Tolypothrix pseudorexia Novis & Visnovsky, 2011

Novis, Phil M. & Visnovsky, Gabriel, 2011, Novel alpine algae from New Zealand: Cyanobacteria, Phytotaxa 22 (1), pp. 1-24 : 14-16

publication ID 10.11646/phytotaxa.22.1.1

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Tolypothrix pseudorexia Novis & Visnovsky

sp. nov.

Tolypothrix pseudorexia Novis & Visnovsky , sp. nov. ( Figs 5A–N View FIGURE 5 )

Trichomata heteropolaria uniseriata, cellulis 10–20 µm latis, 2–7 µm longis, semper brevioribus quam latioribus, materia contenta grandulari, ad parietes transversales subconstricta. Heterocyta plerumque ad basibus ramorum atque hormogoniorum, interdum in paribus intercalaribus disposita, parte parietis singulari polari incrassata. Vagina pallide brunnea , 1–2 µm crassa. Post divisionem trichomatum ad heterocyta lateraliter pseudoramificans. Thylakoides peripherales sed interdum ad centrum cellulae implicatae. Hormogonia primo progressu isopolari, deinde heteropolari post progressum heterocyti ad terminum alterum ex quo crescentia tunc terminata est; hic terminus saepe ad trichoma aliud per pulvillum mucilaginosum connectens, pseudoramum prolongentem saepe angulo recto divergentem formans. Trichomata varie in superficie agari prostrata atque erecta .

Type:— NEW ZEALAND. Westland : Mt Philistine, 1400 m, preserved cultured specimen from sample collected 30 November 2007, CHR610792 View Materials .

Trichomes heteropolar and uniseriate, cells 10–20 µm wide, 2–7 µm long, always shorter than wide, contents granular, slightly constricted at transverse walls ( Fig. 5B–L View FIGURE 5 ). Heterocytes usually at bases of branches and hormogonia ( Fig. 5B–D, H View FIGURE 5 ), occasionally in intercalary pairs ( Fig. 5F View FIGURE 5 ), with single polar wall thickening. Light brown sheath, 1–2 µm thick. False branching lateral, occurring after trichome division at heterocytes ( Fig. 5B, E View FIGURE 5 ). Thylakoids peripheral, but may be infolded towards cell centre ( Fig. 5N View FIGURE 5 ). Hormogonia with isopolar development initially ( Fig. 5G View FIGURE 5 ), becoming heteropolar following the development of a heterocyte at one end ( Fig. 5H View FIGURE 5 ), from which growth then ceases ( Fig. 5I View FIGURE 5 ); this end often attaches to another trichome via a mucilage pad to form a lengthening pseudobranch, often at a right angle ( Figs 5K, L View FIGURE 5 ). Trichomes variously prostrate and erect on agar surface ( Fig. 5A View FIGURE 5 ).

Habitat:— Aerophytic crust on greywacke rock surface, 1640 m, associated with alpine Trentepohlia sp.

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

Etymology:— Resembling the genus Rexia .

Observations:— Erect trichomes are unusual in Tolypothrix , more resembling the species Rexia erecta ( Casamatta et al. 2006) , and suggestive of adaptation to an aerophytic habitat. However, the hormogonia of Rexia can divide in two planes; exhaustive searching of T. pseudorexia failed to establish the occurrence of this feature. The 16S–23S intergenic spacer sequence also differs somewhat from that of Rexia (although differences with published Tolypothrix species are also present). 16S rDNA data were not obtained. However, we also note that this part of the 16S rDNA phylogeny has not been well resolved in the past ( Casamatta et al. 2006).

Culture:— LCR-CYTR.

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