Vannella
Vannella Bovee, 1965 (ref. ID; 2093, 4882, 6796)
Class Flabellinea: Order Vannellida: Family Vannellidae Bovee, 1979 (ref. ID; 6789)
Amoebae: Gymnamoebia (ref. ID; 2093)
Amoebae: Lobosea Carpenter, 1861 (ref. ID; 5772)
Family Vannellidae (Bovee, 1970) Page, 1987 (ref. ID; 4882)
[ref. ID; 2093]
Re-diagnosis; Locomotive form flattened, with flabellate, spatulate, occasionally oval outline; fan-like hyaline veil occupying anterior quarter to half and usually extending around sides of granular mass; no pseudopodia during locomotion; no uroidal filaments. Floating form of most but not all species with rounded central mass and several slender, hyaline pseudopodia tapering to narrow tip. Surface always covered with delicate flexible structures (glycostyles) consisting of central tubule and five radial wings, approximately 95 to 120 nm in height above plasma membrane and 40 to 65 nm in diameter at base. Uninucleate. Nuclear division with nuclear membrane often but not always persisting in part or in whole through metaphase. No cysts known. Marine and freshwater. (ref. ID; 2093)
Type species; Vannella mira (Schaeffer, 1926) (ref. ID; 2093)
[ref. ID; 6796]
Emended diagnosis; Flattened, fan-shaped, spatulate, crescent-shaped, or semicircular amoebae with a large frontal hyaline area. Locomotive cells form neither pseudopodia nor subpseudopodia and are smooth in outline. Cell coat includes pentagonal glycostyles or a layer of densely packed prismatic elements 20-40 nm in thickness. (ref. ID; 6796)
Type species; Vannella mira (Schaeffer, 1926) Smirnov, 2002 (ref. ID; 6796)
- Vannella aberdonica Page, 1980 (ref. ID; 5772, 6796)
- Vannella anglica Page, 1980 (ref. ID; 6796)
- Vannella arabica Page, 1980 (ref. ID; 6796) reported author and year? (ref. ID; 4118)
- Vannella australis (Page, 1983) comb. nov. (ref. ID; 6796 redescribed paper)
Syn; Platyamoeba australis Page, 1983 (ref. ID; 6796)
- Vannella bursella (Page, 1974) comb. nov. (ref. ID; 6796 redescribed paper)
Syn; Platyamoeba bursella Page, 1974 (ref. ID; 6796, 6922)
- Vannella caledonica Page, 1979 (ref. ID; 1883, 2093 original paper, 6796)
- Vannella calycinucleolus (Page, 1974) comb. nov. (ref. ID; 6796 redescribed paper)
Syn; Platyamoeba calycinucleolus Page, 1974 (ref. ID; 6796, 6922)
- Vannella cirifera (Frenzel, 1892) Page, 1988 (ref. ID; 6796)
- Vannella crassa (Schaeffer, 1926) (ref. ID; 6796)
- Vannella danica (ref. ID; 6796 original paper)
- Vannella devonica Page, 1979 (ref. ID; 2093 original paper, 6796) reported author and year? (ref. ID; 6789)
- Vannella douvresi Sawyer, 1975 comb. nov. (ref. ID; 6796 redescribed paper)
Syn; Platyamoeba douvresi Sawyer, 1975 (ref. ID; 6796)
- Vannella ebro Smirnov, 2001 (ref. ID; 6796)
- Vannella flabellata Page, 1974 comb, nov. (ref. ID; 6796 redescribed paper)
Syn; Platyamoeba flabellata Page, 1974 (ref. ID; 6796)
- Vannella langae Sawyer, 1975 comb. nov. (ref. ID; 6796 redescribed paper)
Syn; Platyamoeba langae Sawyer, 1975 (ref. ID; 6796)
- Vannella lata Page, 1988 (ref. ID; 6796)
- Vannella mainensis Page, 1971 comb, nov. (ref. ID; 6796 redescribed paper)
Syn; Platyamoeba mainensis Page, 1971 (ref. ID; 6796)
- Vannella mira Schaeffer, 1926 (ref. ID; 2093, 2359, 2431) or (Schaeffer, 1926) Smirnov, 2002 (ref. ID; 6796)
Syn; Flabellula mira (ref. ID; 2093)
- Vannella miroides Bovee, 1965 (ref. ID; 6796)
- Vannella murchelanoi Sawyer, 1975 comb. nov. (ref. ID; 6796 redescribed paper)
Syn; Platyamoeba murchelanoi Sawyer, 1975 (ref. ID; 6796)
- Vannella nucleolilateralis (Anderson, Nerad et Cole, 2003) comb. nov. (ref. ID; 6796 redescribed paper)
Syn; Platyamoeba nucleolilateralis (Anderson, Nerad et Cole, 2003) (ref. ID; 6796)
- Vannella peregrinia Smirnov & Fenchel, 1996 (ref. ID; 4882 original paper, 6796)
- Vannella persistens Smirnov & Brown, 2000 (ref. ID; 6796)
- Vannella placida (Page, 1968) comb. nov. (ref. ID; 6796 redescribed paper)
Syn; Platyamoeba placida Page, 1968 (ref. ID; 6796)
- Vannella platypodia (Glaser, 1912) (ref. ID; 2093, 2359)
See; Ripella platypodia (ref. ID; 6796)
- Vannella plurinucleolus (Page, 1974) comb. nov. (ref. ID; 6796 redescribed paper)
Syn; Platyamoeba plurinucleolus Page, 1974 (ref. ID; 6796)
- Vannella pseudovannellida (Hauger, Rogerson and Anderson, 2001) comb. nov. (ref. ID; 6796 redescribed paper)
Syn; Platyamoeba pseudovannellida Hauger, Rogerson and Anderson, 2001 (ref. ID; 6796)
- Vannella sensillis Bovee, 1953 (ref. ID; 6796)
- Vannella septentrionalis Page, 1980 (ref. ID; 6796)
- Vannella simplex (Wohlfarth-Bottermann, 1960) (ref. ID; 2093, 2359) or (Wohlfarth-Bottermann, 1960) Bovee, 1965 (ref. ID; 6796) reported author and year? (ref. ID; 6789)
- Vannella weinsteini (Sawyer, 1975) comb. nov. (ref. ID; 6796 redescribed paper)
Syn; Platyamoeba weinsteini Sawyer, 1975 (ref. ID; 6796)
Descriptions
Locomotive form semi-circular to fan-shaped or drop-shaped; posterior edge straight or concave; some cells may acquire drop-shaped form with pronounced 'tail' (see Page 1983, fig.67). The frontal hyaloplasm occupies about half the cell. Greatest dimension 6.5-13 um (average 8.8 um), length/breadth ratio 0.8-1.5 (average 1.0). Single vesicular nucleus 1.9-3.2 um in diameter (average 2.6 um) with central nucleolus 0.9-1.4 um in diameter (average 1.1 um). Floating form thickly flattened, twisted, never rounded up; never with pseudopodia. Locomotive rates at 23 degrees C on a glass surface is 14.8-28.6 um/min (1.5-3.7 times the length of amoebae) (Page 1980). Cell surface includes glycostyles about 120 nm long and simple filaments up to 280 nm long. Description: Page (1980). Illustrations: Page (1980, 1983). Because of the general similarity of the smallest vannelid amoebae, later records of this species (e.g. Butler and Rogerson 2000; Garstecki and Arndt 2000; Vors 1993) require molecular and TEM checks to prove that mentioned strains really are V. aberdonica, and not some other small vanellid amoebae. (ref. ID; 6796)
Habitats
Marine. (ref. ID; 6796)
Type slides by F.C. Page
Britisch Museum of Natural History (holotype 1980:1:24:1; paratype 1980:1:24:2). (ref. ID; 6796)
Available cultures
ATCC50815 isolated by M. Peglar; there is no published LM or EM data on this isolate; its complete 18S rRNA gene sequence was obtained by Peglar et al. (2003; GenBank AY121853). (ref. ID; 6796)
Descriptions
