Euplotes amieti Dragesco, 1970
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publication ID |
https://doi.org/ 10.4467/16890027AP.15.014.3211 |
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persistent identifier |
https://treatment.plazi.org/id/03A7CC65-0A36-FFE2-FF2E-81BDFCA4FE2E |
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treatment provided by |
Felipe |
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scientific name |
Euplotes amieti Dragesco, 1970 |
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Euplotes amieti Dragesco, 1970 ( Figs 1 View Fig and 2 View Fig ; Table 1)
Since this species has never been clearly diagnosed before, we present here an improved diagnosis based on the original description, the African populations and the Chinese population.
Improved diagnosis: Fresh water Euplotes , about 130–240 μm × 70–160 μm in vivo; buccal field prominent and broad, triangular in outline, about 1/2 to 2/3 of body length with about 52–70 membranelles; invari- ably nine frontoventral, five transverse and two left marginal cirri, usually two caudal cirri; 12–15 dorsal kineties with about 18–32 dikinetids in mid-dorsal row; macronucleus typically in the shape of the number three (hereafter, 3-shaped); dorsal silverline system doubleeurystomus type.
Description of Shanghai population: Cells in vivo about 130–200 μm × 70–100 μm, generally asymmet- ric oval in outline; anterior end slightly rounded while posterior end often widely rounded ( Figs 2A, B View Fig ). Cell body dorsoventrally flattened about 2: 1 with dorsal side a little arched and ventral side concave ( Fig. 2D View Fig ). Buccal field broad and triangular in outline, approxi- mately 1/2–2/3 of body length ( Figs 2A, B View Fig ). A conspicuous collar positioned at anterior end of dorsal side ( Figs 2A, B View Fig ). No ridges on dorsal side, but four short, inconspicuous ridges between transverse cirri on ventral side ( Fig. 1A View Fig ). Numerous irregular ellipsoid to oval granules (possibly mitochondria) about 1.5–2 μm across, extremely densely packed beneath dorsal and ventral pellicle ( Fig. 2F View Fig ); about nine bar-shaped granules, ca. 1 μm long, densely packed around dorsal cilia beneath pellicle. Cytoplasm colorless, highly transpar- ent at marginal area, and containing several to many different-sized lipid droplets and several food vacuoles (1.5–2 μm in diameter) in central part ( Figs 1A View Fig , 2B View Fig ). One contractile vacuole 25–30 μm in diameter, adjacent to the rightmost transverse cirrus ( Figs 1A View Fig , 2A View Fig ); pulsat- ing at intervals of 1–2 min. Locomotion typically by moderately fast crawling or slight jerking.
Adoral zone prominent, composed of 60–65 membranelles, commencing at anterior part of frontoventral cirri on ventral side with ca. five membranelles, extending to collar zone on dorsal side with ca. 16 membranelles. Other membranelles extending from collar zone to ventral side with about a 90-degree curve and occupying 1/2–2/3 body length in a sigmoidal shape
Data are based on protargol-impregnated specimens. Measurements in μm. CV, coefficient of variation in %; Max, maximum; Mean, arithmetic mean; Min, minimum; n, number of cells measured; SD, standard deviation.
( Figs 1A, C, E View Fig , 2A, J, K View Fig ). Paroral membrane about 20 μm × 4 μm, composed of many irregularly arranged kinetosomes, positioned below buccal lip, and extending right to the proximal end of the adoral zone ( Fig. 2J View Fig ); cilia of paroral membrane about 6 μm long. Consistently nine frontoventral cirri (ca. 35 μm long), five transverse cirri (ca. 45 μm long), and two left marginal cirri (ca. 35 μm long) ( Figs 1C View Fig , 2J View Fig ); usually two caudal cirri, occasionally three, ca. 30 μm long ( Fig. 2I View Fig ). 12–14 (usually 13) dorsal kineties with dikinetids extending almost entire length of body (four out of 39 specimens analyzed possessed 12 dorsal kineties and another four had 14). Usually 10–12 kinety rows located on dorsal side. Mid-dorsal kinety with 21–24 dikinetids ( Fig. 1D View Fig ). Macronucleus 3-shaped, with many small spheri- cal nucleoli ( Figs 1D View Fig , 2J, K View Fig ); one micronucleus, round to oval, located in the anterior part of the body near the left side, generally set in a distinct depression of the macronucleus. Silverline system on dorsal side of the double- eurystomus type ( Figs 1E, F View Fig , 2L View Fig ). One contractile vacuole pore positioned in the right part of the transverse cirri on ventral side ( Fig. 1E View Fig ).
Morphogenesis ( Figs 3 View Fig and 4 View Fig ): Stomatogenesis starts with the appearance of a small patch of kinetosomes, which is the opisthe’s oral primordium, within a pouch beneath the cortex of the ventral surface, positioned between the cytostome and the left marginal cirri ( Figs 3A View Fig , 4C View Fig ). As the pouch enlarges, kinetosomes proliferate rapidly and begin to align into membranelles from the anterior end and organize towards the posterior ( Figs 3C View Fig , 4E View Fig ).
