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

Cyclopyxis arenata

Cyclopyxis arenata – after Boltovskoy and Lena, 1966 Cyclopyxis arenata (Cushman, 1930) Boltovskoy, 1956 Basionym: Pseudarcella arenata Cushman, 1930 Diagnosis: Hemispherical shell. Convex dorsal side,

Read More »

Cyclopyxis overview 2

C. impressa C. impressa C. stellata C. stellata C. crucistoma C. crucistoma C. crucigenia C. crucigenia C. grospietschi C. grospietschi C. triquestrus C. triquestrus C.

Read More »

Cyclopyxis profundistoma

Cyclopyxis profundistoma – from Kufferath, 1932 Cyclopyxis profundistoma Kufferath, 1932 Diagnosis: The yellowish grey colored test is made of coarser mineral particles, which are connected

Read More »

Cyclopyxis maynei

Cyclopyxis maynei – from Kufferath, 1932 Cyclopyxis maynei Kufferath, 1932 Diagnosis: Test cylindrical, characterized by the size of the aperture, which is 87-97 μm wide

Read More »

Cyclopyxis kahli obliqua

C. kahli var. obliqua , after Decloitre, 1978 Cyclopyxis kahli var. obliqua   Decloitre, 1978 Diagnosis:  Test with all the characteristics of the type species

Read More »