Locomotive form semicircular, spatulate or fan-shaped. The granuloplasmic mass is thick and rounded; frontal hyaloplasm occupies 0.3-0.5 of its total length; posterior edge rounded or irregularly triangular; never straight or drawn out into a tail. Greatest dimension 15-37 um (average 21-24 um); length/breadth ratio 0.7-2.0 (average 1.0-1.2). Single vesicular nucleus 3.8-6.2 um in diameter (average 4.9-5.3 um) with central nucleolus 2.3-3.7 um in diameter (average 2.5-3.0 um). Floating form with blunt hyaline pseudopodia, irregularly distributed and with length not greater than the diameter of central cell mass. Rate of locomotion 13-32 um/min (0.5-1.7 length of an amoeba) (Page 1980). Cell surface includes glycostyles 117-126 nm long and simple filaments up to 240 nm in length. Description: Page (1980). Illustrations: Page (1980, 1983). (ref. ID; 6796)
Habitats
Marine. (ref. ID; 6796)
Type slides by F.C. Page
British Museum of Natural History (holotype 1980:1:24:3; paratype 1980:1:24:4). (ref. ID; 6796)
Available cultures
CCAP1589/8 (type culture) and 1589/11 by F.C. Page. Partial 18S rRNA gene sequence of 1589/8 strain (GenBank AF464913) by Sims et al. (2002); complete 18S rRNA gene sequence of this strain (GenBank AF099101) by Sims et al. (1999). (ref. ID; 6796)
Vannella arabica Page, 1980 (ref. ID; 6796) reported author and year? (ref. ID; 4118)
Descriptions
Locomotive form flabellate or semi-circular. Frontal hyaloplasm occupies about half the body length; posterior end widely rounded, straight or (rarely) concave. Greatest dimension 17-37 um (average 27 um); length/breadth ratio 0.5-1.2 (average 0.8). Single vesicular nucleus 4.2-6.5 um in diameter (average 5.4 um) with central nucleolus 1.9-3.7 um in diameter (average 2.7 um). Floating form a rounded mass, without pseudopodia or with few (not more than three) blunt hyaline pseudopodia, rarely exceeding in length the diameter of the central mass. Locomotive rate 20-48 um/min (1.0-2.1 times the cell length) (Page 1980). Cell surface includes glycostyles about 114 nm long and simple filaments up to 215 nm in length. Description: Page (1980). Illustrations: Page (1980, 1983; Figs.5-9). (ref. ID; 6796)
Molecular identification. (ref. ID; 6922)
Habitats
Marine. (ref. ID; 6796)
Type slides by F.C. Page
British Museum of Natural History (holotype 1980:1:24:5; paratype 1980:1:24:6). (ref. ID; 6796)
Available cultures
CCAP1589/7 (type culture). Complete 18S rRNA gene sequence (GenBank EF051194) obtained in this study. (ref. ID; 6796)
Vannella australis (Page, 1983) comb. nov. (ref. ID; 6796 redescribed paper)
Synonym
Platyamoeba australis Page, 1983 (ref. ID; 6796)
Descriptions
Spatulate or fan-shaped in locomotion. Posterior end often triangular; frontal hyaline zone normally occupies entire anterior half of the cell. The posterior granuloplasmic region is often thick and very refractile. Greatest dimension 22-44 um (average 32.3 um). Length/breadth ratio 0.6-2.5 (average 1.0). Floating form with thick, blunt sometimes curved radiate pseudopodia, in length exceeding the diameter of the central cytoplasmic mass by up to two-fold. Single vesicular nucleus 5.6-8.4 um in diameter (average 6.7 um) with central nucleolus 2.3-4.7 um in diameter (average 3.8 um). Glycocalyx about 30 nm in thickness; consists of densely packed hexagonal elements. Description and illustrations: Page (1983); Figures 10-12. (ref. ID; 6796)
Habitats
Marine. (ref. ID; 6796)
Available cultures
CCAP1565/9 (type culture). Complete 18S rRNA gene sequence (GenBank EF051199) was obtained in the present study. (ref. ID; 6796)
Vannella bursella (Page, 1974) comb. nov. (ref. ID; 6796 redescribed paper)
Synonym
Platyamoeba bursella Page, 1974 (ref. ID; 6796, 6922)
Descriptions
Locomotive form flattened ovoid, semi-circular or spatulate; thickness of the granular region often shaped as a transverse spindle. Posterior edge rounded or convex; surface wrinkles often occur parallel and near to edges. Greatest dimension of locomotive form 12-37 um (average 18-25 um). Single vesicular nucleus 3.7-7.4 um in daimeter with rounded central nucleolus. Locomotive form with several blunt hyaline pseudopodia, often asymmetrically disposed relative to the central cytoplasmic mass. Cell coat of densely packed hexagonal elements is about 26 nm thick. Description: Page (1974). Illustrations: Page (1975, 1983); Figures 13-17. (ref. ID; 6796)
Molecular identification. (ref. ID; 6922)
Habitats
Marine and brackish-water. (ref. ID; 6796)
Type slides by F.C. Page
British Museum of Natural History (holotype 1974:1:9:3; paratype 1974:1:9:4). (ref. ID; 6796)
Available culture
CCAP1565/10 by F.C. Page. Complete 18S rRNA gene sequenced (GenBank EF051195) in the present study. (ref. ID; 6796)
Vannella caledonica Page, 1979 (ref. ID; 1883, 2093 original paper, 6796)
Diagnosis
Locomotive form with anterior edge often wavy; greatest dimension approximately 10 to 25 um, mean about 15 or 16 um; mean length : breadth ratio 1.1 to 1.2; floating form without long, radiate pseudopodia; nucleus approximately 2.8 to 4.7 um, with central nucleolus; slender filaments, sometimes nearly 300 nm long, among glycostyles. Marine. (ref. ID; 2093)
Descriptions
Marine species. (ref. ID; 2093, 6796)
- Light-microscopy: In locomotion the amoebae are commonly flagellate, i.e., flattened with a triangular outline and a deep, arc-like anterior hyaline zone (veil), the anterior edge of which is often but not always wavy. The posterior end sometimes tapers to a narrow tip. The hyaline zone may divide temporarily as the amoeba pushes forward simultaneously on both sides at an angle to its previous line of advance. At times the tapered posterior end is drawn up into the main mass. Flow of the granuloplasm is easily observed. The hyaline zone, measured at the midpoint, occupies from 0.3 to 0.5 of the length of the amoeba. The locomotive rates of 10 amoebae of strain 212 at 23 degrees were 23 to 30 um per minute, or 1.3 to 2.0 times the lengths. Those of 213 at 28 degrees were 22 to 47 um per minute, or 1.6 to 2.3 times the length. The floating forms produced never put out any radiate pseudopodia. This observation was made in repeated examinations of many cells of strain 212 and at least two examinations of many cells of strain 213. The nucleus has the structure most common in small and medium-sized amoebae, with a central nucleolus. It is, as usual, somewhat deformable during cytoplasmic flow. In nuclear division, the nucleolus disappears during prophase. In early metaphase, the nuclear membrane is still present, with a slight deposit sometimes seen on its inner surface. In at least one metaphase figure, with the chromosome (individually not distinguishable) in a well-formed ring, no nuclear membrane was seen. However, one early anaphase had a suggestion of remnants of membrane along either side of the spindle, though no nuclear membrane at all was left in another anaphase little if may more advanced. There seems to be some variation in the time of disappearance of the nuclear membrane, as reported by Page (1968) for Vannella mira. No centriole-like body was seen. Amoebae of this species are well rounded up by late metaphase, sometimes with a thin, flattened hyaline edge. (ref. ID; 2093)
