A unique sessile loricate euglenid, Lepocinclis loricata sp. nov. (Euglenophyta, Phacaceae), from South Africa: Evolutionary implications

Abstract

In this paper, we describe Lepocinclis loricata sp. nov. (Phacaceae), a sessile loricate euglenid that differs from all known loricate taxa by its unique combination of the presence of a lorica, monad morphology, sessile habit, and phylogenetic position within the Phacaceae. Populations of this species inhabit two turbid, silt-rich waterbodies, namely an artificial impoundment in the Western Cape Province and a natural, small river in the Free State Province, South Africa. The cylindrical, transparent loricae of L. loricata sp. nov. are attached to fine clay and silt particles suspended in the water column. Each lorica encloses a rigid, spindle-shaped monad containing numerous chloroplasts without pyrenoids and two large, rod-like paramylon grains. Phylogenetic analyses place L. loricata sp. nov. within the Lepocinclis clade, representing a loricate euglenid identified in the family Phacaceae. This discovery provides new insight into the diversification and adaptive evolution of photosynthetic euglenids and the independent emergence of sessility within the group.