• Reported As
    Cymbella muelleri ((Patrick and Reimer 1975, pl.7, fig. 1))
    Encyonema sinicum ((Krammer 1997, figs 44-55))

Identification

Description

Valves are strongly dorsi-ventral. The dorsal margin is narrowly arched, while the ventral margin is linear. Valve length is 56-76 μm; breadth is 16.5-19 μm. The valve apices are broadly rounded. The axial area is relatively broad in the central part and an oval area is expanded towards the dorsal margin, narrowing at the valve ends. The raphe branches have a slight arch towards the ventral margin. Each raphe branch is positioned nearly centrally within the axial area. Proximal raphe ends are slightly expanded and dorsally deflected. Distal raphe ends curve slightly to the dorsal margin, but are deflected ventrally near the valve apices. The dorsal striae are slightly divergent. Externally, the rows of dorsal areolae closest to the central area are oval, and become lineolate, or apically elongate. Dorsally, central striae number 9 in 10 μm and distal striae number 5-6 in 5 μm. Ventrally, central striae 7 in 10 μm, and distal striae 6 in 5 μm. The density of areolae within a central, dorsal stria is 9 in 5 μm.

Autecology

Original Description

Valvulae sunt valde dorsiventrales. Dorsualis margo anguste arcuata est, sed ventralis margo linearis est. Valvulae longitudo 56-76 μm est; amplitudo 16.5-19 μm est. Valvulae terminationes roundatus late. Axialis superficies est relative ampla in centrali valvula et ovalis extrinsecus. Suturae ramificationes levem habent arcum ad ventralem marginem. Unaquaeque suturae ramificatio posita est fere centrali positione intra axialem superficiem. Suturae extrema proxima leviter sunt expansi et dorsualiter deflexi. Suturae extrema distalia suturae curvaminis leviter inflectuntur marginem ad dorsualem, sed ventraliter sunt deflexa prope valvulae apices. Dorsuales striae sunt in diversum leviter. Externe, primae series sunt ovales fiuntque lineolatae, maiorque fit lineolatarum longitudo ad dorsualem marginem. Dorsualiter, striae numeris 9 sunt in 10 μm; centraliter sunt 7 in 10 μm.

  • Author
    S.A.Spauld. 2010
  • Length Range
    56-76 µm
  • Width
    16.5-19 µm
  • Striae in 10µm
    9

Original Images

Eolimna metafarta orig desc
Original text and images reproduced with permission by Academy of Natural Sciences of Philadelphia.

Cite This Page

Spaulding, S. (2010). Encyonema nicafei. In Diatoms of North America. Retrieved June 17, 2018, from https://diatoms.org/species/encyonema_nicafei

Responses

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