Monomicrocaryon trimarginalis, Chae & Min & Park, 2025
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publication ID |
https://doi.org/10.3897/zookeys.1258.168452 |
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publication LSID |
lsid:zoobank.org:pub:113E0D94-41AC-456E-B25B-E4E08F165B73 |
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DOI |
https://doi.org/10.5281/zenodo.17532429 |
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persistent identifier |
https://treatment.plazi.org/id/08E20446-E18D-51DA-86BE-6E34B0BEECDF |
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treatment provided by |
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scientific name |
Monomicrocaryon trimarginalis |
| status |
sp. nov. |
Monomicrocaryon trimarginalis sp. nov.
Figs 1 A – J View Figure 1 , 2 A – L View Figure 2 , 3 A – I View Figure 3 , Table 1 View Table 1
Diagnosis.
Size 70–90 × 20–30 μm in vivo; body ellipsoidal to slightly ovate. Adoral zone occupies 40 % of the body length and is composed of 17–24 membranelles. Two macronuclear nodules and one micronuclei between two macronuclear nodules. Cortical granules absent. Three frontal cirri; buccal cirrus; 9–13 right and 10–13 left marginal cirri; four frontoventral cirri; two postoral ventral cirri; five transverse cirri. Seven dorsal kineties; four dorsal kineties; and three dorsomarginal kineties.
Type locality.
Soil sample from Gwangdeok Mountain, Hwacheon-Gun, South Korea ( 38 ° 06 ' 44.9 " N, 127 ° 25 ' 57.4 " E) (for details, see Material and methods).
Type material.
Protargol-impregnated slide containing the holotype (Fig. 1 B, C, I, J View Figure 1 ) ( NIBRPR 00001111990) and several paratype specimens ( NIBRPR 00001111991 – NIBRPR 00001111993) were deposited at the National Institute of Biological Resources ( NIBR), South Korea. The holotype specimen was marked by a black ink circle.
Etymology.
Composite of the Latin prefix tri - and Latin adjective marginalis, referring to three marginal dorsomarginal rows.
Description.
Size 70–90 × 20–30 μm in vivo, and 39–54 × 16–25 μm (average 49 × 19 μm) in protargol preparations; length: width ratio about 2.5: 1 (Table 1 View Table 1 ). Outline slightly ovate or elliptical, with both ends rounded (Figs 1 A – F, I, J View Figure 1 , 2 A, B View Figure 2 ). Two globular to ellipsoidal macronuclear nodules, anterior nodule about 8 × 5 μm and posterior nodule about 9 × 5 μm in protargol preparations; one micronuclei, about 3 μm in diameter in protargol preparations, located between macronuclear nodules (Fig. 1 C, G, I View Figure 1 ). Contractile vacuole slightly anterior to mid-body near left margin of the cell, approximately 10 μm in diameter when fully extended (Fig. 1 A, D, E View Figure 1 ). Cytoplasm colorless, with lipid globules, many irregular crystals and food vacuoles.
Adoral zone occupies about 40 % of body length and is composed of 17–24 membranelles, with cilia about 13 μm long (Fig. 1 A, B, I View Figure 1 ; Table 1 View Table 1 ). Paroral and endoral membrane slightly bent and arranged in parallel (Fig. 1 B, I View Figure 1 ). All cirri with cilia 8–15 μm long in vivo (Figs 1 A View Figure 1 , 2 C View Figure 2 ). Eighteen frontoventral-transverse cirri: three frontal cirri close to the adoral zone of membranelles (Fig. 1 A, B View Figure 1 ); buccal cirrus near the anterior end of undulating membranes. Three enlarged frontal cirri near the distal portion of the adoral zone, four frontoventral cirri, buccal cirrus near the anterior end of undulating membranes, and three postoral ventral cirri located in the central body, and two pretransverse cirri (Fig. 1 B, I View Figure 1 ; Table 1 View Table 1 ). Five rod-shaped transverse cirri, about 25 μm long arranged in a V shape, each with a fringed distal end (Fig. 1 B, H, I View Figure 1 ; Table 1 View Table 1 ). One left (10–13 cirri) and right (9–13 cirri) marginal row, both marginal rows non-confluent posteriorly (Fig. 1 B, I View Figure 1 ; Table 1 View Table 1 ). Four dorsal and three dorsomarginal kineties with conspicuously long dorsal cilia 10–15 μm long. Dorsomarginal kinety 5 starts near the anterior end of the cell and extends to 2 / 3 of the body. Three caudal cirri located at the ends of dorsal kineties 1, 2, and 4 on the posterior end of the cell (Fig. 1 C, J View Figure 1 ).
