Four new Planothidium species (Achnanthidiaceae, Bacillariophyceae) from the Karst region of Guizhou in China

By

Li, Yun 李沄
Lu, Lin-Xin
Zhou, Huiwen
Yu, Pan
Kociolek, John Patrick
Pang, Wanting
Wang, Quan-Xi
You, Qingmin

Type

Article

Date of Publication

2025-6-25

Original Publication

PhytoKeys

Volume

259

Pages

81--102

Subjects

Diatoms , karst , monoraphid , new taxa , Planothidium , taxonomy

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers [2010]-

Identifiers

DOI: https://doi.org/10.3897/phytokeys.259.150757

 

Abstract

Four new species of monoraphid diatoms belonging to the genus Planothidium were studied and described from the karst region of Guizhou Province, China. The morphological characteristics of these new species were observed and documented using light and scanning electron microscopy. Planothidium pseudoreichardtiisp. nov. exhibits a broad sinus at the central area on the interior of the rapheless valve, linear shallow depressions and a unique enlarged areola at the end of the striae on the exterior rapheless valve. Planothidium liboensissp. nov. is characterized by 4–5 rows striae on both valves, a cavum at the central area on the interior rapheless valve and irregular depressions on the exterior rapheless valve. Planothidium angustirostratumsp. nov. features elliptical valves with narrowly rostrate apices, a cavum at the central area of interior rapheless valve and circular depressions on the exterior rapheless valve. Planothidium maolanensissp. nov. has elliptical valves without protracted apices, coarsely-spaced striae on the one side of the central area of the both valves. These four new species were compared with other similar Planothidium taxa. In addition, ecological information was provided and the stability of some features was discussed.