- Electron-microscopy: External to the plasma membrane is an amorphous basal layer about 8 nm thick, in which are embedded the bases of glycostyles identical in structure and very close in size to those of the freshwater species. Each consists of five flat wings radially arranged around a central tubule, with which they fuse. At a narrow neck in the distal half of each glycostyle, the wings are reduced to thickenings in the central tube, and the entire structure then flares toward the distal end, with traces of the wings remaining. Since the glycostyles are flexible and move in relation to each other, the measurements vary in sections, but the height of the tip above the plasma membrane was about 94 nm and the diameter of the glycostyle approximately 38 nm at the base, 13 at the neck, and 17 at the tip. Scattered amongst the glycostyles are a smaller number of slender simple filaments, up to 281 nm long. The function of the glycostyles, this adhesion to a bacterium accords with the idea of the glycostyles as sticky structures. Young food vacuoles are lines with a coating, including glycostyles, similar to that on the surface, though such a coating is absent in more advanced digestive vesicles. Some of the rounded vesicles with a very distinct coating resembling the cell surface appear to be carrying membrane for renewal of the surface. Among internal organelles, the mitochondria appeared somewhat less well fixed than others. They were oval to sausage-shaped, the longest seen measuring 1.28 x 0.64 um. The cristae were tubular and anastomosing. The central part of some mitochondria was empty of cristae but contained filaments, and it is not entirely certain that this appearance is due to a deficiency of fixation. The sections examined contained up to two Golgi bodies per cell, neither closely associated with the nucleus. Each consisted of about five cisternae, which were less flatten than those of some other amoebae. The Golgi body as a whole, about 0.6 um wide, had no concave of convex side. The rough endplasmic reticulum consisted of isolated flattened cisternae bearing ribosomes. Filaments were seen here and there in the cytoplasm. The nucleus showed no unusual features. The central nucleolus was granular, sometimes with one dense patch. The perinuclear cisterna varied much in width, and the external surface of the nuclear envelope was studded with ribosomes. (ref. ID; 2093)
- Cysts: Cysts have never been seen in either strain of V. caledonica. (ref. ID; 2093)
Locomotive form fan-shaped or flabellate, often with uneven anterior edge. Frontal hyaline zone arc-shaped; occupies about half the total cell area. Greatest dimension 10-25 um (average 16 um); length/breadth ratio about 1.2. Single nucleus, 2.8-4.7 um in diameter, commonly vesicular, with single central nucleolus, but other configulaions of the nucleolar material also were noted (Page 1979). Floating form without radiating pseudopodia. Cell coat includes glycostyles about 94 nm long and simple filaments up to 281 nm long. Rate of locomotion 22-47 um/min (1.3-2.3 times the length per minute). Description: Page (1979). Illustrations: Page (1979, 1983). (ref. ID; 6796)
Type locality
From the Morar Estuary, Highland Region. (ref. ID; 2093)
Stock strain
The Culture Centre of Algae and Protozoa. (ref. ID; 2093)
Type material
Type slides have been deposited in the British Museum (Natural History). holotype 1978:6:28:3, paratype 1978:6:28:4). (ref. 2093)
Vannella calycinucleolus (Page, 1974) comb. nov. (ref. ID; 6796 redescribed paper)
Synonym
Platyamoeba calycinucleolus Page, 1974 (ref. ID; 6796, 6922)
Descriptions
Locomotive form flattened, ovoid, spatulate or semi-circle. The hyaloplasm occupies half or more of the total body area; posterior edge commonly is straight or convex. Some wrinkles may occur parallel to the edge of an amoeba. Greatest dimension in locomotion 20-56 um (average 21-29 um); length/breadth ratio 0.6-1.3 (average 0.8-0.9). Floating form with several uneven blunt hyaline pseudopodia. Single nucleus 3.7-7.5 um in diameter with peculiar central "calyciform" nucleous, cup-shaped, with depression on one side. Cell coat consists of densely packed hexagonal elements and is about 40 nm in thickness. Description: Page (1974). Illustrations: Page (1974, 1983); Figures 18-22. A strain identified as P. calycinucleolus was illustrated by Smirnov by LM and EM characters (1999), but not sequenced so it is a preliminary identification. (ref. ID; 6796)
Molecular identification. (ref. ID; 6922)
Habitats
Marine, possibly brackish-water. (ref. ID; 6796)
Type slides by F.C. Page
British Museum of Natural History (holotype 1974:1:9:5; paratype 1974:1:9:6). (ref. ID; 6796)
Available culture
CCAP1565/6 (type culture). Complete 18S rRNA gene sequence (GenBank EF051193) was obtained in the present study. (ref. ID; 6796)
Vannella cirifera (Frenzel, 1892) Page, 1988 (ref. ID; 6796)
Remarks
Doubtful species, never reliably re-isolated. The name was arbitrary applied by Page (1976) to recognize a Vannella simplex-like species, possessing minor differences from V. simplex in locomotive and floating form. This strain was described by Page (1976) as V. mira Schaeffer, 1926; later he accepted that V. mira must be marine, so used the name V. cirifera as substitute (see Smirnov 2002 for nomenclatural history). No argument for its similarity with Saccamoeba cirifera Frenzel, 1892 beyond "great resembles of figures" was given; since we now know how polymorphous vannellas can be, this argument can hardly be accepted. This strain was lost long ago. It would be best to establish a neotype of V. cirifera if one finds a freshwater vannellid strain resembling that described by Page (1976, 1988). Formal description of this strain after Page (1976, 1988): 'usually flabellate, seldom somewhat spatulate, greatest dimension 25-55 um; nucleus 4.8-8.3 um; floating form often symmetrical but somewhat irregular, with most of cytoplasm in 1-3 long pseudopodia; slow to settle from floating form; attaches poorly. Cell surface includes glycostyles about 110 nm in length; no simple filaments among glycostyles. It seems that the later character and the low number of pseudopodia in the floating form differentiates it from V. simplex. Description: Page (1976 -as V. mira; 1988). No type material. ATCC strain 50924 (isolator T. Nerad) designated V. cirifera lacks published data, hence we cannot comment on its identification. (ref. ID; 6796)
