• Category
  • Length Range
    10.0-22.5 µm
  • Width Range
    1.9-2.7 µm
  • Striae in 10 µm
    27-30
  • Reported As
    Gomphonema tackei var. brevistriata (Camburn et al. 1978)

Identification

Description

Valves are small, clavate to linear-clavate, with slightly narrowed to bluntly rounded ends. The axial area is narrow, linear, with a few shortened striae forming a small round to rectangular central area. The raphe is straight and the proximal ends are slightly enlarged. The striae are radiate throughout the valve. Cells are somewhat wedge-shaped in girdle view. Striae continue on the mantle and are visible in girdle view. Girdle bands lack perforations.

The images presented here are of specimens from the holotype slide of Gomphonema tackei var. brevistriata, which I consider to be conspecific with Gomphosphenia stoermeri.

The two taxa appear to be identical in light microscopy, overlap in valve dimensions and striae density, and the two type locations are in the southeastern United States.

This taxon is frequently found on prepared slides lying in girdle view. In this orientation, it may be easily confused with other finely striated, small taxa in girdle view such as Achnanthidium.

Autecology

Thomas et al. (2009) illustrate Gomphosphenia stoermeri specimens collected from subaerial epilithic habitats in Great Smoky Mountains National Park. Camburn et al. (1978) described Gomphonema tackei var. brevistriata from epiphytes on the aquatic moss Fontinalis hypnoides var. duraei in Long Branch within the Kings Mountain National Military Park in South Carolina. Camburn (1977) also collected G. tackei var. brevistriata on Cladophora sp. and epilithic habitats in Long Branch, with the largest number of cells occurring between January and April. The pH of Long Branch ranged from 6.4 to 7.3.

This taxon has also been documented in Wisconsin (LaLiberte, unpublished).

Gomphonema Tackei Var Brevistriata  Holotype  Range Stars In Circle  Gc53756
Credit: Gina LaLiberte
Size diminution series in holotype population of Gomphonema tackei var. brevistriata. Stars indicate specimens within the scribed circle on the holotype slide.
G Stoermeri Brevistriata Tackei Comparison
Credit: Thomas et al. 2009; Gina LaLiberte; Friedel Hinz, Hustedt Diatom Study Centre, Alfred Wegener Institute http://apps3.awi.de/Hustedt-Diatoms/H73501-73750/original/H73600-1a.jpg
Left to right, Gomphosphenia stoermeri in Thomas et al. 2009, Gomphonema tackei var. brevistriata from holotype population, Gomphonema tackei Holotype BRM H73600-1a, Hustedt Diatom Study Centre, Alfred Wegener Institute
Gomphosphenia Measurements
Credit: Gina LaLiberte
Overlapping ranges of length and breadth of Gomphosphenia stoermeri measured from Thomas et al. 2009, G. tackei holotype, and Gomphonema tackei var. brevistriata holotype population.
800Px  Cataract Falls Gsmnp1  Brian  Stansberry  Creative  Commons
Credit: Brian Stansberry / Creative Commons
Cataract Falls in Great Smoky Mountains National Park, home of the holotype population of Gomphosphenia stoermeri.
Wi  Gomphosphenia Stoermeri
Credit: Gina LaLiberte
G. stoermeri collected for the US EPA National Rivers and Streams Assessment from an unnamed tributary to Conlan Creek, Clark County, WI (44.55144, -90.6524, site ID FW08WI001). Specimen at upper left collected on 01 September 2009, all others collected on 22 July 2009. pH ranged from 7.05 to 7.07 on the two collection dates.

Original Description

Description: Frustules slightly wedge-shaped in girdle view, without septa or pseudosepta. Valves linear-clavate with large specimens slightly tumid in the central region of the valve, with rounded to narrowly-rounded poles, 10.0–21.1 μm long, 1.5–3.1 μm wide. Axial area linear, narrow, expanded laterally at the center to form a rectangular central area, with stigmata wanting. Raphe straight, filiform, with dilated external proximal ends. Striae parallel to radiate, with 1–3 shortened striae around the central area, 28–35 in 10 μm.

Holotype here designated: CAS Slide 222051

Type locality: Epilithic, subaerial in Cataract Falls, Sevier County, Great Smoky Mountains National Park, Tennessee, 35.6894°N, 83.5389°W.

Etymology: Named in honor of Dr. E.F. Stoermer who has been a mentor, in varying ways and degrees, to each of the authors of this contribution.

In the scanning electron microscope, the valve exterior is dominated by the elongated, uninterrupted striae, without smaller puncta being distinguished (Fig. 134). The raphe has enlarged, elongated proximal ends (Fig. 136), with distal ends only slightly enlarged (Figs 135, 137). Distal raphe ends do not extend onto the valve mantle (Figs 135, 137). Small, round granules are dispersed on the valve face.

Internally, the valve is dominated by a small, mound-shaped central nodule and two relatively large helictoglossae (Fig. 138). The central nodule bears the highly recurved proximal raphe ends curved in one direction only. A series of round occlusions is seen along the valve mantle (Fig. 140). At the headpole a large helictoglossa is seen as well as a series of occluded openings along the valve terminus on the mantle (Fig. 139). Similarly, at the footpole, a large helictoglossa is present. Occlusions are visible along the valve mantle, both on the sides and terminus (Fig. 141).

Comments: This taxon is similar in outline and size to Gomphonema takei [sic] var. brevistriata (Camburn et al. 1978), but differs due to lack of uniformly shortened striae. It is also distinguished from G. takei [sic] Hustedt in that the central area is rectangular, not elliptical (Hustedt 1942, Simonsen 1987). It is distinguished from G. lingulatiformis (Kociolek & Kingston 1999) due to the difference in shape. Ultrastructurally, internal proximal raphe ends are unlike other members of the genus, which are widely reported to be anchor-shaped (Lange-Bertalot 1995, Kociolek et al. 1988, Kociolek & Stoermer 1990, Kociolek & Kingston 1999).

This small form is easily overlooked in samples. It co-occurs with small species of Achnanthidium, Diadesmis and Nupela.

GSMNP Distribution: Found only in Cataract Falls and Place of 1000 Drips in subaerial habitats (CATF-1, POTD-2, POTD-4).

  • Author
    Kociolek and E.W.Thomas 2009
  • Length Range
    10.0-21.1 µm
  • Width
    1.5-3.1 µm
  • Striae in 10µm
    28-35

Original Images

Gomphosphenia Stoermeri orig illus
Gomphosphenia Stoermeri orig illus SEM
Gomphosphenia Stoermeri orig desc

Cite This Page

LaLiberte, G. (2018). Gomphosphenia stoermeri. In Diatoms of North America. Retrieved October 23, 2019, from https://diatoms.org/species/gomphosphenia_stoermeri

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Gomphosphenia stoermeri from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:

ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.