Daniel and Kelly’s Extraordinary Universe Listener Questions #33
Mar 19, 2026
They tackle bizarre parasites like tongue worms, the fish-tongue–replacing parasite, Loa loa, and raccoon roundworm. They trace fossil clues and host shifts that hint at ancient parasite journeys. They unpack why SI units were redefined, from cesium clocks to fixing the speed of light. They also share nightmare-inducing parasite tales and risks from invasive pythons.
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Ancient Tongue Worms Are Crustacean Relatives
- Pentastomid tongue worms are crustacean-related, wormlike parasites that use hooked head projections to anchor in reptile lungs and suck blood.
- Fossil larvae date to ~485 million years ago, suggesting either ancient parasitism or later shift from free-living ancestors to vertebrate hosts.
Fossils Suggest Tongue Worms Shifted Hosts Over Time
- Fossil evidence shows pentastomid larvae at the Cambrian-Ordovician boundary but not attached to hosts, so their host range likely changed over time.
- A 425-million-year-old specimen attached to an ostracod suggests an aquatic origin and later host shifts into fish and tetrapods.
Watch Introduced Hosts To Track Emerging Pentastomids
- Pentastomids are understudied because they mainly infect wildlife not economically important livestock, pets, or humans in many regions.
- Monitor non-native species spread (e.g., Burmese pythons in Florida) because introduced hosts can bring novel pentastomids into new ecosystems.