Camburn 1978 Category: Asymmetrical biraphid
BASIONYM: Gomphonema mehleri Camburn 1978
Contributor: Ian Bishop - March 2016
Length Range: 33-59 µm
Width Range: 9.4-12.5 µm
Striae in 10 µm: 7.5-9 at center; 11-12 at headpole; 12-13 at footpole
Valves are lanceolate to lanceolate-clavate and broadest near the center of the valve. From the center, the valve evenly tapers to a rounded headpole and variably expanded footpole. The axial area is nearly parallel, becoming tapered at the apices. Striae are coarsely punctate. Striae are weakly radiate at the center valve, becoming nearly parallel at the headpole and strongly radiate at the footpole. In line with the median striae on one side is a single, isolated stigma. Areolae are coarse and rectangular, numbering 16-20 in 10 µm. The raphe is lateral. An apical porefield present at footpole.
This taxon is relatively rare in the southeast region of the US (see Autecology section). It may be that similar species of Gomphonema have been misidentified as G. mehleri. The type image and description are included below from Camburn et al. (1978). Note that specimens illustrated in Kociolek and Kingston (1999) have a higher stria density that the type. Specimens illustrated in Thomas et al. (2009) are smaller, more narrow and have a higher stria density than the type. These differences are larger than expected within our morphological species concept and imply a greater diversity of species in the genus Gomphonema in the southeast than has been recognized.
Basionym: Gomphonema mehleri
Author: Camburn 1978
Length Range: 52-60 µm
Width Range: 11-11.5 µm
Striae in 10 µm: 8-9 at center valve, up to 11 near the apices
Gomphonema mehleri Camburn sp. nov. PL. XV, Figs. 235-236
Valva lanceolata, latissima in medio, attenuata ad apicem et basem rotundatum, apice parum latiore. Area axiali et centrali aream latam lanceolatum formanti. Raphe filmentosa. Strii medianis in unico latere areae centralis puncto singulo terminantibus. Striis distincte punctatis, circa 15 punctis in 10 µm, pro maxima parte radiatis ad fere parallelas ad apicem. Striis 8-9 in 10 µm in medio valvae ad 11 in 10 µm prope apices. Longitudo 52-60 µm. Latitudo 11-11.5 µm.
Holotypus: A.N.S.P. - G.C. #53754, in collectione generali diatomarum Academiae Scientarum Naturalium Philadelphiae.
Valves lanceolate, broadest in the middle, narrowed toward the rounded apex and basis, apex slightly broader. Axial and central area forming a broad, lanceolate area. Raphe filamentous. Median stria on one side of the central area ending in an isolated punctum. Striae distinctly punctate, ca. 15 puncta in 10 µm, radiate throughout most of the valve to almost parallel at the apex. Striae, 8=9 in 10 µm at the center of the valve to 11 in 10 µm near the apices; Length, 52-60 µm; Breadth, 11-11.5 µm.
Holotype: A.N.S.P. - G.C. # 53754, In general diatom collection, Academy of Natural Sciences of Philadelphia.
Camburn, K.E., Lowe, R.L., and Stoneburner, D.L. (1978). The haptobenthic diatom flora of Long Branch Creek, South Carolina. Nova Hedwigia 30: 149-279.
Kociolek, J.P. and Kingston, J.C. (1999). Taxonomy, ultrastructure, and distribution of some gomphonemoid diatoms (Bacillariophyceae: Gomphonemataceae) from rivers in the United States. Canadian Journal of Botany 77: 686-705. 10.1139/cjb-77-5-686
Thomas, E.W., Kociolek, J.P., Lowe, R.L. and Johansen, J.R. (2009). Taxonomy, ultrastructure and distribution of gomphonemoid diatoms (Bacillariophyceae) from Great Smoky Mountains National Park (U.S.A.). Nova Hedwigia, Beiheft 135: 201-237.
Gomphonema mehleri was described from South Carolina (Long Branch Creek; ANS GC53754). Specimens illustrated here were collected from rivers in Georgia (Little Haynes Creek) and North Carolina (Briar Creek). Note that complete location data is given for each image, by selecting and clicking on the image.