Birojimia soyaensis, Kim & Jung & Min, 2016

Kim, Kang San, Jung, Jae Ho & Min, Gi Sik, 2016, A New Soil Ciliate, Birojimia soyaensis nov. spec. (Ciliophora: Urostylida) from South Korea, Acta Protozoologica 55 (3), pp. 135-144 : 136-138

Birojimia soyaensis nov. spec.

Diagnosis: Body size in vivo 170–200 μm × 40–50 μm; body slender, elongate, and somewhat twisted; cell color grayish to transparent; cortical granules present; contractile vacuole located near midbody at left margin; 53–69 macronuclear nodules; 2 or 3 micronuclei; adoral zone approximately 25–35% of body length in stained specimens; 3 frontal cirri present; III/2 and buccal cirrus present; midventral complex consists of midventral cirral pairs only; pretransverse ventral and transverse cirri present; 1 left and 4 right marginal rows, including 3 compound rows, 5 long dorsal kineties, with additional 3 shortened kineties in anteriorly compound rows; 8–11 caudal cirri.

Type locality: Wetland soil on Soya Island, South Korea, 37°12’ N and 126°10’ E

Type specimens: The holotype slide (NIBRPR 0000107151) and single paratype slide (NIBRPR 0000107152) containing protargol-impregnated specimens, have been deposited in the National Institute of Biological Resources , South Korea .

Etymology: The name originates from the name of the island (Soya) on which the species was discovered.

Description: Body size in vivo 170–200 μm × 40–50 μm, with an average of 184.9 μm × 42.1 μm in stained specimens ( Figs 1A , 2A , 3A ). Body outline usu- ally elongate, elliptical, and somewhat twisted at right marginal region, slightly flexible, colorless to slightly grayish at low magnification. Macronuclear nodules size 3–9 μm × 2–6 μm in vivo (on average 6.5 μm × 4 μm in protargol-impregnated specimens), 53–69 in number, distributed everywhere, except in the anterior and posterior portions of the cell; 2 or 3 micronuclei (on average 5 μm × 4 μm in protargol-impregnated specimens), oval to spherical shape ( Figs 1C , 2I , 3A ). In vivo, colorless cortical granules, size 0.4–1.2 μm in diameter, irregularly distributed, partially in longitudinal lines on ventral side, sparsely arranged in short longitudinal rows on dorsal side, and rod-shaped in lateral view, average size in vivo 3.0 μm × 1.0 μm ( Figs 1D–F , 2D, F, J ). Contractile vacuole in midbody near left cell margin, about 15 μm in diameter when fully extended, dividing into 2 collecting canals ( Figs 2B, C ).

Adoral zone composed of 37–48 membranelles, about 25–35% of body length in protargol-impregnated specimens ( Table 1). Bases of largest membranelles 8-μm long, adoral zone of membranelles slightly curved like a “question mark” ( Figs 1B , 3A, B ). Paroral and endoral membranes slightly curved, crossing each other ( Figs 1B , 3B ). Pharynx conspicuous in stained specimens, with 2–3 μm short rods in the wall, similar to B. terricola and B. litoralis ( Figs 1B , 3D ) ( Berger 2006; Foissner 2016).

Frontal and transverse ventral cirri about 12-μm long, and other cirri about 9–10-μm long ( Figs 2A, B, D, H ). Three enlarged frontal cirri, 2 frontoterminal cirri, III/2 and buccal cirrus present ( Figs 1B , 3B ). Midventral complex composed of 13–17 midventral cirral pairs only, beginning close to cirrus III/2 ( Figs 1B , 3A, B ). Marginal ciliature composed of 1 left and 4 right rows, including 3 compound ones. Three “compound” rows (with bristles anteriorly and cirri posteriorly; Foissner and Stoeck 2011) on right margin; inner right marginal cirral row and left marginal cirral rows (LMR) composed of cirri only; LMR extended to center of rear body margin as J-shape; 1 or 2 pretransverse ventral and 4 to 8 transverse cirri ( Figs 1B, C, G , 3A–C, E, F ).

