Tunifilids (Class Tunifilida) are a group of microsyntherids (kingdom Microsynthera) of phylum Aluminestrae. Despite their classification under Aluminestrae, tunifilids generally have steel cores, not aluminum. They are characterized by their steel core(s), coated in membrane(s) of other material.

The membranes of tunifilids fully conceal and envelop the core, and the body must be evenly pliable throughout its length. In addition to these qualifications, tunifilids are found coiled around a substrate or in linear form. With these delineations, pipe cleaners are not tunifilids due to their uneven membrane, and coated paper clips are not tunifilids due to their semi-rigid shape and odd structure. Electrical wire is not included due to their non-steel cores.

Tunifilids have several common names, including “twisty tie”. A group of tunifilids may be referred to as a “tangle” (e.g. “a tangle of tunifilids”).

ADDENDUM (July 4th, 2026): It has come to our attention the existence of “Pseudotunifillids” with completely plastic cores. These are not in class Tunifilida, and are not of phylum Aluminestrae. Rather, they are of phylum Plasticae. The formal description of this group is pending.

Ecology

Tunifilids are often found on the following substrates:
– Around bags of bread, other produce
– Closing the plastic wrappers of large lollipops
– Attaching the bows to the tops of gift bags
– Attaching plant stems to stakes
– Closing bundles of cords

Many tunifilids serve a similar niche to occlupanids, and may replace them in certain environments.

Life Cycle

Tunifilids are hermaphrodites and possess two forms of reproduction: Asexual and sexual. Asexual reproduction occurs when tunifilids are left undisturbed for long periods of time, allowing the body to grow to incredible lengths. Often, these long tunifilids grow around a substrate, “spool”, before smaller segments break off as new tunifilids.

Sexual propagation is less often observed in most tunifilids, except Dipapyra vulgaris. There are at least two modes of development after fertilization. In the first kind, a fertilized tunifilid finds a substrate, often a confined location under an overhang, and excretes an adhesive. Live kin are birthed on this nutritious adhesive, and develop on the substrate until they are ready to break off and find a host. The other mode of development involves a fertilized tunifilid finding a suitable nest, before laying kin directly into the nest. These kin then grow without the aid any substrate or adhesive.

Once mature, tunifilids search for suitable hosts, where they feed, continue to develop, and search for mates.