world of amoeboid organisms

Nebela ansata
Cornutheca ansata, photomicrograph: Robert K. Booth

Cornutheca ansata (Leidy, 1879) Kosakyan et al., 2016

Diagnosis: Test pyriform in broad lateral view, laterally compressed, with a pair of hollow horns protruding, one on either side of the neck one-third of the distance from the pseudostome to the fundus. Test almost transparent or slightly yellowish-brownish, composed of small oval particles probably predated from small euglyphids. Pseudostome slightly curved in broad lateral view.

Dimensions: Test length (195) 220-264 (270) µm, width (between the ends of the lateral horns): (110) 130-150 (169) µm, width of the main body 90-125 µm, horn length 25-59 µm. Pseudostome 40-55 µm wide.

Ecology: in Sphagnum-dominated peat lands in the north-eastern part of North America.

Remarks: This easy recognizable, even for non-specialists, and remarkable species has a very limited distribution range in the temperate part of eastern North America. Joseph Leidy found this remarkable-looking shelled protozoan while making microscopical investigations of samples from Sphagnum, collected from cedar swamps near Absecom and Malaga, Gloucester County in New Jersey, USA. Since these initial investigations, only four publications have reported finding this species, at a site near the original Leidy locality (Stokes, 1882; Hoogenraad & de Groot, 1952) and at a site near Lanoraie, in southern Quebec (Fantham & Porter,1945). Recently it has been rediscovered in New Jersey and Nova Scotia (Heger et al, 2011).

Literature: Heger, T. J., Booth, R. K., Sullivan, M. E., Wilkinson, D. M., Warner, B. G., Asada, T., Mazei, Y., Meisterfeld, R. and Mitchell, E. A. D.: Rediscovery of Nebela ansata (Amoebozoa: Arcellinida) in eastern North America: biogeographical implications – Journal of Biogeography 38, issue 10, 1897-1906, 2011.

Nebela ansata-like
This specimen was collected from the Sima-Moor in Tirol, Austria (2012). It shows two faint lateral projections, comparable with those in C. ansata, shell length 178 µm.
Nebela ansata
C. ansata, from Leidy, 1879
Nebela ansata
C. ansata, from Leidy, 1879
Ferry Siemensma, created February 24, 2019; last modified January 05, 2022
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