Diatoms of North AmericaDiatoms of North America

Aulacoseira pusilla

(Meister) Tuji and Houki 2004

Aulacoseira Pusilla Guide
  • Category
    Centric
  • Diameter
    4.5-7.5 µm
  • Width Range
    2.2-4.5 µm
  • Striae in 10 µm
    24-26
  • Reported As
    Aulacoseira subborealis ((Nygaard) Denys, Muylaert and Krammer 2003)

Identification

Aulacoseira pusilla LM3 Aulacoseira pusilla LM4 Aulacoseira pusilla LM5 Aulacoseira pusilla LM6 Aulacoseira pusilla LM1 Aulacoseira pusilla LM2
View image metadata
Aulacoseira pusilla SEM3 Aulacoseira pusilla SEM2 Aulacoseira pusilla SEM1

Description

Cells are cylindrical and form short chains. Valves are 4.5-7.5 µm in diameter, with a mantle height of 2.2-4.5 µm. The ratio of the mantle height to valve diameter is usually is close to or slightly less than 1. The mantle has slightly convex sides and the valve face is flat or very slightly convex. Rows of pervalvar areolae are curved to the right (dextrorse) and number 24-26 in 10 µm. The collum is approximately 1/4 - 1/5 of the mantle height. The valve face has scattered small and faint areolae. The spines are robust, pointed and each spine originates from two or three pervalvar costae. The ringleiste is solid and shelf-like.

This taxon was originally described from Lake Suwa, Japan (Meister 1913). It was later documented from this species lakes and ponds in Japan, including Lake Biwa and its lagoon, Katata Lagoon (Tuji and Houki 2004).

Autecology

This taxon has been reported widely across the US, although it was described from Japan. Records should be carefully examined to determine if this apparent disjunct distribution of a single taxon is accurate.

Original Description

Schalen zylindrisch, Gürtelseite rechteckig mit geraden Seiten und wenig abgerundeten Ecken. Die benachbarten Zellen sind eng verbunden und weichen an den Rändern nur wenig auseinander, so daβ ein schwacher Pseudosulcus gebildet wird. Die Ränder der Zellen sind mit sehr kurzen Zähnchen besetzt, die nicht bei allen Zellen sichtbar sind. Die Schalenseite ist rund ohne erkennbare Struktur. Die Mantelfläche ist mit geradlinigen, der Pervalvarachse parallel laufenden, sehr schwachen, schwer sichtbaren Porenreihen besetzt, deren Zahl etwa 20 in 10 μ betragen dürfte. Der Sulcus bildet eine schmale, aber ziemlich stark nach innen dringende Hohlkehle. Der Durchmesser der Schalen beträgt 6—8 μ, die Höhe der ganzen Zelle 6—9 μ, die Höhe der punktierten Mantelfläche 2—31/2 μ. Im Sommer sind die Fäden ganz kurz, meist nur aus 3 Zellen gebildet, im Herbst treten längere Fäden mit 8—12 Zellen auf; die Fäden sind immer gerade. Im Plankton des Suwasees durch das ganze Jahr ziemlich häufig. Habitus der M. distans, aber viel kleiner und ungleich feiner punktiert.

  • Basionym
    Melosira pusilla
  • Author
    F.Meister 1913
  • Length Range
    6-8 µm
  • Width
    6-9 µm
  • Striae in 10µm
    20

Original Images

Orig Illr Aupus
Orig Descr Aupus

Cite This Page

Potapova, M. (2010). Aulacoseira pusilla. In Diatoms of North America. Retrieved December 26, 2024, from https://diatoms.org/species/45206/aulacoseira_pusilla

Responses

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

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