Morphogenesis.
Stomatogenesis begins with the development of a dense basal body that forms the oral primordium of the opisthe, which appears anterior to the leftmost transverse cirri (Figs 2 C View Figure 2 , 3 A View Figure 3 ). A loosely arranged group of basal bodies develops anterior to the right side of the oral primordium, forming the undulating membrane anlagen of the opisthe (Fig. 2 D, E View Figure 2 ).
In the opisthe, the scattered basal bodies at the anterior end of the oral primordium develop into frontoventral-transverse cirral anlagen ( FVT anlagen) I, II and III of the opisthe (Fig. 2 D View Figure 2 ). We were unable to determine whether FVT anlagen VI is formed from FVT anlagen VI of the proter or from IV / 2. FVT anlagen V and VI originate from cirri V / 4 and V / 3, respectively (Fig. 2 D View Figure 2 ). In the proter, FVT-anlagen II and III are newly formed from cirri II / 2 and III / 2, respectively (Figs 2 E, G View Figure 2 , 3 B, C View Figure 3 ). FVT-anlagen IV develops from cirrus IV / 3 (Fig. 2 E, G View Figure 2 ). FVT anlagen V and VI originate from FVT anlagen V and VI of the opisthe (Figs 2 G View Figure 2 , 3 C View Figure 3 ). Six frontoventral-transverse cirral anlagen are formed in both proter and opisthe (Fig. 3 C View Figure 3 ). These cirral anlagen then broaden, break apart and migrate to their final positions as distinct cirri (Figs 2 G, I, K View Figure 2 , 3 F, H View Figure 3 ). Cirri IV / 2, VI / 3 and VI / 4 are not involved in the development of FVT cirri and are reabsorbed in later stages of division (Fig. 2 I, K View Figure 2 ). The FVT anlagen I – VI form the pattern 1: 3: 3: 3: 3: 4: 4 in this order. (Figs 2 I, K View Figure 2 , 3 F, H View Figure 3 ).
Right marginal anlagen develop within the right parental marginal row (Fig. 2 G View Figure 2 ). Formation of left marginal anlagen by the basal body could not be observed. We confirmed that the development of the right marginal anlagen develops before the left marginal anlagen.
The dorsal ciliature is formed by two groups of primordia. The dorsal kineties anlagen develop intrakinetally within parental kineties 1–3 below the mid-body (Fig. 2 F View Figure 2 ). Subsequently, these primordia proliferate, elongate, and divide to move into the proter and opisthe respectively (Figs 2 H View Figure 2 , 3 D View Figure 3 ). In late dividers, the rightmost of the three ridges bends at the posterior end, giving rise to the formation of new dorsal kineties 3 and 4 (Figs 2 J, L View Figure 2 , 3 I View Figure 3 ). Three caudal cirri are generated at the posterior end of each of the new dorsal kineties 1, 2 and 4 (Figs 2 J, L View Figure 2 , 3 I View Figure 3 ).
Phylogenetic analyses.
The SSU rRNA gene sequence of Monomicrocaryon trimarginalis sp. nov. ( PX 139273) has a length of 2909 bp and GC content of 46.5 %. It differs from that of M. euglenivorum fimbricirratum ( OP 339741 View Materials ) in seven nucleotides, which corresponds to about 0.004 pairwise distance (Table 2 View Table 2 ). The pairwise distances and number of nucleotide differences between the available Monomicrocaryon species range from 0.004 to 0.012 and 7 to 20, respectively (Table 2 View Table 2 ). In the phylogenetic analysis, M. trimarginalis sp. nov. nests within a highly supported clade (99 % ML / 1.0 BI) that also contains M. euglenivorum euglenivorum, and the species M. euglenivorum euglenivorum, and M. trimarginalis sp. nov., clusters with Quadristicha setigera with low support (64 % ML / 0.6 BI) (Fig. 4 View Figure 4 ).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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