Holotype: NMV F147463, Station 103, two microslides displaying several infertile stems. On sertulariid hydroid, 437m depth, Australian Antarctic territory [67°03'S 74°29'E].
Paratypes: NMV F147464, two microslides displaying stems; NMV F147476, one microslide displaying a small colony. On sertulariid hydroid, 437m depth, Australian Antarctic territory [67°03'S 74°29'E].
The species name, ‘elegantulum’ refers to the elegantly simple hydrocaulus.
Stems arising from a creeping hydrorhiza; stolons tubular, smooth to crumpled.
Hydrocaulus minute, variable in length, simple, unbranched, walls cylindrical, narrow, smooth, without nodes but with occasional shallow constrictions marking zones of regrowth after breakage. Hydrocaulus with either a single terminal hydrotheca or a linear series of up to six hydrophores each arising from diaphragm of preceding hydrotheca; base of hydrophore swollen above supporting diaphragm.
Hydrotheca moderately deep, trumpet-shaped, expanding strongly from diaphragm to margin; rim circular, weakly outrolled; no replication of margin. Diaphragm delicate, transverse to concave, no desmocytes visible.
Perisarc thickest in proximal stem region, thinning distally; very thin on hydrotheca.
Antarctica.
Subtidal, epiphytic on hydroids.