Navicula nunivakiana

R.M.Patrick and Freese 1961      Category: Symmetrical biraphid


Navicula notha


Navicula oblonga

LM scalebar = 10 µm = 20 pixels.


Contributor: Paul Hamilton | Kalina Manoylov - November 2011
Length Range: 84-96 µm
Width Range: 23–27 µm
Striae in 10 µm: 8


Valves are lanceolate with rounded central margins and apices. Striae are radiate throughout the valve. The central area is asymmetrically rectangular and the axial area is broad and straight. Striae on one or both sides of the central area vary in length and are irregularly spaced. The striae are formed between internal costae giving a light interstriae and darker striae appearance in LM. The raphe is lateral, undulating and curving towards the proximal raphe ends. The proximal ends curve to one side of the central area. The distal fissures are scythe shaped. Areolae are distinct and round. A central nodule is evident. In girdle view the frustules are crescent shaped because of one convex and one concave valve face.

Original Description

Author: R.M.Patrick and Freese 1961
Length Range: 87-100 µm
Width Range: 21-27 µm
Striae in 10 µm: 7-12

Original Description

Navicula nunivakiana sp. nov. Pl. 2, Fig. 5

Valva lanceolata, attenuata ad apices rostratos, rotundatos aliquantulum. Area axiali angusta, distincta. Fissuris externis terminalibus raphis magna et versa in eodem cursu. Raphe undulata leniter. Area media inaequali in forma, transversa et asimili. Striis punctatis distincte et crasse, radiatis; paene parallelis inaequalibus in longitudine circum, aream mediam. Striis, 7-12 in 10 µ. Longitudo, 87-100 µ. Latitudo, 21-27 µ.

Valve lanceolate tapering toward the somewhat rostrate, rounded ends. Axial area narrow, distinct. External terminal fissures of the raphe large and turned in the same direction. Central area irregular in shape, transverse and asymmetrical. Striae distinctly and coarsely punctate, radiate; almost parallel and irregular in length about the central area. Striae, 7-12 in 10 µ Length, 87-100 µ. Breadth, 21-27 µ.

This species is distinguished by its slightly undulate raphe and the shape of the central area.

Occurrence in collection rare.

Specimen illustrated.-Station 116 (A-G.C. 8232) . Holotype.

Type locality.-Alaska, Sec. Jud. Div., Nunivak Archaeology Site, Barrow. Coll. L. R. Freese, 8 August 1951.

Distribution.—GEOGRAPHICAL—In addition to the type locality, specimens were found at Barrow Village, Freshwater Lake, Station 148, Coll. L. R. Freese, 18 August 1951 (A-G.C. 8262) . ECOLOGICAL Fresh water. Holotype from moss squeezings on slope of lagoon above high tide level. pH, 7.4. Other specimens from lake plankton. pH, 7.6; temp., 6° C ; alk., 23 ppm (as CaCO3) ; hardness, 50 ppm (as CaCO3) ; Cl, 58 ppm.

Original Images

Cite This Page:
Hamilton, P., and Manoylov, K. (2011). Navicula nunivakiana. In Diatoms of the United States. Retrieved April 26, 2018, from

Species: Navicula nunivakiana

Contributor: Paul Hamilton | Kalina Manoylov

Reviewer: Sarah Spaulding


Cox, E.J. (1988). Taxonomic studies on the diatom genus Navicula V. The establishment of Paribellus gen. nov. for some members of Navicula sect. Microstigmaticae. Diatom Research 3: 9–38. 10.1080/0269249X.1988.9705014

Patrick, R.M. and Freese, L.R. (1961). Diatoms (Bacillariophyceae) from Northern Alaska. Proceedings of the Academy of Natural Sciences of Philadelphia 112(6):129-293.

Witkowski, A., Lange-Bertalot, H. and Metzeltin, D. (2000). Diatom Flora of Marine Coasts I. Iconographia Diatomologica 7: 1-925.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Navicula nunivakiana CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

A brackish to highly alkaline species found from the type locality along the shoreline at the northern tip of Alaska. The pH of the lake is circumneutral with high levels of both calcium carbonate and sodium chloride.