Lowe and Kociolek 1984 Category: Asymmetrical biraphid
REPORTED AS: Gomphonema appalachianum (Thomas et. al 2009, pg. 227, Pl. 11, Fig 112-115)
Valves are lanceolate-clavate with a rounded headpole and footpole. The axial area is broadly lanceolate and expanded at center valve. Raphe is lateral, with proximal raphe ends narrowly separated.The central area lacks a stigmoid. Striae are parallel to nearly parallel at center valve, becoming barely radiate at the apices.
The species G. appalachianum, also described from the southeast (Thomas et al. 2009), appears to be a later heterotypic synonym of G. christenseni. Here, the type images of G. christenseni are presented. Our observations of the G. christenseni specimens on the holotype slide is consistent with the original description (below). Note that in Thomas et al. (2009), images portraying G. christenseni appear to be an undescribed taxon. The specimens portrayed as “G. christenseni by Thomas et al. are considerably broader than the original description, and range in breadth from 8.4-11.2 µm (Pl. 11, Figs 109-11).
Author: Lowe & Kociolek 1984
Length Range: 32-62 µm
Width Range: 6-8 µm
Striae in 10 µm: 12-13
Valvae lineari-clavate, 32-62 X 6-8 μm, parviores rotundatae et subapiculatae. Area axialis extremis distalibus parva, ad centrum proper strias incompletas expansa. Area centralis ut videtur silliceor quam pars major valvae. Raphe filiformis. Striae 12-13 per 10 μm, versus medium valvae parallelae, extremibus plus minus radiatae.
Holotypus: A.N.S.P. - G.C. #53920, in collectione diatomarum Academiae Scientarum Naturalium Philadelphiae.
Valves linear-clavate, becoming rounded and almost apiculate in smaller specimens. Valve length 32-62 μm, breadth 6-8 μm. Axial area small at the distal ends, becoming expanded due to a shortening of the striae towards the central area. Central area appears more heavily silicified than the rest of the valve and lacks an isolated punctum or stigma. Striae parallel at mid-valve, becoming slightly radiate at the ends. Striae 12-13 in 10 μm. Raphe filiform.
Holotype: A.N.S.P. -G.C. #53920. In general diatom collection, Academy of Natural Sciences of Philadelphia.
Type locality: Great Smoky Mountains. National Park, Big Creek 100 m downstream from foot bridge, Big Creek Watershed, epiphytic on submerged Fontinalis. Collected by R. Lowe, 9-15-77 #5-3.
GSMNP Distribution: Observed at lower elevations in many streams, however, never in large numbers.
Cite This Page:
Vaccarino, M., and Tyree, M. (2016). Gomphonema christenseni. In Diatoms of the United States. Retrieved April 24, 2017, from http://westerndiatoms.colorado.edu/taxa/species/gomphonema_christenseni
Species: Gomphonema christenseni
Lowe, R.L. and Kociolek, J.P. (1984). New and rare diatoms from Great Smoky Mountains National Park. Nova Hedwigia 39(3-4): 465-476.
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.
Tuji, A. (2003). Freshwater diatom flora in the bottom sediments of Lake Biwa (South Basin): Part 2: Gomphonema sensu lato. Bull. Natn. Sci. Mus., Tokyo, Ser. B, 29(3), pp. 97-107.
NADED ID: 37343
This taxon was originally described from the Great Smoky Mountains, where it was found in many streams in lower elevations, in low abundance. More recently, it has been found in low numbers in other rivers of the southeast (US Geological Survey regional survey of 2014).
The species has also been reported from the Kumano River, from Kirishima Heights, and from Lake Biwa, Japan (Tuji 2003).