Bicudoa amazonica C.E. Wetzel, Lange-Bertalot & Ector,

Wetzel, Carlos E., Lange-Bertalot, Horst, Morales, Eduardo A., Bicudo, Denise De C., Hoffmann, Lucien & Ector, Luc, 2012, Bicudoa amazonica gen. nov. et sp. nov. (Bacillariophyta) - a new freshwater diatom from the Amazon basin with a complete raphe loss in the Eunotioid lineage, Phytotaxa 75 (1), pp. 1-18: 7-9

publication ID

http://doi.org/ 10.11646/phytotaxa.75.1.1

DOI

http://doi.org/10.5281/zenodo.5067809

persistent identifier

http://treatment.plazi.org/id/C727879B-FF87-4C18-01DE-DAC9FD1AF871

treatment provided by

Felipe

scientific name

Bicudoa amazonica C.E. Wetzel, Lange-Bertalot & Ector
status

sp. nov.

Bicudoa amazonica C.E. Wetzel, Lange-Bertalot & Ector  sp. nov.

Diagnosis microscopio photonico: Frustula aspectu cinguli fere rectangulata. Valvae late ellipticae, lineari-ellipticae ad lineares apicibus cuneatis denique curte rostratis. Valvae dorsiventrales quia ad axem apicalem leviter ad levissime asymmetricae margine una semper convexa altera modice concava in mediis partibus quoad specimina media et maiora. Longitudo 40–120 μ m, latitudo 17–20 μ m. Area axialis (id est sternum) angustissima plerumque excentrica sita. Areae angustae marginales prope limbos adsunt. Alterae areae absunt. Systema raphidea nulla. Striae transapicales, sicut in Eunotia  , subparallelae saepe plusminusve irregulariter sitae inter se, sub apices transientes distincte radiantes, 10–12 in 10 μ m, sub apices modice densius sitae usque ad 16 in 10 μ m. Interstriae comparate latiores. Areolae vix aspectabiles quia circiter 75–80 in 10 μ m. Structura chromatophorum incognita. Diagnosis microscopio electronico: Aspectus externus: Frontes  valvarum fere planae cum foraminibus areolarum uniseriatis omnino comparate minimis circularibus (hic apertis) diameter circiter 0.1 μ m. Series foraminum curte interruptae sterno angustissimo et latius interruptae ad iuncturam inter frontem et limbum valvae ubi series apicalis spinarum verrucosa num est tum series continuantes in limbis. Campi porellorum absunt. Aspectus internus: Superficies  interna perforata areolis circularibus crateriformibus apertis. Depressiones transapicales id est alveoli vacant. Systema raphidea ut in familia Eunotiaceae  sive ut in familia Bacillariaceae  nulla. Etiam rimoportulae et porelli apicales ut in familia Fragilariaceae  et alteris familiis diatomearum araphidearum vacant. Cingulum frustulorum: cingulum utraeque valvae 3–10 copulis apertis vel clausis constans. Omnes copulae preditae multis areolis uniseriatis transapicaliter (vel quodammodo pervalvariter ita ut in Eunotia nec  in familia Fragilariaceae  vel alteris familiis araphideis).

Light microscopy observations: —Valves isopolar, moderately dorsiventral, broadly linear with slightly constricted center in large specimens; cuneate to sub-rostrate ends ( Figs 7–13View FIGURES 7–20). Dorsal margins consistently convex. Ventral margins variable, either less concave in small valves or nearly straight to concave in mediumsized and large specimens. Length 40–120 µm, width 17–20 µm. Axial area or sternum extremely narrow, sometimes displaced toward ventral side of valve ( Fig. 8View FIGURES 7–20) or centrally positioned ( Fig. 9View FIGURES 7–20). Narrow lateral area located close to the valve margins, visible in both valves and girdle view. Raphe system, helictoglossae and rimoportulae lacking. Transapical striae subparallel often irregularly spaced, 10–12 in 10 µm, becoming radiate toward the ends where they are more densely spaced (up to 16 in 10 µm) ( Fig. 12View FIGURES 7–20). Costae comparatively much wider. Areolae observable in LM. Plastids unknown. Frustules rectangular in girdle view ( Fig. 14View FIGURES 7–20). Cells forming band-like colonies (no more than 4 joined cells observed).

