Larvacean

Part of speech: noun

Definitions

1. A type of marine invertebrate belonging to the class Larvacea, known for its unique larval stage that resembles a tadpole
2. An organism that filters seawater for food using a mucous house made of secreted materials
3. A member of an order within the subphylum Tunicata, characterized by its free-swimming lifestyle and distinctive body structure

Etymology: Larvacean is a plain scientific coinage: it is simply the Latin-style name "Larvacea" with the English suffix "-an" added, the same ending that turns "Rome" into "Roman" or "Victoria" into "Victorian". "Larvacea" is the name of the order itself, so a larvacean is literally a member of that group. The formal name is built from the Latin "larva" (a ghost or mask, later a larval or immature form), and it was given to these animals by naturalists who classified them, not by the Romans, who had no concept of such creatures. The name points to the animals' distinctive lifecycle. Adult larvaceans look like tadpole-shaped swimmers that keep their larval-looking body into adulthood, which is why the root "larva" was chosen for the order's name. Their drifting, free-swimming habit and the gelatinous house they build around themselves to filter food from seawater are features that the name does not describe, but they are what make the group notable to marine biologists.