In March 2020 a camera 631 metres down filmed a coil of animal 47 metres around, and nobody can say how many animals were in it.
The case file on what a siphonophore is: the 47 metre spiral at Ningaloo and why its own discoverers hedged the record, Thomas Henry Huxley at twenty on HMS Rattlesnake drawing animals that fell apart in the net, the 1849 Medusae paper that built the Hydrozoa, and the conclusion he reached in 1859 that goes the wrong way. Huxley argued the colony was ONE animal whose parts had become organs, the polyorgan theory; Vogt, Leuckart, Kolliker and Gegenbaur argued the opposite. The modern anatomy went against him: zooids are homologous to free living individuals, grown by budding from a single fertilised egg, never separate at any point. Then Erenna's red lures at 1,600 metres, Praya dubia at 50 metres, and the 2025 genomes that split the Portuguese man o' war into four species. The verdict: the evidence did not fail Huxley, the category did, and it still has not been fixed.
CHAPTERS
0:00 The Ningaloo Spiral Discovery
1:59 Huxley on HMS Rattlesnake
6:10 Anatomy of the Zooids
8:16 How a Siphonophore Grows
9:54 Deep Ocean Hunting Strategies
11:57 Studying Fragile Marine Life
14:47 Rethinking Biological Categories
Full source list in the YouTube description: youtube.com/@thenightfathom
Narration and visuals were made with the help of AI tools.