Tetracyclus rupestris

(Braun ex Rabenh.) Grunow in Van Heurck 1885      Category: Araphid
BASIONYM: Denticula thermalis var. rupestris Kütz. 1849
SYNONYM(S): Gomphogramma rupestre (Kütz.) Braun in Rabenh. 1853 

Tetracyclus hinziae


Thalassiosira baltica

LM scalebar = 10 µm = 80 pixels.


Contributor: Ian Bishop - January 2016
Length Range: 8-22 µm
Width Range: 4.7-8.4 µm
Striae in 10 µm: 24-28


Valves are elliptic-lanceolate, with broad, unconstricted apices. The axial area is wide and indistinct. Striae are parallel, with individual erratic striae that intrude into the axial area. Costae are primary and robust, and become inflated and relatively indistinct in axial area; 3-4 in 10 µm. A single rimoportula is present at one valve end. Girdle bands are incomplete. Septae extend approximately 1/4 of the way into the valve, and alternate orientation from one band to the next.

Original Description

Basionym: Denticula thermalis var. rupestris
Author: Kütz. 1849
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Bishop, I. (2016). Tetracyclus rupestris. In Diatoms of the United States. Retrieved April 19, 2018, from http://westerndiatoms.colorado.edu/taxa/species/tetracyclus_rupestris

Species: Tetracyclus rupestris

Contributor: Ian Bishop

Reviewer: Sarah Spaulding


Kützing, F.T. (1849). Species Algarum. Lipsiae. F.A. Brockhaus, 922 pp.

Van Heurck, H. (1881). Synopsis des Diatomées de Belgique. Atlas. Ducaju & Cie., Anvers. pls 31-77.

Van Heurck, H. (1885). Synopsis des Diatomées de Belgique. Texte. Martin Brouwers & Co., Anvers. p. 157. (description).

Williams, D.M. (1987). Observations on the genus Tetracyclus Ralfs (Bacillariophyta) I. Valve and girdle structure of the extant species. British Phycological Journal 22: 383-399. 10.1080/00071618700650451

Links & ID's

Index Nominum Algarum (INA)

Transfer INA
Original INA

California Academy of Sciences (CAS)

Tetracyclus rupestris CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

The specimens imaged for this page were collected from Nantahala River near Rainbow Springs, North Carolina. Similar to T. hinziae and T. glans (2/4 of the other extant Tetracyclus species known) populations in the Pacific Northwest, T. rupestris is found to co-occur with specific araphid taxa in the Tabellaria, Meridion, and Odontidium genera.