Eight dorsal bristle rows, cilia approximately 3–4- μm long in vivo, all dorsal kineties associated with cirral rows or caudal cirri: 5 long dorsal kineties (DK) associated with caudal cirri at rear end of cell; 3 shortened kineties associated with marginal rows (= compound rows) ( Figs 1B, C, F , 2G , 3A, C, E, F ). Two bipolar kineties (DK1, DK2) and 3 shortened rows (rows 1 to 3) commencing from the anterior portion, while DK 3 to 5 and row 4 commencing near midbody, between DK 2 and row 3; 2 bipolar DK1 and 2 extending along left body margin ( Figs 1C, G , 3E ). First and fifth dorsal ki- nety associated with 3 or 4 caudal cirri, second to fourth kineties combined 1 or 2 caudal cirri. Eight to 11 caudal cirri, conspicuous and approximately 11-μm long in vivo ( Figs 1C , 2H , 3F ).

B. soyaensis feeds on fungi, testate amoebae, soil particles, and small protozoa ( Fig. 3A ).

Molecular analysis: The GenBank accession number of B. soyaensis is KY176378 (1761bp). In the phylogenetic tree, B. soyaensis formed a (partial) clade with Anteholosticha , Hemicycliostyla, Pseudokeronopsis , Pseudourostyla , and Uroleptopsis . Of these, B. soyaensis showed the closest relationship with the genus Hemicycliostyla : H. sphagni and H. franzi (pairwise distance: H. sphagni , 0.17; H. franzi , 0.18) ( Fig. 4 ).

Figures

Figs 1A–G. Morphology of Birojimia soyaensis nov. spec. from live (A, D–F) and protargol-impregnated (B, C, G) specimens. A, B, E, F – ventral view; C, D, E – dorsal view; B, C – ventral and dorsal views of the holotype specimen: B – arrow indicates pharynx; D – ex- trusive cortical granules (arrow), dorsal cilia (arrowhead); E – arrangement of cortical granules on ventral side; F – arrangement of cortical granules on dorsal side; G – ciliary pattern of cirral rows and dorsal kineties. AZM – adoral zone of membranelles; BC – buccal cirrus; CC – caudal cirri; DK – dorsal kineties; EM – endoral membrane; FC – frontal cirri; FTC – frontoterminal cirri; LMR – left marginal cirral row; Ma – macronuclei; Mi – micronuclei; MP – midventral pairs; PM – paroral membrane; PTC – pretransverse ventral cirri; TC – trans- verse cirri; 1, inner right marginal cirral row; 2–4, compound rows. Scale bars: 100 μm.

Figs 2A–J. Photomicrographs of Birojimia soyaensis nov. spec. from live specimens. A, D, E – ventral view; B, C, F, H – dorsal view: B, C – arrows indicate contractile vacuole and collecting canals; D – distribution of cortical granules (arrowhead) and inner right cirral row (arrow); E – distribution of cortical granules on the ventral side, arrowhead indicates a longitudinal row of cortical granules; F – arrows indicate cortical granules on the dorsal side; G – arrow indicates dorsal cilia; H – arrows indicate caudal cirri; I – macronuclear nodules (arrow), micronuclei (arrowhead); J – cortical granules in lateral view (arrow). Scale bars: 100 μm.

Figs 3A–F. Photomicrographs of Birojimia soyaensis nov. spec. from protargol-impregnated specimens. A, B, D – holotype specimen. A – ventral view of specimen; B – anterior portion of ventral view; C – posterior portion of ventral view; D – pharynx; E – anterior portion of dorsal view; F – posterior portion of dorsal view.AZM – adoral zone of membranelles; BC – buccal cirrus; CC – caudal cirri; DK – dor- sal kineties; EM – endoral membrane; FC – frontal cirri; FTC – frontoterminal cirri; LMR – left marginal cirral row; Ma – macronuclei; Mi – micronuclei; MP – midventral pairs; PM – paroral membrane; PTC – pretransverse ventral cirri; TC – transverse cirri; 1 – inner right marginal cirral row; 2–4 – compound rows. Scale bars: 100 μm.

Fig. 4. Phylogenetic tree of 18S rRNA gene sequences, showing the position of Birojimia soyaensis nov. spec. on the basis of Maximum Likelihood (ML) and Bayesian Inference (BI). Bootstrap values for ML and posterior probability values for BI are represented on the inte- rior branches. Black circles indicate the species of the family Holostichidae (sensu Berger 2006 system).