Chlamydodon rectus, OZAKI & YAGIU, 1941

CHLAMYDODON RECTUS OZAKI & YAGIU, 1941 View in CoL

( FIGS 4, 5; TABLE 2)

Because the ciliary pattern of C. rectus is unavailable in previous studies, we supply an improved diagnosis here.

Improved diagnosis: Medium Chlamydodon species; 70–110 × 40–50 µm in vivo with an ovoid or reniform shape; a continuous CSB; 30–38 somatic kineties, containing 10–16 right, four postoral, and 15–19 left kineties; mostly five terminal fragments; eight to ten contractile vacuoles; 16–22 nematodesmal rods.

Deposition of voucher slides: One voucher slide with protargol-stained specimens was deposited in Natural History Museum, London, with the registration number NHMUK 2016.3.21.3.

Description: Cell size about 95–110 × 40–50 µm in vivo. Body ovoid or reniform in outline with anterior end broadly rounded and posterior end somewhat tapered ( Figs 4A, C, 5A–D). Right margin convex and left margin sigmoidal. CSB encircled cell perimeter, c. 2.5 µm in width ( Fig. 5G). Cell containing lots of tiny yellow granules in middle of cell ( Fig. 5G) and several diatoms when collected ( Figs 4B, 5J, K), which renders cytoplasm somewhat yellowish; but after maintained in lab for 24 h, it turning greyish or colourless. One small patch-like orange pigment spot positioned at anterior left of cell ( Fig. 5G). Cytostome located at anterior quarter of cell and surrounded by 16–21 nematodesmal rods ( Fig. 5E). About ten contractile vacuoles, 3–5 µm in diameter, irregularly distributed in ventral side ( Figs 4A, 5A, G). Single ellipsoidal macronucleus ( Fig. 5G), centrally located, about 28 × 20 µm in vivo. Cilia 7 µm long.

Totally 31–38 somatic kineties in ventral side, consisting of 10–16 right kineties, four postoral kineties, and 15–19 left kineties ( Figs 4E, 5F, I). Equatorial fragment undetected. Four to eight (mostly five) terminal fragments arranged along anterior end of rightmost somatic kinety ( Figs 4F, 5H).

Oral ciliature typical of genus ( Figs 4D, E, 5F): two parallel circumoral kineties with inner one relatively short; single preoral kinety commencing at middle of outer circumoral kinety and extending leftward to midpoint of anterior suture. Single circle of kinetosomeslike dots around cyrtos detected after protargol staining.

SSU rRNA gene sequence: The SSU rRNA gene sequence of C. rectus has been deposited in the GenBank database with the accession number, length, and G + C content as follows: KT461932 View Materials , 1517 bp, and 46.61%.