Difflugia styla, 119-139 µm

 
Difflugia styla Ogden & Zivkovic, 1983

Diagnosis: Shell transparent, ovoid with a more or less distinct aboral spine; shell composed of small to medium flattish pieces of quartz, and a network of organic cement is often seen around the aperture as part of the shell matrix; aperture circular and surrounded by smallish particles.

Dimensions: Ogden and Zivkovic, 1983: one specimen: length 97, breadth 54, diameter of aperture 29. My measurements (n > 20): 111 – 139 µm.

Ecology: Freshwater, sediments of ditches; I found this species around the Naardermeer.

Remarks: The description given by Ogden and Zivkovic has been based on one single specimen, without any knowledge about the variability of this species. They distinguish it from D. elegans which has a rough, irregular surface made of angular quartz particles and diatom frustules and which has a slight constriction of the neck which gives the aperture a flared appearance. My specimens fit well to the description of D. styla, but more species will fit. However, the photomicrograph is a better criterion, it is a type figure. This shell lacks however the very short but distinct neck of the Dutch specimens, and is also smaller, but this may fall within the variability.

This species might be identical with Difflugia elegans.

Difflugia styla
Photo of D. styla published by Ogden & Zivkovic, 1983
Difflugia styla, 111-127 µm

 

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