Vannella crassa (Schaeffer, 1926) (ref. ID; 6796)
Remarks
This was never re-isolated since the initial description, but its remarkable size and good description by Schaeffer (1926) would probably allow recognition, if found. A description compiled from Schaeffer's obsevations follows. Locomotive form triangular or fan-shaped. Frontal hyaloplasm forms a wide anterior margin and occupies less than half the total cell area. The anterior edge is smooth, but its margin is frequently deeply incised; the posterior edge is irregular triangular or drawn out into a characteristic tail. Length in locomotion 40-50 um. Rate of locomotion ~25 um/min. Single vesicular nucleus ~12 um in diameter with spherical central nucleolus ~5 um in diameter. Floating form with numerous irregular blunt hyaline pseudopodia. Description: Schaeffer (1926). No available culture or type material. (ref. ID; 6796)
Habitat
Marine. (ref. ID; 6796)
Vannella danica (ref. ID; 6796 original paper)
Descriptions and illustrations
Smirnov et al. (2002); Figures 23-27. (ref. ID; 6796)
Molecular identification. (ref. ID; 6922)
Habitats
Brackish-water, thrives at marine salinity. (ref. ID; 6796)
Available culture
CCAP1589/17 (type culture). Complete 18S rRNA gene sequences (GenBank EF051203-EF051206) were obtained in the present study. (ref. ID; 6796)
Vannella devonica Page, 1979 (ref. ID; 2093 original paper, 6796) reported author and year? (ref. ID; 6789)
Diagnosis
Locomotive form with anterior edge usually smooth and regular; greatest dimension approximately 14 to 33 um, mean approximately 22 um; mean length: breadth ratio 0.9; floating form sometimes with slender, radiate pseudopodia, with length sometimes more than twice diameter of central mass; nucleus approximately 3.7 to 5.6 um, with two or more peripheral nucleoli; no slender filaments among glycostyles. Marine. (ref. ID; 2093)
Descriptions
Marine species. (ref. ID; 2093, 6796)
- Light-microscopy: In their locomotive form and behaviour these amoebae demonstrate in a diagrammatic fashion the characters of the genus, with a broad, flabellate outline in a large proportion of amoebae attached to the under side of a cover glass. The edge of the hyaline area is usually very smooth and more regular than that sometimes seen in V. caledonica. The hyaloplasm occupies the anterior 0.4 to 0.5 of the amoeba, measured in the middle, and often extends around the sides. The thickness of the amoeba increases gradually toward the posterior end, and which is often convex to pyramidal. The locomotive rates of ten amoebae (temperature about 22 degrees C) were 11 to 33 um per minute, or 0.9 to 1.9 times the lengths of the amoebae. Although the locomotive forms might be mistaken for a Platyamoeba, the radiate floating form is typical of a Vannella. A few minutes after suspension in liquid, a minority of cells take on the radiate form, with long, slender, hyaline pseudopodia, which are fairly fine at the tip but not sharply pointed even to the light microscope. These may become helical. They are often irregular distributed and dissimilar, so that the floating form is usually asymmetrical. The nucleus has peripheral nucleoli, which may appear to number from one to four, rarely five. These appear from hematoxylin preparations eventually to take the form of bands, which may be positioned more or less at right angles to each other. Depending on the angle of vision and the focal plane, one may see only one nucleolar mass, which may appear to be central, since the nucleoli are superimposed on each other from that angle, or one may in a given plane see the ends of two bands and hence apparently four nucleoli. However, from the variety of configurations seen, it is possible that the nucleoli grow from compact bodies to bands, and the fusion of nucleoli cannot be ruled out. It is, however, certain that the presence of multiple peripheral nucleoli is not simply an immediately post-mitotic stage but a character of the normal interphase nucleus as seen in other genera of Gymnamoebia. During nuclear division, the nuclear membrane is intact during at least part of metaphase, and distinct caps which appear to be remnant of the nuclear membrane are seen on the polar side of each chromosome set well into anaphase, perhaps to early telophase in some cases. No centriole was observed. The amoebae are well rounded up during the middle stage of mitosis, though they may become more discoid in late anaphase. (ref. ID; 2093)
- Electron-microscopy: The glycostyles of V. devonica resemble those of V. caledonica and of the freshwater species of Vannella in every detail, including size, with allowance for variations due to flexibility and to angle of cutting. However, V. devonica, like the freshwater strain of V. mira, lacks the simple filaments found on V. caledonica, V. platypodia and V. simplex. The difference between hyaloplasm and granuloplasm (ectoplasm and endoplasm) was more marked at the electron-microscopical level than in V. caledonica, and cytoplasmic filaments in bundles were both more common and more prominent particularly in the outer region. Some longitudinally oriented filaments were seen in pseudopodia but not definite filamentous cores as in Vexillifera sp. or Pseudoparamoeba pagei. The oval to sausage-shaped mitochondria had tubular, anastomosing cristae. These mitochondria, often more slender than those seen in V. caledonica, had a maximum measured size of 1.17 x 0.37 um. As many as three Golgi bodies were identified in a single section, although some sections contained none. These bodies had no particular positions. The cisternae, numbering approximately five, were flatter than those of V. caledonica, and the Golgi bodies, about 0.5 um wide often had a convex-concave form. Rounded or oval vesicles with a lining resembling the surface coat and possibly transporting renewal membrane to the surface were seen. Sacs which were sometimes but not always flattened and bore ribosomes on their external surface presumably comprised the endplasmic reticulum. In sections of nuclei, several nucleolar pieces or, more rarely, a single apparently central nucleolues were seen. Probable explanations have been given in the light-microscopical description. The common configuration had one larger and one smaller nucleolus against the nuclear envelope, with less compact aggregations of dark material which may have been chromosomal material often visible throughout the nucleus. The perinuclear cisterna had a more regular width than in V. caledonica, perhaps attributable to less swelling in fixation. (ref. ID; 2093)
- Cyst: No cysts are known for V. devonica. (ref. ID; 2093)
