Stentor coeruleus Ehrenberg 1831
Creators: name: Taher, Md Abu
name: Kabir, Ahmed Salahuddin
name: Shazib, Shahed Uddin Ahmed
name: Kim, Min Seok
name: Shin, Mann Kyoon
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Chromista
Ciliophora
Heterotrichea
Heterotrichida
Stentoridae
Stentor
Stentor coeruleus

description: Stentor coeruleus (Pallas, 1766) Ehrenberg, 1831
(Figs. 1, 2, Tables 1, 2)
Improved diagnosis: The Korean Stentor coeruleus population is highly contractile, cell size is 250–400 × 105–160 µm in vivo but can become more than 1000 µm during complete extension. 100–239 × 80–185 µm after protargol impregnation. They are trumpet-shaped when completely extended, but freely motile or contracted specimens are inverted pear-shaped. Under low magnification, specimens are blue green in color but at higher magnification cortical granules are reddish brown in the absence of symbiotic algae; a contractile vacuole is present on the left of the oral cavity. 55–65 somatic kineties are longitudinally arranged; 20–25 peristomial kineties are vertically arranged within adoral zone membranelles; 145–165 adoral membranelles comprise the peristome. The moniliform macronucleus is composed of 6–15 spherical nodules. Micronucleus and lorica were not observed in the present study.
Locality and habitat: freshwater pond, Bugokji pond in Samrak-ri, Maam-myeon, Goseong-gun, Gyeongsangnam-do province, Korea (35°01′35.2′′N, 128°20′40.2′′E).
Voucher material: A slide with protargol-stained specimens was deposited in the National Institute of Biological Resources (NIBR), Incheon, Korea, with registration number NIBRPR0000109602. The slide includes many specimens, but the relevant specimens are marked by a black ink circle on the slide.
Description: The freely motile cell is inverted pear-shaped and size ranges 250–400 × 105–160 µm (on average 325 × 125 µm) (Figs. 1A, 2B). After extension, when cell relaxed, the body looks like trumpet-shaped and size ranges, 575–1050 µm in length and 120–135 µm in width in the peristomial area (Fig. 1A). The specimens shrink considerably after protargol impregnation, i.e., 100–239 × 80–285 µm (on average 165 × 116 µm) (Figs. 1D, E, 2 H–J). Greenish (due to limitations of microscope and camera, CG appears greenish-brown in pictures) cortical granules (~ 0.5 µm in diameter) irregularly arranged densely between somatic kineties (Fig. 2D). The transparent cortex makes cytoplasmic organelles easily identifiable (Figs. 2B, E, G). 55–65 somatic kineties composed of dikinetids longitudinally arranged parallel to the antero-posterior axis of cell (Figs. 1D, E, 2D, J). Each somatic cilium is 11–12 µm long (Fig. 1C). One contractile vacuole without any visible collecting canal located left of the buccal cavity about 38 µm in diameter during diastole (Fig. 2E). 20–25 peristomial kineties present in the peristomial region (Figs. 1D, E, 2C, I). The size of the peristomial cilia is similar to that of somatic cilia. The buccal cavity is clearly visible. Adoral zone of membranelles conspicuous, consisting of 145–165 membranelles (Figs. 1D, E, 2C, I). Adoral zone of membranelles surrounding the peristome ends at the buccal cavity (Figs. 1A, D, 2B, C, I). The breadth of adoral membranelles 12–13 µm long, feather-like extension is nearly 33 µm. The paroral membrane is typical of the genus, consisted of a single and continuous row of thin cilia, 20–35 µm long (Fig. 2C). Nuclear apparatus comprised of 6–12 spherical macronuclear nodules and each nodule are connected by macronuclear bridges; nodules are globular (20–22 µm in diameter in vivo) to ellipsoidal (25–30 µm in length), usually located at the mid-body; however, the position of macronuclear nodules is not fixed (Figs. 1E, 2G, H). Micronucleus was not observed. Food vacuoles are 20–30 µm in diameter; contain bacteria and algae (Figs. 1A, 2B). Lipid droplets 1.5–3.5 µm in diameter scattered throughout the body (Fig. 2E). Holdfast organelle present at the posterior end of the cell (Fig. 2F).
description: Published as part of Taher, Md Abu, Kabir, Ahmed Salahuddin, Shazib, Shahed Uddin Ahmed, Kim, Min Seok & Shin, Mann Kyoon, 2020, Morphological Redescriptions and Molecular Phylogeny of Three Stentor Species (Ciliophora: Heterotrichea: Stentoridae) from Korea, pp. 435-452 in Zootaxa 4732 (3) on pages 436-437, DOI: 10.11646/zootaxa.4732.3.6, http://zenodo.org/record/3667262