Like modern octopuses:
Researchers have revealed the soft tissues of a 165-million-year-old ammonite fossil using 3D imaging.
They found that the now-extinct molluscs sported hyponomes: tube-like syphons through which water is expelled to jet propel animals forward in water, as found in modern squid and octopuses. They also found strong muscles that ammonites used to retract into their shells to defend against predators…
The findings add insight into how ammonites lived and provide evidence that coleoids, the sub-group of animals containing squid, octopuses, and cuttlefish, might be evolutionarily closer to ammonites than previously thought.Imperial College, London, “Ammonite muscles revealed in 3D from Jurassic fossil” at ScienceDaily (December 8, 2021) The paper is closed access.
Is “might be evolutionarily closer to ammonites than previously thought” another way of saying that a complex system developed much earlier than thought?
At The Scientist: The spider web as a “giant engineered ear” As Dan Robitzki puts it, they “outsource” their hearing to the web (like the web was a microphone?) Quoted at The Scientist: “Evolutionarily speaking, spiders are just weird animals,” Jessica Petko, a Pennsylvania State University York biologist who didn’t work on the new study, writes in an email to The Scientist. “While it has been long known that spiders sense sound vibration with sensory hairs on their legs, this paper is the first to show that orb weaving spiders can amplify this sound by building specialized web structures.”