Newly-discovered Fossil of Primordial Octopus Had Ten Arms Instead of Eight

Syllipsimopodi Bideni: Recently, a fossil of a species called Syllipsimopodi bideni was recently discovered in central Montana (US).

Key Highlights:

  • It is the earliest known related of today's octopuses, with ten limbs, two of which are twice as long as the other eight.
  • It has been named after the US president, Joe Biden.

About Syllipsimopodi bideni:

  1. Syllipsimopodi is about 4-3/4 inches (12 cm) long.
  2. It had a torpedo-shaped body and a squid-like appearance.
  3. It also is the oldest-known creature with suckers, which enable the arms to better grasp prey and other objects.
  4. It represents the only member of the octopus lineage with 10 arms, meaning two were lost in later evolution.
  5. The fossil helps in understanding how octopuses evolved.
  6. The preserved fossil reveals two parallel rows of suckers up and down each arm, dating to about 328 million years ago.
  7. Syllipsimopodi pushes back by 82 million years the origins of a group called vampyropods that includes today's octopuses.

Note: Vampyropods are soft-bodied cephalopods typically characterized by eight arms and an internalized chitinous shell or fin supports.

  1. "Syllipsimopodi" means "prehensile foot" - its arms are an evolutionary modification of the foot of mollusks -- and "bideni" recognizes U.S. President Joe Biden, who had just been inaugurated when the study was submitted for publication.
  2. Capture of prey is facilitated by the two longer tentacles with the eight shorter arms helping to manipulate the prey and transport it to the beak.
  3. Syllipsimopodi prowled the warm waters of a tropical bay - Montana at the time was situated close to the equator.
  4. It may have been a mid-level predator, eating smaller invertebrates.
  5. Syllipsimopodi lived during the Carboniferous Period, a time of important evolutionary changes in other marine life that included the appearance of more modern-looking fishes.

About Octopuses:

  1. Octopuses are the most intelligent invertebrates, and among the most intelligent animals overall.
  2. Octopuses, ranging from the one-inch (2.5 cm) star-sucker pygmy octopus to the 30-foot (9-meter) giant Pacific octopus, are known for their otherworldly appearance, with bulbous heads, large eyes and beak-like jaws.
  3. They have three hearts and blue blood, they squirt ink to deter predators, and being boneless, they can squeeze into (or out of) tight spaces.
  4. They are adept at camouflage - changing colors and even textures to mimic their surroundings - and can maneuver their bodies into tiny cracks and crevices.
  5. They also are capable of tool use and problem-solving.
  6. They are cephalopods, a marine invertebrate group dating back to roughly 530 million years ago and distinguished by having arms or tentacles.

Note: Cephalopods are a group of marine invertebrates that include octopuses, squids and cuttlefish.