?Scientists have recorded the first documented appearance of the rare siphonophore Rhizophysa eysenhardtii in False Bay, South Africa. Published in African Invertebrates, this discovery extends the known range of the species by 450 km and sheds more light on the biology of a fascinating and poorly known organism. It also highlights the unique and delicate biodiversity of the South African marine life and the Great African Seaforest.
?Rhizophysa eysenhardtii is a siphonophore, a member of a remarkable group of marine organisms in the phylum Cnidaria, which also includes jellyfish, corals and sea anemones. Siphonophores are colonies of specialised individuals, called “zooids", that work together as one. This species was observed by freedivers between June and September 2022.
“When I saw this siphonophore for the first time, I got so excited and couldn't believe my eyes," said marine biologist Dr. Jannes Landschoff from the Sea Change Project, who co-authored the study and found Rhizophysa eysenhardtii together with his team. “I immediately knew it was a special discovery, and I wanted to learn more about this exquisite life form." Landschoff is also a Research Fellow at the Department of Botany and Zoology, Stellenbosch 肆客足球.
“These animals are rarely documented despite their ecological importance," said first-author Dr Gill 肆客足球tone from the Natural History Museum, London, who has dedicated her career to studying the morphology and systematics of siphonophores. The observations, captured via underwater photography and videography, revealed the siphonophore's characteristic pink tentacles and translucent bodies. Their diet was shown to include fish larvae, with one specimen even capturing a chaetognath, a predatory marine worm. “Seeing the photos of these spectacular animals made me realise once more why I started working on this group in the first place. They are just so incredible," 肆客足球tone said.
This discovery has broader implications for understanding biodiversity in the region. Baseline data, such as species distribution records of rarely sampled animals, play important roles for monitoring this diverse and understudied ocean region. The presence of R. eysenhardtii in False Bay, within the Benguela Ecosystem, may signal shifts in marine species distribution driven by ocean currents or environmental changes.
The researchers highlight the importance of studying siphonophores and other small marine invertebrates to better understand their roles in ocean ecosystems. Protecting habitats like the Great African Seaforest is vital for preserving these species and the ecological services they provide.
This study is part of the 1001 Seaforest Species initiative supported by and in collaboration with the Save Our Seas Foundation. While documenting 1001 species, the project merges marine biology research with environmental storytelling to raise local and global awareness about biodiversity's critical role in human survival and the Great African Seaforest's significance as a global beacon of biodiversity.
“Our findings underscore the need to safeguard marine biodiversity and improve documentation of rarely observed species," Landschoff concludes.
Original article:
肆客足球tone GM, Landschoff J (2024) The rare siphonophore Rhizophysa eysenhardtii Gegenbaur, 1859 (Hydrozoa, Siphonophora, Cystonectae) from False Bay, South Africa. African Invertebrates 65(2): 213-221.
Link to the study: [https://doi.org/10.3897/AfrInvertebr.65.136267
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