Phycokey - Roya

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Name derivation:

Classification:
Roya West and G.S.West 1896; 5 of 11 species descriptions are currently accepted taxonomically (Guiry and Guiry 2013). Order Desmidiales; Family Desmidiaceae (Or: Order Zygnematales ; Family Mesotaeniaceae ) Roya classification is uncertain, was placed in the Zygnematales (along with Mougeotia, Spirogyra, and Xanthidium and others, although the genus has affinities with the placoderm desmids (Brook and Williamson 2010). Roya is the only saccoderm desmid known to possesses loroxanthin. This could mean that the genus is closely related to the placoderm desmids. The presence of loroxanthin indicates a more advanced species (Donohue and Fawley 1995). Roya obtuse contains a plastid tRNA^Leu group-I intron, evidence of an RNA-world as the RNA is capable of self-splicing and removal of itself from genomes (Besendahl et al. 2000). Evidence suggests that Roya is a more derived genus as they are a part of the Desmidiales; however, the genus is relatively unadvanced as it was derived before others in the Desmidiales (McCourt et al. 2000).
Morphology:
Cells solitary, small to medium sized (22-195 µm), elongate-cylindric (length 4-60 times width), slightly curved or straight, with broadly rounded or truncate ends. Chloroplast an axial ribbon with row of up to 12 pyrenoids; cells with two chloroplast observed. Nucleus parietal at middle of cell (often in median notch in chloroplast), or between chloroplasts, if two present. Ultrastructure of cell wall two layered. Asexual reproduction only by transverse cell division. Sexual reproduction by conjugation known for 2 species (Guiry and Guiry 2013).
Similar genera:
Several genera of cylindrical placoderm desmids can be confusing until somewhat minor variations in wall shapes and decor are scrutinized. The most common include Docidium, Gonatozygon, Penium, Pleurotaenium, Roya and Triploceras.
Habitat:
Freshwater, oligotrophic, somewhat acidic ponds and bogs.

References:
Besendahl, A., Y. Qiu, J. Lee, J.D. Palmer and D. Bhattacharya 2000. The cyanobacterial origin and vertical transmission of the plastid tRNA^Leu group-I intron. Current Genetics 37(1): 12-23. Brook, A.J., and D.B. Williamson 2010. A monograph on British Desmids: Families Mesotaeniaceae, Peniaceae, Closteriaceae. Ray Society, London. Donohue, C.M. and M.W. Fawley 2008. Distribution of the xanthrophyll loroxanthin in desmids (Charophyceae Guiry, M.D. and G.M. Guiry 2013. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 22 May 2013. McCourt, R.R., K.G. Karol, J. Bell, K.M. Helm-Bychowski, A. Grajewska, M.F. Wojciechowski and R.W. Hoshaw 2000. Phylogeny of the conjugating green algae (Zygnemophyceae) based on the rbcL sequences. Journal of Phycology 36: 747-758. West, W. & West, G.S. 1896. On some new and interesting freshwater algae. Journal of the Royal Microscopical Society 16: 149-165.

Name derivation:

Roya West and G.S.West 1896; 5 of 11 species descriptions are currently accepted taxonomically (Guiry and Guiry 2013). Order Desmidiales; Family Desmidiaceae

(Or: Order Zygnematales ; Family Mesotaeniaceae )

Roya classification is uncertain, was placed in the Zygnematales (along with Mougeotia, Spirogyra, and Xanthidium and others, although the genus has affinities with the placoderm desmids (Brook and Williamson 2010).

Roya is the only saccoderm desmid known to possesses loroxanthin. This could mean that the genus is closely related to the placoderm desmids. The presence of loroxanthin indicates a more advanced species (Donohue and Fawley 1995).

Roya obtuse contains a plastid tRNA^Leu group-I intron, evidence of an RNA-world as the RNA is capable of self-splicing and removal of itself from genomes (Besendahl et al. 2000).

Morphology:

Similar genera:

Habitat:

References:

Name derivation:

Roya West and G.S.West 1896; 5 of 11 species descriptions are currently accepted taxonomically (Guiry and Guiry 2013). Order Desmidiales; Family Desmidiaceae

(Or: Order Zygnematales ; Family Mesotaeniaceae )

Roya classification is uncertain, was placed in the Zygnematales (along with Mougeotia, Spirogyra, and Xanthidium and others, although the genus has affinities with the placoderm desmids (Brook and Williamson 2010).

Roya is the only saccoderm desmid known to possesses loroxanthin. This could mean that the genus is closely related to the placoderm desmids. The presence of loroxanthin indicates a more advanced species (Donohue and Fawley 1995).

Roya obtuse contains a plastid tRNALeu group-I intron, evidence of an RNA-world as the RNA is capable of self-splicing and removal of itself from genomes (Besendahl et al. 2000).

Morphology:

Similar genera:

Habitat:

References:

Roya obtuse contains a plastid tRNA^Leu group-I intron, evidence of an RNA-world as the RNA is capable of self-splicing and removal of itself from genomes (Besendahl et al. 2000).