Cymbella tropica Krammer, 2002

Silva, Weliton Jose da, Jahn, Regine, Ludwig, Thelma Alvim Veiga, Hinz, Friedel & Menezes, Mariangela, 2015, Typification and taxonomic status re-evaluation of 15 taxon names within the species complex Cymbella affinis / tumidula / turgidula (Cymbellaceae, Bacillariophyta), PhytoKeys 53, pp. 1-25 : 9

Cymbella tropica Krammer Figs 64-70

Cymbella tropica Krammer, Diatoms Europe 3: 61, Figs 44:1-10, 49: 12, 13, 2002.

Holotype.

Preparation 1015D IOK, in the Alfred-Wegener-Institut für Polar- und Meeresforschung (BRM), Bremerhaven, Germany.

Lectotype

(designated here). An individual on preparation 1015D IOK, in the Alfred-Wegener-Institut für Polar- und Meeresforschung (BRM), Bremerhaven, Germany, represented by Fig. 64 .

Type locality.

Venezuela, Rio Manizanes, coll. Rumrich, 4.4.1990.

Valves lanceolate, dorsiventral, dorsal and ventral margins convex; ends barely protracted, rounded, or subcapitate, slightly deflected to ventral margin; length 34.5-42.7 µm, breadth 10.0-12.0 µm, L/B ratio 3.1-4.0; axial area linear, arched, central area indistinct to slightly rounded; striae 9-12 in 10 µm, becoming 11-12 toward ends, 1 isolated pore; 21-24 punctae in 10 µm.

Remarks.

Krammer (2002) described Cymbella tropica and recorded differences in the size, length/breadth ratio, and the presence of only one stigma as consistent diagnostic differences between this species and Cymbella turgidula . Tuji (2007) recorded the occurrence of specimens of Cymbella turgidula with 1-3 isolated pores, which was also observed by Krammer (2002) in his material. We observed a continuum between the metric characteristics of Cymbella tropica and Cymbella turgidula , even in those characters that were considered by Krammer (2002) as differentiating. However, the outline was more lanceolate, the ends more protracted and slightly deflected to the ventral side, and the degree of dorsiventrality was lower in Cymbella tropica compared to Cymbella turgidula .

Figures

Figures 64 - 70. Cymbella tropica Krammer from Venezuela in preparation 1015 D IOK, holotype 64 Lectotype, designated here. Scale bar: 10 µm.