Rare salp discovered in Norway - Helicosalpa virgula
Helicosalpa is a genus of rare salps, and specimens can become over 15 meters long. They are typically recorded in southern latitudes, but recently a few specimens were recorded to the north of Norway.
Only three Helicosalpa species have been described in the world, and with a little help from marine citizen scientists, we are hoping to gain tissue samples for genetic analysis. Help us to find samples from all three species!
Yes, you read it right! Salps are free-swimming tunicates, of which Helicosalpa is one genus. They have a fascinating lifecycle. You may encounter helicosalps either as solitary specimens, a few centimeters long, or giant chains which may become over 15 meters. The long chains look a bit like a ‘giant helix’, and are able to swim by twisting their chains.
Helicosalps begin their lifecycle as solitary salps, and through ‘budding’ (asexual reproduction) they produce a small, long chain with lots of individs. When long enough, this small chain breaks off from the single salp, and floats away. The small chain is growing by filtrating and eating particles from the water mass. When the chain has grown large enough, and meets another chain, they exchange egg and sperm and produce single salps (sexual reproduction).
Salps are tunicates, and belong within Chordata phylum, together with humans, for example. All chordates have a dorsal nerve cord, at least parts of their lives. Helicosalps are among the most rare salps. They have been recorded both from the Atlantic and Pacific Ocean, but are typically seen in the tropics, or in the Mediterranean Sea.
“Helicosalps are among the most rare salps. They have been recorded both from the Atlantic and Pacific Ocean, but are typically seen in the tropics, or in the Mediterranean Sea.”
Only three species have been described: Helicosalpa virgula, H. komaii and H. younti. In the Atlantic, only H. virgula has been recorded. Helicosalpa are so rare that even scientists have seen very few live specimens, and scientific descriptions of species have been based on preserved specimens.
If you have worked with preserved animals, you’ve noticed they look a lot different from live animals: they’ve shrunk, lost color and are somewhat deformed. Because of this, noone knew for sure what these three Helicosalpa species looked like alive – until now:
Through our research study (Ringvold et al.*) we conducted google searches looking for pictures and videos of helicosalps from divers all around the world.
A few photos were also borrowed from other researchers.
Gradually, it became clear to us what the three specimens looked like alive!
H. virgula can be seen in Figure 1 (previous page). Notice the yellow, cone-shaped gonads with long protrusions; these are characteristic for H. virgula. In our next project, we wish to sample a small piece of each Helicosalpa species (a tissue sample) in order to conduct genetic analysis.
*Ringvold et al. 2020 - Encounters with the rare genus Helicosalpa (Chordata, Thaliacea, Salpida), using citizen science data. Marine Biology Research. 16 (5) 369-379.