Broad flabellate, or fan-shaped locomotive form. Frontal hyaloplasm occupies from 1/2 to 2/3 of the total body area and has smooth anterior edge. The thickness of the amoeba increases gradually to the posterior end, which is convex to pyramidal, Locomotive form 14-33 um in greatest dimension (average 22 um), length/breadth ratio 0.5-1.4 (average 0.9). Single nucleus 3.7-5.6 um in diameter with 1-5 peripheral nucleoli (may appear to have vesicular nucleus under the LM because the nucleoli often superimpose). Floating form of radial type, with long, slender tapering hyaline pseudopodia, which may become helical. Locomotive rate 11-33 um/min (0.9-1.9 time the cell length) (Page 1979). Cell surface coat includes glycostyles about 94 nm in length without simple filaments among them. Description: Page (1979). Illustrations: Page (1979, 1983); Figures 32-38. (ref. ID; 6796)
Type locality
From the Kingsbridge Estuary at Kingsbridge, South Devon. (ref. ID; 2093)
Stock strain
The Culture Centre of Algae and Protozoa. (ref. ID; 2093)
Type material
Type slides have been deposited in the British Museum (Natural History). Holotype 1978:6:28:5, paratype 1978:6:28:6. (ref. ID; 2093)
Available culture
CCAP1589/5 (type culture). ATCC strain PRA-137 isolated by T. Nerad from salt marsh sediment and identified as V. devonica lacks published data. Complete 18S rRNA gene sequence of CCAP1589/5 strain (GenBank number EF051196) obtained in the present study. (ref. ID; 6796)
Vannella douvresi Sawyer, 1975 comb. nov. (ref. ID; 6796 redescribed paper)
Synonym
Platyamoeba douvresi Sawyer, 1975 (ref. ID; 6796)
Descriptions
In locomotion, discoid to wide ovoid with smooth anterior margin. Narrow transverse ripples or waves flow anteriorly, often one after the other, and quickly disappear on reaching the anterior margin; lateral rides or ripples absent. Length in locomotion 12-15 um (average 13 um), width 10-16 um (average 12 um). Single vesicular nucleus about 3 um in diameter, nucleolus about 2 um in diameter. Floating form with multiple blunt pseudopodia not exceeding in length the diameter of the central mass of cytoplasm. Ultrastructure unknown. Rate of locomotion 40-45 um/min. Description and illustrations: Sawyer (1975). Neither type material nor culture available. (ref. ID; 6796)
Habitat
Marine, can survive up to 7.5 ppt salinity but without multiplication. (ref. ID; 6796)
Vannella ebro Smirnov, 2001 (ref. ID; 6796)
Descriptions
Fan-shaped or semicircular amoeba, with a tendency to form waves or even short longitudinal ridges on the frontal hyaloplasm. Length of locomotive form 25-40 um (average 30 um); breadth 35-60 um (average 41 um). Length/breadth ratio 0.5-1.0. Single vesicular nucleus about 8 um in diameter with rounded central nucleolus about 4 um in diameter. Floating form variable, with 4-8 long, thick tapering hyaline pseudopodia in fresh isolates, and without pseudopodia in older cultures. Cell coat consisting of glycostyles about 140 nm long without associated simple filaments. Description and illustrations: Smirnov (2001); Figures 39-41. (ref. ID; 6796)
Habitats
Marine, suvives 6-90 ppt salinity. (ref. ID; 6796)
Available culture
CCAP1589/14 (type culture). Partial 18S rRNA gene sequenced by Smirnov et al. (2002) and in the present study (GenBank EF051198). (ref. ID; 6796)
Vannella flabellata Page, 1974 comb. nov. (ref. ID; 6796 redescribed paper)
Synonym
Platyamoeba flabellata Page, 1974 (ref. ID; 6796)
Descriptions
Locomotive form flabellate or ovoid with rounded or convex posterior edge. Surface wrinkles often parallel to or near the edges. The hyaloplasm occupies about 2/3 of the total cell area. Greatest dimension of the locomotive form is 20-42 um (average 26-30 um). Length/breadth ratio 0.7-1.5 (average 1.0). Single vesicular nucleus 3.7-7.0 um in diameter. Floating form asymmetrical, with numerous blunt, uneven hyaline pseudopodia not exceeding the diameter of the central cytoplasmic mass. Cell coat of densely packed hexagonal elements is 26-28 nm thick. Description: Page (1974). Illustrations: Page (1974, 1983). (ref. ID; 6796)
Habitats
Marine, possibly brackish; thrives in freshwater media. (ref. ID; 6796)
Type slides by F.C. Page
British Museum of Natural History (holotype 1974:1:9:1; paratype 1974:1:9:2). No available cultures. (ref. ID; 6796)
Vannella langae Sawyer, 1975 comb. nov. (ref. ID; 6796 redescribed paper)
Synonym
Platyamoeba langae Sawyer, 1975 (ref. ID; 6796)
Descriptions
In locomotion, broadly triangular to ovoid with a slightly convex posterior margin. Frontal hyaloplasm from 1/3 to 1/2 of the total body area. Length of the locomotive form 7-12 um (average 9 um), breadth 5-10 um (average 8 um). Single vesicular nucleus about 2.5 um in diameter, nucleolus 1.5-2 um in diameter. Floating form without radial pseudopodia, rod- or peg-shaped with one end slightly wider than the other. Rate of locomotion 15-20 um/min. Ultrastructure unknown. Description and illustrations: Sawyer (1975). No formally designated type material. (ref. ID; 6796)
Habitat
Marine, can survive up to 7.5 ppt salinity. (ref. ID; 6796)
Available culture
ATCC50816 by T.K. Sawyer. (ref. ID; 6796)
Vannella lata Page, 1988 (ref. ID; 6796)
Descriptions
Locomotive form semicircular or widely fan-shaped; width of a moving cell usually is much greater than the breadth. The frontal hyaline area occupies about 2/3 of the total cell area and commonly extends along sides. Maximal dimension of the locomotive form 24-46 um (average 33 um); length/breadth ratio 0.5-1.0 (average 0.6). Single vesicular nucleus 3.7-6.5 um in diameter (average 5.1 um). Floating form with 3-14 more or less symmetrically distributed long, tapering pseudopodia. Cell surface coat includes glycostyles with simple filaments among them. Description and illustrations: Page (1988); Figures 42-46. (ref. ID; 6796)
Habitats
Freshwater. (ref. ID; 6796)
Type slides by F.C. Page
British Museum of Natural History (holotype 1986:8:11:1; paratype 1986:8:11:2). (ref. ID; 6796)
Available culture
CCAP1589/12 by F.C. Page. Complete 18S rRNA gene sequenced (GenBank number EF051201) in the present study. (ref. ID; 6796)
Vannella mainensis Page, 1971 comb. nov. (ref. ID; 6796 redescribed paper)
Synonym
Platyamoeba mainensis Page, 1971 (ref. ID; 6796)
Descriptions
