realized I hadn’t fed my Geonemertes in two weeks, so I offered it an isopod. didn’t expect to see it strike, so the video isn’t the sharpest, but what a cool way of hunting!
the worm fires its sticky proboscis like a harpoon, presumably injecting venom at some point.
this is Geonemertes pelaensis, one of a scant few terrestrial examples of a mostly marine phylum (Nemertea). it’s an invasive species in the US and elsewhere, implicated in lowering counts of some soil arthropods.
Common Atlantic Ribbon Worm (Tubulanus polymorphus)
Family: Tubulanus Family (Tubulanidae)
IUCN Conservation Status: Unassessed
Like other ribbon worms, this brightly coloured marine worm has a relatively long but extremely thin unsegmented body, and is an active predator; after locating prey using a set of chemical-sensing pits on its head it extends a sticky, flexible, tube-like appendage known as a proboscis (although unlike the proboscises of some insects this structure is separate from their digestive system) from just above its mouth, ensnaring prey and injecting it with paralysing venom. After prey (mainly smaller marine invertebrates, especially other worms) has been subdued the proboscis either passes it into a simple mouth or, if its too large to be swallowed whole, secretes fluids that break food down externally to accommodate for the worm's lack of an ability to chew.
hello my dears... springtail rides a microscopic ribbon worm!
i found this really tiny ribbon worm on a leaf, and you can tell just how tiny with the springtail in picture for scale
i love the ribbon worm's beady little eyes (it actually has four of them! but two are smaller and harder to see). this ribbon worm, with its dark brown body colour consisting of small white flecks, most closely matches a specimen collected from Luzon in Philippines, i.e. the species is still uncertain
as for the springtail, it's also really cute! but its also hard for me to say what kind they are, due to their extremely small size and diversity
Nemertea: Ribbon Worms. These simple organisms are mostly seafloor-dwelling, but some may live in freshwater or even on land. Most are predators of small invertebrates, but some are herbivorous or symbiotic with a host. Instead of crawling, Nemerteans secrete a thick mucus and use thousands of tiny hair-like cilia to glide across the slimy surface. Their most distinctive feature is their internal proboscis, which can be everted inside-out of their bodies and used to capture prey.
Ctenophora: Comb Jellies. The largest animal phylum to swim using hair-like cilia. Their cilia are arranged in rows, called combs or ctenes, down the length of their body. The cilia move in a wave-like pattern that generates colorful reflecting light shows. Almost all Ctenophores are predators of small plankton as they drift in the ocean. They inhabit a variety of marine habitats from the coastal intertidal to the open ocean.
Animals in the Phylum Nemertea, commonly known as “Ribbon Worms” or “Proboscis Worms,” are small and mostly slim with a venomous proboscis that everts just above to mouth to capture prey.
There are about 1,300 known species of nermertean. Most nemerteans are carnivores, feeding on annelids, clams, and crustaceans. Some species are scarvengers. Some species are filter feeders that utilize a sucker at the front and back ends of their bodies to attach to a host. Most nemerteans detect the world through the use of chemoreceptors, but some species have simple eyes that allow them to distinguish light from dark. They move slowly, using cilia to walk on a trail of slime. Some larger species can “slither.” Many are brightly colored and patterned. Most nemerteans are marine, living in either the open ocean or on the sea floor, but some species are freshwater, and some are even terrestrial.
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Previously, nemerteans were split into two groups by whether they had a “little dagger” on their proboscis or not. (This classification no longer applies as one of the “unarmed” orders was closer related to the “armed” group than the rest of the “unarmed” group. It’s still fun to imagine worms with little daggers tho.)
The Bootlace Worm (Lineus longissimus) (seen in the first image) is one of the longest known animals, with specimens up to 55 m (180 ft) long being reported. This is longer than the Lion’s Mane Jellyfish, the sauropod dinosaurs Argentinosaurus and Patagotitan, and the record-holding longest Blue Whale. Like other nemerteans, the Bootlace Worm can also stretch up to 10 times its resting length. They’re not considered the largest animals though, because they’re only 5 to 10 mm (0.20 to 0.39 in) wide!
As a defense against predators, the Bootlace Worm produces a toxic mucus which contains a strong neurotoxin and smells faintly of “iron or sewage.” The mucus has been shown to kill arthropods, and is being studied for its use as a natural pesticide.
Some larger species can regenerate, breaking into pieces when disturbed, after which the fragments can grow into full individuals!
Some nemerteans have a branched proboscis that comes out as a “mass of sticky spaghetti” that can then be used to pull prey into its mouth. If you love horror movies, this is the animal for you! I’m not easily grossed out, but I genuinely can’t stomach this video, so viewer discretion is advised! (Thankfully, this one didn’t have a “little dagger.”
Distribution: Widely distributed in the cold southern seas surrounding Antarctica, as far north as Peru.
Habitat: Epibenthic and marine; found in intertidal zones down to depths of 3590 metres.
Diet: Scavenger and predator; feeds on detritus diatoms, gastropods, amphipods, isopods, vertebrate carrion, sponges, jellyfish, seastars, molluscs, anemones and polychaete worms.
Description: P. corrugatus is a huge ribbonworm that can grow up to 2 metres in length. Like all ribbonworms, this species does not have a dedicated respiratory system, instead breathing through its skin; animals who breathe this way are typically quite small so the oxygen can reach every part of their body, which makes this worm's size even more impressive. Luckily, the Southern ocean is oxygen-rich, and the ribbonworm has a slow metabolism that uses up little oxygen. When it starts to lack oxygen, it flattens itself out to maximize oxygen diffusion throughout its body.
Despite its size, P. corrugatus still has predators. In order to defend itself, it has a proboscis it can deploy in moments, covered in barbs and adhesives (which it also uses to hunt its prey!). If this isn't enough to dissuade predators, it also has an acidic mucus with a pH of 3.5.
