Holotype: NMV F82728, microslide preparation of fertile colony mounted in Malinol, Geelong Arm of Port Phillip Bay, Victoria, Australia 38°06'S 144°30Έ, depth 12 m.
Paratype: NMV F82729, microslide preparation of infertile colony mounted in Malinol, Geelong Arm of Port Phillip Bay, Victoria, Australia 38°06’S 144°30Έ, depth 12 m.
The specific name, troglodyta, refers to the cryptic, burrow-dwelling habit of the species.
Colonies minute, hydrorhiza consisting of one or two short intersecting stolons creeping on inside of worm tube; stolons thin, knobbly, transparent, sediment grains embedded in perisarc.
Hydrorhiza supporting one or two hydranths on pedicels of varying length, perisarc thin, varying from almost smooth to wrinkled or rugose, terminating in a swollen, collar-like gelatinous theca supporting the hydranth.
Hydranth long, spindle-shaped, very extensile; hypostome conical, mouth quadrate, surrounded by a single whorl of 14 long, moniliform tentacles, a large intertentacular web between bases of tentacles.
Hydranth with two kinds of nematocysts:
i) Abundant small macrobasic mastigophores arranged in circlets around tentacles; capsule 6-7 x 1-1.5 µm, butt 10-12 µm long, tube long and thin.
ii) Larger, less abundant ?haplonemes in body of hydranth, around hypostome and in pedicel; capsule 11-12 x 2-2.5 µm, tube insufficiently discharged for measurement. Medusa bud borne on a long pedicel below hydrotheca, proximal part of pedicel sheathed in perisarc, stalk thereafter long, naked; gonophore with a very thin, transparent ovoid sheath rounded apically, the developing medusa clearly visible inside.
Colour: Colonies and medusa buds transparent and colourless.
Southeastern Australia (Victoria).
Subtidal, inhabiting polychaete burrows in soft sediments.