Locomotive form fan-shaped, oblong, or spatulate. Frontal hyaloplasm occupies up to 2/3 of the total body area; amoeba often form fine longitudinal lines or wrinkles near sides. Greatest dimension of locomotive form 19-37 um (average 26 um); length/breadth ratio 1.0-1.4 (average 1.1) usually greater than breadth. Single vesicular nucleus 3.7-6.5 um in diameter (average 5.6 um) with central nucleolus 2-4 um in diameter. Rate of locomotion 44-62 um/min. Floating form usually irregularly rounded up, sometimes with several slender, blunt pseudopodia. Cell coat of densely packed hexagonal elements is 20-22 nm thick. Description: Page (1971). Illustrations: Page (1971, 1983). Neither type material nor available cultures. (ref. ID; 6796)
Habitats
Marine, thrives in freshwater media. (ref. ID; 6796)
Vannella mira Schaeffer, 1926 (ref. ID; 2093, 2359, 2431) or (Schaeffer, 1926) Smirnov, 2002 (ref. ID; 6796)
Synonym
Flabellula mira (ref. ID; 2093)
Descriptions
Type species. (ref. ID; 2093)
The glycocalyx of this species consists of a basal layer approximately 28 nm thick and glycostyles of the same structure and size as those of V. platypodia. Careful examination has not revealed any simple filaments on the surface of this species. (ref. ID; 2359)
Locomotive form fan-shaped, semicircular, or (rarely) spatulate. Prominent folds or lobes on the frontal hyaloplasm. Length and breadth of locomotive form 15-35 um; (average length 28.5 um; average breadth 26.5 um) length/breadth ratio 0.5-1.8 (average 1.08). Single vesicular nucleus, ~6 um in diameter with central spherical nucleolus ~3 um in diameter. Floating form non-symmetrical, with up to 11 straight or coiled pseudopodia, often with distinct conical thickening of the basement. Pseudopodia of the floating form have rounded, not pointed ends and are relatively thick. Cell coat consisting of glycostyles, about 130 nm in length without associated simple filaments. Description and illustrations: Smirnov (2002); Figs.47-50. (ref. ID; 6796)
Habitats
Freshwater species. (ref. ID; 2093)
Marine. (ref. ID; 6796)
Measurements
Length 25 um, breadth 15-25 um, a nucleus with a diameter of 5 um and a central nucleolus, and floating form with long pseudopodia. (ref. ID; 2093)
Available culture
CCAP1589/15 (type culture; neotype). (ref. ID; 6796)
Descriptions
This species is known only from line drawings by Bovee (1965). It is desirable to establish a neotype if a similar strain is re-isolated. A description compiled from Bovee's observations follows: Locomotive form flabellate or semicircular. Frontal hyaloplasm occupies more than half of the total body area and often is so extended laterally that it nearly surrounds the granuloplasmic mass. Frontal edge often wavy. Greatest dimension of locomotive form 25-35 um. Single vesicular nucleus 4-4.5 um in diameter. Floating form very regular, with tapered pseudopodia of almost equal length. Few bipyramidal crystals up to 1.5 um in the cytoplasm are reported (unusual for Vannella). Description and illustrations: Bovee (1965), Page (1976, 1988 - both use the same picture by Bovee). Ariza et al. (1989) illustrated a strain that fits well with the above the characters. No type material. ATCC30945 culture isolated by J.L. Griffin and designated Vannella miroides lacks LM/EM data, but its complete 18S rRNA gene was sequenced by Peglar et al (2003) (GenBank AY183888). (ref. ID; 6796)
Habitat
Freshwater. (ref. ID; 6796)
Vannella murchelanoi Sawyer, 1975 comb. nov. (ref. ID; 6796 redescribed paper)
Synonym
Platyamoeba murchelanoi Sawyer, 1975 (ref. ID; 6796)
Descriptions
Locomotive form ovoid or rounded, sometimes spatulate, with flattened posterior margin. Frontal hyaloplasm occupies about half the total body area. Length in locomotion 8-13 um (average 11 um), breadth 6-11 um (average 9 um). Single vesicular nucleus ca. 2-2.5 um in diameter, nucleolus ~1.2-2 um. Floating form without pseudopodia, with crumpled or wrinkled surface. Rate of locomotion 20-30 um/min. Ultrastructure unknown. Description and illustrations: Sawyer (1975). Neither type material nor culture available. (ref. ID; 6796)
Habitat
Marine, can survive 7.5 ppt salinity. (ref. ID; 6796)
Vannella nucleolilateralis (Anderson, Nerad et Cole, 2003) comb. nov. (ref. ID; 6796 redescribed paper)
Synonym
Platyamoeba nucleolilateralis (Anderson, Nerad & Cole, 2003) (ref. ID; 6796)
Descriptions
Locomotive form discoid to flabellate. Frontal hyaloplasm occupies more than half of the total body area. Length in locomotion is 12-24 um (average 15.6 um), breadth 7.5-15 um (average 12.2 um). Single nucleus 2.5-3.5 um in diameter (average 3 um) with one or (rarely) two laterally located nucleoli. Floating form asymmetric and has 1 to 4 long, tapering pseudopodia with pointed tips. Rate of locomotion 29-42 um/min. Cell coat of densely packed hexagonal elements, about 30 nm thick (measured in micrograph). Description and illustrations: Anderson et al. (2003). (ref. ID; 6796)
Habitat
Isolated from salt marches in Assateague Island, VA, but tolerates salinity down to 2.5 ppt. (ref. ID; 6796)
Available culture
ATCC50987 by T. Nerad. (ref. ID; 6796)
Vannella peregrinia Smirnov & Fenchel, 1996 (ref. ID; 4882 original paper, 6796)
Diagnosis
Locomotive form varies from broad fan-shaped to flagellate with a long, spatulate posterior end, but usually is irregularly semi-circular, often with a transverse, spindle-shaped thickening of the posterior part of the granular region. The frontal hyaloplasm occupies 1/3-2/3 of the total body length. The length of the locomotive form is 4.5-14 um (average: 9 um) and the breadth is 3-13 um (average: 8 um). The L/B ratio varies between 0.7 and 1.7 (average: 1.1). The floating form is twisted and wrinkled, without pseudopodia. Vesicular nucleus 2-3 um in diameter with a single, spherical central nucleolus in diameter with a single, spherical central nucleolus up to 0.6-0.9 um in diameter. The perinulear cisternae are enlarged and the external and the inner nuclear membranes make contact only at the sites of nuclear pores. The thickness of the basal layer of the cell coat is 10-13 nm; the length of the glycostyles is 42-60 nm. Simple filaments, up to 300 nm in length, are very abundant. Anaerobic. (ref. ID; 4882)
Descriptions
Locomotive form broad fan-shaped to flabellate with a long, spatulate posterior, but usually irregularly semi-circular, often with a transvese, spindle-shaped thikening of the posterior part of the granular region. Frontal hyaloplasm occupies 1/3-2/3 of the total body length. The length of the locomotive form is 4.5-14 um (average: 9 um) and the breadth is 3-13 um (average: 8 um). The length/breadth ratio varies between 0.7 and 1.7 (average: 1.1). Floating form twisted and wrinkled, without pseudopodia. Vesicular nucleus 2-3 um in diameter with a single, spherical central nucleolus up to 0.6-0.9 um in diameter. Cell coat includes glycostyles only 42-60 nm long and less regularly organized than in other vannellas. Simple filaments among glycostyles up to 300 nm in length are very abundant. Description and illustrations: Smirnov and Fenchel (1996); Smirnov (1999). (ref. ID; 6796)
