Three new species of Cymbellales (Bacillariophyceae) from Réunion Island

Abstract

Recent surveys of the epilithic diatoms of Réunion Island led to the discovery of three new species: Crucicostulifera bebourensis, Encyonopsis cilaosensis, Encyonopsis palmeti. Crucicostulifera bebourensis is the second species to be included in this recently described genus typified by Crucicostulifera areolata (Hustedt) Taylor & Lange-Bertalot. Both species share the main diagnostic features of the genus. However, Crucicostulifera bebourensis differs from Crucicostulifera areolata (Hustedt) Taylor & Lange-Bertalot in the cingulum composed of at least three open bands whereas the latter species has a single valvocopula on each valve. Encyonopsis cilaosensis and Encyonopsis palmeti can be differentiated from other Encyonopsis species by a combination of characters including valve outline, number of striae in l0 µm, maximum length/breadth ratio, areolae structure and presence or absence of intermissio. Both new species show a particular organization of the cingulum. Crucicostulifera bebourensis occurs in acidic waters with very low conductivity and nutrient concentration. Encyonopsis cilaosensis is found in alkaline waters with high conductivity whereas Encyonopsis palmeti is reported from slighty alkaline waters with low conductivity.

Encyonopsis indonesica sp. nov. (Bacillariophyceae, Cymbellales), a new diatom from the ancient lake Matano (Sulawesi, Indonesia)

“…Though described less than a quarter of a century ago, over 170 taxa have been assigned to Encyonopsis (Kociolek et al 2020). Many taxa were transferred by Krammer (1997b) from other genera in his initial circumscription of the genus, but since then new species of the genus have been described from western North America (Bahls 2013;Graeff and Kociolek 2013;Kociolek et al 2014;Mark et al 2019), Central America (Wydrzycka and Lange-Bertalot 2001), South America (Metzeltin and Lange-Bertalot 2007;Wengrat et al 2015), Europe (Van de Vijver et al 2012;Kennedy et al 2019), Asia (Krammer 2003;Potapova et al 2014), Madagascar (Metzeltin and Lange-Bertalot 2002), and Reunion Island (Le Cohu et al 2014).…”