Table 1.
Morphometric data on Apoamphisiella vernalis from Belém-PA, Brazil.
Table 2.
Uncorrected P-distances among the terminals in the cluster of the “non-stylonychine dorsomarginalians” in which A. vernalis was placed.
Fig 1.
Photomicrograhps of Apoamphisiella vernalis from life under bright field.
(A, B) Ventral side. (C) Dorsal side of slightly contracted specimen. (D, E) Detail of contractile vacuole; systole in (E). (F) Ventral side, to show cortical granules (arrowheads). AZM, adoral zone of membranelles; CV, contractile vacuole. Scale bars: A, B, C. 50 μm; F. 10 μm.
Fig 2.
Photomicrograhps of Apoamphisiella vernalis, from life with DIC (A, D, E) and bright field (B, C).
(A) Cortical granules on dorsal side of body. Arrowheads show dorsal bristles. (B) Clusters of cortical granules near caudal cirri (arrowheads). (C) Aculeate crystals of specimen from a mineral water culture, after cell rupture. (D, E) Cytoplasmic crystals (arrowheads) inside specimens from raw samples of Tucunduba river (D) and from a ruptured cell from a culture made with mineral water (E); black arrowheads show lipid droplets, white arrowheads mark aculeate crystals, and arrow shows a polygonal crystal. Scale bars: 10 μm.
Fig 3.
Diagrammatic representations of protargol-impregnated specimens of Apoamphisiella vernalis.
(A) Ventral side. (B) Dorsal side of typical specimen. Asterisk marks field of scattered dikinetids; white arrowhead shows a scattered dikinetid located between dorsal kineties 3 and 4. (C) Dorsal side of specimen with supernumerary scattered dikinetids (asterisk), possibly an outlier. AZM = adoral zone of membranelles; BC = buccal cirrus; CC = caudal cirri; DK(n) = dorsal kineties; DMK = dorsomarginal kineties; E = endoral; FC = frontal cirri; FVC = frontoventral cirri; LMR = left marginal cirral row; LVR = left ventral cirral row; Ma = macronuclear nodule; Mi = micronucleus; P = paroral; PpC = postperistomal cirrus; PTC = pretransverse cirri; RMR = right marginal cirral row; RVR = right ventral cirral row; TC = transverse cirri. Scale bars: 50 μm.
Fig 4.
Scanning electron micrographs of Apoamphisiella vernalis.
(A) Ventral side. Arrowhead points to postperistomal cirrus. (B) Dorsal side. Asterisk marks scattered dikinetids; arrow shows anterior end of dorsal kinety 4. Scale bars: 20 μm.
Fig 5.
Scanning electron micrographs of Apoamphisiella vernalis.
(A–C) Anterior region of ventral side. (A) Black arrowhead shows lateral membranellar cilia; white arrowhead shows postperistomal cirrus. (B) Black arrowhead shows leftmost frontal cirrus; black asterisk marks buccal cirrus; white asterisk marks oral lip. (C) Detail of distal ends of endoral and paroral. Arrowhead shows lateral membranellar cilia. (D) Detail of left marginal cirri to show barren basal bodies (arrowheads). E = endoral; P = paroral. Scale bars: A, B. 10 μm; C, D. 5 μm.
Fig 6.
Scanning electron micrographs of Apoamphisiella vernalis on ventral side.
(A) Right marginal cirral row. Arrowheads show barren basal bodies. (B) Ventral rows. White arrowhead points to barren basal bodies in the left row; black arrowhead in the right row. (C) Barren basal bodies in pretransverse (white arrowhead) and transverse cirri (black arrowhead). Scale bars: 5 μm.
Fig 7.
Scanning electron micrographs of Apoamphisiella vernalis on dorsal side.
(A) Anterior region. Black arrowhead points to dorsomarginal kinety with relatively wider-spaced kinetosomes, thus possibly a retained parental structure. White arrowheads show typical dorsomarginal kineties. (B) Posterior region. Asterisks mark spaced dorsal bristles, possibly parental structures, at the field of scattered dikinetids. (C) Specimen with one dorsal bristle (white asterisk) between dorsal kineties 3 and 4. Black asterisk marks kinety 4. (D) Anterior region of specimen with three typical dorsomarginal kineties (arrowheads). (E) Detail of dorsal dikinetid showing that anterior basal body is ciliated. (F) Detail of caudal cirri to show barren basal bodies (arrowheads). Scale bars: A, B, D. 10 μm; F. 3 μm.
Fig 8.
Photomicrograhps of Apoamphisiella vernalis from life, under stereomicroscope.
(A) Specimens of A. vernalis (asterisks). Black arrowhead marks a dead rotifer being sucked by a specimen of A. vernalis; white arrowhead shows a live rotifer. (B–F) Specimen of A. vernalis attempting to swallow a dead rotifer.
