A new analysis of fossilised specimens of Vampyronassa rhodanica — an ancient species of cephalopod related to octopus, squid and cuttlefish — uncovers how the animal may have been well adapted to actively hunt prey in the open ocean. The paper, published in Scientific Reports, reveals that the species likely had suckers that could hold on to prey, unlike its modern-day descendant, the vampire squid, which feeds on drifting organic matter.
Vampyronassa rhodanica is thought to be one of the oldest relatives of the modern-day vampire squid (Vampyroteuthis infernalis), which lives in extreme deep ocean environments, away from the shoreline, often with little oxygen. However, less is known about the physical characteristics of V. rhodanica as the body is rarely found fossilized due to being largely formed of soft tissue.
Alison Rowe and colleagues used a non-destructive 3-D imaging technique to reanalyse well-preserved V. rhodanica fossils from La Voulte-sur-Rhône (Ardèche, France) dating to more than 164 million years ago. The eight-armed specimens were small, measuring around 10 cm in length, and had elongated oval-shaped bodies with two small fins.
Similar to modern vampire squid, the suckers on V. rhodanica were likely not toothed. However, unlike vampire squid, the fossil specimens displayed evidence of robust suckers on the tips of two specialised, long dorsal arms.
Based on similar modern-day species, the authors propose that V. rhodanica used these suckers to create a watertight seal, producing a secure suction force. The authors suggest these suckers would also have aided the manipulation and retention of prey.
The authors propose that the presence of muscular suckers on each of the arms and sensory conical appendages for detecting prey suggests that V. rhodanica was an active predatory hunter. This is in contrast with its more opportunistic descendant the vampire squid, which has adapted to a low energy, deep ocean lifestyle.
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