Comments
The locomotive morphology of this species (semi-circular or flagellate form with a long, spatulate posterior end) and the organisation of the cell coat (glycostyles) are characteristics of the members of the genus Vannella Bovee, 1965, family Vannellidae (Bovee, 1970) Page, 1987 (Page 1983, 1988). But the glycostyles of the present species are much finer, shorter and more irregular than that of other Vannella spp. The fact that the glycostyles are identical in shape and size in all other marine and freshwater Vannella spp. (Page 1980; Page & Blakey 1979) does not support the inclusion of the present species in this genus. On the other hand, the glycostyles in V. peregrinia were not preserved sufficiently well to reconstruct their structure with certainty. An alternative generic home for this species could be the genus Platyamoeba, but all the species of this genus are very homogenous with respect to the organisation of their cell coat (Page 1980; Page & Blakey 1979). The formation of the posterior spatulate projection and the temporary existence of two hyaline zones, moving in different directions are also not characteristics of Platyamoeba, but they are typical for Vannella (Page 1983). A floating form without radiating pseudopodia is typical for Platyamoeba but it is also known for some Vannella spp. (Page 1980, 1983). The establishment of a new genus based only on the structure of the cell coat (which is not even clear in all details) is not warranted. Thus, by now it is most reasonable to classify this species in the genus Vannella. (ref. ID; 4882)
Known habitat
Marine, upper layer of anaerobic sediments, in and beneath mats of colourless sulphur bacteria. Niva Bay, the Sound (15 km South from Helsingor), Denmark. (ref. ID; 4882)
Brackish-water, can thrive in anerobic conditions. (ref. ID; 6796)
Type slides
Deposited at the British Museum of Natural History (holotype 1995:9:6:3; paratype 1995:9:6:4). (ref. ID; 4882, 6796)
Descriptions
Locomotive form rather regular, semi-circular, or flabellate; more rarely oval or spatulate. Frontal hyaloplasm occupies about half of the total body area. The posterior end of the body slightly drawn back in some specimens. Length in locomotion 23-35 um (average 29 um); breadth 23-40 um (average 34 um), length/breadth ratio 0.6-1.1. Vesicular nucleus 3.5-5 um in diameter with a single central nucleolus, 2.6-3.3 um in diameter. Floating form rather polymorphic, generally asymmetric, with up to 8 tapering pseudopodia of well-developed, but may have only 2-3 long, sometimes helical pseudopodia, or only several short, blunt pseudopodia with rounded ends. Cysts 13-16 um in diameter, with thick "gelatinous" outer coat, clearly visible using light microscope. They are double walled, with clearly separated walls. Inner wall very fine, outer wall wrinkled, about 100 nm in thickness. The cell coat consists of a layer of glycostyles, about 110 nm in height, without simple filaments among them. Description and illustrations: Smirnov and Brown (2000); Figures 51-53. (ref. ID; 6796)
Molecular identification. (ref. ID; 6922)
Habitats
Soil. (ref. ID; 6796)
Available culture
CCAP1589/13 (type culture). Partial 18S rRNA gene sequence (GenBank number EF051207) was obtained in the present study. (ref. ID; 6796)
Vannella placida (Page, 1968) comb. nov. (ref. ID; 6796 redescribed paper)
Synonym
Platyamoeba placida Page, 1968 (ref. ID; 6796)
Descriptions
Locomotive form spatulate, oval, or broadly elongate; anterior edge arched or truncate, posterior edge straight or irregularly triangular. Frontal hyaloplasm occupies from 1/3 to 2/3 of the total body area. Surface wrinkles sometimes occur parallel to or near edges. Maximal dimension in locomotion is 15-35 um, length/breadth ratio 0.6-1.9 (average 1.2). Single vesicular nucleus 3.4-5.5 um in diameter. Floating form with short, blunt hyaline pseudopodia in length not exceeding the diameter of the central mass. Cysts 7-10.5 um in diameter, double walled. Cyst walls closely apposed; inner wall thicker than outer. Cell coat includes apparently hexagonal prismatic elements and is about 15 nm thick. Description and illustrations: Page (1968 as Rugipes placidus; 1988, 1991; Page and Blakey 1979); Figs 54-57. (ref. ID; 6796)
Habitats
Soil. (ref. ID; 6796)
Available culture
CCAP1565/2 (type culture); CCAP1565/14 isolated by S. Brown in 1999 and identified by LM and EM as P. placida (Brown and Smirnov 2004). Partial 18S rRNA gene sequence of 1565/2 strain by Fahrni et al. (2003) (GenBank AY294250); complete sequence EF051200. (ref. ID; 6796)
See
Ripella platypodia (ref. ID; 6796)
Descriptions
Fresh water species. Its glycocalyx consists of a basal layer approximately 18 nm thick and, rising above that layer, two sorts of structures. Arranged in closely set rows are structures which Page et al. shall call glycostyles, since they are much more complex than simple filaments but are not separable from the surface as are the scales of some protozoa, including the amoebae Paramoeba eilhardi Schaudinn, 1896 and Mayorella riparia Page, 1972. A glycostyle is set on a pentagonal base approximately 65 nm in diameter, and rises to a height of about 110 nm above the basal layer. From its base to the narrowest point, it consists of five flat wings arranged about a central tubule, or united medially to form that tubule. The base is the broadest point of the entire structure, and each wing articulates with an angle of the pentagonal base, bifurcating just before reaching the corner. The narrowest point of the glycostyle, with a diameter of an about 12 nm, is located approximately five-eighths of its length from base to tip. The wall looks thickest at this point, where the greatly narrowed wings are essentially incorporated into the tubule. Distal to this neck, the structure flares, with a pentagonal cross-section into which the wings are partly incorporated as ribs, to a funnel-like end 24 nm or less in diameter. Chromium-shadowed preparations are in agreement with this structure. Before the tubular structure of the glycostyle was understood, it was thought that the glycostyle wings were filaments crossing to the opposite side at the narrowest point, but examination of a number of glycostyles in sections and in chromium-shadowed whole mounts demonstrates that this is not so. The appearance of crossing-over (if not an artifact of sectioning) may in some cases be due to a slight twisting of the glycostyle. No glycostyles were ever seen to be separated from the cell surface. (ref. ID; 2359)
