Achnanthes undulorostrata
Lowe and Sherwood 2009 Category: Monoraphid
BASIONYM: Achnanthes undulorostrata Lowe and Sherwood 2009
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 May 19, 2013, from http://westerndiatoms.colorado.edu/taxa/species/achnanthes_undulorostrata
Species: Achnanthes undulorostrata
Contributor: Rex Lowe
Reviewer: Sam Rushforth
Image Credit: Rex Lowe
- Valves triundulate
- Ends broadly rounded
- Proximal ends slightly unilaterally deflected
- Rapheless valve with eccentric axial area
Valves are triundulate with broadly rounded ends. The raphe valve has a nearly rectangular central area, extending to the valve margins. The proximal raphe ends are deflected slightly unilaterally deflected. The rapheless valve has an axial area positioned near the valve margin.
Compare
Achnanthes undulorostrata is most similar to A. felinophila from which it differs by its more broadly-rounded rather than cunate ends.
Achnanthes felinophila
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)
California Academy of Sciences (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.