Staurastrum bicudoi C.B.Araújo, 2023

Staurastrum bicudoi C.B.Araújo , sp. nov.

Description: Cells as long as broad; semicells with divergent and step processes; the processes run towards the base out into parallel sides with three concentric rows of widely spaced granules, terminating in five small spines; apex visible and triradiate; sinus shallow and open; isthmus with a single or two rows of sharp granules; the ornamentation consists of fine thorns; vertical view triradiate; membrane hyaline. Cells 21–30 μm long (with processes), 15–20 μm (without processes), 14–18.5μm wide (with processes), 7.0–9.5 μm (without processes), 5.0–6.5 μm isthmus width.

Holotype: Material numbered ( SP428487 ) [other organisms present], a formaldehyde-fixed sample deposited in the Herbário Científico do Estado ‘Maria Eneyda P. Kauffmann Fidalgo – SP’, at the Instituto de Pesquisas Ambientais, São Paulo, São Paulo State, Brazil. Population partially illustrated here from light microscopy ( Figs 1–4 View Figs 1–8 ).

Type locality: Brazil. São Paulo: Itirapina Municipality, a small pond covered by Sphagnum sp. , located in the “ Reserva Experimental de Itirapina ”, Lat. 22°13.836ʹS, Long. 47°49.165ʹW, 22 May 2017, C.B. Araújo ( SP428487 ).

PhycoBank Registration: http://phycobank.org/103632

Habitat: This new species was found in the study area associated to Sphagnum sp. ; Electrical conductivity (EC): 0.012 mS/cm, pH: 4.39, Oxygen dissolved (OD): 12.69 mg /L, Water temperature (WT): 22.51ºC.

Etymology: The epithet honours the eminent Brazilian phycologist Dr Carlos Eduardo de Mattos Bicudo, for his inestimable contribution to the dissemination of knowledge of phycology, especially desmids, in Brazil and America.

Distribution in Brazil: This species was noted in the Amazon region as Staurastrum donellii Kurt Förster ( Förster 1963: Serra da Lua, Roraima State, fig. 5); Staurastrum pseudozonatum [ var. minutum ] f. rectum Kurt Förster & Eckert ( Förster 1964: Rio das Femmeas, Tocantins State, fig. 6); Staurastrum donnellii var. simplex Croasdale & A.M.Scott ( Scott & al. 1965: Vigia Municipality, Pará State, fig. 7); Staurastrum pseudozonatum var. minutissimum Kurt Förster ( Förster 1969: “Igarapé Mapiri” and “Lago Jurucuí”, Santarém Municipality, Pará State, fig. 8) and the present study (Itirapina Municipality, São Paulo State, figs 1-4).