Xanthidium concinnum var. longispinum M.A.Santos & C.W.N.Moura, 2022

Santos, Maria Aparecida Dos, Ramos, Geraldo José Peixoto & Moura, Carlos Wallace Do Nascimento, 2022, Taxonomic notes on genera Bourrellyodesmus and Xanthidium (Zygnematophyceae) from Chapada Diamantina, Bahia, Brazil, Phytotaxa 536 (3), pp. 228-242 : 231-236

publication ID

https://doi.org/ 10.11646/phytotaxa.536.3.3

DOI

https://doi.org/10.5281/zenodo.6343761

persistent identifier

https://treatment.plazi.org/id/5921D53A-FFF9-AC08-47A8-F96AFD9AFCCA

treatment provided by

Plazi

scientific name

Xanthidium concinnum var. longispinum M.A.Santos & C.W.N.Moura
status

var. nov.

Xanthidium concinnum var. longispinum M.A.Santos & C.W.N.Moura var. nov. ( Figs 2 View FIGURES 1–6 , 17–24 View FIGURES 8–30 )

Diagnosis:—It differs from the nominate variety by having a long spine in each lateral margin, a pair of minute spines on the apical margin, and the face of the semicells has a central protrusion, ornamented with a spine with an inflated base. Cell dimensions: length without spines 11–13 μm, with spines 12–16 μm, width without spines 9–14.6 μm, with spines18–23 μm, thickness 8–9 µm, isthmus 3–4 μm, lateral spines 3.5–5.3 μm long.

Holotype:—Material numbered ( HUEFS 253751 About HUEFS !) [pro parte], deposited at Herbarium of State University of Feira de Santana. Population partially illustrated here ( Figs. 2 View FIGURES 1–6 , 17–24 View FIGURES 8–30 ).

Paratypes:—Material numbered ( HUEFS 253744 About HUEFS , HUEFS 253747 About HUEFS ) [pro parte], deposited at Herbarium of State University of Feira de Santana .

Type locality:— BRAZIL. Bahia: Andaraí, Marimbus do Baiano, Lagoa do Baiano , Lat. 12°45’33.2” S, Long. 41°18’29.1” W, 18 February 2018, M. A GoogleMaps . Santos , J. T . X. Neto & F. M . Costa s/n ( HUEFS 253751 About HUEFS ) .

Habitat:—The new species was rarely found in the study area, occurring generally associated to periphyton of Cabomba caroliniana and Utricularia foliosa ; EC 0.01 mS. cm-1 (±0.01); DO 6.4 (±0.7); TDS 0.02 (±0.02); pH 6.9 (±0.4); T 32° C (±0.5); WT 63 cm (±20.7).

Etymology:—The varietal epithet refers to the long spines present in the lateral margins of semicells.

Differential diagnosis:—Morphologically, the newly described variety resembles Xanthidium concinnum var. boldtianum West (1892: 167 , as ‘ boldtiana ’) and Xanthidium concinnum var. scottii C.E.M.Bicudo in Prescott et al. (1982: 62). However, the former differs by having no short apical spines on each apical angle and central obtuse protrusion on the face of semicells, whereas the latter differs by having downward-projected spines at the lateral margins and the mid-region of the semicells.

Xanthidium concinnum var. longispinum should be compared to X. concinnum var. guyanense Thérézien (1985: 121) , an endemic variety from French Guiana, which differs mostly by lacking the crown of small spines surrounding the lateral spine.

We also observed variation in spines dimensions in the apical angles, from longer (2.5–3 μm long) to shorter (0.3–1 μm long), which is difficult to view. The spine on the lateral margin of the semicells can be slightly or widely converging, and sometimes measuring approximately 1/3 of the width of the cell.

In addition to Bahia, the var. longispinum has been registered in the State of Mato Grosso do Sul by Paula et al. (2014: 428, figs. 50, 51), but as a misapplied name X. concinum W. Archer (1883: 285) , based on specimens collected from the Upper Paraná River floodplain.

M

Botanische Staatssammlung München

A

Harvard University - Arnold Arboretum

J

University of the Witwatersrand

T

Tavera, Department of Geology and Geophysics

F

Field Museum of Natural History, Botany Department

DO

Société d'Agriculture Sciences et Arts

C

University of Copenhagen

Kingdom

Plantae

Phylum

Charophyta

Class

Conjugatophyceae

Order

Zygnematales

Family

Desmidiaceae

Genus

Xanthidium

Loc

Xanthidium concinnum var. longispinum M.A.Santos & C.W.N.Moura

Santos, Maria Aparecida Dos, Ramos, Geraldo José Peixoto & Moura, Carlos Wallace Do Nascimento 2022
2022
Loc

Xanthidium concinnum var. longispinum

Therezien, Y. 1985: )
1985
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