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Aneumastus carolinianus

(Patrick) Lange-Bert. 2001      Category: Symmetrical biraphid
BASIONYM: Navicula caroliniana Patrick 1959

Amphora pediculus


Aneumastus minor

LM scalebar = 10 µm = 40 pixels.


Contributor: Meredith Tyree - September 2017
Length Range: 38-58 µm
Width Range: 13.7-18.2 µm
Striae in 10 µm: 11-13


Valves are widely lanceolate, with acutely rounded apices. The raphe is undulate and complex. The proximal raphe ends are expanded. The axial area is relatively narrow and slightly lanceolate. The central area is a small irregular stauros, delimited by 5-7 unevenly shortened striae on each side. Striae are radiate throughout, becoming most strongly radiate at the apices. Striae are uniseriate in the central region, with nearly square areolae arranged in distinguishable pairs, 22-24 areolae in 10 µm. Striae become biseriate, with more densely spaced areolae, 25-28 areolae in 10 µm, at the valve margin.

Original Description

Basionym: Navicula caroliniana
Author: Patrick 1959
Length Range: 44-45 µm
Width Range: 15-16 µm
Striae in 10 µm: 11-12

Original Description

Navicula caroliniana

Valva lanceolata, apicibus leniter attenuatis, semirostratis, rotundis. Area axiali angusta. Raphae undulato. Area centrali transversa, inaequali in forma. Striis radi-antibus per valvam; inaequali in longitudine circa aream centralem; interdum vicissim longioribus et brevioribus. Striis fractis constiuere lineas inaequales et longitudinales. Striae, 11-12 in 10 μ. Longitudo, 44-45 μ (specimen typicum, 45 μ).Latitudu, 15-16 μ (specimen typicum, 15 μ).

Valve lanceolate with slightly attenuate, semi-rostrate, rounded ends. Axial area narrow. Raphe undulate. Central area transverse, irregular in shape. Striae radiate throughout the valve; irregular in length about central area; may be alternately long and short; broken to form irregular longi-tudinal lines. On the margins of the valve, the striae sometimes give the appearance of being composed of two rows of puncta. Striae, 11-12 in 10 μ. Length 44-45 μ (type, 45 μ). Breadth 15-16 μ (type, 15 μ).

This specimen belongs in the same group as N. tuscula. It is similar to N. constantini Skv. in both the structure of the striae and the raphe, which is undulate.

Specimen illustrated.–A-G.C. 44496 Type locality.–South Carolina, Aiken County, Savannah River at Mile 175 from the mouth of the river, October, 1953. Distribution.–Known only from the type locality.

Original Images

Cite This Page:
Tyree, M. (2017). Aneumastus carolinianus. In Diatoms of the United States. Retrieved May 22, 2018, from

Species: Aneumastus carolinianus

Contributor: Meredith Tyree

Reviewer: Alison Minerovic


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

Patrick, R.M. (1959). New species and nomenclatural changes in the genus Navicula (Bacillariophyceae). Proceedings of the Academy of Natural Sciences of Philadelphia 111 (1959): 91-108 .

Stoermer, E., Kreis, R. and Andresen, N. (1999). Checklist of Diatoms from the Laurentian Great Lakes. II. Journal of Great Lakes Research.

Links & ID's

Index Nominum Algarum (INA)


California Academy of Sciences (CAS)

Aneumastus carolinianus CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

Aneumastus caroliniana was described from South Carolina, but has been reported from the Great Lakes (Stoermer et al. 1999). Specimens shown here were collected from two reference-quality streams in West Virginia. This species tends to be uncommon and low in abundance.