Triangulopteris

Triangulopteris (from Latin triangulus 'triangular' and Greek πτερόν 'wing') is a genus of centrohelids, single-celled amoebae that are generally covered with scales or spicules. It contains one species, Triangulopteris lacunata (from Latin lacuna 'hole'), which was described in 2021 from soil samples obtained across geographically distant Ukrainian and Russian territories. This species is one of the few representatives of centrohelids in poorly studied soil microbial ecosystems. The type strain, HF-25, was isolated from permafrost.

Triangulopteris lacunata cells are usually covered by two kinds of silica scales: plates cales and spine scales. The organism is distinguished from other centrohelids by the appearance of its spine scales, which are composed of a basal plate from which a thin shaft emerges, surrounded by two lateral wings. Their unique characteristic consists of two 'pockets' formed between the wings and the basal plate, which has not been observed in any other centrohelid. After several years, the type strain was reported to lose its normal scales and developed thin organic spicules instead, a phenomenon reported in a few other centrohelids.