Measurements
10-25 um. (ref. ID; 2359)
Vannella plurinucleolus (Page, 1974) comb. nov. (ref. ID; 6796 redescribed paper)
Synonym
Platyamoeba plurinucleolus Page, 1974 (ref. ID; 6796)
Descriptions
Locomotive form ovoid or spatulate; posterior edge rounded, straight, or slightly conex. Hyaloplasm occupies most of the total cell area; the granuloplasm is often a small ovoid mass along the posterior edge. Surface wrinkles sometimes occur parallel to or near edges. Maximal dimension in locomotion 8-34 um (average 11-26 um); length/breadth ratio 0.9-1.2 (average 1.0-1.1). Single nucleus 2.4-6.5 um in diameter. Nucleolar material in several parietal pieces (usualy two or three). Rate of locomotion 15-47 um/min. Floating form with short, blunt hyaline pseudopodia, in length not exceeding the diameter of the central mass. Cell coat includes apparently hexagonal prismatic elements and is 25-27 nm thick. Description and illustrations: Page (1974, 1983); Figs.58-60. The strain called 'Platyamoeba plurinucleolus' by Smirnov (1999) has peculiar surface structure and floating form and may be a new species of Clydonella, not V. plurinucleolus. (ref. ID; 6796)
Habitats
Marine, thrive up to 10 ppt slinity. (ref. ID; 6796)
Type slides by F.C. Page
British Museum of Natural History (holotype 1974:1:9:7; paratype 1974:1:9:8). (ref. ID; 6796)
Available culture
CCAP1565/7 (type culture) and CCAP1565/11. Complete 18S rRNA genes sequenced from both CCAP strains (GenBank EF051186-EF051190) in the present study. ATCC strain 50745 of T. Sawyer identified as P. plurinucleolus must be described as a new species. (ref. ID; 6796)
Vannella pseudovannellida (Hauger, Rogerson and Anderson, 2001) comb. nov. (ref. ID; 6796 redescribed paper)
Synonym
Platyamoeba pseudovannellida Hauger, Rogerson and Anderson, 2001 (ref. ID; 6796)
Descriptions
Locomotive form ovoid or spatulate, sometimes with pronounced tail. Frontal hyaloplasm occupies about half the total body area; posterior end concave, flat or irregularly triangular. Length of the locomotive form 8.5-22.5 um (average 14.2 um), length/breadth ratio about 1.02. Single vesicular nucleus 2.1 um in diameter with central nucleolus about 0.9 um in diameter. Rate of locomotion 20.4 um/min. Floating form with relatively long, uneven, blunt hyaline pseudopodia; some floating cells produce tapering pseudopodia. Cell coat does not include glycostyles and is a nearly amorphous layer ~10 nm thick, maybe because of fixation problems. Description and illustrations: Hauger et al. (2001). No culture available. (ref. ID; 6796)
Habitats
Saltwater. (ref. ID; 6796)
Type slides
British Museum of Natural History (holotype 2001:6:25:1). (ref. ID; 6796)
Descriptions
Locomotive form fan-shaped, semicircular or spatulate. The hyaloplasm occupies from 1/2 to 2/3 of the total body area. The anterior edge of the cell is often eneven, finely dentate; the cell sometimes forms longitudinal ridges and transverse waves on the frontal hyaloplasm. Length of the locomotive form 13-20 um; breadth 15-24 um. Single vesicular nucleus about 3 um in diameter with central endosome about 1.5 um in diameter. Floating form of radial type, with long, tapering pseudopodia, tending to coil spirally (it is unclear why Page (1983, p.31) indicated that 'pseudopodia of floating form are short' for this species -see illustrations by Bovee and Sawyer). Ultrastructure unknown. Description: Bovee (1953) (in some sources indicated 1950, but that was his Ph.D.thesis- not a formal publication). Description: Bovee and Sawyer (1979); Sawyer (1975, includes photographs). Neither type material nor cultures available. (ref. ID; 6796)
Habitats
Marine. (ref. ID; 6796)
Descriptions
Locomotive form fan-shaped or spatulate; frontal hyaloplasm occupies about half the total body area. Posterior edge of cell concave, straight, or pyramidal. Greatest dimension in locomotion 15-33 um (average ~22 um); length/breadth ratio 0.5-1.3 (average 0.8-0.9). Locomotive rate about 3 cell lengths per minute. Single vesicular nucleus 3.7-5.6 um in diameter with central nucleolus 1.9-3.2 um in diameter. Floating form with asymmetrically distributed short, thick hyaline pseudopodia not exceeding twice the diameter of the cental cytoplasmic mass. Cell surface includes glycostyles with few simple filaments among them. Description and illustrations: Page (1980, 1983); Figures 61 and 62. (ref. ID; 6796)
Habitats
Marine. (ref. ID; 6796)
Type slides by F.C. Page
British Museum of Natural History (holotype 1980:1:24:7; paratype 1980:1:24:8). (ref. ID; 6796)
Available culture
CCAP1565/10 (type culture). Complete 18S rRNA gene sequenced (GenBank EF051197) in the present study. (ref. ID; 6796)
Vannella simplex (Wohlfarth-Bottermann, 1960) (ref. ID; 2093, 2359) or (Wohlfarth-Bottermann, 1960) Bovee, 1965 (ref. ID; 6796) reported author and year? (ref. ID; 6789)
Descriptions
The basal layer of its glycocalyx is approximately 24 nm thick, and its glycostyles and simple filaments are indistinguishable from those of the much smaller V. platypodia. (ref. ID; 2359)
Molecular identification. (ref. ID; 6922)
Comments
This species was illustrated in numerous papers; probably the most representative illustrations are in Wohlfarth-Bottermann (1960 as Hyalodiscus simplex); Haberey and Hulsmann (1973); Page (1976, 1988, 1991); Ariza et al. (1989); Smirnov et al. (2002); Figures 28-31. (ref. ID; 6796)
Habitats
Freshwater. (ref. ID; 6796)
Measurements
35-80 um. (ref. ID; 2359)
Available culture
CCAP1589/3 by N. Hulsmann (not the original strain, isolated by Wohlfarth-Bottermann in 1960, but originating from the same pond) and ATCC50295 by T. Nerad (the latter lacks published data). Complete sequence of the 18S rRNA gene from CCAP1589/3 obtained in the present study (GenBank EF051208; EF051209); sequences of other strains: EF051210-EF051211). (ref. ID; 6796)
Vannella weinsteini (Sawyer, 1975) comb. nov. (ref. ID; 6796 redescribed paper)
Synonym
Platyamoeba weinsteini Sawyer, 1975 (ref. ID; 6796)
Descriptions
Locomotive form ovoid to discoid with smooth rounded anterior margin and flattened or slightly convex posterior margin. Frontal hyaloplasm occupies about 2/3 of the total cell area or even more; the cell tends to form longitudinal ridges and transverse ripples on the hyaloplasm. Length in locomotion 11-14 um (average 12 um); breadth 12-16 um (average 13 um). Single vesicular nucleus ca. 3 um in diameter with rounded central nucleolus. Rate of locomotion about 40 um/min. Floating form with short, blunt hyaline pseudopodia. Description and illustrations: Sawyer (1975). Neither ultrastructure nor type material. (ref. ID; 6796)
Habitats
Marine. (ref. ID; 6796)