Pseudourostyla cristatoides, Jung, Jae-Ho, Park, Kyung-Min & Min, Gi-Sik, 2012

Jung, Jae-Ho, Park, Kyung-Min & Min, Gi-Sik, 2012, Morphology, morphogenesis, and molecular phylogeny of a new brackish water ciliate, Pseudourostyla cristatoides n. sp., from Songjiho lagoon on the coast of East Sea, South Korea, Zootaxa 3334, pp. 42-54 : 44

Pseudourostyla cristatoides n. sp. ( Figs. 1–48 ; Tables 1–3 )

Diagnosis. Size 220–265 × 85–125 μm in vivo; body slender to ellipsoidal, grayish to colourless under low magnification. Extrusomes (trichocyst type) narrowly spaced in cortex; two contractile vacuoles on left side of cell at 25% and 75% of body length; 84–115 adoral membranelles, 20–30 frontal, 2 frontoterminal, 1 buccal, and 2 pretransverse, 6–12 transverse cirri; 17–25 midventral pairs; 5–7 left, and 4–5 right marginal rows; 10–13 dorsal kineties; about 30–106 macronuclear nodules.

Type locality. Songjiho lagoon (38°20′N, 128°30′E) in South Korea.

Type slides. One holotype slide ( MABIK PR00026477) and three paratype slides ( MABIK PR00026478–PR00026480) with protargol-impregnated specimens including dividing individuals have been deposited in the Marine Biodiversity Institute of Korea of the Ministry of Land, Transport and Maritime Affairs of Korean Government. Four additional paratype slides have been deposited in the National Institute of Biological Resources, South Korea (NIBRPR0000103116–NIBRPR0000103119). The holotype specimen ( Figs. 3–5 , 32–34 ) and other relevant specimens have been marked by circles on the bottom of the slides.

Etymology. Composite of the congeneric species name cristata and the Greek comparative suffix - ides, meaning “like cristata ”.

Figures

FIGURES 1 – 5. Morphology of Pseudourostyla cristatoides n. sp., from life (1, 2) and after protargol impregnation (3 – 5). 1. Ventral view of a representative individual, arrows indicate contractile vacuoles. 2. Ventral views of the process of forming contractile vacuoles. 3 – 5. Ventral (3) and dorsal views (4, 5) of the holotype specimen, arrow denotes the anteriormost midventral pair. AZM, adoral zone of membranelles; BC, buccal cirrus; DK, dorsal kineties 1; EM, endoral membrane; FC, frontal cirri forming bicorona; FTC, frontoterminal cirri; LMR, outermost left marginal row; Ma, macronucleus; Mi, micronucleus; MP, midventral pair; PM, paroral membrane; RMR, outermost right marginal row; TC, transverse cirri. Scale bars: 100 μm.

FIGURES 6 – 14. Pseudourostyla cristatoides n. sp., dividers after protargol impregnation. 6, 7. Ventral view of early dividers, the buccal cirrus (arrowheads) is dedifferentiated, arrows mark basal body patches left of some postoral midventral cirri, and proter’s oral primordium (asterisk) develops from a “ pocket ” of buccal cavity. 8. Ventral view of late early divider, showing forming adoral membranelles, fronto-ventral-transverse cirral (asterisks) and marginal cirral anlagen (left, arrows; right, arrowheads). The posterior cirri of rear corona participate in the fronto-ventral-transverse cirral anlagen. 9 – 12. Ventral and dorsal views of middle dividers, the leftmost frontal cirrus develops from the anterior end of undulating membranes and migrates posteriorly (asterisks), the dorsal kineties originate by intrakinetal formation (arrows), and the micronuclei are slightly inflated. 13, 14. Ventral and dorsal view of late divider, arrows denote anteriorly migrating frontoterminal cirri. Ma, macronucleus; Mi, micronucleus. Scale bars: 100 μm.

FIGURES 15 – 18. Pseudourostyla cristatoides n. sp., dividers after protargol impregnation. 15 – 18. Ventral and dorsal views of late dividers, the micronuclei are finished division and arrows denote anteriorly migrating frontoterminal cirri. Mi, micronuclei. Scale bars: 100 μm.

FIGURES 19 – 23. Pseudourostyla cristatoides n. sp., reorganizers after protargol impregnation. 19 – 21. Ventral and dorsal views of middle reorganizers, the marginal rows originate by common anlage (left, arrow; right, arrowhead), the dorsal kinety anlagen form intrakinetally, and asterisk marks posteriorly migrating buccal cirrus. 22, 23. Ventral and dorsal view of late reorganizer, showing the anteriorly migrating frontoterminal cirri (arrow). Scale bars: 100 μm.

FIGURES 24 – 31. Photomicrographs of Pseudourostyla cristatoides n. sp. from life (bright field illumination, 24 – 29) and methyl green-pyronin impregnation (30, 31). 24 – 26. Dorsal views, arrows mark contractile vacuoles. 27. Ventral view to show arrangement of cirri. 28, 29. Dorsal views, arrow denotes narrowly spaced extrusomes, arrowheads in 29 indicate dorsal bristles. 30, 31. Extruded cortical granules (trichocyst type). Scale bars: 100 μm

FIGURES 32 – 42. Photomicrographs of Pseudourostyla cristatoides n. sp. during interphase (32 – 34, holotype specimen) and morphogenesis (35 – 42) after protargol impregnation. 32, 34. Ventral views, with arrow and arrowhead indicating macronucleus and micronucleus, respectively. 33. Dorsal view showing complete dorsal kineties and each arrow marks the leftmost and the rightmost dorsal kineties. 35, 36. Ventral views of individuals in early dividing stage, arrows indicate oral primordium patches, arrowhead denotes dedifferentiated buccal cirrus. 37, 38. Ventral views of middle dividers, arrows and arrowheads indicate left and right marginal anlagen, respectively. 39 – 42. Ventral (39, 40, 42) and dorsal view (41) of late dividers showing migrating buccal cirrus (arrow in 39), frontoterminal cirri (arrows in 40, 42), pretransverse cirri (arrowheads in 40), and dorsal kineties anlagen 1 and 11 (arrows in 41). Scale bars: 100 μm.

FIGURES 43 – 47. Reorganization in Pseudourostyla cristatoides n. sp. after protargol impregnation. 43, 44. Ventral (43) and dorsal (44) view of middle reorganizer showing left marginal row anlagen (arrow in 43), dorsal kineties anlagen (arrow in 44), extrusomes (arrowhead in 44). 45 – 47. Ventral views of late reorganizers displaying migrating buccal cirrus (arrow in 45), migrating frontoterminal cirri (arrow in 46, 47). Scale bars: 100 μm.

FIGURE 48. Phylogenetic tree of 18 S rRNA gene sequences showing the position of Pseudourostyla cristatoides n. sp. based on maximum likelihood (ML) and Bayesian inference (BI). Both bootstrap values for ML and posterior probability values for BI are represented on branches. Nodes with a solid circle show fully supported branches (100 % ML, 100 % BI).