An additional anlage, the primordium for the paroral membrane (UM-anlage), appears within the subcortical pouch, which is located close to the posterior end of the oral primordium ( Figs 3C View Fig , 4E View Fig ).
Following this, the UM-anlage begins to lengthen and becomes broader. Throughout the entire morphogenetic process, the parental adoral zone remains nearly intact ( Figs 3C, E View Fig , 4E View Fig ).
Development of frontal-ventral-transverse cirral anlagen (FVT-anlagen): at the same time as the oral primordium is formed, two sets of FVT-anlagen develop de novo as multiple basal bodies anterior to the transverse cirri ( Figs 3A View Fig , 4B View Fig ); each set consists of five streaks (anlagen II–VI). Each cirral streak ex- tends in both directions with a proliferation of kinetosomes. Obviously, no parental ciliary organelles are involved in the formation of these anlagen. The cirral streaks then broaden and break apart in a 3:3:3:2:2 pattern ( Figs 3C View Fig , 4D View Fig ), migrating to develop as distinct cirri to daughter cells.
Immediately following the breakup of the FVTanlagen, two small patches of kinetosomes appear in the outermost region of the cortex near the original leftmost frontal cirrus and between two adoral zone membranelles ( Figs 3C View Fig , 4E View Fig ). These patches form new anlage for the frontal cirrus I/1 of the proter and opisthe respectively. These two anlagen are formed de novo, i.e. evidently no old cirrus or paroral membrane is involved in the formation of the anlagen. Subsequently, these two anlagen develop into the frontal cirrus I/1 by rapid proliferation of kinetosomes and migrate to their final positions ( Figs 3E, G View Fig ).
Development of marginal cirri: the anlagen of the left marginal cirri for the proter and opisthe are formed de novo. One anlage for the marginal cirri forms as a short row of kinetosomes near the parental adoral zone in the proter, and the other near the newly formed adoral zone in the opisthe ( Fig. 4F View Fig ). Each anlage subsequently enlarges and segments to form the marginal cirri for daughter cells ( Figs 3C View Fig , 4H View Fig ).
Nuclear division: each end of the macronucleus has a recognizable replication band in the early stage ( Fig. 3B View Fig ). As the replication bands progress, the macronucleus changes shape to become a short strand after the process of replication of the nuclear apparatus ( Figs 3D, F View Fig , 4A View Fig ). As the daughter cells separate, the nodular macronucleus divides to form the 3-shaped nucleus, both in the proter and the opisthe.
Development of dorsal ciliature: on the dorsal side, the proliferation of new basal bodies occurs in the midline of each parental dorsal kinety in a non-typical primary mode, i.e. dorsal kinety anlagen composed of densely arranged basal bodies are not formed ( Fig. 4G View Fig ). With further proliferation, these sparsely distributed anlagen break apart and develop into two groups of kine- tal rows, moving anteriorly and posteriorly, eventually replacing the old structures ( Figs 4I, J View Fig ).
In the proter, two caudal cirri are formed at the posterior end of the right-most two dorsal kinety anlagen ( Figs 3C, D View Fig , 4J View Fig ). Meanwhile, in the opisthe, two caudal cirri are formed at the end of the right-most two dorsal kinety rows ( Figs 3C, D, E, F View Fig ).
SSU rRNA gene sequence and phylogenetic analyses ( Fig. 5 View Fig ): The SSU rRNA gene sequence of Euplotes amieti was deposited in GenBank with accession number KJ524911. The length and GC content of the SSU rRNA gene (not including primers) were 1783 bp and 43.97%, respectively. Phylogenetic trees based on the SSU rRNA gene sequences were constructed using two different methods: Bayesian inference (BI) and maximum-likelihood (ML). The topologies of the BI and ML trees were almost identical and, for purposes of illustration, they were therefore merged into a single tree ( Fig. 5 View Fig ).
We included a broad selection of all the SSU rRNA gene sequences of the order Euplotida from GenBank in the phylogenetic analyses. As shown in Fig. 5 View Fig , the order Euplotida is composed of five families, namely Aspidiscidae , Certesiidae , Euplotidae , Gastrocirrhidae , and Uronychiidae . The Order Euplotida is monophy- letic in all analyses.
All available SSU rRNA gene sequences of the Euplotes -complex were included in our phylogenetic analyses. The analyses provide full bootstrap support and posterior probability (PP) for the monophyly of Euplotidae (100% ML, 1.00 BI). As shown in Fig. 5 View Fig , all Euplotes -complex species form a well-supported group with full posterior probability and bootstrap values (100% ML, 1.00 BI). This group includes six major clades designated according to Yi et al. (2009) based on morphological and phylogenetic information, although support for several of the nodes is rather low ( Jiang et al. 2010) and the relationships of Euplotes dammamensis (JX185743), Euplotes parabalteatus (FJ346568) and Euplotes sinicus (FJ423448) remain unresolved.
We obtained all the SSU rRNA sequences from five isolates of Euplotes eurystomus . Euplotes amieti clusters with four isolates of E. eurystomus in Clade I with full support values (100% ML, 1.00 BI), apart from Euplotes eurystomus iso5 (AF452707), which groups with E. aediculatus (EU103618) in Clade I with maximum support.
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