mnold1's Favorites

Magnification of all photos: 1000× (oil immersion)
Habitat: muddy water from the edge of a swamp. Associated plants: Cephalanthus occidentalis
Using stage micrometer for calibration, colony estimated to be about 25 µm wide.

Magnification of photos: 400×, 400×, 1000×, 1000×, 1000×, 1000× (oil immersion)
Habitat: muddy water from the edge of a shallow pond. Associated plants: Boltonia asteroides
Using stage micrometer for calibration, cell estimated to be about 35 µm long (including tail) and 24 µm wide.

Magnification of all photos: 1000× (oil immersion)
Habitat: muddy water from the edge of a shallow pond.
Using stage micrometer for calibration, colony (excluding spines) estimated to be about 26 µm wide.

Cryptopharynx setigerus KAHL, 1926, a psammobiontic karyorelectean ciliate from the fine sand sulfidic intertidal benthos of the marina at Moneybogue Bay in Westhamtpon Beach. The cell measures 80 um.

Here is a translation of Kahl's original 1928 description of the species: Cryptopharynx setigerus KAHL, 1926 Size 40-100 um Slim oval (3:1). Front third protruding to the left (1/3 width of the body). Ventral surface flat, dorsal with hump leaving the front third and a closed edge free. Ventral surface loosely ciliate in furrowed rows. The insertions are arranged in transverse rows that cross the longitudinal rows in a rhombic manner. Intermediate stripes rib-shaped. The furrows run spirally (see illustration) and notch the edge; here each notch bears on the dorsal surface an erect stinger. The rows wrap around the very left. Mouth lying in front; it is oval on a protruding cone, appears open, shows short rods that are difficult to see on the edge, but there are clearly visible rods inside; the cilia of the perioral row hit over the edge, no additional adorable ciliation. Dorsal hump is yellowish and granulated, with gelatinous coating on the outside. Two nuclei with one or two micronuclei, exactly like those of Loxodes. Contractile vacuole at the back of the hump, small, often difficult to see, often behind the middle left also a vacuole (whether contractile?); Anus at the back of the hump. Movement very sluggish, very flexible. Halobiont, sapropel. Eats almost exclusively Rhodobacteria.

The Infraciliature of Cryptopharynx setigerus KAHL, 1928 and Apocryptopharynx hippocampoides nov. gen., nov. spec. (Ciliophora, Karyorelictea), with an Account on Evolution in Loxodid Ciliates. WILHELM FOISSNER. Arch. Protistenkd. 146 (1995/96): 309-327

Magnification of all photos: 1000× (oil immersion)
Habitat: muddy water from the edge of a swamp. Associated plants: Cephalanthus occidentalis
Using stage micrometer for calibration, body (excluding feet) estimated to be about 140 µm long.
Using stage micrometer for calibration, estimated to be about 118 µm long and 23 µm wide.

Phacus orbicularis Hübner 1886 from a sample fed with boiled wheat seed from the edge benthos of freshwater glacial kettle hole Kellis Pond. The cells measure from 46 up to 52 um in length. The s[pepcies was firsts described by Hübner 1886 (1). We can clearly see the horizontal "struts" perpendicular to the longitudinal pellicular strips first described by Lefevre in 1931 and, after much confusion see (2) felt by Kozmala et al 2007 to be the distinguishing character for P. orbicularis (2).

"Species. Ph. orbicularis n. spec. My illustration Fig. 1. Body is almost circular, not painted at the front. The crooked torsion is very developed, the body appears flat. The mouth fold only leads to a slight upward bulging of the dorsal ligaments. The abdominal area on the right side (back view) is visible at the top, but it does not cause any abnormal curvature of the back area. Cuticle delicately striped. Chromatophores, cell nucleus, main vacuole according to the genus character. A large granule in the shape of a disc with a central opening, resting on the ventral surface, in front of or behind the cell nucleus. Terminal spine clearly visible, 1:6 of the body length, pointed left and upwards (back view). Flagellum of body length. Size = 0.07 mm. end spine. Br. = 0.045 mm. Occasionally, among other Euglenaceae, bird meadows" (1).

"Phacus orbicularis Hübner, Programm d. Realgymnasiums Stransund: 5, fig. 1, 1886. Emend. Zakrys´ et Kosmala. Emended diagnosis: Cells flat, 29–75 um long and 22–49 um wide, widely ovoid, ending with a more or less prominent and curved tail. Fine, numerous struts—perpendicular to the longitudinal axis—located between periplast strips" (2). "Periplast ornamentation was recognized as a main diagnostic character, distinguishing P. orbicularis from P. pleuronectes and P. hamelii. Phacus orbicularis has struts running perpendicular to the longitudinal axis of the strips, while P. pleuronectes and P. hamelii do not" (2). Support for this morphologic character being distinctive to P. orbicularis among congeners: " On the SSU rDNA tree, obtained by the Bayesian method, P. orbicularis, P. pleuronectes, and P. hamelii belong to three distinct clades" (2).

