Hippodonta capitata

(Ehrenberg) Lange-Bertalot, Metzeltin and Witkowski 1996      Category: Symmetrical biraphid
BASIONYM: Navicula capitata Ehrenberg 1838

Hannaea arcus

 

Hippodonta capitata subsp. iberoamericana
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LM scalebar = 10 µm = 80 pixels.

Observations

Contributor: Marina Potapova - February 2011
Length Range: 12-28 µm
Width Range: 4.9-8.5 µm
Striae in 10 µm: 8-11

Description

Valves are elliptical-lanceolate with capitate to subcapitate apices. The axial area is narrow and linear. The central area is small, round or elliptical. The raphe is straight, filiform, with slightly expanded external proximal ends. The distal raphe ends are deflected to the secondary valve side. The striae are biseriate, radiate in the valve center and convergent at the apices. The areolae are elongated and generally oriented in the apical axis. Internally the striae open into shallow alveoli. A hyaline area and one or two apical rows of areolae are present at each end of the valve.

Original Description

Basionym: Navicula capitata
Author: Ehrenberg 1838
Length Range: µm
Striae in 10 µm:

Original Description

N. striata, testula brevi ovato-lanceolata, utroque fine constricta obtuse, in centesima lineae parte 10 strias offerens.

Original Images

Cite This Page:
Potapova, M. (2011). Hippodonta capitata. In Diatoms of the United States. Retrieved May 24, 2013, from http://westerndiatoms.colorado.edu/taxa/species/hippodonta_capitata

Species: Hippodonta capitata

Contributor: Marina Potapova

Reviewer: Pat Kociolek

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Image Credit: Marina Potapova

  1. Valves 4.9-8.5 μm wide
  2. Apices capitate or subcapitate
  3. Striae biseriate, 8-11 in 10 μm

Valves are elliptical-lanceolate with capitate to subcapitate apices. The striae are biseriate, 8-11 in 10 μm. A hyaline area is present at each end of the valve.

Compare

Hippodonta capitata differs from H. hungarica and H. capitata subsp. iberoamericana by capitate or subcapitate apices. The valves of H. capitata are, on average, wider and striae are more robust compared to H. capitata subsp. iberoamericana.

Hippodonta hungarica

Hippodonta capitata subsp. iberoamericana

Citations

Cox, E.J. (1987). Studies on the diatom genus Navicula Bory. VI. The identity, structure and ecology of some freshwater species. Diatom Research 2: 159-174.

Ehrenberg, C.G. (1838). Die Infusionsthierchen als vollkommene Organismen. Ein Blick in das tiefere organische Leben de Natur. erlag von Leopold Voss, Leipzig. pp. 1-xvii, 1-548, pls. 1-64.

Lange-Bertalot, H. (2001). Navicula sensu stricto, 10 genera separated from Navicula sensu lato, Frustulia. Diatoms of Europe 2: 1-526.

Lange-Bertalot, H., Metzeltin, D. and Witkowski, A. (1996). Hippodonta gen. nov. Umschreibung und Begrundung einer neuen Gattung der Naviculaceae. Iconographia Diatomologica 4: 247-275.

Patrick, R.M. and Reimer, C.W. (1966). The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1. Monographs of the Academy of Natural Sciences of Philadelphia 13.

Links & ID's

Index Nominum Algarum (INA)

California Academy of Sciences (CAS)

Hippodonta capitata CAS

North American Diatom Ecological Database (NADED)

NADED ID: 213001

Autecology Discussion

Habits

Size Range

101-1000 µm3 (ie Amphora veneta)

Motility

moderately motile (e.g. Navicula tripunctata)

Attachment

unattached

Habitat

benthic

Colony

solitary

EMAP Assessment

Sampling for the Environmental Protection Agency (EPA) western Environmental Monitoring and Assessment Program (EMAP) study was completed during the years 2000-2004 (see citations at bottom of this page). Streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming). Over 1200 sites on streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming) were selected for sampling based on a stratified randomized design. This type of design insures that ecological resources are sampled in proportion to their actual geographical presence. Stratified randomized design also allows for estimates of stream length with a known confidence in several “condition classes” (good or least-disturbed, intermediately-disturbed, and poor or most-disturbed) for biotic condition, chemistry and habitat.

EMAP Distribution

Hippodonta capitata

Distribution

The distribution map represents the relative abundance of this Hippodonta capitata in the western EMAP study. Relative abundance is a measure of the proportion of cells of this species based on a "fixed count" of 300 total diatom cells counted and identified. Each of the western EMAP sample sites is shown, either with a black dot for sites where Hippodonta capitata was not recorded, or with a red circle indicating the relative abundance of Hippodonta capitata.

Note that the size of the proportional symbols varies between species to help show both abundant and rare species.

Scale for the map to the left

EMAP Response Plots

Hippodonta capitata

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Hippodonta capitata 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.

EMAP citations

Results are published in:

Johnson, T., Hermann, K., Spaulding, S., Beyea, B., Theel, C., Sada, R., Bollman, W., Bowman, J., Larsen, A., Vining, K., Ostermiller, J., Petersen, D. Hargett, E. and Zumberge, J. (2009). An ecological assessment of USEPA Region 8 streams and rivers. U.S. Environmental Protection Agency Region 8 Report, 178 p.

Stoddard, J. L., Peck, D. V., Olsen, A. R., Larsen, D. P., Van Sickle, J., Hawkins, C. P., Hughes, R. M., Whittier, T. R., Lomnicky, G. A., Herlihy, A. T., Kaufman, P. R., Peterson, S. A., Ringold, P. L., Paulsen, S. G., and Blair, R. (2005). Environmental Monitoring and Assessment Program (EMAP) western streams and rivers statistical summary. U.S. Environmental Protection Agency Report 620/R-05/006, 1,762 p.

Stoddard, J. L., Peck, D. V., Paulsen, S. G., Van Sickle, J., Hawkins, C. P., Herlihy, A. T., Hughes, R. M., Kaufman, P. R., Larsen, D. P., Lomnicky, G. A., Olsen, A. R., Peterson, S. A., Ringold, P. L., and Whittier, T. R. (2005). An ecological assessment of western streams and rivers. U.S. Environmental Protection Agency Report 620/R-05/005, 49 p.