Godleya alpina Novis & Visnovsky, 2011

Novis, Phil M. & Visnovsky, Gabriel, 2011, Novel alpine algae from New Zealand: Cyanobacteria, Phytotaxa 22 (1), pp. 1-24 : 14

Godleya alpina Novis & Visnovsky , gen. et sp. nov. ( Figs 4A–N )

Trichomata isopolaria uniseriata, cellulis 7–15 µm lata, 2.5–5 µm longa, semper brevioribus quam latioribus, materia contenta grandulari, ad parietes transversales subconstricta. Cellulae terminales rotundatae. Heterocyta ad utrumque polum intercalaria, interdum ante fragorem trichomatum geminata. Vagina pallide brunnea vel rufobrunnea usque ad 2 µm crassa. Pseudorami rariores, interdum laterales, maximam partem binarii per fragorem inter cellulas vegetativas, saepe post formationem flexus praesentes. Thylakoides peripherales in latum crescentes. Hormogonia plerumque longitudine cellularum 2–4, progressu isopolari. Trichomata in superficie agari prostrata.

Type:— NEW ZEALAND. Westland : Mt Philistine, 1400 m, preserved cultured specimen from sample collected 30 November 2007, CHR610793 .

Trichomes isopolar and uniseriate, cells 7–15 µm wide, 2.5–5 µm long, always shorter than wide, contents granular, slightly constricted at transverse walls ( Figs 4A–G ). Terminal cells rounded ( Fig. 4H ). Heterocytes intercalary with wall thickenings at each pole ( Fig. 4E ), occasionally paired prior to trichome fragmentation ( Fig. 4F ). Light brown to reddish-brown sheath up to 2 µm thick. False branching uncommon, occasionally lateral ( Fig. 4C ), mainly binary through fragmentation between vegetative cells ( Fig. 4D ), often occurring after loop formation ( Fig. 4I ). Thylakoids peripheral and widened ( Fig. 4N ). Hormogonia usually 2–4 cells long, with isopolar development ( Figs 4J–M ). Trichomes prostrate on agar surface ( Fig. 4A ).

Habitat:— Alpine herbfield soil, 1640 m, associated with scattered Chionochloa sp.

Distribution:— Mt Philistine, Arthur’s Pass National Park, New Zealand.

Etymology:— Named after the illustrious New Zealand botanist Dr Eric Godley.

Observations:— This species is difficult to classify. Although the isopolar trichomes, hormogonial development, and type of false branching suggest the family Scytonemataceae , 16S rDNA data group Godleya with an Antarctic specimen of Coleodesmium in the family Microchaetaceae . Results of the Bayesian analysis further unite this group into a clade with other representatives of this family ( Fig. 1 ). The family Microchaetaceae is characterised by heteropolar trichome development ( Komárek & Anagnostidis 1989), which is not seen in Godleya , the false branching of which is also characteristic of Scytonemataceae . One possibility is that Coleodesmium sp. ANT.LH52B.5 is a misidentified member of the Scytonemataceae ; the descriptive material available for this strain ( Taton et al. 2006) lacks information on development of hormogonia or type of false branching. On the other hand, sequences from Scytonema and Scytonematopsis fall into a robustly supported clade in our analysis (albeit including some other taxa; Fig. 1 ). If our interpretation of the molecular results is correct, the morphological features presently used to delimit the Scytonemataceae may be phylogenetically questionable.

Komárek & Anagnostidis (1989) note that microchaetacean taxa often form scytonematoid branching in culture. Superficially this could partly explain our results. However, the heterocytes with two pores and the strictly isopolar development of the trichomes, the latter especially a diacritical feature of Scytonemataceae , suggest otherwise.

Cultures:— LCR-CY2, LCR-CYTOL.

Figures

FIGURE 1. Phylogenetic analysis of selected Nostocales inferred from 16S rDNA sequences. Sequences contributed in this study are in bold. The tree typology is that inferred using MRBAYES v3.0B4 (5 million generations). Numbers associated with nodes are Bayesian PP/MPB percentages (500 replicates); these are shown only when PP> 0.94. Scale bar represents 0.1 changes per site.

FIGURE 4. Godleya alpina Novis & Visnovsky (photographed from cultures LCR-CYTOL and LCR-CY2). A–M light micrographs, N transmission electron micrograph, A. Typical tapered, curved, isopolar trichomes; heterocytes are lacking in 10% BG-11 medium. B. False branching sometimes results in more than two emergent branches (arrows). C. Tolypothrix-like false branching (arrow indicates base of false branch). D. Scytonematoid false branching, especially common in older cultures. E. Culturing on distilled water agar results in development of intercalary heterocytes (h) with two thickened poles. F. Adjacent intercalary heterocytes occur prior to trichome division (arrow). G. Trichomes as a whole are seldom straight around the tapered central region. H. Trichome ends are usually straight and untapered. I. Loop formation (arrow) precedes scytonematoid-type branching. J–M. Hormogone development is strictly isopolar. N. Cells in longitudinal section showing sheath (s) and peripheral thylakoid membranes (tm), which are widened. Scales: 50 µm in B (use for A–M), 1 µm in N.