Partenskyella glossopodia gen. et sp. nov., the first report of chlorarachniophyte that lacks pyrenoid

S Ota, D Vaulot, F Le Gall, A Yabuki, K Ishida

Abstract

A new chlorarachniophyte, Partenskyella glossopodia gen. et sp. nov., is described from a culture isolated from the Mediterranean Sea pelagic waters and maintained as strain RCC365 at the Roscoff Culture Collection (France). Vegetative cells of P. glossopodia are non-motile naked spherical cells. However, flagellate and amoeboid stages are also present in its life cycle. The cells are 2–4 μm in diameter containing a pale-green, cup-shaped chloroplast, 1–2 mitochondria, a nucleus, and a Golgi apparatus. Vesicles containing storage product-like material are also present. The chloroplast is surrounded by four membranes possessing a nucleomorph in the periplastidal compartment. The minute cell size and the absence of a pyrenoid at any stage of the life cycle are unique characteristics among the chlorarachniophytes, which justifies our proposition for a new genus for strain RCC365.