Written by Jannes Landschoff
This collection of taxonomic and biodiversity research projects, focused on South Africa’s Great African Seaforest, is made possible through invaluable collaborations with leading local and international scientists. These partnerships are essential for describing new and poorly understood species—from parasitic crustaceans and endoparasitic snails to mantis shrimps and sponge-hermit crab associations—advancing the foundational knowledge of this unique marine ecosystem.
In 2016, while deep into my taxonomic work on hermit crabs along South Africa’s east coast, I noticed something unusual while photographing a specimen. One side of the crab’s body looked deformed. On closer inspection, I gently lifted the gill chamber and saw a small knob-like growth. As I moved it, the tiny lump detached and turned out to be a very small, asymmetrical female isopod; and beside it, an even smaller, perfectly symmetrical male. Until that moment, I had no idea such creatures existed: parasitic crustaceans of just a few millimetres that attach to the gills of crabs and feed by sucking their body fluids.
A few months later, at an international crustacean conference, I met Prof. Jason Williams, one of the world’s few leading experts on these parasites. I showed him the specimens and he immediately recognised them as bopyrid isopods, noting that very few were known from South Africa. Years later, Jason’s and my paths crossed again, first in New Zealand, and later when Jason visited a conference in Stellenbosch. We spoke about the limited taxonomic expertise in South Africa and about the growing 1001 Seaforest Species initiative. A week later, and to my great surprise, an email arrived from Jason saying that he had started working on the isopod, and that it was indeed a new species to science.
Describing such small species is highly technical and demands deep, specialised expertise built over decades. Perhaps one day – and if in South Africa we had more time, more focus, increased capacity – we could describe animals better ourselves. But for now, collaborations and help by international experts on such specialised groups are invaluable. Eventually, we published the new species in SOSA’s Ocean Discovery Notes. So this small parasitic isopod marked the beginning of something much larger.
(lead authors: Dr. Tsuyoshi Takano and Prof. Yasunori Kano)
At the very beginning of my research career, I worked extensively on the biology of brittle stars. South Africa has many different species, and some of them do something quite remarkable: they brood their young inside small brood chambers. My supervisor Prof. Charles Griffiths and I were fascinated by how different species carried out this behaviour, so when I began my PhD, we set up a project to study the biology of the equitailed brittle star Amphiura capensis. This project became the Bachelor (Honours) thesis of Rebecca MacKinnon. Neither of us could have imagined where this would eventually lead.
Several months into the project, Rebecca and I discovered something very peculiar. Inside some of the brood pouches were small, white, round globules. They were just over a millimetre in size. It took us a while to realise that these were parasitic snails belonging to the family Eulimidae, a group I did not even know existed before. Finding experts who could tell us more proved even harder. Eventually, we sent the few specimens we had to Prof. Yasunori Kano and his student Dr. Tsuyoshi Takano at the University of Tokyo, both experts on this highly specialised group of parasitic snails. From there began a long and meticulous taxonomic process, led by our Japanese collaborators.
Nearly ten years later, we are delighted to be part of a fascinating study showing that our South African species represents not only a new species but also a completely new genus to science. Even more remarkably, their biology, with the internal parasitism of brittle stars, is itself new to science.
Although Rebecca has long since graduated and moved on in her career, almost a decade after her first discovery she now has a species named after her: Introphiuricola rebeccae n. gen., n. sp. This story is a reminder that biological research often takes patience and persistence, and we are deeply grateful to Prof. Kano and Dr. Takano for their dedication and collaboration in helping reveal yet another wonder of our local biodiversity.
This is a project in which I primarily played an advisory role, while the work itself was carried out by then M.Sc. student Rouane Brokensha and Prof. Charles Griffiths as supervisor. The project also took place during the early stages of the 1001 Seaforest Species initiative, when Rouane formed part of the small founding team trying to shape and define how such an ambitious undertaking could begin. Despite the uncertainty and challenges of that formative period, she remained focused on producing an important taxonomic revision of a remarkable crustacean group.
Mantis shrimps, or stomatopods, are extraordinary, elongated crustaceans distantly related to shrimps and crabs. They are renowned for their highly specialised raptorial appendages, capable of delivering some of the fastest and most powerful strikes in the animal kingdom. The diversity of stomatopods in South Africa is considerable, with numerous endemic species occurring only in this region and playing important ecological roles in marine ecosystems. Rouane undertook the challenging task of revising the entire group for Southern Africa, producing the first comprehensive monographic treatment of regional stomatopods, including several new records for Mozambique.
The work is extensively illustrated with highly technical and detailed scientific drawings, meticulously produced by Rouane herself. The result is an invaluable resource of more than 120 pages documenting the 31 species currently known from South African waters. The resulting publications represent a major achievement and an important milestone in advancing knowledge of stomatopod biodiversity both locally and globally. Rouane has since continued into her own academic career, further deepening our understanding of mantis shrimp biology and marine biodiversity through her ongoing postgraduate research.
One of the most remarkable hermit crabs in South Africa is the Hercules hermit crab Cancellus makrothrix. What makes this species so unusual is how different it is from typical hermit crabs in both form and behaviour. It carries exceptionally large gastropod shells, has a nearly straight pleon rather than the strongly curved body typical of most hermit crabs, and belongs to a genus whose species usually live inside rocks or wood rather than shells. It also broods its young on the body and preys on animals such as sea urchins.
The species had not been recorded in South Africa for roughly a century since its original description, which was itself poorly illustrated and taxonomically inadequate. For years, my mentor in hermit crab taxonomy Dr. Rafael Lemaitre and I discussed the need to properly revise and redescribe the species using modern standards, together with detailed photographic documentation.