"Our studies also point out periplast ornamentation, described as ‘‘struts’’ by Leedale (1985), which are positioned perpendicular to the longitudinal axis of the strips. The struts were present in all P. orbicularis strains surveyed by us (Fig. 1, n and u)— all SSU sequences for the P. orbicularis strains clade together on the 18S rDNA tree (Fig. 2)—but struts were not observed in P. pleuronectes or P. hamelii (Fig. 1, o and t). Lefevre (1931) was the first to notice ‘‘perpendicular stripes’’ in P. orbicularis and take them into account in his drawings. Lefevre’s drawings were used later by Pochmann (1942, fig. 78, k and n), albeit without any commentary. This action suggests that both Lefevre and Pochmann, as well as others, did not consider struts to be a diagnostic feature distinguishing P. orbicularis from P. pleuronectes. This also might be the reason for not considering struts as diagnostic in spite of their appearing on drawings of several other species (P. rostafinski [Drezepolski _ 1921 ⁄ 1922, pl. 1, fig. 3]; P. platalea [Drezepolski _ 1925, pl. 3, fig. 110]; P. caudata var. minor and var. ovalis [Drezepolski 1925, pl. 3, figs. 107 and 111]; _ P. longicauda [Lefe´vre 1931, pl. 3, fig. 32]; Phacus triqueter [Leander and Farmer 2001, fig. 3a]). The presence of perpendicular struts on the iconotype of P. platalea Drezepolski 1925 (fig. 110), as well as its _ other features, such as the size and shape of the cell and the relatively long (12–15 lm) tail, prompted us to consider P. platalea as a synonym of P. orbicularis. In our view, the presence of struts is a good diagnostic feature for distinguishing P. orbicularis from P. pleuronectes since it is not susceptible to individual, developmental, and environmental variability. Moreover, struts are clearly visible under the light microscope, even in very small cells (in which case, a brief drying out of the material facilitates observations; Fig. 1, n and u)" (2)

1. Hübner, E.F.W. (1886). Euglenaceen-Flora von Stralsund. Programm des Realgymnasiums Stralsund 1886: 1-20, 1 pl..
2. MORPHOLOGICAL AND MOLECULAR EXAMINATION OF RELATIONSHIPS AND EPITYPE ESTABLISHMENT OF PHACUS PLEURONECTES, PHACUS ORBICULARIS, AND PHACUS HAMELII. Sylwia Kosmala, Magdalena Bereza, Rafał Milanowski, Jan Kwiatowski, and Bozena Zakrys. J. Phycol. 43, 1071–1082 (2007)

My recent sample from the shoreline benthos of freshwater glacial kettle hole Kellis Pond is rich in these tiny testate amoebae which average 21.6 um in diameter. The test is usually stained brown, is not invaginated and is flattened hemispherical in profile, has an aperture around 4/5 of the test diameter, and is finely textured with uniformly spaced and sized grains on the aboral surface. I have yet to observe pseudopodia in a couple hundred cells, but in one cell I saw what looks like a broad lobose pseudopod. The resident rounded amoebae have a large round macronucleus with a large central nucleolus and a single contractile vacuole. I note amoebae which have left their test ( or have yet to form it).

Imaged in Nomarski DIC on Olympus BH2S using SPlan 100 1.25 oil immersion objective plus variable phone camera cropping on Samsung Galaxy S9+.

Thanks to Ferry Siemensma for identifying this as Pyxidicula operculata.

From Ferry Siemensma's Microworld: https://arcella.nl/pyxidicula-operculata/

Pyxidicula operculata, (Agardh, 1827) Ehrenberg, 1838

Diagnosis: shell discoid or hemispherical, composed of organic material, which varies in color, being transparent or light yellow in young individuals and becoming darker with age to be either brown or red-brown; aperture almost as wide as the total diameter of the shell; shell uniform in outline with a slight thickening around the margin; this thickening is a slightly depressed rim, which is recurved to give a small lip; shell covered by regularly spaced pits or pores, but the surface is smooth on the apertural margin; a single vesicular nucleus with a centric nucleolus; pseudopodia short, lobose or digitate.

Dimensions: Diameter 13.6-31 µm.

Ecology: On aquatic vegetation. Very common, but easily overlooked.

Remarks: Portions of the broken rim show that it is a thin extension of the shell wall, which is constructed of a single layer of regular, interlocking alveoli. These alveoli are rectangular in vertical section with a depth of about 0.3 µm and have a solid content and thin walls. The contents of the alveoli did not permit embedding resin to penetrate the whole wall, and as a consequence sectioned material gave poor results. Nevertheless, sufficient information is available to reconstruct diagrammatically a cross-section through the wall. Each alveolus is surrounded by a single membrane-like structure, which is referred to as the shell matrix, and at the outer surface the shell wall is bilaminar. See for further information Ogden (1987).