Mateola curvata (Nordstedt) Coesel, Algological Studies

Araújo, Camila Barbosa de, Bicudo, Carlos Eduardo de Mattos, Takiyama, Luís Roberto & Melo, Sérgio de, 2020, Pseudofilamentous desmids (Zygnematophyceae) from an Amazonian floodplain lake (Macapá, AP, Brazil), Iheringia, Série Botânica (e 2020010) 75, pp. 1-14 : 9

Mateola curvata (Nordstedt) Coesel, Algological Studies 86: 15. 1997.

Desmidum curvatum Nordstedt , Lunds Universitets Årsskrift 25: 1, pl. 1, fig. 4-6. 1889.

( Fig. 18 )

Cell 1.4 times longer than broad, 29-35 μm long, 20- 32 μm broad, 7-8 μm broad at the apex, and 18-19 μm broad at the isthmus. Semicells subquadrate with 4 conical lobes that curved upwards and diverging from each other at first and then converging between lobes of adjacent cells; slightly narrower apex; deep median constriction; wide open median sinus; hyaline to brown cell wall; axial chloroplast.

Material examined: BRAZIL, AMAPÁ, Macapá, Curralinho Lake , 12.II.2008, C.B. Araújo (SP469224), 13.V.2008, C.B. Araújo (SP469227) .

Comments: this species is easily identified, due to its semicells morphology with 4 conical lobes curved upward, divergent or convergent shape between adjacent cells, and apex slightly narrower than the rest of the semicell. Salisbury (1936) considered this species morphologically different from all other desmids species (including all Desmidium taxa). Thus, he proposed a new genus named Mateola and Mateola acutiloba Salisbury as species type. However, this new proposition was taxonomically unacceptable because the latter material was already used by Norsdstedt (1889) when he proposed Desmidium curvatum Norsdstedt. Coesel (1997) examined vegetative cells and sexual stages of this species from material collected in French Guiana. He observed a reasonable number of cell division stages, identifying a unique cell division septum to define the new genus Mateola . According to Coesel (1997), the conjugation process occurs via formation of elongate conjugation tubes, followed by the fusion of emerging gametes in between the mating gametangial cells, as well as the smooth walled compressed-globose zygospores. For Coesel (1997), in fact, there are two good reasons to consider Mateola a good genus, as follows: (1) D. curvatum species is morphologically distinct; and (2) this species does not show any particular ultrastructure like pore patterns present in other Desmidium species. Thus, the present study is in agreement with Coesel (1997) that Desmidum curvatum should be considered the basionym, and Mateola acutiloba should be considered synonym of Mateola curvata .

Distribution in Brazil: Bahia ( Oliveira 2011); Pará ( Scott et al. 1965, Förster 1969, Thomasson 1971); São Paulo (Nordstedt 1889); Federal District ( Leite & Senna 1992).

Figures

Figs. 16-23. Pseudofilamentous desmids of Curralinho Lake, Macapá,Amapá, Brazil. 16 A-B. Hyalotheca dissiliens var. dissiliens. A. fungi in the cell wall of the algae, B. detailed cells; 17 A-B. H. javanica. A. detailed pseudofilament, B. detailed cells; 18. Mateola curvata; 19 A-B. Phymatodocis nordstedtiana var. nordstedtiana f. minor. A. pseudofilament frontal view, B. pseudofilament lateral view; 20. Spondylosium desmidiiforme; 21. S. pulchrum var. pulchrum; 22. S. rectangulare var. rectangulare; 23 A-B. S. rectangulare var. goyazense, detailed cells and pseudofilaments. Scale bars = 10 µm.