Sellaphora hohnii

Potapova and Ponader 2008      Category: Symmetrical biraphid
BASIONYM: Sellaphora hohnii Potapova and Ponader 2008

REPORTED AS: Navicula cristula (Hohn 1961, p. 162, pl. 2, fig. 6) 

Sellaphora californica

 

Sellaphora meridionalis

LM scalebar = 10 µm = 80 pixels.



Observations

Contributor: Marina Potapova - February 2013
Length Range: 28-47 µm
Width Range: 8.9-9.8 µm
Striae in 10 µm: 20-23

Description

Valves are elliptic to linear-elliptic with subrostrate apices. The raphe branches have a groove on each side. The grooves are approximately 1 µm wide and covered externally by non-porous conopea. Both grooves and conopea are interrupted by a transversely rectangular or bow-tie-shaped central area bordered by irregularly, shortened striae. The raphe is straight with expanded external central raphe ends and terminal fissures deflected toward the secondary side. The striae are radiate, becoming convergent near apices.



Original Description

Basionym: Sellaphora hohnii
Author: Potapova and Ponader 2008
Length Range: 28-47 µm
Width Range: 8.9-9.8 µm
Striae in 10 µm: 20-23

Original Description

Sellaphora hohnii Potapova & Ponader, sp. nov. TYPE: USA. Florida: Silver Springs, 20 September 1955, J.L. Yount. (Holotype: ANSP GC 44484). Fig. 3A. Synonym: Navicula cristula Hohn excl. Typus, Trans. Am. Micr. Soc. 53(2): Fig. 2/6, 1961. Valvae ellipticae, apicibus subrostratis, 28–47 µm longae, 8.9–9.8 µm latae. Area axialis recta. Sulci utroque fissurae raphis latere, ca. 1 µm lati, conopeis non porosis. Sulci et conopea area centralis interruptis. Area centralis transverse rectangulata, versus marginem dilatata. Striae uniseriatae, radiatae, ad apices parallelae vel convergentes, 20-23 in 10 µm. Areolae parvae circulares, 53-55 in 10 µm. Raphe recta, extremis centralis dilatatis, fissurae terminales deflectis ad latus secundarium valvae. Valves are elliptical, with subrostrate apices, 28-47 µm long, 8.9-9.8 µm wide (Fig. 3). The axial area is straight, formed by grooves, one at each side of the raphe. Grooves are approximately 1 µm wide and are covered externally by non-porous conopeum (Fig. 3E, F, H). Grooves and conopea are interrupted by the central area, which is transversely rectangular or bow-tie-shaped, and bordered by striae of an irregular length. The striae are uniseriate, radiate throughout most of the valve, but parallel or convergent near the apices, 20-23 in 10 µm near the valve ends, the striae are interrupted and internally form “polar bars” (Fig. 3G), which are also visible on LM photographs (Figs 3A-D). The areolae are small, rounded, approximately 53-55 in 10 µm. As in other species of Sellaphora they are occluded internally by hymens (Fig. 3G). The raphe is straight, with expanded central endings, and terminal fissures curved to the secondary side of the valve (Fig. 3F). This species closely resembles S. californica Potapova (Potapova and Charles, 2004), but differs from it by having wider and less drawn-out apices. In quantitative terms, this shape difference is partly described by the ratio of the pole width to maximum valve width, which is ca. 1: 1.8 in S. hohnii, and ca. 1: 2.5 in S. californica. S. hohnii is also similar to S. tibia Antoniades & Hamilton (Antoniades et al., 2008) which has the same conopeum and raphe structure, but S. tibia has a more linear valve form and lower areolae density. Etymology: Hohn (1961) found this species in Silver Springs, Florida and identified it as Navicula geitleri Guermeur & Manguin. The name “N. geitleri Guermeur & Manguin” was, however, illegitimate because of the earlier N. geitleri Hustedt. Hohn, therefore, established N. cristula as a replacement name for N. geitleri Guermeur & Manguin. Examination of the drawing of “N. geitleri” in Guermeur and Mangiun (1953) shows that this diatom, described from Europe, is different morphologically from the Sellaphora found in Silver Springs. Since the type of N. cristula is a diatom described by Guermeur & Manguin, and this species is different from the Sellaphora from Silver Springs, we describe the latter as a new species and name it in honor of Dr. Matthew H. Hohn.

Original Images


Cite This Page:
Potapova, M. (2013). Sellaphora hohnii. In Diatoms of the United States. Retrieved October 25, 2014, from http://westerndiatoms.colorado.edu/taxa/species/sellaphora_hohnii

Species: Sellaphora hohnii

Contributor: Marina Potapova

Reviewer: Sam Rushforth

Citations

Hohn, M. (1961). The relationship between species diversity and population density in diatom populations from Silver Springs, Florida. Transactions of the American Microscopical Society 80(2):140-165.

Potapova, M. and Ponader, K.C. (2008). New species and combinations in the diatom genus Sellaphora (Sellaphoraceae) from southeastern United States. Harvard Papers in Botany 13: 171-181.

Links & ID's

Index Nominum Algarum (INA)

California Academy of Sciences (CAS)

Sellaphora hohnii CAS

North American Diatom Ecological Database (NADED)

NADED ID:

Autecology Discussion

Sellaphora hohnii has only been reported, so far, from Silver Springs, Florida. The waters are circumneutral (pH 7.1-7.2), of average mineral content (conductivity 430-460 S/cm), low phosphorus concentrations (dissolved orthophosphate below detection limit) and moderate concentration of nitrogen.