world of amoeboid organisms

Menu
Acanthocystis clavata
From Siemensma, 1991

Acanthocystis tubata Dürrschmidt, 1987

Diagnosis: Periplast, ca. 25 µm in diameter, with two types of siliceous scales. Details of protoplast unknown. Plate scales ovoid or elliptical, 2.9-3.7 µm long and 2.2 µm wide, patternless, except for an axial thickening. Spine scales, 6-11 µm long and 0.23 µm wide at the narrowest point. Shaft cylindrical, gradually expanding towards the distal end. Apex, 0.4 µm in dia­meter, covered by a thin siliceous layer. A circle of about 12 conical teeth surrounds the apical margin. Base of the shaft supported by a circular, centrally depressed base­plate (diameter 1.2 µm) with peripheral rim.

Ecology: Surface sample collected 1982 in a swamp near Maramaranui, North Island, New Zealand.

Remarks: Dürrschmidt: A. tubata specimens reveal in the light microscope a striking similarity to A. mimetica Penard (1904), in the gradually expanded spine scale shafts, their circular base-plates and the dimensions of cells and scales. The only feature which contradicts an identification with A. mimetica is the absence of a conspicuous horse­shoe-like rim reported by Penard from the surface of the plate scales. Such a ‘rim’ appears sometimes during the LM observation of uneven structured plate scales, especially when these are somewhat tilted. Those scales are present, for instance in A. rotundata Nicholls ssp. rotoairense and A. pantopodeoides Nicholls (syn. A. cuneiformis Dürrschmidt. Thus it is assumed to be only an optical effect. However, the plate scales of A. tubata are flat. As no type material has been left by Penard, as inquiries at the following institutes revealed (British Museum, London; Museum D’Histoire Naturelle, Geneva; The Royal Microscopical Society, London; Museum National d’Histoire Naturelle, Paris) it will remain unclear on which specimens Penard based the diagnosis of A. mimetica.

A. tubata is easily recognized under the electron microscope by the shape of the spine scales. No variation in scale structure has been observed in specimens from different localities.

Recent posts

Haplomyxa spec.

Main cell body Haplomyxa spec. Description: The cell has a central body from which numerous granuloreticulopodia emerge. The cell body can be small or large,

Read More »

Haplomyxa spec.

Haplomyxa spec. These video’s show an undescribed Haplomyxa species which was collected from a mesotrophic freshwater pond in the Netherlands, January 2020, and kept in Petri

Read More »

Chlamydophrys-schaudinn

Fritz Schaudinn (1871 – 1906) was a German zoologist. He was the co-discoverer of the causative agent of syphilis and did research on amoebas, particularly

Read More »

Alabasta longicollis

Alabasta longicollis, after Penard, 1890 Alabasta longicollis  (Penard, 1890) Diagnosis: Test pyriform, very elongated (3 times as long as wide), transparent, very little compressed, embedded

Read More »

Alabasta kivuense

Alabasta kivuense, after Gauthier-Lièvre and Thomas, 1961 Alabasta kivuense  Gauthier-Lièvre and Thomas, 1961 Diagnosis: In frontal view, the test is finger-shaped with subparallel sides, the

Read More »

Paulinella micropora

Paulinella micropora, – from Lhee et al., 2017 Paulinella micropora Lhee, Yang, Kim, Andersen & Yoon, 2017 Diagnosis: Test elongate, with five columns of scales,

Read More »