New fossil genus and new extant species of diatoms (Stephanodiscaceae, Bacillariophyceae) from Pleistocene sediments in the Neotropics (Guatemala, Central America): adaptation to a changing environment?

  • Several taxa of Stephanodiscaceae were found in the upper section of Pleistocene sediments from Lake Petén-Itzá (Guatemala). A new fossil genus Cyclocostis Paillès gen. nov. and new extant species Discostella gabinii Paillès & Sylvestre sp. nov. are described. Cyclocostis gen. nov. is characterized by a strongly tangentially undulated valve surface, coarse unequal striation reaching a central punctum in the valve center, an absence of central lamina and domed criba, widely open alveoli with one median recessed costa bearing marginal fultoportulae and a single rimoportula all within a ring. A single valve face fultoportula is present on the raised part of the valve opposite the rimoportula. Differences relative to similar genera and the delimitation of a new genus are discussed. Discostella gabinii sp. nov. is distinguished by circular and flat valves, a small central area bearing 5 to > 30 scattered large areolae giving a colliculate appearance, medium-sized alveoli, marginal fultoportulae on every 4–5th costa, a single rimoportula and internally smooth valve center. Differences to similar taxa in the genus Discostella are discussed. The succession of the species of Cyclotella, Discostella and Cyclocostis gen. nov. in our record could represent eco-phenotypic responses to particular environmental stress / change.

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Author:Christine Paillès, Florence Sylvestre, Alain Tonetto, Jean-Charles Mazur, Sandrine Conrod
Parent Title (English):European journal of taxonomy : 726:1-23
Series (Serial Number):European journal of taxonomy : EJT (726:1-23)
Publisher:Muséum National dHistoire Naturelle
Place of publication:Paris
Document Type:Part of Periodical
Date of Publication (online):2020/11/30
Date of first Publication:2020/11/30
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2020/12/01
Tag:Cyclocostis rolfii; Discostella gabinii; Guatemala; Pleistocene; Stephanodiscaceae; diatom; genus
Page Number:23
First Page:119
Last Page:23
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 59 Tiere (Zoologie) / 590 Tiere (Zoologie)
Sammlungen:Sammlung Biologie / Sondersammelgebiets-Volltexte
Licence (German):License LogoCreative Commons - Namensnennung 4.0