title: Kraftionema allantoideum, a new genus and family of Ulotrichales (Chlorophyta) adapted for survival in high intertidal pools.
abstract: The marine, sand-dwelling green alga Kraftionema allantoideum gen. et sp. nov. is described from clonal cultures established from samples collected in coastal, high intertidal pools from south eastern Australia. The species forms microscopic, uniseriate, unbranched, 6-8 μm wide filaments surrounded by a gelatinous capsule of varying thickness. Filaments are twisted, knotted, and variable in length from 4 to 50 cells in field samples but straighter and much longer in culture, up to 1.5 mm in length. Cell division occurs in several planes, resulting in daughter cells of varying shape, from square to rectangular to triangular, giving rise to gnarled filaments. Mature cells become allantoid, elongate with rounded ends, before dividing one time to form bicells comprised of two domed cells. Adjacent bicells separate from one another and mature filaments appeared as a string of loosely arranged sausages. A massive, single, banded chloroplast covered 3/4 of the wall circumference, and contained a single large pyrenoid encased in a starch envelope that measures 1.5-2.5 μm. Filaments were not adhesive nor did they produce specialized adhesive cells or structures. Reproduction was by fragmentation with all cells capable of producing a new filament. No motile or reproductive cells were observed. Filaments in culture grew equally well in freshwater or marine media, as well as at high salinity, and cells quickly recovered from desiccation. Phylogenetic analysis based on the nuclear-encoded small subunit ribosomal RNA (18S) shows the early branching nature of the Kraftionema lineage among Ulotrichales, warranting its recognition as a family (Kraftionemaceae).
authors.affiliation: School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Wetherbee
authors.affiliation: School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia.
authors.forename: Heroen
authors.initials: H
authors.lastname: Verbruggen
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D059001:Aquatic Organisms / Q000145:classification* / Q000235:genetics / Q000648:ultrastructure; D000460:Chlorophyta / Q000145:classification* / Q000235:genetics / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D009517:New South Wales; D010802:Phylogeny; D048030:RNA, Algal / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017423:Sequence Analysis, RNA; D013045:Species Specificity; D014739:Victoria
chemical_list: D048030:RNA, Algal; D012337:RNA, Ribosomal, 18S
keywords: 
  Kraftionema
  ; 18S nuclear ribosomal DNA; Chlorophyta; Kraftionemaceae; Ulotrichales; molecular phylogeny; sand dwelling