Cosmarium diamantinum G.J.P.Ramos & C.W.N.Moura, 2019

Ramos, Geraldo José Peixoto, Costa, Fabiana De Matos, Santos, Maria Aparecida Dos & Moura, Carlos Wallace Do Nascimento, 2019, Taxonomic novelties, new records, and rare species of desmids from the Chapada Diamantina region, Brazil, Phytotaxa 391 (3), pp. 185-196 : 186-187

publication ID

https://doi.org/ 10.11646/phytotaxa.391.3.2

persistent identifier

https://treatment.plazi.org/id/FB1D87F6-FFC9-FFCC-FF7D-D323FA8026E6

treatment provided by

Felipe

scientific name

Cosmarium diamantinum G.J.P.Ramos & C.W.N.Moura
status

sp. nov.

Cosmarium diamantinum G.J.P.Ramos & C.W.N.Moura , sp. nov. ( Figs 2–6 View FIGURES 2–27 )

Cells somewhat longer than wide; semicells subtriangular, with a deep median constriction; sinus distinctly open; lateral margins divergent; upper margin straight to slightly rounded, semicells elliptic in apical view, semicells in lateral view with a widely oblong outlines; semicell wall covered with sharp granules arranged in 3 slightly curved rows near the apices, median region smooth, with 1 row of granules in the isthmus region. Zygospores not observed. Cell dimensions: length 36–38 μm, width 32–35 μm, isthmus 10–12 μm.

Holotype: material numbered ( HUEFS 244147 About HUEFS !) deposited at Herbário da Universidade Estadual de Feira de Santana , population illustrated here in LM ( Figs 2-6 View FIGURES 2–27 ).

Etymology: The epithet refers to diamond, main mineral from Chapada Diamantina region.

Type locality and habitat characteristics: Collected at Pico das Almas, Rio de Contas , Bahia state, Brazil. Lat. 13º 31’ 20” S, Long. 41º 55’ 56” W. Sample collected by A. V. F. Lima s/n ( HUEFS 244147 About HUEFS ) on 01 May 2011. Cosmarium diamantinum occurred in an ephemeral puddle in the mountain GoogleMaps ;

Notes: The new species is similar to Cosmarium furcatum Kurt Först. & F.Eckert (1964: 391) , though the latter differs by having a pair of bifurcated spines at the angles, in addition to a uniformly ornamented cell wall, and being half the size of the former. Due to the angular spines, Förster (1964) had difficulty accommodating the species in the genus Cosmarium when it was first described, suggesting that it might be some representative of another genus, such as Staurastrum .

The ornamentation pattern of Cosmarium diamantinum is interesting, with slightly curved rows of sharp granules near apices, whereas the mid-region of the semicell lacks ornamentation. In addition, it presents an ornamentation formed by a row of granules in the region of the isthmus, which is well detached in the lateral view ( Fig.5 View FIGURES 2–27 ).

LM

Secçáo de Botânica e Ecologia

A

Harvard University - Arnold Arboretum

V

Royal British Columbia Museum - Herbarium

F

Field Museum of Natural History, Botany Department

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