Achnanthes undulorostrata

Lowe and Sherwood 2009      Category: Monoraphid
BASIONYM: Achnanthes undulorostrata Lowe and Sherwood 2009

Achnanthes tumescens

 

Achnanthidium alpestre

LM scalebar = 10 µm = 40 pixels.



Observations

Contributor: Rex Lowe - December 2011
Length Range: 29-37 µm
Width Range: 8.0-9.5 µm
Striae in 10 µm: 14-15 on raphe valve, 12-13 on rapheless valve

Description

Valves are triundulate, with broadly rounded ends. The raphe valve has a narrow axial area and a nearly rectangular central area extending to the valve margins. The raphe is externally sinuous, with proximal ends deflected slightly in one direction and distal ends curved strongly towards mantle in the opposite direction. The rapheless valve has an axial area near the valve margin. Striae are punctate and radiate throughout on the raphe valve. On the rapheless valve, the striae are parallel in the center, becoming radiate with respect to the axial area then becoming slightly to strongly curved at the ends.



Original Description

Basionym: Achnanthes undulorostrata
Author: Lowe and Sherwood 2009
Length Range: 30.5-35.5 µm
Width Range: 8.0-9.5 µm
Striae in 10 µm: 14-15 in 10 µm on raphe valve, 12-13 in 10 µm on rapheless valve

Original Description

Valves triundulate with broadly rounded ends, 30.5-35.5 µm long, 8.0-9.5 µm wide. Raphe valve with narrow axial area and a nearly rectangular central area extending to the valve margins. Raphe externally sinuous, with proximal ends deflected slightly in one direction, with distal ends curved strongly towards mantle in opposite direction (Fig. 63). Internal raphe slits with proximal ends slightly deflected to one side (Fig. 64). Rapheless valve with axial area near valve margin. Striae punctate, radiate throughout on raphe valve (Figs 55¬-58), on rapheless valve parallel in the center, becoming radiate with respect to the axial area, slightly to strongly curved at the ends (Figs 59-62, 65-66), 14-15 in 10 µm on raphe valve, 12-13 in 10 µm on rapheless valve. Intemal costae separating striae, wíth oblique ridges in rapheless valve resulting in a spiral pattern visible in SEM (Fig. 66). Puncta 16 in 10 µm on both valves.

Original Images


Cite This Page:
Lowe, R. (2011). Achnanthes undulorostrata. In Diatoms of the United States. Retrieved April 21, 2014, from http://westerndiatoms.colorado.edu/taxa/species/achnanthes_undulorostrata

Species: Achnanthes undulorostrata

Contributor: Rex Lowe

Reviewer: Sam Rushforth

Citations

Lowe, R.L., Sherwood, A.R. and Ress, J.R. (2009). Freshwater species of Achnanthes Bory from Hawai’i. Diatom Research 24(2): 327-340.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Achnanthes undulorostrata CAS

North American Diatom Ecological Database (NADED)

NADED ID:

Autecology Discussion

Achnanthes undulorostrata was described from the island of Maui, Hawaii. It was also found in collections from Oahu. This taxon occurs in relatively dry sites in association with A. tumescens, Pinnularia borealis, Diadesmis spp. and Cosmioneis spp.