world of amoeboid organisms

Menu
Paravannella minima
Paravannella minima – from Kudryavtsev, 2014

Genus Paravannella Kudryavtsev, 2014

Diagnosis: Amoebae of fan-shaped morphotype usually below 10 µm in size and with a smooth outline. Floating form radial, with short, blunt hyaline pseudopodia. Glycocalyx may contain pentagonal glycostyles and simple filaments.

Type species (by monotypy): P. minima Kudryavtsev, 2014

Paravannella minima Kudryavtsev, 2014

Diagnosis: Measured length of the locomotive form 4.7–9 µm (average 5.8 µm), breadth 4.5–10 µm (average 6.7 µm), length:breadth ratio 0.62–1.2 (average 0.88); n = 100. Locomotive form rounded, oval or semicircular with smooth outline without folds or wrinkles. Single vesicular nucleus 1.7–3.3 µm (average 2.4 µm) in diameter, with central nucleolus, 1–2 µm in diameter (average 1.4); n=61. Radial floating form with short blunt hyaline pseudopodia not exceeding the diameter of the central cytoplasmic mass; rarely adopted.

Glycocalyx contains pentagonal tower-shaped glycostyles 100–125 nm long (average 113 nm) and simple filaments 190–291 nm long (average 249 nm) embedded in a basal amorphous layer 12–20 nm thick.

Ecology: Freshwater (aquarium filter mud), aerobic.

Remarks: Differs clearly from all sequenced vannellid genera in having two helices E23-2 and E23-3 in the region V4 of the SSU rRNA gene; similar to Ripella spp., Vannella aberdonica, V. langae, V. murchelanoi and V. peregrinia in the size of the locomotive form, but differs clearly from Ripella in having a smoother outline of the locomotive form, less frequent formation of a drop-shaped locomotive form with tapering posterior end, and a floating form with shorter pseudopodia; differs from the similar species of Vannella in having a floating form with radiating pseudopodia and a freshwater origin.

Reference: Kudryavtsev, A., 2014. Paravannella minima n. g. n. sp. (Discosea, Vannellidae) and distinction of the genera in the vannellid amoebae. Eur. J. Protistology 50, 258–269

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 »