Fig 9.
Diagrammatic representations of protargol-impregnated specimens of Apoamphisiella vernalis showing stages of divisional morphogenesis.
(A) Ventral side of an early divider showing oral anlage and early development of fronto-ventral-transverse anlagen. White arrowhead shows disaggregating buccal cirrus; black arrowhead shows disaggregating left frontoventral cirrus; double arrowhead points to right frontoventral cirrus, still intact at this stage. White arrow shows postperistomal cirrus; black arrow shows early fronto-ventral-transverse anlagen of the opisthe. (B) Ventral side of a middle divider showing fronto-ventral-transverse anlagen (numbered) and right marginal anlagen (asterisks). White arrowheads shows disaggregating endoral and paroral; black arrowheads show extra anlagen originating between anlagen IV and V of both proter and opisthe. (C) Dorsal side of the same divider showing dorsal kineties anlagen of proter (white arrowheads) and opisthe (black arrowheads). OA = oral anlage; ? = insufficiently impregnated region. Anlagen labeled with roman numbers, where “o” names the opisthe and “p” names the proter. Scale bars: 50 μm.
Fig 10.
Diagrammatic representations of protargol-impregnated specimens of Apoamphisiella vernalis showing stages of divisional morphogenesis.
(A) Ventral side of middle divider. White arrowhead shows left frontal cirrus segregating from undulating membranes anlage; black arrowheads show formation of transverse cirrus by each of the extra anlagen of proter and opisthe; white and black asterisks mark left and right marginal rows anlagen, respectively, for proter and opisthe. Dorsomarginal anlagen shown by arrows. The double arrowhead shows macronuclear nodules fused into a single mass. (B) Dorsal side of same divider, showing juvenile caudal cirri of proter (white arrowheads) and opisthe (black arrowheads), fragmentation of rightmost dorsal anlage (arrows), and dividing macronucleus and micronuclei. E = endoral; Ma = macronucleus; Mi = micronucleus; P = paroral. Scale bars: 50 μm.
Fig 11.
Diagrammatic representation of protargol-impregnated late dividers of Apoamphisiella vernalis showing dividing macronucleus and micronuclei, and ventral side with juvenile fronto-ventral-transverse cirri linked according to anlagen and numbered.
(A) Specimen with two extra transverse cirri (arrowheads). (B) Specimen with one extra transverse cirri and with dorsomarginal anlagen visible (arrows). Ma = macronucleus; Mi = micronuclei. Anlagen labeled with roman numbers, where “o” names the opisthe and “p” names the proter. Scale bar: 50 μm.
Fig 12.
Photomicrograhps of Apoamphisiella vernalis, after protargol-impregnation, showing stages of divisional morphogenesis of ventral side.
(A) Early divider showing oral anlage. Black arrow shows early development of fronto-ventral-transverse anlagen of opisthe; white arrow shows postperistomial cirrus. (B) Anterior region of same specimen showing disaggregating buccal (white arrowhead) and left frontoventral cirrus (black arrowhead). Double arrowhead shows right frontoventral cirrus. Arrows show macronuclear DNA replication band. (C) and (D) Specimens from Minas Gerais showing origin of anlage IV of the proter from disaggregation of right frontoventral cirrus (double arrowhead). (E) Anterior region of middle divider showing proter’s anlagen. White arrowheads show disaggregating undulating membranes. (F) Detail of morphogenesis of the opisthe in the same divider. Black arrowheads and asterisks in C and D show extra anlagen originating between anlagen IV and V, and right marginal row anlage, respectively, for proter and opisthe. (G) Proter of middle divider. White arrowhead shows juvenile left frontal cirrus detaching from undulating membranes anlage; black arrowhead points to juvenile transverse cirrus developing from extra anlage formed between anlagen IV and V. White and black asterisks mark left and right marginal anlagen, respectively; arrow marks dorsomarginal kinety anlage. (H) Same specimen, focal plane of nuclear apparatus, to show macronucleus as a single mass and dividing micronucleus. E = endoral; Ma = macronucleus; Mi = micronucleus; OA = oral anlage; P = paroral. Anlagen labeled with roman numbers, where “o” names the opisthe and “p” names the proter.
Fig 13.
Photomicrograhps of Apoamphisiella vernalis after protargol-impregnation, showing stages of divisional morphogenesis of ventral side.
(A) Opisthe of middle divider showing left (white asterisk) and right (black asterisk) marginal rows anlagen and dorsomarginal kineties anlagen (arrow). (B) Detail of juvenile dorsomarginal kineties (arrow) of opisthe. (C) Proter of late divider showing juvenile fronto-ventral-transverse cirri linked according to anlagen. Black arrowhead shows transverse cirrus formed by extra anlage. (D) Late divider showing distribution of juvenile macronuclear nodules in proter (white asterisks) and opisthe (black asterisks). Ma = macronuclear nodule; Mi = micronucleus.
