Phylum Round 1

Cycliophora: An incredibly specialized phylum, the Cycliophorans consist of a single genus. These animals live exclusively on the mouthparts of lobsters. Yes, all Cycliophorans. This is considered a commensal relationship, as the lobster is not harmed by the Cycliophorans' presence. This phylum has an interesting reproductive strategy involving cloned dwarf versions of the male, embryos that drain all nutrients from the mother, and larvae that must be strong swimmers to hopefully re-colonize the host lobster's new exoskeleton whenever it molts.

Gnathostomulida: Jaw Worms. All animals in this phylum are "meiofauna", meaning they live in the spaces between grains of sediment on the seafloor. They are covered in hair-like cilia, which aids in navigating their micro-environment. As the name implies, they have a strong set of jaws, often with tiny teeth for grinding food. They are hermaphroditic, and strangely, each "lays" a single egg that breaks through the parent's body wall and adheres to a nearby grain of sand. Thankfully, the parent is able to quickly heal from this wound. These animals are important for maintaining chemical cycles between the sediment and water above, and they are a rich food source for higher organisms in the bottom-dwelling food chain. They are also very sensitive to pollution, making them important "bio-indicators".