Micrasterias jenneri var. semicirculare G.J.P.Ramos & C.W.N.Moura, 2019
publication ID |
https://doi.org/ 10.11646/phytotaxa.391.3.2 |
DOI |
https://doi.org/10.5281/zenodo.13727247 |
persistent identifier |
https://treatment.plazi.org/id/FB1D87F6-FFCF-FFC9-FF7D-D719FB472366 |
treatment provided by |
Felipe |
scientific name |
Micrasterias jenneri var. semicirculare G.J.P.Ramos & C.W.N.Moura |
status |
var. nov. |
Micrasterias jenneri var. semicirculare G.J.P.Ramos & C.W.N.Moura , var. nov. ( Figs 51–54 View FIGURES 51–65 )
Diagnosis— This variety differs from the nominate variety by having a semicircular outline, with lateral lobes broadly rounded, whereas M. jenneri var. jenneri has an oblong outline and lateral lobes concave. Another difference from the nominate variety is the incision between the lateral lobes that is about the same size as the incision between the apical and basal lobes, being shorter in the nominate variety
Cell dimensions: length 145–165 μm, breadth 109–123 μm, apical lobe 32–64 μm, isthmus 32–36 μm.
Holotype: material numbered ( HUEFS 244148 About HUEFS !) deposited at Herbário da Universidade Estadual de Feira de Santana , population illustrated here in LM ( Figs 51–54 View FIGURES 51–65 ).
Etymology: The epithet refers to semicircular outline of the cells.
Type locality and habitat characteristics: Collected at “Vale do Capão”, Palmeiras, Bahia state, Brazil. Lat. 12º 30’ 31” S, Long. 41º 29’ 10” W. Sample collected by G. J. P.Ramos s/n ( HUEFS 244148) on 26 February 2017. Micrasterias jenneri var. semicirculare occurred in periphyton, with quiet and warm waters, associated to filamentous algae.
Notes: Micrasterias jenneri Ralfs (1848: 76) has been rarely reported in floristic studies in South America, and the few existing records are from material collected in Brazil ( Bicudo & Ventrice 1968, Bicudo & Picelli-Vicentim 1988, Moresco et al. 2009, Bicudo et al. 2015), and generally identified as Micrasterias jenneri var. simplex West (1890: 287) .
Tomaszewicz (1977) and Sormus (1991) discussed the relationships between the nominate variety and var. simplex , and concluded that the latter variety is a developing morphological expression (i.e., an immature form) of the former, in which the lateral lobes have not undergone a division process. Currently, Micrasterias jenneri var. simplex is considered a taxonomic synonym of Micrasterias jenneri Ralfs ( Guiry & Guiry 2018) .
Regarding the new variety, Micrasterias jenneri var. semicirculare , a population analysis (ca. 50 specimens examined) indicated that the semicircular outline, broadly rounded in the lateral lobes, is consistent and distinct from the nominate variety (which has an oblong outline) described by Ralfs. The lateral lobes are also slightly different, being more concave in the nominate variety than in var. semicirculare . We therefore consider those features sufficient to propose this taxon as a new variety.
Micrasterias jenneri var. semicirculare can be confused with M. denticulata Brébisson ex Ralfs (1848: 70) , although the latter differs mainly by having lateral subdivided into lobules of the third or fourth order.
LM |
Secçáo de Botânica e Ecologia |
G |
Conservatoire et Jardin botaniques de la Ville de Genève |
J |
University of the Witwatersrand |
P |
Museum National d' Histoire Naturelle, Paris (MNHN) - Vascular Plants |
HUEFS |
Universidade Estadual de Feira de Santana |
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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Micrasterias jenneri var. semicirculare G.J.P.Ramos & C.W.N.Moura
Ramos, Geraldo José Peixoto, Costa, Fabiana De Matos, Santos, Maria Aparecida Dos & Moura, Carlos Wallace Do Nascimento 2019 |
Micrasterias jenneri var. semicirculare
Ralfs, J. 1848: ) |