Cavinula davisiae

Bahls 2013      Category: Symmetrical biraphid
BASIONYM: Cavinula davisiae Bahls 2013

REPORTED AS: Navicula variostriata (Hein 1990, p. 76, plate 31, figs. 7-9) | Navicula cf. variostriata (Pienitz et al. 2003, p. 47, plate 14, fig. 6) 

Cavinula cocconeiformis

 

Cavinula pseudoscutiformis

LM scalebar = 10 µm = 80 pixels.



Observations

Contributor: Loren Bahls - September 2012
Length Range: 14-31 µm
Width Range: 7.5-9.9 µm
Striae in 10 µm: 26-32

Description

Valves are elliptic-lanceolate with broadly rounded apices. The axial area is narrow and linear. The central area is orbicular and large, about 1/2 the width of the valve. The raphe is filiform and straight with distinctly expanded proximal ends. Distal raphe fissures are deflected abruptly in opposite directions, some distance from each apex. Striae are radiate throughout and alternately long and short around the central area. Areolae in the striae adjacent to the central area tend to be larger than areolae elsewhere and somewhat elongate transapically. Areolae number 26-35 in 10 µm. Internally, under SEM, proximal raphe ends are T-shaped and areolae are occluded by hymenes.



Original Description

Basionym: Cavinula davisiae
Author: Bahls 2013
Length Range: 14-31 µm
Width Range: 7.5-9.9 µm
Striae in 10 µm: 26-32

Original Description

Valves elliptic-lanceolate with broadly rounded apices. Valve length 14–31 μm; valve width 7.5–9.9 μm. Axial area narrow and linear; central area orbicular and large, about 1/2 valve width. Raphe filiform and straight with distinctly expanded proximal ends. Terminal raphe fissures hooked abruptly in opposite directions some distance from each apex. Striae radiate throughout, alternately long and short around the central area, 26–32 in 10 μm. Areolae round, 26–35 in 10 μm. Areolae of striae adjacent to central area larger and somewhat elongate transapically. Internally, proximal raphe ends T-shaped and areolae occluded by hymenes.

Original Images


Cite This Page:
Bahls, L. (2012). Cavinula davisiae. In Diatoms of the United States. Retrieved October 21, 2014, from http://westerndiatoms.colorado.edu/taxa/species/cavinula_davisiae

Species: Cavinula davisiae

Contributor: Loren Bahls

Reviewer: Sarah Spaulding

Citations

Bahls, L. (2013). New diatoms (Bacillariophyta) from western North America. Phytotaxa 82(1): 7-28.

Hein, M. (1990). Flora of Adak Island, Alaska: Bacillariophyceae (Diatoms). Bibliotheca Diatomologica (H. Lange-Bertalot, ed.), Band 21, J. Cramer, Berlin, 133 pp.+ 53 plates.

Pienitz, R., Fedje, D. and Poulin, M. (2003). Marine and Non-Marine Diatoms from the Haida Gwaii Archipelago and Surrounding Coasts, Northeastern Pacific, Canada. In Bibliotheca Diatomologica (H. Lange-Bertalot and P. Kociolek, eds.), Band 48, J. Cramer, Stuttgart, 146 pp.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

North American Diatom Ecological Database (NADED)

NADED ID:

Autecology Discussion

Cavinula davisiae is documented here from the Pacific Northwest. Besides the type locality (photo below), C. davisiae has been confirmed from a stream in southwest Montana and a small pool in Waterton Lakes National Park, Alberta (Montana Diatom Collection). This species has been misidentified as Navicula variostriata Krasske and is probably more widespread than our records show. Hein (1990) reported it (as N. variostriata) from Adak Island, Alaska, and Pienitz et al. (2003) reported it (as N. cf. variostriata) from islands off the Pacific Coast of western British Columbia, Canada. It appears to prefer oligotrophic or dystrophic waters with circumneutral pH and low conductivity.

Images

Clover Lake, Mount Rainier National Park, Pierce County, Washington: type locality for Cavinula davisiae.

Credit/Source: flickr