Pseudococcomyxa simplex (Mainx) Fott, 1981

Novis, Phil M. & Visnovsky, Gabriel, 2012, Novel alpine algae from New Zealand: Chlorophyta, Phytotaxa 39, pp. 1-30 : 25

Pseudococcomyxa simplex (Mainx) Fott

Reference: Novis et al. 2008: 353–354, Fig 3A–I .

Observations:— Previously, only data for rbc L were available for this species from Mt Philistine. The 18S data presented here show that Pseudococcomyxa simplex from Mt Philistine is a close relative of P. simplex UTEX 274 ( Fig. 8 ). Both of these strains belong to a clade that includes species of Coccomyxa as well as Paradoxia spp. This clade is distinct from a second clade comprising other species of Coccomyxa ; clearly this genus is polyphyletic and requires revision. Interestingly, the oblique division plane characteristic of Pseudococcomyxa ( Broady 1987, Novis et al. 2008) is also evident in Paradoxia multiseta Svirenko 1928 during vegetative division ( Hegewald & Reymond 1987). Some species currently regarded as Coccomyxa , such as C. confluens (Kützing) Fott 1974 , appear to share this feature (Ettl & Gärtner 1995), although how it is distributed phylogenetically is presently unclear. It may be a morphological feature that can be used to separate the two clades.

Figures

FIGURE 3. Cryptodesmus ellipsoideus (photographed from culture LCR-CG7). A–D, light micrographs, E, F, transmission electron micrographs. A. Cells of varying age, size and shape in agarised culture. B. Cells often form autosporangia (arrows) of 2–4 autospores. C. More rarely, larger sporangia form (arrows), containing 8 or 16 autospores. D. Remnant mother cell walls (mc) are commonly observed in cultures. E. The chloroplast (cp) is parietal, containing starch (st) and a single prominent pyrenoid (pyr), which has a starch sheath with few segments (sp) and often a single thylakoid (tm) traversing the matrix. Small protrusions (pro) are visible on the external surface of the cell wall. F. The membranes surrounding dividing cells are layered and convoluted (arrows). Scales: 10 µm in A (use for A–D), 1 µm in E and F.

FIGURE 8. Phylogenetic analysis of the Trebouxiophyceae inferred from 18S 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). Scale bar represents 0.1 changes/site.