Credit: Sylvia Lee
Living cell from soil in a puddle made by a rain storm
Hantzschia amphioxys
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Category
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Length Range25-150 µm
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Width Range5-12 µm
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Striae in 10 µm16-26
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Contributor
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ReviewerSarah Spaulding - Feb 2023
Identification
Description
Valves are bent and constricted at the center ventral margin so that the valve face is asymmetric to the apical axis. Specimens vary from highly arched to nearly straight, in smaller valves. Apices are small, strongly protracted in larger specimens, and slightly reflexed toward the dorsal margin. Frustules in girdle view are rectangular and slightly bent in the center. The raphe is excentric and located within a canal. Cells occur with the raphe on the same side on both valves. The central nodule is distinct and rectangular. Striae are indistinctly punctate, nearly parallel to radiate and may become curved toward the apices. In some specimens, two striae are aligned per fibula. Fibulae are unequally spaced along the length of the valve, with 6-10 fibulae in 10 µm.
Krammer and Lange-Bertalot (1991, p. 128) describe much finer striae for this taxon, which have not been seen in specimens from North America.
As indicated by Krammer and Lange-Bertalot (1988), the identity of this commonly reported species is uncertain. The Ehrenberg (1843) images of this species show a species clearly asymmetric to the
apical axis.
Autecology
This species has been reported, sometimes in relatively large numbers, from streams and rivers in North America, but these reports have not been verified. Larger populations of this taxon reside in soil and other aerophilous habitats.
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Size Range, µm3
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Motility
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Attachment
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Habitat
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Colony
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Occurrence
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BCG
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Waterbody
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Distribution
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Credit: Sylvia Lee
Active soil biofilms on the campus of Iowa Lakeside Lab
Original Description
Eunotia amphioxys, anguste linearis dorso leviter conver laevi, ventre leviter concavo subtiliter striato, apicibus subito attenuatis. Icon!
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BasionymEunotia amphioxys
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AuthorEhrenb. 1843
Original Images
Citations & Links
Citations
Links
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Index Nominum Algarum
Cite This Page
Kociolek, P., Polaskey, M., Lee, S. (2015). Hantzschia amphioxys. In Diatoms of North America. Retrieved December 16, 2024, from https://diatoms.org/species/50310/hantzschia_amphioxys
Responses
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Hantzschia amphioxys 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.
Hantzschia amphioxys
- Valves bent and constricted at center
- Raphe on the same side on both valves
- Apices protracted
- Striae indistinctly punctate
Valves are bent and constricted at the center ventral margin. Raphe on the same side on both valves within a cell. so that the valve face is asymmetric to the apical axis. The apices are protracted, especially in larger specimens. Striae are indistinctly punctate, nearly parallel to radiate and may become curved toward the apices.