Frustulia rexii

Graeff and Kociolek in Graeff et al. 2012      Category: Symmetrical biraphid
BASIONYM: Frustulia rexii Graeff and Kociolek in Graeff et al. 2012

Frustulia quadrisinuata

 

Frustulia saxonica

LM scalebar = 10 µm = 40 pixels.



Observations

Contributor: Carrie Graeff - March 2011
Length Range: 68-111 µm
Width Range: 17.5-21.0 µm
Striae in 10 µm: 26–28 in the center, 28 at the ends

Description

Valves rhomboid with a very slight constriction near the rounded poles. Striae are mostly parallel, but slightly convergent and may be wavy at apices. Externally, areolae lanceolate or round with the most rounded areolae positioned near the valve center. Adjacent to external central area, areolae may be slightly expanded. Internally, areolar openings are round. Areolae circumradiate the apices, but the striae are greatly reduced. Longitudinal striae are parallel over the majority of the valve face, but become slightly wavy at the valve center. External central area possessing an irregular grouping of small poroids, varying in number. Rows of areolae adjacent to either side of raphe terminate before distal raphe end. The areola density is 26 in 10 µm. Internal longitudinal ribs are robust and widen significantly, but smoothly, at the central area before becoming constricted at the central nodule. Longitudinal ribs widen very abruptly near the apices, then terminate bluntly at the helictoglossa. Longitudinal ribs fuse with the linear helictoglossa to form a wide, prominent porte-crayon structure. External proximal raphe ends are expanded into shallow, crescent-moon shapes.



Original Description

Basionym: Frustulia rexii
Author: Graeff and Kociolek in Graeff et al. 2012
Length Range: 68-111 µm
Width Range: 17.5-21.0 µm
Striae in 10 µm: 26–28 in the center, 28 at the ends

Original Description

Valves rhomboid with a very slight constriction near rounded poles; 68.0–111.0 μm long, 17.5–21.0 μm wide. Striae with density of 26–28 in 10 μm at valve centre, 28 in 10 μm at valve ends. Striae mostly parallel but slightly convergent and sometimes wavy at apices (Figs 42 and 44). Externally, areolae lanceolate or round (Figs 51 and 52) with the most rounded areolae being located near valve centre (Fig. 52). Adjacent to external central area, areolae can be slightly expanded (Figs. 45, 46, and 52). Internally, areolar openings round (Figs 54 and 55). Areolae extend around apices, but striae greatly reduced (Fig. 51). Longitudinal striae parallel over majority of valve but become slightly wavy at valve centre (Figs 42 and 45). External central area possessing an irregular grouping of small poroids of varying number (Figs 44, 47, and 52). Rows of areolae adjacent to either side of raphe terminate before distal raphe ending (Fig. 51). Internal longitudinal ribs robust, widen significantly but smoothly at central area before constricting at central nodule (Figs 53 and 55). Longitudinal ribs widen very abruptly near apices, then terminate bluntly at helictoglossa (Figs 42, 45, and 53). Longitudinal ribs fuse with the linear helictoglossa to form a wide and prominent porte-crayon structure (Fig. 54). External proximal raphe ends expanded into shallow crescent-moon shapes (Figs 51 and 52).

Original Images

Original text and images reproduced with permission by Magnolia Press.


Cite This Page:
Graeff, C. (2011). Frustulia rexii. In Diatoms of the United States. Retrieved October 31, 2014, from http://westerndiatoms.colorado.edu/taxa/species/frustulia_rexii

Species: Frustulia rexii

Contributor: Carrie Graeff

Reviewer: Sarah Spaulding

Citations

Graeff, C.L., Kociolek, J.P. and Burliga, A.L. (2012). Valve morphology of four species of Frustulia (Bacillariophyta), including two described as new. Phytotaxa.

Lange-Bertalot, H. (2001). Navicula sensu stricto, 10 genera separated from Navicula sensu lato, Frustulia. Diatoms of Europe 2: 1-526.

Links & ID's

Index Nominum Algarum (INA)

California Academy of Sciences (CAS)

North American Diatom Ecological Database (NADED)

NADED ID:

Autecology Discussion