Scanning electron microscope observations: —In external view, valve face slightly curved with a shallow longitudinal depression near the valve center ( Fig. 21View FIGURES 21–27). Striae uniseriate situated both on valve face and mantle, interrupted by lateral area developing on the junction between valve face and mantle ( Figs 22–25View FIGURES 21–27). Areolae small, circular with foramina ca. 0.1 µm in diameter ( Fig. 22View FIGURES 21–27). Each foramen lies in a shallow depression visible in oblique view ( Figs 23–25View FIGURES 21–27). Valve face showing wart-like growths and siliceous thickenings, which allow the connection between contiguous valves ( Fig. 25View FIGURES 21–27). Sternum narrow, sometimes displaced toward the ventral side of the valve. Apical pore fields absent. The cingulum is composed of 3–10 open copulae that are perforated by pervalvar multiporoid striae arranged in discernible rows ( Fig. 27View FIGURES 21–27). Girdle band areolae density 75–80 in 10 µm. A small linear depression is present near the apex at the junction between valve face and mantle. In both external and internal view, rimoportulae are always absent. Internally, but never in external view, one raphe slit vestige is present in some specimens ( Figs 28, 30–31View FIGURES 28–32), but in most cases it is completely lacking ( Figs 28 and 32View FIGURES 28–32).

Type: — BRAZIL. Amazonas: Rio Negro basin, Alto Rio Negro , 0° 30’ 43’’ S, 64°49’45’’W, 11 March 2005; Wetzel C. E. & Ector L., sample n° 265; Holotype here designated SP –400.480, depicted here in Fig. 8View FIGURES 7–20, deposited at the ‘ Herbário Científico do Estado Maria Eneyda P. Kauffmann Fidalgo’( SP), São Paulo, Brazil. Sample from feces of an adult specimen of the freshwater turtle Podocnemis erythrocephala Spix (1824)  . Isotypes: slide BR –4167 (Meise) and slide BM –101392 (London).GoogleMaps 

Etymology: —The new genus is dedicated to Prof. Dr. Carlos Eduardo de Mattos Bicudo at the ‘Instituto de Botânica de São Paulo’ for his pioneering work on freshwater microalgae in Brazil and for the relevant role on the formation of Brazilian phycologists; ‘ amazonica’ refers to the type locality.

Additional material examined: — BRAZIL. Amazonas : Rio Negro basin, Alto Rio Negro, 03 March 2005; Wetzel C  . E  . & Ector L  ., phytoplankton, sample n° 82; SP–400.297; BRAZIL. Amazonas : Rio Negro basin, Alto Rio Negro, 04 March 2005; Wetzel C  . E  . & Ector L  ., periphytic biofilm growing on submerged Arecaceae  palm tree, sample n° 104; SP–400.319; BRAZIL. Amazonas : Rio Negro basin, Alto Rio Negro, 04 March 2005; Wetzel C  . E  . & Ector L  ., phytoplankton, sample n° 106; SP–400.321; BRAZIL. Amazonas : Rio Negro basin, Alto Rio Negro, 04 March 2005; Wetzel C  . E  . & Ector L  ., periphytic biofilm growing on a submerged trunk, sample n° 116; SP–400.331; BRAZIL. Amazonas : Rio Negro basin, Alto Rio Negro, 04 March 2005; Wetzel C  . E  . & Ector L  ., phytoplankton, sample n° 117; SP–400.332; BRAZIL. Amazonas : Rio Negro basin, Alto Rio Negro, 11 March 2005; Wetzel C  . E  . & Ector L  ., phytoplankton, sample n° 260; SP–400.475; BRAZIL. Amazonas : Rio Negro basin, Alto Rio Negro, 11 March 2005; Wetzel C  . E  . & Ector L  ., phytoplankton, sample n° 261; SP–400.476.

C

University of Copenhagen

E

Royal Botanic Garden Edinburgh

L

Nationaal Herbarium Nederland, Leiden University branch

SP

Instituto de Botânica

P

Museum National d' Histoire Naturelle, Paris (MNHN) - Vascular Plants

BR

Embrapa Agrobiology Diazothrophic Microbial Culture Collection

BM

Bristol Museum