• Tollana1234567@lemmy.today
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    7 days ago

    sponges and cnidarians beat them to it, 500-600million years. and jellyfish have been exploding in numbers all over due to temperature rises, generally more tolerant to pollution than fishes, and lack of too many predators.

    • binux@sh.itjust.works
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      7 days ago

      Those aren’t quite as specified as horseshoe crabs though (which are a taxonomic family, just above genus and species respectively). Sponges and jellyfish are both much more varied and encompass more than one class.

      Similarly I can say that Reptiles beat horseshoe crabs since they’ve been around at least ~50 million years longer than the latter, but that wouldn’t really be a fair comparison because they encompass far more species than just horseshoe crabs. Regarding lasting a long time evolutionarily while staying relatively undiversified, horseshoe crabs are still uniquely notable. They aren’t called living fossils for nothing.