A few years into the 1001 Seaforest Species project, Rafa provided invaluable help in bringing this work together. Although taxonomic redescriptions rarely receive the attention given to newly discovered species, they are fundamental to biodiversity science. They make species identifiable and accessible for future ecological and biological research. In South Africa, many species are still known only from outdated or incomplete descriptions, making this kind of foundational work critically important, and something we would undertake far more often if greater time, funding, and research capacity were available. I am deeply grateful that we managed to do this for at least one of the more conspicuous and intriguing species!
Collaborators. Emer. Prof. Charles Griffiths, Dr Ruiqi Li, Prof. Jinchun Li
This is a story that, to me, stands as one of the strongest examples of how underwater tracking, nature exploration, academic research, and storytelling can come together in a powerful and deeply interconnected way.
It began some years ago, when I was still a student at the University of Cape Town, and Craig was in what felt like one of his most focused personal quests to understand the kelp forest through direct lived experience. During this time, Craig called me one day, excited, saying he had found the “heart of the ocean”. What he had discovered was a heart urchin, a burrowing echinoid that lives beneath the sand. While empty tests of these animals were relatively common, the living animals themselves had rarely been observed directly. It was the subtle underwater tracking skills Craig had developed over many years of diving that guided him to this discovery.
On a subsequent dive, Craig showed me where and how these urchins lived. I realised they hosted a range of commensal organisms living among their spines. One of these was a small bivalve. We collected a few specimens and examined them in the laboratory together with Charles, but it quickly became clear that the available regional guides and taxonomic literature were insufficient to identify them.
Charles then sent specimens to Dr Paul Valentich-Scott, who I later coincidentally met a few months afterwards in the deep basement of the Smithsonian National Museum of Natural History. I remember walking through a long, quiet corridor and finding him opening small drawers of shells in a side room. That meeting stayed with me, because it reflected a level of curiosity and commitment where even the smallest organisms receive extraordinary attention and care. It also made clear how much effort and dedication is required to describe a species, and the depth of passion needed to do so.
Over the following years, Paul took the lead on the study, and the manuscript gradually developed, layer by layer, almost like a painting forming on a blank canvas. A major breakthrough came when Dr Ruiqi Li and Prof. Jinchun Li from the University of Colorado Boulder joined the work and were able to contribute genetic sequencing data that helped clarify the taxonomic placement of the species.
Eventually, the paper was published, and the small commensal bivalve received its formal scientific name: the Heart urchin clam Brachiomya ducentiunus — species number 201 of the 1001 Seaforest Species. The study also refined the taxonomic understanding of related species in the region, contributing more broadly to biodiversity knowledge of the kelp forest and surrounding coastal ecosystems.
Collaborators: Dr Toufiek Samaai, Dr Robyn Payne, Benedicta Ngwakum, Prof Peter Teske
This is one of those projects where many moving parts had to fall into place over many years. The original specimens came from the SAEON-led offshore marine invertebrate monitoring programme associated with the then Department of Fisheries and the Environment benthic fishing surveys. During my PhD on hermit crabs, we requested that unusual-looking hermit crabs be retained. A year later, I, and later several postgraduate students, had the opportunity to join these cruises ourselves, and gradually more of these remarkable sponge-associated hermit crabs accumulated.
The biology of this association is fascinating because the sponge effectively builds the home for the hermit crab. When we first showed the specimens to then PhD student Robyn Payne, she immediately suspected the sponge was a new species to science. This was not surprising, as no such sponge-hermit crab association had previously been reported from South Africa.
As is often the case in taxonomy, formally describing the species took many years. Robyn completed much of the foundational work alongside the other authors before moving on from academia. After a long period without the capacity to continue the project, Dr Toufiek Samaai took the lead on the manuscript and ultimately helped bring the paper to publication.
One particularly exciting aspect of the study was the inclusion of a 3D scan, produced with the help of Prof. Anton du Plessis, who at the time was based at the Stellenbosch scanning facility. The scan revealed a tiny seed shell hidden at the apex of the sponge structure, only a few millimetres long and completely overgrown by the sponge. This showed that a tiny juvenile hermit crab first settles into the shell, after which the sponge larva settles and starts growing around it, continuously enlarging the opening and creating a living sponge home for the crab.
I am deeply grateful to all the authors who helped bring this work to completion. My own role was often simply to keep the momentum alive over the years, something the 1001 Seaforest Species project fortunately allowed me to do. Sponge taxonomy is highly specialised work and an excellent example of the importance of experts such as Toufiek and his team, whose knowledge is invaluable to South African biodiversity research.
(with Gill Mapstone, Mark Gibbons & team, and Nick Bezio)
Over many years of diving, Craig recorded and beautifully photographed numerous species of gelatinous plankton, including jellyfish, ctenophores, and siphonophores. Photographs such as these can hold important scientific value, as they often capture observations that would otherwise be missed. Gelatinous animals face a particular challenge in taxonomy because collecting physical specimens is difficult, and preserved animals stored in alcohol or formalin generally look vastly different from their delicate and striking appearance in life – if they preserve at all!
Many of these observations and photographs were shared with the extended research network of Prof. Mark Gibbons and contributed valuable distributional and biodiversity records. Particularly exciting discoveries were further investigated by Gill Mapstone, a world-leading expert on siphonophores. This collaboration resulted in two distributional range-extension reports on rare species. The first documented the genus Lilyopsis for the first time in South African waters. The second centred on specimens I photographed, which Gill identified after extensive study as Rhizophysa eysenhardtii. Together we developed these observations into a small research publication as the first occurrence of this species in False Bay.
I have also been collaborating with Nick Bezio, who has been helping us further improve knowledge of the comb jellies (ctenophores) occurring in South African waters.
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