Sparganophilus sp. (unidentified)
A tube-building worm in the Seagrass Meadow, filmed in December 2024 inside a glass-wall tunnel extending tentacle-like structures to capture food; eleven days later it had left the burrow and was moving in the open, which the observer flagged as possibly a stress response.
A tube-building worm found in the Seagrass Meadow, identified by the observer as Sparganophilus. On December 12, 2024, it was filmed for the first time inside a tunnel constructed against the tank glass, with tentacle-like structures extending outside the tube. On December 23, 2024, the worm had left the burrow and was out in the open; the observer flagged this as unusual behavior, possibly a stress response. The identification is tentative and the "tentacle" feeding behavior described does not match typical oligochaete biology; the possibility that this is a polychaete worm is noted.
**If Sparganophilus (Oligochaeta)**
Sparganophilus is a genus of aquatic and semi-aquatic oligochaetes, related to earthworms but adapted to life in or near freshwater. They burrow in soft sediments of streams and riverbanks, and some species can tolerate temporary immersion in water. They are deposit feeders, ingesting sediment and processing organic matter as they burrow, in the manner of most oligochaete worms. Sparganophilus do not build structured tubes (in the architectural sense) and do not extend feeding tentacles; deposit feeding occurs through simple sediment ingestion while burrowing.
Finding Sparganophilus in a marine saltwater environment (Seagrass Meadow) would be highly unusual. The genus is strictly freshwater to semi-aquatic, and saltwater would be inhospitable under natural conditions. This raises the question of whether the miniBIOTA worm was introduced as a freshwater or terrestrial hitchhiker in substrate or plant material and survived in an unexpected location, or whether the identification is incorrect.
Several marine polychaete families build tubes against hard surfaces (including glass) and extend feathery radioles or tentacles from the tube opening to capture suspended particles. Sabellidae (feather duster worms) and Serpulidae (calcareous tube worms) are common in marine systems and are commonly introduced to saltwater aquaria. If the miniBIOTA worm is a tube-building sabellid or serpulid, the December 12, 2024 video description ("tunnel constructed against the glass, tentacles extending outside to capture prey or food") would be entirely consistent with normal behavior. Sabellidae and Serpulidae are suspension filter feeders, not deposit feeders.
The December 23, 2024 observation of the worm "out in the open" and outside its tube is less consistent with sabellid behavior (which are tube-obligate) but could represent a stressed or displaced individual. The observer's own note flags this as unusual.
If the identification is correct and the worm is an oligochaete, it would function as a sediment deposit feeder in the Seagrass Meadow, processing organic particles and contributing to nutrient cycling in the substrate. This role would complement Hair Worm, Southern Lugworm, and other Seagrass Meadow infaunal worms.
If the worm is a tube-building polychaete, its role would be as a suspension filter feeder, drawing suspended particles from the water column, an ecologically distinct role closer to the barnacle and mussel community than to the deposit-feeding guild.
No introduction record is on file. The worm was first observed on December 12, 2024, building a tunnel against the Seagrass Meadow glass. No deliberate introduction is documented; the worm most likely arrived as a hitchhiker in seagrass, substrate, or live rock material.
First observed December 12, 2024 in a self-constructed tunnel against the Seagrass Meadow glass, with tentacle-like structures extending from the tube opening to capture food; video recorded. Observed December 23, 2024 outside the burrow and moving in the open; observer noted this as unusual and possibly a stress response. Likely the same individual in both observations. No further observations on file. Introduction route unknown; probable hitchhiker in substrate or plant material.
Feeding method and trophic role are uncertain pending identity confirmation. The December 2024 observation described tentacle-like structures extending from the tube to capture food, which is more consistent with suspension filter feeding (polychaete) than with deposit feeding (Sparganophilus/Oligochaeta). If deposit feeding, the worm would complement Hair Worm and Southern Lugworm in the Seagrass Meadow infaunal guild. If suspension filter feeding, it would occupy a niche similar to Cerith Snail and Marine Copepod.
The combination of Seagrass Meadow (saltwater) location and the tentative identification as Sparganophilus (normally freshwater) creates an unresolved ecological tension. If this is a polychaete, standard marine invertebrate tolerance ranges apply. No measurements on record.
No reproductive observations in miniBIOTA. Only one individual has been documented across two observation events.
No ecological interactions involving Sparganophilus have been documented in miniBIOTA beyond the two December 2024 observations. The worm was observed alone; no predation, competition, or mutualism events are on record.
Follow this species across the habitats where it currently appears in the miniBIOTA biosphere.
