstruction, and Ninda Baptista (Angola) performed fieldwork.

Interview with Werner Conradie, Chad Keates, Ninda L. Baptista, and Javier Lobón-Rovira

Why has the taxonomy of African Shovel-snout snakes been so complicated?

While widespread, the group is infrequently encountered, resulting in a relatively low number of samples being collected through time. This, coupled with the animals’ curious skull structure and anomalous ecology, has puzzled scientists for decades. While we finally seem to have a grip on the higher-level taxonomy (their relatedness to other snakes), their relations among each other remain incomplete. One thing is for sure, the next few years will likely result in the discovery and description of many more.

Live P. confusa. Photo by Bill Branch

Please walk us through your research process.

Similar to solving a puzzle, the process starts off by acquiring the pieces. The pieces come in the form of samples, collected by us and by scientists, accessioned in museums all over the world. Once all the pieces are in one place, it becomes our job to piece them all together and build a picture of the taxonomy of the group. We start in the corners, ironing out our hypotheses. Once we have the outline, a theory of the species composition of the group, we get to work building the puzzle using evidence from multiple different species concepts.

We use genetics, morphology, ecology, and skull osteology and through fitting these concepts together we start to see our species and the boundaries between them. Large chunks of the puzzle begin to take shape, revealing our picture with ever-increasing clarity. As we find, orientate, and fit the last pieces of our puzzle through the creation and completion of the manuscript, we finish the puzzle and in doing so provide you with the complete picture: the updated taxonomy of Angolan shovel-snout snakes.

When did you realize you were dealing with new-to-science species?

It’s hard to pinpoint exactly, but the idea grew from the moment Werner Conradie picked up the first snake whilst on the first expedition with the Okavango Wilderness Project, back in 2016. Funded by National Geographic and managed by the Wild Bird Trust, this paper would not be possible without them, because without the transport and logistical support, most of our dataset would never have been found.

What makes these new species unique?

With the aid of modern nano computerised tomography scanning technology, we observed that one of the new species has a well-developed postorbital bone. We still don’t know the purpose of this postorbital bone and why it is absent in the others. We believe it might serve as additional muscle attachment points that aids them on feeding on different kinds of lizard eggs than the others.

Kalahari Shovel-snout snake (Prosymna lisima) from southeastern Angola. Photo by Chad Keates

This is also the first new species of Shovel-snouted snake described in nearly 30 years.

In the late 1980’s Zimbabwean herpetologist, Donald Broadley noted that eastern populations of the Angolan Shovel-snouted snake may be a different species. It took nearly 50 years before more material was collected and with the aid of modern technology, like genetic analysis and CT-scanning, we could show he was correct and described it as a new species.  

What can you tell us about their appearance and behavior?

The Shovel-snouted snakes are unique snakes with a beak-like snout that allow them to dig into sandier soils. Thus most of the time they are below the surface and only come out after heavy rains. They also possess unique backward pointed lancet-shaped teeth that they use for cutting open lizard eggs. These snakes specialize in feeding mostly on soft-shell lizard eggs. They find a freshly laid clutch of eggs and one by one, they swallow them whole. They cut them laterally so that the yolk can be released.

Kalahari Shovel-snout snake (Prosymna lisima) from southeastern Angola. Photo by Chad Keates

Do they interact with people?

These snakes may be encountered by people tending to their lands or crossing the road, but, for the most part, they are incredibly secretive. Because of their ability to burrow in soft soils, these animals are infrequently encountered, only forced to the surface during heavy rain and by the urge to breed and to feed. If encountered, however, these snakes pose absolutely no harm, as they possess no venom. When threatened, these animals may wind themselves into a tight coil to protect their heads.

Kalahari Shovel-snout snake (Prosymna lisima) from southeastern Angola. Photo by Chad Keates

What is the ecological role of these snakes?

Much like most small vertebrates, these animals form an important component of the food web. They consume lizard eggs, exerting a regulatory force on newborn lizards, and serve as food for larger snakes, rodents, and birds. Animals like these form the bedrock of any healthy ecosystem as they contribute to energy exchanges and the flow of nutrients down and up and down again.

Bonus question: how did you get involved in herpetology?

Everyone in the group has a soft spot for reptiles and amphibians’. Irrespective of our contrasting upbringing and our nation of origin, we all came to herpetology independently. While it is hard to unpack the moment that we all fell in love with these weird and wonderful creatures, one thing is for sure, it’s a lifetime commitment.

About the Authors

Werner Conradie holds a Masters in Environmental Science (M. Env. Sc.) and has 17 years of experience with southern African herpetofauna, with his main research interests focusing on the taxonomy, conservation, and ecology of amphibians and reptiles. Werner has published numerous principal and collaborative scientific papers, and has served on a number of conservation and scientific panels, including the Southern African Reptile and Amphibian Relisting Committees. He has undertaken research expeditions to many African countries including Angola, Botswana, Lesotho, Malawi, Mozambique, Namibia, South Africa, Zambia, and Zimbabwe. Werner is currently the Curator of Herpetology at the Port Elizabeth Museum (Bayworld), South Africa.

Chad Keates is a post-doctoral fellow at the African herpetology lab at Port Elizabeth museum (Nelson Mandela University, based in the SAIAB Genetics Platform). Having recently completed his PhD in Zoology, Chad’s research focusses are African herpetofauna and their evolutionary and ecological structuring. In Chad’s short professional career, he has published several principal and collaborative peer-reviewed scientific papers and book chapters. Chad is also a strong advocate for reptile and amphibian awareness and regularly conducts walks, talks and presentations as well as produces numerous popular scientific outputs on the subject. He has undertaken numerous expeditions to many African countries such as Angola, Zambia and South Africa with a variety of both professional and scientific organisations.

Ninda Baptista is an Angolan biologist, holds an MSc degree in Conservation Biology from the University of Lisbon, and is currently enrolled for a PhD in Biodiversity, Genetics and Evolution in the University of Porto, addressing the diversity of Angolan amphibians. Over the last 12 years she has worked on environmental consulting, research and in-situ conservation projects in Angola, including priority areas for conservation such as Kumbira, Mount Moco and the Humpata plateau. She conducted herpetological surveys throughout the country and created a herpetological collection (Colecção Herpetológica do Lubango), currently deposited in Instituto Superior de Ciências da Educação da Huíla (ISCED – Huíla). Ninda is an author of scientific papers and book chapters on Angolan herpetology and ornithology. She also works on scientific outreach, producing magazine articles, books for children and posters about the country’s biodiversity in collaboration with Fundação Kissama.

Javier Lobón-Rovira is PhD student at Cibio, Portugal, working to unveil evolutionary pattern in southern Africa gekkonids. As Biologist he has worked in different conservation projects and groups around the globe, including reptiles and amphibians at Veragua Rainforest Foundation, Costa Rica or big mammals in Utah, USA. However, as photographer, he has collaborated with different Conservation NGOs in Africa, America and Europe and manage to publish on International Journals as National Geographic, Africa Geographic or Nature’s Best Magazine. 

Read the study:

Conradie W, Keates C, Baptista NL, Lobón-Rovira J (2022) Taxonomical review of Prosymna angolensis Boulenger, 1915 (Elapoidea, Prosymnidae) with the description of two new species. ZooKeys 1121: 97-143. https://doi.org/10.3897/zookeys.1121.85693

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