world of amoeboid organisms

Menu
From Siemensma, 1991

Acanthocystis valdiviense Dürrschmidt, 1987

Diagnosis: Periplast, 20-25  µm in diameter (measurement based on whole mount), with 3 kinds of scales. Details of protoplast unknown. Plate scales, 1.2-1.8×1.0 to 1.5 µm, elliptical or ovoid, periphery with a small thickened rim, and with an axial thickening poorly developed and sometimes asymmetrically placed in the centre. Otherwise they are thin and patternless. Spine scales of two kinds, all with tubular straight shafts (0.17  µm in diameter), round base-plates (0.58 µm in diameter) and apically always with 4 pointed teeth. The base-plates are centrally depressed and surrounded by a narrow marginal rim. One kind of the spine scale (S1) is 5-7 µm long, with only slightly expanded distal ends and short distal teeth. The other (S2) is usuall half as long (ca. 2.6 µm) with distinctly expanded apices and longer apical teeth.

Ecology: Collected in 1979 from a paludal forest in southern Chile.

Remarks: The most distinctive characteristics of A. valdiviense are (1) the fixation of the number of apical points to 4 (6-8 in A. pectinata sspp. and A. polymorpha), (2) the minor flaring of the distal portion of spine scale type (S2) (0.4-0.6 µm compared to 1.1-1.5  µm in A. pectinata sspp. and ca. 2.0 µm in A. polymorpha), and (3) the length of the cylindrical portion of the shaft (2.2 µm compared to 1.3 µm in A. pectinata and 4-8  µm in A. polymorpha). There are also differences in the appearance of the plate scales. These are conspiciously larger in the case of A. polymorpha and more electron dense, while in A. pectinata sspp. additional ornamentations such as slits and dots are developed.

A. valdiviense bears also a certain resemblance to A. pusilla, for instance in the shape of the spine scales. However, both taxa are distinguished by the presence of only one type of spine scale, by the varying number of apical teeth (4-7), the less expanded distal ends, and by the pyriform and dotted plate scales.

Recent posts

Sphenoderia compressa

Sphenoderia compressa, after Badewitz, 2002 Sphenoderia compressa Badewitz, 2002 Diagnosis: Test ovoid, oval in cross section, hyaline, covered with relatively small, oval, rather irregularly arranged

Read More »

Tracheleuglypha elongata

T. elongata, A-C after Thomas and Gauthier-Lièvre, 1959; D after Van Oye, 1959 Tracheleuglypha elongata Van Oye, 1959 Diagnosis: Test similar to T. dentata, but

Read More »

Tracheleuglypha acolla

T. acolla, after Bonnet and Thomas, 1960 Tracheleuglypha acolla Bonnet and Thomas, 1955 Diagnosis: Test ovoid, non compressed, round in cross-section, with large oval overlapping

Read More »

Cyclopyxis kahli oblonga

C. kahli f. oblonga , after Tarnogradskii, 1959 Cyclopyxis kahli f. oblonga  (Tarnogradskii, 1959) Centropyxis kahli f. oblonga Tarnogradskii, 1959 Diagnosis:  Test with all the

Read More »

Cyclopyxis leclercqi

Cyclopyxis leclercqi – from Beyens and Chardez, 1986 Cyclopyxis leclercqi Beyens and Chardez, 1986 Diagnosis: Shell circular in apertural view, dorso-ventrally compressed with a swollen

Read More »

Haplomyxa saranae

Haplomyxa saranae Dellinger, 2014 Diagnosis: cell body from small rounded (0.1 mm) to large elongated shape (up to 3.5 x 0.3 mm), usually flat but

Read More »