Gomphoneis oreophila

Stancheva and Kociolek 2016      Category: Asymmetrical biraphid

Gomphoneis olivaceum

 

Gomphoneis pseudo-okunoi

LM scalebar = 10 µm = 40 pixels.



Observations

Contributor: Rosalina Stancheva - January 2017
Length Range: 51-105 µm
Width Range: 10.3–16 µm
Striae in 10 µm: 10–12

Description

Valves are nearly lanceolate, slightly clavate, tumid at the center with straight to convex margins, rounded headpole and narrower foot pole. Axial area is relatively narrow, straight and slightly expanded only at the center to form a small linear-elliptical central area bearing one stigma. Raphe is lateral, slightly arched. Striae are parallel to slightly radiate in the center, more strongly radiate toward the poles,distinctly biseriate under LM. Longitudinal lines located close to the valve margin (submarginal) more distinct when the valve is tilted. Frustules are cuneate in girdle view with single irregular row of areolae “missing” in the central part.

Under SEM, the striae are composed of double rows of circular puncta which extend onto the mantle.Spines are not present at the head pole. At the foot pole the apical pore field is separated from the striae by unornamented silica, and the porelli are distinct and larger than the areolae. One round stigma is visible externally in the central area.Internally, a large axial plate, narrow marginal lamina, and pseudosepta at both poles can be seen. The axial plate terminates before reaching the helictoglossa at the foot pole. The marginal lamina is narrower near the central area. The elongate central nodule is slightly raised and bears a slit-like stigma.



Original Description

Basionym:
Author: Stancheva and Kociolek
Length Range: 51–105 µm
Width Range: 10.3–16 µm
Striae in 10 µm: 10–12

Original Description

Gomphoneis oreophila Stancheva & Kociolek, sp. nov. (Figs 46–71)

LM observations

Valves are nearly lanceolate, slightly clavate with rounded head pole and narrower foot pole (Figs 46–57). Margins are straight to convex and tumid at the center. Cells are 10.3–16 μm wide, 51–105 μm long; initial valves 15–17 μm wide, 120–125 μm long (Figs 53, 54). Axial area is relatively narrow, straight and slightly expanded only at the center to form a small linear-elliptical central area bearing one stigma (Figs 46–52). Raphe is slightly arched, distinctly lateral. Striae are nearly parallel to slightly radiate in the center, more strongly radiate toward the poles, 10–12 in 10 μm. Striae distinctly biseriate. Longitudinal lines located close to the valve margin (submarginal, Figs 49, 52, 54, 56) better visible when the valve is tilted. Initial valves bent, tumid in the center , bearing in the central area one stigma and 2 to many areolae (Figs 53, 54). Frustules are cuneate in girdle view with single irregular row of puncta missing in the central part (Fig. 58).

SEM observations Externally, the striae are composed of double rows of circular puncta which extend onto the mantle (Figs 59, 60, 62). The rape is more or less straight, or slightly arched, but not undulate (Figs 59, 60). Distal raphe ends are slightly bent before the apices and extend into the mantle (Figs 62, 63). Spines are not present at the head pole (Figs 61–63). At the foot pole the apical pore field is separated from the striae by unornamented silica, and the porelli are distinct and larger than the puncta (Figs 64). Externally, one round stigma is visible in the central area (Fig. 65), accompanied by several areolae in the initial cells (Fig. 66).

Internally, a large axial plate, narrow marginal lamina, and pseudosepta at both poles can be seen (Fig. 67). The axial plate terminates before reaching the helictoglossa at the foot pole (Figs 67, 70) where radiate striae with circular puncta are visible (Figs 70, 71). The marginal lamina is narrower near the central area (Figs 68, 69). The elongate central nodule is slightly raised and bears a slit-like stigma and recurved proximal raphe ends (Fig. 68).

Type:—USA. California: Rice Creek, Sierra Nevada Mts, 40.39999º N, 121.44109º W, Jennifer York, July 1, 2015 (holotype UC2050496 circled specimen on slide; isotype RS! 009, circled specimen on slide and material, CSUSM, USA).

Etymology:—This species epithet means “mountain-loving” referring to where it has been found.

Distribution and ecological notes:—Found only in the type locality which is high elevation site in the Sierra Nevada Mts, CA (1902 m a.s.l.). Habitat is characterized by low nutrients (TN 0.04 mg L-1, TP 0.05 mg L-1), low conductivity (74.8 μS cm-1), slightly alkaline (62 mg L-1 CaCO3), and pH 8.3 (see Table 1).

Comments: —The large size and position of the longitudinal lines near the margin suggest a close relationship between this taxon and species such as G. herculeana (Ehrenb.) Cleve (1894: 73), G. mammilla (Ehrenb.) Cleve (1894: 73) and G. minuta (Stone) Kociolek & Stoermer (1988: 56). However, in these species the longitudinal lines are positioned approximately midway between the axial area and margin, or closer to the axial area, and apical spines are common (Kociolek & Stoermer 1988). The lanceolate shape of this species clearly separates it from these large species of the genus, as well as Gomphoneis linearis Kociolek & Stoermer (1986: 146–7) in which the longitudinal lines are positioned close to the valve margin. The latter species, known from only a few specimens from a single locality in Oregon (Kociolek & Stoermer 1986), differs in the shape of the valves, being more linear in outline (as opposed to having a distinctly lanceolate outline), has proportionately more broadly rounded headpoles, and is smaller (Table 2). Furthermore, the central striae around the stigma are radial with closely spaces tips in some specimens (see Kociolek & Stoermer 1986, Figs 25 and 26), in contrast to nearly parallel central striae in G. oreophila.

Original Images


Cite This Page:
Stancheva, R. (2017). Gomphoneis oreophila. In Diatoms of the United States. Retrieved August 16, 2017, from http://westerndiatoms.colorado.edu/taxa/species/gomphoneis_oreophila

Species: Gomphoneis oreophila

Contributor: Rosalina Stancheva

Reviewer: Sarah Spaulding

Citations

Kociolek, J.P. and Stoermer, E.F. (1986). Observations on North American Gomphoneis (Bacillariophyceae). II. Descriptions and ultrastructure of two new species. Transactions of the American Microscopical Society 105: 141-151 . http://www.jstor.org/stable/3226386

Stancheva, R., Sheath, R.G. and Kociolek, J.P. (2016). New freshwater gomphonemoid diatoms from streams in the Sierra Nevada mountains, California, USA. Phytotaxa 289 (2): 118-134.

Links & ID's

Index Nominum Algarum (INA)

California Academy of Sciences (CAS)

North American Diatom Ecological Database (NADED)

NADED ID:

Autecology Discussion

This taxon is only known, to date, in the type locality, which is high elevation site (1902 m a.s.l.) in the Sierra Nevada Mountains, California. The site is characterized by low nitrogen (TN 0.04 mg L-1), relatively high phosphorus (TP 0.05 mg L-1), low conductivity (74.8 μS cm-1), slightly alkaline (62 mg L-1 CaCO3), and pH 8.3 (Stancheva and Kociolek 2016).