Fig 14.
Photomicrographs of Apoamphisiella vernalis from Minad Gerais after protargol-impregnation, showing stages of divisional morphogenesis.
(A) and (B) Ventral side of middle-to-late divider showing anlagen for proter (A) and opisthe (B). Arrowheads mark surplus transverse cirri in the proter (notice that surplus transverse cirri are also present in the opisthe, but out of focus in the image). (C) Middle divider showing dorsal kineties anlagen for the proter (white arrowheads) and opisthe (black arrowheads). (D) Fragmentation of right dorsal anlagen (arrows) and formation of caudal cirri (arrowheads). Anlagen labeled with roman numbers, where “o” names the opisthe and “p” names the proter.
Fig 15.
Photomicrograhps of postdividers of Apoamphisiella vernalis, after protargol-impregnation.
(A) Ventral side of proter postdivider. Black arrowhead points to terminus of left marginal row. White and black arrows show parental left and right marginal cirri, respectively. (B) Ventral side of opisthe postdivider. Black arrowhead shows postperistomal cirrus, which did not yet reach its final position behind buccal vertex. White arrowhead shows parental transverse cirri. White and black arrows show parental left and right marginal cirri, respectively. (C) Dorsal side of specimen from A, with black arrowhead showing terminus of left marginal row. (D) Dorsal side of specimen from B. Asterisks in C and D mark scattered dikinetids between dorsal kineties 3 and 4, possibly resulting of late multiple fragmentation of rightmost dorsal anlage. CC = caudal cirri; DK(n) = dorsal kinety.
Fig 16.
Photomicrograhps of Apoamphisiella vernalis from Minas Gerais, after protargol-impregnation, to show variations in morphogenesis pattern of ventral ciliature.
(A) Proter and (B) opisthe of middle divider with two ventral cirral rows (arrows) producing one extra anlage between each anlagen V and VI (arrowheads); arrows point to parental ventral rows. (C–E) Specimen with three ventral cirral rows (arrows) at different focal planes. Arrowhead in C points to right marginal cirral row; arrowhead in D shows early development of undulating membranes anlage of opisthe; arrowhead in E points to anlage formation within rightmost ventral row of opisthe. OA = oral anlage; anlagen labeled with roman numbers, where “o” names the opisthe and “p” names the proter.
Fig 17.
Photomicrograhps of Apoamphisiella vernalis from Minas Gerais, after protargol-impregnation, to show variations in morphogenesis pattern of ventral ciliature.
(A) Middle divider (oriented with anterior end of cell towards left side of the page) with three ventral cirral rows (arrows) producing at least four juvenile ventral rows for the proter (black asterisks) and six for the opisthe (white asterisks). (B–D) Interphase specimens resulting from dividers with deviant morphogenetic patterns. (B) Specimen with a truncated (amphisiellid?) right ventral row (black arrowhead) and increased number of cirri produced by anlage IV, forming a row homologous to postperistomal cirrus (white arrowheads). (C) Specimen with at least three long ventral rows (arrowheads). (D) Specimen with shortened ventral rows (asterisks) between long ventral rows supposedly homologous to left and right ventral rows of typical specimens (white arrowheads). Black arrow shows extra cirrus behind right frontoventral cirrus.
Fig 18.
Bayesian inference (50% majority rule consensus) tree of Hypotricha, emphasizing the relationships within the Dorsomarginalia (uroleptids, stylonychines and “non-stylonychine dorsomarginalians”) and some incertae sedis representatives.
Values associated to nodes are Bayesian posterior probabilities / maximum-likelihood bootstrap support. * = full support; ? = node contradicted in the maximum-likelihood tree. Scale bar = substitutions per 100 nucleotide positions.
Table 3.
P values of statistical tests for tree comparisons considering different topological constraint scenarios.
Fig 19.
Diagram showing homologies among ventral cirri of Cyrtohymena, European and North American Paraurostyla weissei, and Apoamphisiella on stylized drawings.
*The rightmost ventral cirral row of European P. weissei corresponds to the posterior segment of an amphisiellid row. Fronto-ventral-transverse anlagen are numbered in romans. IV? = anlage supposedly related to IV; Vi … Vj = serial homology of anlage V, where “i” is the leftmost and “j” the rightmost in the series; aAR = anterior segment of the amphisiellid cirral row; B = buccal; F = frontal; FV = frontoventral; Pp = postperistomal; PT = pretransverse; T = transverse; VR = ventral cirral row; - = inapplicable.