• Category
  • Length Range
    13.0-14.7 µm
  • Width Range
    4.2-4.3 µm
  • Striae in 10 µm
    19 on raphe valve, 19-21 on rapheless valve

Identification

Description

Valves are linear-elliptical with capitate apices. Axial area on raphe valve narrowly lanceolate; axial area on rapheless valve linear. Both valves lack a distinct central area. The raphe is straight. Striae on raphe valve are slightly radiate to parallel; each stria in the middle of the raphe valve consists of a transapically elongated areola. The striae on rapheless valve are slightly radiate to parallel; each stria consists of two transapically elongated areolae and the areolae are separated by a narrow longitudinal hyaline area on each side of the valve.

The specimens illustrated here (from high elevation lakes in Wyoming) represent the first verified record of K. nitidiformis in the US. These specimens have striae that are more parallel than the slightly radiate striae illustrated in the iconotype.

Autecology

To date, K. nitidiformis has been verified from Holly Lake, Grand Teton National Park, Wyoming. Several records at ANSP have been misidentified as K. nitidiformis, rather than K. amoena.

Img 1552
Credit: S. Spaulding
Holly Lake, Grand Teton National Park

Original Description

Valvae elliptico-lanceolatae apicibus protractis, capitatis, 12-18 μm longae, 4,5-5 μm latae. Raphovalva: Raphe recta filiformis, area axialis angustissima linearis, area centralis nulla. Striae transapicales radiantes, leviter in media parte et in finibus capitatis, magis sub apicibus, circiter 21/10 μm. Areovalva: Area axialis angustissima linearis sicut rapho-valva. Striae transapicales paulum aut modice radiantes, 21/10 μm, bilateraliter linea hyalina intermissae.

Schalen elliptisch-lanzettlich mit schmaler bis breiter vorgezogenen kopfigen Enden, Länge 12-18 μm, Breite 4,5-5 μm, R-Schale mit gerade verlaufenden, fadenförmigen Raphenästen und sehr enger, linearer Axialarea, Zentralarea fehlt. Str. in der Mitte schwächer, vor den kopfigen Enden stärker radial und polar wieder schwächer radial ver-laufend, um 21/10 μm. RL-Schale ebenfalls mit sehr enger, linearer Axialarea, Zentralarea fehlt. Str. schwach radial bis annähernd parallel, 21/10 μm, auf jeder Seite von einer feinen hyalinen Linie unterbrochen. Holotypus: Coll. Krasske 4795b (Fig. 74: 19-22) Fundort des Holotypus: Kilpisjärvi in Finnland, Grundschlamm

Vorkommen: mehrere Exemplare in verschiedenen Proben am Typen-habitat, ein weiteres Exemplar auf den Färöer-Inseln gefunden, eine weitere (fragliche) RL-Schale in einem Süβwasseraquarium. Das Wasser an den Fundorten ist aufgrund der Diatomeenflora als mäβig elektrolyt-arm, oligotroph, circumneutral zu charakterisieren.

Die Sippe zeigt Konvergenzen zu A. amoena (incl. der synonymisierten Sippen, insbesondere A. orientalis Hustedt), zur fragwürdigen A. nitida Cleve-Euler (siehe dort) und — was die Strukturen, nicht den Umriβ betrifft — auch A. suchlandtii. Ihre Merkmalskombination ist jedoch anders.

  • Basionym
    Achnanthes nitidiformis
  • Author
    Lange-Bert. in Lange-Bert. and Krammer 1989
  • Length Range
    12-18 µm
  • Width
    4.5-5 µm
  • Striae in 10µm
    21

Original Images

K Nitidiformis  Orig Ill
K Nitidiformis  Orig Descr

EMAP Assessment

EMAP Distribution

Achnanthes Nitidiformis  Lange  Bertalot 40
Map 40

Response Plots

Achnanthes Nitidiformis  Lange  Bertalot

Cite This Page

Otu, M, and Spaulding, S. (2011). Karayevia nitidiformis. In Diatoms of North America. Retrieved June 23, 2018, from https://diatoms.org/species/karayevia_nitidiformis

Responses

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